Chapter 25: Moduleslinear-chapter25

164 files changed, 10422 insertions, 3897 deletions

diff --git a/src/main/java/com/seaofnodes/simple/IterPeeps.java b/src/main/java/com/seaofnodes/simple/IterPeeps.java
index 18ff470a..9fac7a99 100644
--- a/src/main/java/com/seaofnodes/simple/IterPeeps.java
+++ b/src/main/java/com/seaofnodes/simple/IterPeeps.java
@@ -1,6 +1,7 @@
 package com.seaofnodes.simple;
 
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Opto;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 import com.seaofnodes.simple.util.Ary;
@@ -39,7 +40,7 @@ import java.util.Random;
  * <li>Our strong invariant is that for all Nodes, either they are on the worklist
  *   OR no peephole applies.  This invariant is easy to check, although expensive.
  *   Basically the normal "iterate peepholes to a fixed point" is linear, and this
- *   check is linear at each peephole step... so quadratic overall.  Its a useful
+ *   check is linear at each peephole step... so quadratic overall.  It's a useful
  *   assert, but one we can disable once the overall algorithm is stable - and
  *   then turn it back on again when some new set of peepholes is misbehaving.
  *   The code for this is turned on in `IterPeeps.iterate` as `assert
@@ -80,6 +81,10 @@ public class IterPeeps {
                     // Everybody gets a free "go again" in case they didn't get
                     // made in their final form.
                     _work.push(x);
+                    // A self-returning peephole can have rewritten its input
+                    // edges.  The new defs gained a user and may have
+                    // backwards, user-sensitive peepholes of their own.
+                    for( Node z : x._inputs ) _work.push(z);
                     // If the result is not self, revisit all inputs (because
                     // there's a new user), and replace in the graph.
                     if( x != n ) {
@@ -117,22 +122,35 @@ public class IterPeeps {
         Node changed = code._stop.walk( n -> {
             Node m = n;
             Type nval = n.compute();
-            if( (!n.iskeep() || n._nid<=8) &&  // Types must be forwards, even if on worklist
-                ( dir
-                  ? nval.isa(n._type) // Pesi: new value lifts over old
-                  : n._type.isa(nval) // Opto: new value falls over old
-                  ) ) {
-                if( list.on(n) ) return null;
-                m = n.peepholeOpt();
-                if( m==null ) return null;
-            }
-            System.err.println("BREAK HERE FOR BUG");
+
+            // Types must be forwards, even if on the worklist.
+            boolean checkType = !n.iskeep() ||
+                n._nid <= 8 ||
+                (n instanceof ProjNode && n.in(0) instanceof StartNode);
+
+            boolean monotonic = dir
+                ? nval.isa(n._type) // Pesi: new value lifts over old
+                : n._type.isa(nval); // Opto: new value falls over old
+            assert !checkType || monotonic : "Non-monotonic peep: "+n+"#"+n._nid+" old="+n._type+" new="+nval+" inputs="+inputTypes(n)+" peep="+m;
+            if( list.on(n) )
+                return null;
+
+            assert n.nOuts() > 0 : "Unused live node: "+n;
+            m = n.peepholeOpt();
+            assert m==null : "Peep fired and not on worklist, "+n.getClass().getSimpleName()+"#"+n._nid+" -> "+m;
             return m;
         });
         code._midAssert = false;
         return changed==null;
     }
 
+    private static String inputTypes(Node n) {
+        StringBuilder sb = new StringBuilder("[");
+        for( Node in : n._inputs )
+            sb.append(in==null ? "null" : in.getClass().getSimpleName()+"#"+in._nid+"="+in+":"+in._type+":keep="+in.iskeep()).append(',');
+        return sb.append(']').toString();
+    }
+
     /**
      * Classic WorkList, with a fast add/remove, dup removal, random pull.
      * The Node's nid is used to check membership in the worklist.
@@ -180,12 +198,18 @@ public class IterPeeps {
             for( E n : ary )
                 push(n);
         }
+        public void addAll( E[] es ) {
+            for( E n : es )
+                push(n);
+        }
+
 
         /**
          * True if Node is on the WorkList
          */
         public boolean on( E x ) { return _on.get(x._nid); }
         boolean isEmpty() { return _len==0; }
+        Node[] asAry() { return Arrays.copyOf(_es,_len); }
 
         /**
          * Removes a random Node from the WorkList; null if WorkList is empty
diff --git a/src/main/java/com/seaofnodes/simple/Parser.java b/src/main/java/com/seaofnodes/simple/Parser.java
index f80e8f2c..4c2dfc84 100644
--- a/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/src/main/java/com/seaofnodes/simple/Parser.java
@@ -1,12 +1,14 @@
 package com.seaofnodes.simple;
 
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.print.GraphVisualizer;
 import com.seaofnodes.simple.type.*;
 import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.Utils;
 import com.seaofnodes.simple.node.ScopeNode.Kind;
+
+import static com.seaofnodes.simple.util.Utils.TODO;
+
 import java.util.*;
 
 /**
@@ -18,16 +20,32 @@ import java.util.*;
  */
 public class Parser {
 
-    public static ConstantNode ZERO; // Very common node, cached here
-    public static ConstantNode NIL;  // Very common node, cached here
-    public static XCtrlNode XCTRL;   // Very common node, cached here
-
     // Compile driver
     public final CodeGen _code;
 
     // The Lexer.  Thin wrapper over a byte[] buffer with a cursor.
     private Lexer _lexer;
 
+    // Class prefix string; TODO: use something short: "%"
+    public static final String CLZ = "class:";
+    private static final String clzPrefix = CLZ;
+    public static String addClzPrefix( String x ) {
+        assert !x.startsWith(clzPrefix);
+        return (clzPrefix+x).intern();
+    }
+    public static boolean startsClzPrefix( String s ) {
+        return s.startsWith(clzPrefix);
+    }
+    public static boolean isPublicClassName( String name ) {
+        if( startsClzPrefix(name) ) name = name.substring(clzPrefix.length());
+        return !name.isEmpty() && name.charAt(0)!='_' && name.indexOf("._")==-1;
+    }
+
+    // Source file for compilation
+    public CompUnit _ref;
+
+    // Current classname being parsed
+    private String _nestedType;
     /**
      * Current ScopeNode - ScopeNodes change as we parse code, but at any point of time
      * there is one current ScopeNode. The reason the current ScopeNode can change is to do with how
@@ -79,34 +97,16 @@ public class Parser {
      */
     public final Stack<ScopeNode> _xScopes = new Stack<>();
 
-    ScopeNode _continueScope;
-    ScopeNode _breakScope;      // Merge all the while-breaks here
-    FunNode _fun;               // Current function being parsed
+    ScopeNode _breakScope;      // Merge all the while-breaks    here
+    ScopeNode _continueScope;   // Merge all the while-continues here
+    ScopeNode _returnScope;     // Merge all the function exits  here
+    TypeStruct _ctorOpenStruct; // Open struct being initialized by an allocation constructor block.
 
     // Mapping from a type name to a Type.  The string name matches
     // `type.str()` call.
-    public static HashMap<String, Type> TYPES = defaultTypes();
-
-    // Mapping from a type name to the constructor for a Type.
-    public final HashMap<String, StructNode> INITS;
-
-
-    public Parser(CodeGen code, TypeInteger arg) {
-        _code = code;
-        _scope = new ScopeNode();
-        _continueScope = _breakScope = null;
-        ZERO  = con(TypeInteger.ZERO).keep();
-        NIL  = con(Type.NIL).keep();
-        XCTRL= new XCtrlNode().peephole().keep();
-        TYPES = defaultTypes();
-        INITS = new HashMap<>();
-    }
-
-    @Override
-    public String toString() { return _lexer.toString(); }
-
-    public static HashMap<String, Type> defaultTypes() {
-        return new HashMap<>() {{
+    public static final HashMap<String, Type> TYPES = new HashMap<>();
+    public static final HashMap<String, Type> INIT_TYPES =
+        new HashMap<>() {{
             put("bool",TypeInteger.U1 );
             put("byte",TypeInteger.U8 );
             put("f32" ,TypeFloat  .F32);
@@ -124,170 +124,363 @@ public class Parser {
             put("val" ,Type.TOP);    // Marker type, indicates type inference
             put("var" ,Type.BOTTOM); // Marker type, indicates type inference
         }};
+
+
+    public Parser(CodeGen code ) {
+        _code = code;
     }
 
+    @Override
+    public String toString() { return _lexer==null ? "" : _lexer.toString(); }
+
     // Debugging utility to find a Node by index
     public Node f(int nid) { return _code.f(nid); }
 
+    // Read and set CTRL
     private Node ctrl() { return _scope.ctrl(); }
     private <N extends Node> N ctrl(N n) { return _scope.ctrl(n); }
+    // Read and set Memory
+    private Node mem() { return _scope.mem(1); }
+    private void mem(Node mem) { _scope.mem(mem); }
+    // Structural label for precise memory Phis.  The '$' prefix cannot be
+    // referenced in Simple source.
+    public static String memName(int alias) { return ("$"+alias).intern(); }
 
-    public void parse() {
+    // Ordinary parsing carries one whole-memory value.  Alias partitioning is
+    // graph optimization, not parser state.
+    private void storeMem( Node st, int alias, Node prior ) {
+        mem(alias==1 ? st : mergeAlias(prior,alias,st));
+    }
 
+    // A semantic graph partition representing the complete memory after a
+    // precise alias update.  ScopeNode treats this as one opaque value.
+    private Node mergeAlias(Node bulk, int alias, Node precise) {
+        assert bulk != null : "Missing bulk memory for alias #"+alias;
+        MemMergeNode merge = new MemMergeNode(false,null,bulk);
+        merge.alias(alias,precise);
+        return peep(merge);
+    }
+
+
+    public Ary<FRefNode> parse( CompUnit ref ) {
+        assert _scope == null && _breakScope == null && _continueScope == null && _returnScope == null;
+        _lexer = new Lexer(ref._src);
+        // Starting Scope has control, memory, initial arguments
+        _scope = new ScopeNode();
         _scope.define(ScopeNode.CTRL, Type.CONTROL   , false, null, _lexer);
         _scope.define(ScopeNode.MEM0, TypeMem.BOT    , false, null, _lexer);
-        _scope.define(ScopeNode.ARG0, TypeInteger.BOT, false, null, _lexer);
-
-        ctrl(XCTRL);
-        _scope.mem(new MemMergeNode(false));
+        // Track active scopes for Graph display
+        _xScopes.push(_scope);
+        ctrl(_code.XCTRL);
+        mem(con(TypeMem.BOT));
 
-        // Parse the sys import
-        _lexer = new Lexer(sys.SYS);
-        while( !_lexer.isEOF() ) {
-            parseStatement();
-            _lexer.skipWhiteSpace();
-        }
+        // File-level struct declaration
+        _ref = ref;
+        _nestedType = ref._cname;
+        String typeName = addClzPrefix(ref._cname);
 
-        // Reset lexer for program text
-        _lexer = new Lexer(_code._src);
-        _xScopes.push(_scope);
+        ReturnNode clzret = parseStruct( true, typeName );
 
-        // Parse whole program, as-if function header "{ int arg -> body }"
-        parseFunctionBody( _code._main,loc(),"arg");
-
-        // Kill an empty default main.  Keep only if it was explicitly defined
-        // (programmer asked for a "main") or it has stuff (i.e. beginner
-        // default main).
-        FunNode main = _code.link(_code._main);
-        StopNode stop = _code._stop;
-        // Gather an explicit main
-        FunNode xmain = null;
-        for( Node n : stop._inputs )
-            if( n instanceof ReturnNode ret && "main".equals(ret.fun()._name) )
-                if( xmain != null ) throw Utils.TODO();
-                else xmain = ret.fun();
-
-        if( main.ret().expr()._type==Type.TOP && main.uctrl()==null ) {
-            // Kill an empty default main; so it does not attempt to put a
-            // "main" in any final ELF file
-            main.setDef(1,XCTRL); // Delete default start input
-            stop.delDef(stop._inputs.find(main.ret()));
-            if( xmain != null )
-                _code.setMain(xmain);
+        if( !_lexer.isEOF() ) throw _errorSyntax("unexpected");
 
-        } else {
-            // We have a non-empty default main.
-            if( xmain != null )
-                // Found an explicit "main" AND we have a default "main"
-                throw error("Cannot define both an explicit main and a default main");
-            main._name = "main";
+        // At the top scope and every new var should be a FRef, and these
+        // should immediately resolve to a file-based name which is a Simple
+        // class type.
+        Ary<FRefNode> frefs = new Ary<>(FRefNode.class);
+        for( int i=2; i<_scope._vars._len; i++ ) {
+            FRefNode fref = (FRefNode)_scope._inputs.at(i);
+            CompUnit cu = ParseAll.findCompUnitOrThrow(_code,_ref,fref._name);
+            fref._con = TypeMemPtr.make((byte)2,TypeStruct.make(addClzPrefix(cu._cname),true),true);
+            frefs.push(fref);
         }
 
-        if( !_lexer.isEOF() ) throw _errorSyntax("unexpected");
+        // The class being published
+        ref._clz = (TypeStruct)TYPES.get(typeName);
 
         // Clean up and reset
         _xScopes.pop();
         _scope.kill();
-        for( StructNode init : INITS.values() )
-            init.unkeep().kill();
-        INITS.clear();
-        stop.peephole();
+        _scope = null;
+
+        return frefs;
     }
 
+
+
     /**
      *  Parses a function body, assuming the header is parsed.
      */
-    private ReturnNode parseFunctionBody( TypeFunPtr sig, Lexer loc, String... ids) {
-        // If this is a method, record & restore the existing struct fields,
-        // which are also the struct initializers.  The method might update
-        // mutable fields, so when the function parse is done reset back to
-        // pre-function-parse values.
-        Node[] preParse = new Node[_scope.nIns()];
-        for( int i=0; i<_scope.nIns(); i++ )
-            preParse[i] = _scope.in(i)==null ? null : _scope.in(i).keep();
+    private ReturnNode parseFunctionBody( TypeFunPtr sig, Lexer loc, String[] ids) {
+        // Record & restore the existing scope vars.  The function parse might
+        // update fields, so when the parse is done reset back to the pre-parse
+        // state.
+        Node[] preParse = _scope.save();
+
+        // Parse function body normally
+        ReturnNode ret = _parseFunctionBody(null, sig,loc,ids);
+
+        // Reset all fields to pre-parse days
+        _scope.restore(preParse);
+        return ret;
+    }
+
+
+    // Parse a function body
+
+    // Stack the {break,continue,return} scopes and a new lexical scope.
+    // Build a FunNode and parameters, extending scope by parm names.
+    // Parse the function body
+    // - while( not end-of-function )
+    // - - parseStatement
+    // - - If isInit, also incrementally extend the self-type.
+    // If isInit
+    // - upgrade and close the self-type
+    // - Gather fields and store values
+    // - <init> returns self, not last
+    // Unstack the {break,continue,return} scopes.
+
+    private ReturnNode _parseFunctionBody( String funName, TypeFunPtr sig, Lexer loc, String[] ids) {
+        boolean isInit = FunNode.isInit(funName);
+        boolean isCtor = isInit || isExplicitConstructorName(funName);
+        String typeName = isCtor ? ((TypeMemPtr)sig._sig[0])._obj._name : null;
 
         // Stack parser state on the local Java stack, and unstack it later
-        FunNode oldfun  = _fun;
-        ScopeNode breakScope = _breakScope; _breakScope = null;
+        _scope.push(new Kind.Func(funName));
+        ScopeNode    breakScope =    _breakScope;    _breakScope = null;
         ScopeNode continueScope = _continueScope; _continueScope = null;
+        ScopeNode   returnScope =   _returnScope;   _returnScope = null;
 
-        FunNode fun = _fun = (FunNode)peep(new FunNode(loc(),sig,_nestedType,null,_code._start));
+        int oldUID = _code.UID(); // Used to approximate function size
+        FunNode fun = (FunNode)peep(new FunNode(loc(),sig, funName, _ref, null, _ref._start));
         // Once the function header is available, install in linker table -
         // allowing recursive functions.  Linker matches on declared args and
         // exact fidx, and ignores the return (because the fidx will only match
         // the exact single function).
         _code.link(fun);
 
-        Node rpc = new ParmNode("$rpc",0,TypeRPC.BOT,fun,con(TypeRPC.BOT)).peephole();
-
-        // Build a multi-exit return point for all function returns
-        RegionNode r = new RegionNode( null,null,null).init();
-        assert r.inProgress();
-        PhiNode rmem = new PhiNode(ScopeNode.MEM0,TypeMem.BOT,r,null).init();
-        PhiNode rrez = new PhiNode(ScopeNode.ARG0,Type.BOTTOM,r,null).init();
-        ReturnNode ret = new ReturnNode(r, rmem, rrez, rpc, fun).init();
-        fun.setRet(ret);
-        assert ret.inProgress();
-        _code._stop.addDef(ret);
-
+        Node rpc = new ParmNode("$rpc",0,TypeRPC.BOT,fun,ConstantNode.seed(TypeRPC.BOT).peephole()).peephole();
 
         // Pre-call the function from Start, with worse-case arguments.  This
         // represents all the future, yet-to-be-parsed functions calls and
         // external calls.
-        _scope.push(new Kind.Func());
-        ctrl(fun);              // Scope control from function
+        _scope.ctrl(fun);              // Scope control from function
         // Private mem alias tracking per function
-        MemMergeNode mem = new MemMergeNode(true);
-        mem.addDef(null);       // Alias#0
-        mem.addDef(new ParmNode(ScopeNode.MEM0,1,TypeMem.BOT,fun,con(TypeMem.BOT)).peephole()); // All aliases
-        _scope.mem(mem);
+        Node defaultMem = new ProjNode(_ref._start,1,ScopeNode.MEM0).peephole();
+        Node privMem = new ParmNode(ScopeNode.MEM0,1,TypeMem.BOT,fun,defaultMem).peephole();
+        mem(privMem);
         // All args, "as-if" called externally
         for( int i=0; i<ids.length; i++ ) {
             Type t = sig.arg(i);
-            _scope.define(ids[i], t, false, new ParmNode(ids[i],i+2,t,fun,con(t)).peephole(), loc);
+            // Args take a default input if called from Start/external-world
+            _scope.define(ids[i], t, i==0 && ids[0]=="self", new ParmNode(ids[i],i+2,t,fun,ConstantNode.seed(t).peephole()).peephole(), loc);
         }
 
-        // Parse the body
-        Node last=ZERO;
-        while (!peek('}') && !_lexer.isEOF())
-            last = parseStatement();
+        // Parse the function body.
+        Node last=_code.ZERO;   // Last statement as the default result
 
-        // Last expression is the return except for the top-level main
-        if( ctrl()._type==Type.CONTROL )
-            if( fun.sig() != _code._main )
-                fun.addReturn(ctrl(), _scope.mem().merge(), last);
-            else {
-                fun.setDef(1,XCTRL); // Kill default main
-                _code.addAll(fun._outputs);
+        int nvar = 0;
+        while (!peek('}') && !_lexer.isEOF()) {
+            // Parse a statement; record last statement as default return
+            last = _code.add(parseStatement());
+            // For <init> and <clinit>, local vars are really struct fields and
+            // get exposed as discovered.  This allows late local functions to
+            // use early declared fields.
+            if( isInit )
+                nvar = updateSelfAsFieldsDiscovered( typeName, nvar );
+        }
+
+        ParmNode self = fun.parm(2);
+        // Last expression is the return
+        if( ctrl()._type==Type.CONTROL ) {
+            // Constructors get special return types
+            if( fun.isClz() ) {
+                // <clinit> only returns an integer, which becomes an OS exit code
+                // if the <clinit> is run directly
+                //if( !(last._type instanceof TypeInteger) )
+                //    last = _code.ZERO;
+                assert last!=null;
+            } else if( isCtor ) {
+                last = fun.parm(3);
             }
-
-        // Pop off the inProgress node on the multi-exit Region merge
-        assert r.inProgress();
-        r   ._inputs.pop();
-        rmem._inputs.pop();
-        rrez._inputs.pop();
-        r._loc = loc();         // Final position
-        assert !r.inProgress();
-
-        // Force peeps, which have been avoided due to inProgress
-        ret.setDef(1,rmem.peephole());
-        ret.setDef(2,rrez.peephole());
-        ret.setDef(0,r.peephole());
-        ret = (ReturnNode)ret.peephole();
-
-        // Function scope ends
-        _scope.pop();
-        _fun = oldfun;
-        _breakScope = breakScope;
+            addReturn(last);
+            // exit path is now dead (nothing live after a "return")
+        }
+        if( isCtor )
+            upgradeSelfTypeAndStoreFields( typeName, fun.isClz(), self, fun.parm(3), isInit );
+
+        // Build a return from the _returnScope.
+        // Can be no returns for never-exit functions
+        Node rctl = _returnScope==null ? _code.XCTRL      : _returnScope.ctrl().peephole();
+        Node rmem = rctl==_code.XCTRL  ? con(TypeMem.TOP) : _returnScope.mem();
+        Node expr = rctl==_code.XCTRL  ? con(Type.TOP)    : _returnScope._inputs.last().peephole();
+        ReturnNode ret = (ReturnNode)peep(new ReturnNode(rctl, rmem, expr, rpc, fun));
+        fun.setRet(ret);
+        // Approximate function size, for inlining heuristics
+        fun._approxUIDs = _code.UID() - oldUID;
+        for( Node cend : ret.outs() )
+            if( cend instanceof CallEndNode )
+                throw TODO(); //_code.add(cend); // have call ends ALREADY? just barely made the Return
+
+        // Export (and keep-alive) functions until prove dead
+        _ref.addFun(_code,fun);
+
+        // Unstack parser state
+        if( _returnScope != null ) _returnScope.kill();
+        _returnScope   =   returnScope;
         _continueScope = continueScope;
-
-        // Reset all fields to pre-parse days
-        for( int i=0; i<preParse.length; i++ )
-            _scope.setDef(i,preParse[i]==null ? null : preParse[i].unkeep());
+        _breakScope    =    breakScope;
+        _scope.pop();
 
         return ret;
     }
 
+    private int updateSelfAsFieldsDiscovered( String typeName, int nvar ) {
+        int lex = _scope.klast()._lexSize + 2/*Skip self and selfMem*/;
+        // Load self type in and out of the TYPES hashtable.
+        TypeStruct tself = (TypeStruct)TYPES.get(typeName);
+        // Start looking for newly declared vars at the lexical scope start,
+        // skipping two ("self" and "selfmem") and fields seen already.
+        while( lex + nvar < _scope.nIns() ) {
+            Var v = _scope.var(lex + nvar++);
+            // Field with sharper type
+            Field old = tself.field(v._name);
+            Field fld = old == null
+                ? Field.make(v._name,v.type(),_code.alias(_ref._cname),v._final)
+                : Field.make(v._name,v.type(), old._alias,           old._final);
+            tself = tself.addOrUpdate(fld);
+        }
+        TYPES.put(typeName,tself);
+        return nvar;
+    }
+
+
+    void upgradeSelfTypeAndStoreFields( String typeName, boolean isClz, ParmNode self, ParmNode smem, boolean upgrade ) {
+        int lex = _scope.klast()._lexSize;
+        assert _scope.var(lex)._name=="self";
+        TypeStruct tself = (TypeStruct)TYPES.get(typeName);
+        int base = lex+2;       // Skip ctrl, mem
+        if( upgrade ) {
+            // Default <init>/<clinit> defines the struct and can sharpen fields.
+            // A named constructor only initializes the already-closed struct.
+            for( int i=0; i<tself.nkids(); i++ ) {
+                Field tfld = tself._fields[i];
+                int vidx = fieldVarIdx(base,tfld._fname);
+                if( vidx == -1 )
+                    continue;
+                Var v = _scope.var(vidx);
+                // Forward-ref fields where placed in tself but will get promoted
+                // to an outer scope - and should not be in tself.
+                if( v._fref )
+                    tself = tself.remove(i--);
+                else if( v.type() != tfld._t ) {
+                    assert v.type().isa(tfld._t);
+                    tself = tself.replace( tfld.makeFrom( v.type() ) );
+                }
+            }
+
+            // Close Struct type after parsing struct body.
+            TYPES.put( tself._name, tself = tself.close() );
+            // Improve self, selfMem types in scope.
+            // Class self-type is a singleton pointer.  Instance <init> receives the
+            // broad allocation pointer, while private memory tracks initialized fields.
+            self._declaredType = self._type = isClz ? TypeMemPtr.make((byte)2,tself,true) : TypeMemPtr.make(constructorRecv(tself));
+            FunNode fun = self.fun();
+            fun.setSig(fun.sig().makeFrom(self._type,0));
+            if( !isClz )        // <init> returns upgraded private memory
+                smem._declaredType = smem._type = TypeMem.makePrivate(tself);
+        }
+
+        // When can _returnScope be null here? A never-exit constructor will
+        // not have any returns, and thus no need to gather values and store
+        // them into the (never) constructed object
+        if( _returnScope==null )
+            return;
+
+        // A MemMerge to gather field updates as stores.  Classes update the
+        // normal public memory.  <init> updates the private memory that got
+        // passed in - is treated like a normal argument and not like memory.
+        Node mmm = isClz ? _returnScope.mem(1) : smem;
+
+
+        // Store constructor results into fields
+        for( int i=0; i<tself.nkids(); i++ ) {
+            Field fld = tself._fields[i];
+            int vidx = upgrade
+                ? fieldVarIdx(base,fld._fname)
+                : fieldVarIdxBefore(lex,fld._fname);
+            if( vidx == -1 )
+                continue;
+            Var v = _scope.var(vidx);
+            if( v._fref ) continue; // Forward refs not declared here
+            // NewNode's TOP field is the zero-code poison for a required
+            // field.  The parser Var retains the typed nullable state for
+            // early-read diagnostics; only a user constructor writes memory.
+            if( upgrade && v._uninit ) continue;
+            Node val = _returnScope.in(vidx);
+            if( !upgrade && v._uninit && val._type instanceof TypeNil tn && tn.nullable() )
+                throw error("'"+tself._name+"' is not fully initialized, field '"+
+                            fld._fname+"' is only partially set in the constructor",v._loc);
+            // Store value into extended struct
+            Node prior = mmm.keep();
+            Node st = peep(new StoreNode(null, fld._fname, fld._alias, fld._t, null, prior, self, off(tself,fld._fname), val, fld._final));
+            mmm = mergeAlias(prior,fld._alias,st);
+            prior.unkeep();
+        }
+        mmm = mmm.peephole();
+
+        if( !isClz )
+            // Stuff private mem into normal expression return value.
+            _returnScope.setDef(_returnScope.nIns()-1,mmm);
+        else
+            // Parser memory is one opaque whole-memory edge.  Publish the
+            // completed class-field aggregate as the <clinit> return memory.
+            _returnScope.mem(mmm);
+            //_code.add(mmm);
+    }
+
+    private int fieldVarIdx( int base, String name ) {
+        for( int i=base; i<_scope.nIns(); i++ )
+            if( _scope.var(i)._name == name )
+                return i;
+        return -1;
+    }
+
+    // Named constructors update field Vars from the enclosing initializer
+    // scope.  Constructor arguments and locals begin at limit and must not
+    // shadow the field state gathered into private memory.
+    private int fieldVarIdxBefore( int limit, String name ) {
+        for( int i=limit-1; i>=0; i-- )
+            if( _scope.var(i)._name == name )
+                return i;
+        return -1;
+    }
+
+    private boolean isConstructorDecl(String name) {
+        TypeStruct self = _scope.constructorSelf();
+        return self != null && name == initFieldName(self._name);
+    }
+
+    private boolean inExplicitConstructor() {
+        if( !(_scope.klast() instanceof Kind.Func func) )
+            return false;
+        return isExplicitConstructorName(func._name);
+    }
+
+    private boolean isExplicitConstructorName(String funName) {
+        TypeStruct self = _scope.constructorSelf();
+        return self != null && funName == (self._name+"."+initFieldName(self._name)).intern();
+    }
+
+    private static TypeStruct constructorRecv(TypeStruct self) {
+        Field[] fs = new Field[self._fields.length];
+        for( int i=0; i<fs.length; i++ ) {
+            Field fld = self._fields[i];
+            fs[i] = fld._t instanceof TypeFunPtr ? fld : fld.makeFrom(fld._t.glb(true));
+        }
+        return TypeStruct.make(self._name,self._open,fs);
+    }
+
+
     /**
      * Parses a block
      *
@@ -300,9 +493,11 @@ public class Parser {
     private Node parseBlock(Kind kind) {
         // Enter a new scope
         _scope.push(kind);
-        Node last = ZERO;
-        while (!peek('}') && !_lexer.isEOF())
+        Node last = _code.ZERO;
+        while (!peek('}') && !_lexer.isEOF()) {
+            _code.add(last);
             last = parseStatement();
+        }
         // Exit scope
         last.keep();
         _scope.pop();
@@ -325,8 +520,9 @@ public class Parser {
         else if (matchx("break")   ) return parseBreak();
         else if (matchx("continue")) return parseContinue();
         else if (matchx("struct")  ) return parseStruct();
+        else if (inStructDeclaration() && matchx("new")) return parseConstructorDeclaration();
         else if (matchx("#showGraph")) return require(showGraph(),";");
-        else if (matchx(";")       ) return null; // Empty statement
+        else if (matchx(";")       ) return _code.ZERO; // Empty statement
         // Break ambiguity around leading function types and starting a block
         else if (peek('{') && !isTypeFun() ) {
             match("{");
@@ -336,6 +532,31 @@ public class Parser {
         else return parseDeclarationStatement();
     }
 
+    private boolean inStructDeclaration() {
+        return _scope.klast() instanceof Kind.Func fun && FunNode.isInstance(fun._name);
+    }
+
+    // Constructor declaration: new TypeName = { args -> body };
+    private Node parseConstructorDeclaration() {
+        TypeStruct self = _scope.constructorSelf();
+        assert self != null;
+        String name = requireId();
+        String expect = initFieldName(self._name);
+        if( name != expect )
+            throw error("Constructor name '" + name + "' must match type name '" + expect + "'");
+        require("=");
+        Node ctor = constructorFunc(name);
+        TypeFunPtr sig = (TypeFunPtr)ctor._type;
+        String clzName = addClzPrefix(self._name);
+        TypeStruct clz = (TypeStruct)TYPES.get(clzName);
+        Field old = clz==null ? null : clz.field("<ctor>");
+        if( old != null )
+            throw error("Redefining constructor '" + name + "'");
+        Field fld = Field.make("<ctor>",sig,_code.alias(_ref._cname),true);
+        TYPES.put(clzName,clz==null ? TypeStruct.make(clzName,true,fld) : clz.add(fld));
+        return require(ctor,";");
+    }
+
     /**
      * Parses a while statement
      *
@@ -386,7 +607,7 @@ public class Parser {
         // used as an indicator to switch off peepholes of the region and
         // associated phis; see {@code inProgress()}.
 
-        ctrl(new LoopNode(loc(),ctrl()).peephole()); // Note we set back edge to null here
+        ctrl(new LoopNode(loc(),null,ctrl()).peephole()); // Note we set back edge to null here
 
         // At loop head, we clone the current Scope (this includes all
         // names in every nesting level within the Scope).
@@ -476,12 +697,12 @@ public class Parser {
             _xScopes.push( exit );
         }
         _scope = exit;
-        return ZERO;
+        return _code.ZERO;
     }
 
     private ScopeNode jumpTo(ScopeNode toScope) {
         ScopeNode cur = _scope.dup();
-        ctrl(XCTRL); // Kill current scope
+        ctrl(_code.XCTRL); // Kill current scope
         // Prune nested lexical scopes that have depth > than the loop head
         // We use _breakScope as a proxy for the loop head scope to obtain the depth
         while( cur.depth() > _breakScope.depth() )
@@ -499,7 +720,7 @@ public class Parser {
 
     private void checkLoopActive() { if (_breakScope == null) throw error("No active loop for a break or continue"); }
 
-    private Node parseContinue() { checkLoopActive(); _continueScope = require(jumpTo( _continueScope ),";"); return ZERO; }
+    private Node parseContinue() { checkLoopActive(); _continueScope = require(jumpTo( _continueScope ),";"); return _code.ZERO; }
     private Node parseBreak   () {
         checkLoopActive();
         // At the time of the break, and loop-exit conditions are only valid if
@@ -508,7 +729,7 @@ public class Parser {
         _breakScope.removeGuards(_breakScope.ctrl());
         _breakScope = require(jumpTo(_breakScope ),";");
         _breakScope.addGuards(_breakScope.ctrl(), null, false);
-        return ZERO;
+        return _code.ZERO;
     }
 
     // Look for an unbalanced `)`, skipping balanced
@@ -518,7 +739,7 @@ public class Parser {
             // Next X char handles skipping complex comments
             switch( _lexer.nextXChar() ) {
             case Character.MAX_VALUE:
-                throw Utils.TODO();
+                throw TODO();
             case ')':
                 if( --paren<0 ) {
                     posT( pos() - 1 );
@@ -568,7 +789,7 @@ public class Parser {
         case ":"    -> parseAsgn();      //     pred ?  asgn;
         case "&&"   -> parseLogical();   //     pred && expr
         case "||"   -> pred;             //     pred || expr_is_ignored
-        default     -> throw Utils.TODO();
+        default     -> throw TODO();
         };
         lhs.keep();
         _scope.removeGuards(ifT);
@@ -593,7 +814,7 @@ public class Parser {
         case ":"    -> (doRHS=match(fside)) ? parseAsgn()      : con(lhs._type.makeZero());
         case "&&"   -> rhs = pred;
         case "||"   -> rhs = parseLogical();
-        default     -> throw Utils.TODO();
+        default     -> throw TODO();
         };
         rhs.keep();
         _scope.removeGuards(ifF);
@@ -616,10 +837,10 @@ public class Parser {
 
         // Merge results
         RegionNode r = ctrl(tScope.mergeScopes(fScope,loc()));
-        Node ret = peep(new PhiNode("",lhs._type.meet(rhs._type).glb(false),r,lhs.unkeep(),rhs.unkeep()));
+        Node ret = peep(new PhiNode("",r,lhs.unkeep(),rhs.unkeep()));
         // Immediately fail e.g. `arg ? 7 : ptr`
         ParseException err;
-        if( !fside.equals("else") && (err=ret.err()) !=null )  throw err;
+        if( !fside.equals("else") && (err=ret.err()) !=null ) throw err;
         r.peephole();
         return ret;
     }
@@ -635,11 +856,56 @@ public class Parser {
      */
     private Node parseReturn() {
         var expr = require(parseAsgn(), ";");
+        return addReturn(expr);
+    }
+    private Node addReturn(Node expr) {
+        expr.keep();
         // Need default memory, since it can be lazy, need to force
         // a non-lazy Phi
-        _fun.addReturn(ctrl(), _scope.mem().merge(), expr);
-        ctrl(XCTRL);            // Kill control
-        return expr;
+        mem();                 // Force a pending lazy bulk-memory Phi
+        // For <init> and <clinit> - all fields in scope will be live-on-exit
+        // and stored into `self` and need to have lazy-phi's inserted.
+        int lexN = _scope.enclosingFuncOrDecl();
+        Kind.Func k = (Kind.Func)_scope._kinds.at(lexN);
+        if( FunNode.isInit(k._name) ) {
+            int nestedLexSize = lexN+1 < _scope.depth() ? _scope._kinds.at(lexN+1)._lexSize : _scope.nIns();
+            for( int i=k._lexSize; i<nestedLexSize; i++ )
+                _scope.update(_scope.var(i),null);
+            if( _returnScope != null ) {
+                Var vexpr = _returnScope._vars.pop();
+                Node oldX = _returnScope.removeLast();
+                int rlen = _returnScope.nIns();
+                while( rlen  < nestedLexSize ) {
+                    _returnScope._vars.add(_scope.var(rlen));
+                    _returnScope.addDef(con(_scope.var(rlen++).type().makeZero()));
+                }
+                _returnScope._vars.add(vexpr);
+                _returnScope.addDef(oldX);
+            }
+        }
+
+        // No prior merge point?  Just clone and hang on to it
+        if( _returnScope == null ) {
+            _returnScope = _scope.dup();
+            while( lexN+1 < _returnScope.depth() )
+                _returnScope._pop(); // Pop a nested block scope until we hit the function scope
+            _returnScope.define("$expr", expr._type.glb(false), true, expr, null);
+
+        } else {
+            // For <init> and <clinit> - ALL FIELDS IN LAST SCOPE are live
+            // and need to have lazy-phi's inserted.
+
+            // And fields might not match.... will need matching Var/define with default values
+            int rlen = _returnScope.nIns()-1;
+            RegionNode r = ctrl(new RegionNode(null, null,_returnScope.ctrl(), _scope.ctrl()).init().keep());
+            _returnScope._merge(_scope, r, rlen);
+            Node oldExpr = _returnScope.in(rlen);
+            _returnScope.setDef(rlen,new PhiNode("$expr", r, oldExpr, expr).peephole());
+            _code.add(r);
+            _returnScope.ctrl(r.unkeep());
+        }
+        ctrl(_code.XCTRL);      // Kill control
+        return expr.unkeep();
     }
 
     /**
@@ -647,7 +913,7 @@ public class Parser {
      * @return {@code null}
      */
     Node showGraph() {
-        System.out.println(new GraphVisualizer().generateDotOutput(_code._stop,_scope,_xScopes));
+        System.out.println(new GraphVisualizer().generateDotOutput(_ref,_scope,_xScopes));
         return null;
     }
 
@@ -656,7 +922,6 @@ public class Parser {
     private Node parseAsgn() {
         int old = pos();
         String name = _lexer.matchId();
-        int old_pre_equals = pos();
         // Just a plain expression, no assignment.
         // Distinguish `var==expr` from `var=expr`
         if( name==null || KEYWORDS.contains(name) || !matchOpx('=','=') )
@@ -665,62 +930,72 @@ public class Parser {
         // Find variable to update
         Var def = _scope.lookup(name);
         if( def==null )
+            def = defineOpenConstructorField(name);
+        if( def==null )
             throw error("Undefined name '" + name + "'");
 
-        // If a method var, allow nested blocks and methods, but not fcns or other structs.
-        // Else safety check for accessing fields out of function scope.
-        if( instance(def) ) {
-            pos(old_pre_equals);  // setup for `self.name = expr`
-            Node self = _scope.in(_scope.lookup("self")); // Insert self reference
-            return parsePostfixName(self,name);
-        }
-
         // TOP fields are for late-initialized fields; these have never
         // been written to, and this must be the final write.  Other writes
         // outside the constructor need to check the final bit.
         if( _scope.in(def._idx)._type!=Type.TOP && def._final &&
             // Inside an allocation, final assign is OK, outside nope.
             // The alloc() call added the allocation scope
-            !(_scope.inAllocation() && def._idx >= _scope._kinds.last(-1)._lexSize) )
+            !(_scope.inConstructor() && def._idx >= _scope.klast()._lexSize) &&
+            !inExplicitConstructor() )
             throw error("Cannot reassign final '"+name+"'");
 
         // Parse assignment expression
         Node expr = parseAsgn();
 
         // Lift expression, based on type
-        Node lift = liftExpr(expr.keep(), def.type(), def._final, true);
+        Type decl = def.type(); // Declared type
+        Node lift = convertExpr(expr.keep(), decl).keep();
         // Update
         _scope.update(name,lift);
+
+        // Check for storing into an instance field instead of a local var
+        int kx = _scope.kindx(def); // Declaration scope
+        int fx = _scope.enclosingFunction(); // Enclosing function scope
+        Kind kk = _scope._kinds.at(kx);
+        Kind fk = _scope._kinds.at(fx);
+        // Access instance field from 'self'
+        if( kx+1 == fx && kk instanceof Kind.Func inst && FunNode.isInstance(inst._name) &&
+            fk instanceof Kind.Func method && !inExplicitConstructor() ) {
+            // Named field offset on an unknown struct type
+            TypeMemPtr self = (TypeMemPtr)_scope.var(fk._lexSize).type();
+            TypeStruct sobj = (TypeStruct)TYPES.get(self._obj._name);
+            Field fld = sobj.field(name);
+            int alias = fld._alias;
+            Node ptr = _scope.in(method._lexSize);
+            Node off = fldoff(ptr,name);
+            Node prior = mem().keep();
+            Node st = new StoreNode(loc(), name, alias, decl, ctrl(), prior, ptr, off, lift, inExplicitConstructor()).peephole().keep();
+            storeMem(st,alias,prior);
+            st.unkeep();
+            prior.unkeep();
+        }
+        lift.unkill();
+
+
         // Return un-lifted expr
         return expr.unkeep();
     }
 
-    // Make finals deep; widen ints to floats; narrow wide int types.
+    // Widen ints to floats; narrow wide int types.
     // Early error if types do not match variable.
-    private Node liftExpr( Node expr, Type t, boolean xfinal, boolean isLoad ) {
-        if( expr._type instanceof TypeMemPtr tmp && TYPES.get(tmp._obj._name).isFRef() )
-            throw error("Must define forward ref "+tmp._obj._name);
-        // Final is deep on ptrs
-        if( xfinal && t instanceof TypeMemPtr tmp ) {
-            t = tmp.makeRO();
-            expr = peep(new ReadOnlyNode(expr));
-        }
+    private Node convertExpr( Node expr, Type t ) {
+        // A FunPtr carries the semantic edge to its function's Return.  Do not
+        // hide that edge behind a Convert which can fold to a plain constant.
+        if( expr instanceof FunPtrNode && t instanceof TypeFunPtr )
+            return expr;
         // Auto-widen array to i64 (cast ptr to raw int bits)
         if( t == TypeInteger.BOT && expr._type instanceof TypeMemPtr tmp && tmp._obj.isAry() )
-            expr = peep(new AddNode(peep(new CastNode(t,ctrl(),expr)),off(tmp._obj,"[]")));
-        // Auto-widen int to float
-        expr = widenInt( expr, t );
-        // Auto-narrow wide ints to narrow ints.  For loads, emit code to force
-        // the loaded value to match the declared sign/zero bits.  For stores,
-        // just force the type, acting "as if" the store silently truncates.
-        Type et = expr._type;
-        if( isLoad ) { expr = zsMask(expr,t); et = expr._type; }
-        else if( et instanceof TypeInteger && t instanceof TypeInteger ) et=t;
-
-        // Type is sane
-        if( et!=Type.BOTTOM && !et.shallowISA(t) )
-            expr = peep(new CastNode(t.isConstant() ? t : t.widen(),null,expr));
-        return expr;
+            return peep(new AddNode(peep(new PtrToIntNode(expr)),off(tmp._obj,"[]")));
+        // Null check has to eventually pass
+        if( t == Type.NIL && expr._type instanceof TypeMemPtr tmp && tmp.notNull() )
+           return peep(new CheckCastNode(t,null,expr));
+        // Widen ints to floats, narrow wide types
+        return peep(new ConvertNode(t,expr));
     }
 
     private Node widenInt( Node expr, Type t ) {
@@ -761,11 +1036,17 @@ public class Parser {
         // Optional initializing expression follows
         boolean xfinal = false;
         boolean fld_final = false; // Field is final, but not deeply final
+        boolean uninit = false;    // Required non-null constructor field
         Node expr;
         if( match("=") ) {
-            expr = isExternDecl()
-                ? externDecl(name,t)
-                : parseAsgn();
+            if( isExternDecl() ) {
+                expr = externDecl(name,t);
+                t = expr._type; // Upgrade declared type to the exact extern decl type
+            } else if( isConstructorDecl(name) ) {
+                expr = constructorFunc(name);
+            } else {
+                expr = parseAsgn();
+            }
             // TOP means val and val is always final
             xfinal = (t==Type.TOP) ||
                 expr instanceof ExternNode ||
@@ -773,8 +1054,6 @@ public class Parser {
                 (t!=Type.BOTTOM &&
                  // no Bang AND
                  !hasBang &&
-                 // Locals are not-final by default
-                 !_scope.inFunction() &&
                  // not-null (expecting null to be set to not-null)
                  expr._type != Type.NIL &&
                  // Pointers are final by default; int/flt are not-final by default.
@@ -787,13 +1066,23 @@ public class Parser {
                 t = expr._type;
                 if( !xfinal ) t = t.glb(false);  // Widen if not final
             }
+
+            // Final is deep on ptrs
+            if( xfinal && t instanceof TypeMemPtr tmp ) {
+                t = tmp.makeRO();
+                expr = peep(new ReadOnlyNode(expr));
+            }
+
             // expr is a constant function
             if( t instanceof TypeFunPtr && expr._type instanceof TypeFunPtr tfp && tfp.isConstant() ) {
-                if( expr instanceof ExternNode ) t = expr._type; // Upgrade declared type to exact function
-                else _code.link(tfp).setName(name); // Assign debug name to Simple function
+                FunNode fun = _code.link(tfp);
+                if( fun != null )
+                    fun.setName(name); // Assign debug name to Simple function
             }
 
         } else {
+            // Since no initializer, not-final but might need an initializer
+
             // Need an expression to infer the type.
             // Also, if not-null then need an initializing expression.
             // Allowed in a class def, because type/init will happen in the constructor.
@@ -801,34 +1090,33 @@ public class Parser {
                 throw errorSyntax("=expression");
             // Initial value for uninitialized struct fields.
             expr = switch( t ) {
-                // Nullable pointers get a NIL; not-null get a TOP which
-                // signals that they *must* be initialized in the constructor.
-            case TypeNil tn -> tn.nullable() ? NIL : con(Type.TOP);
-            case TypeInteger ti -> ZERO;
+                // Required pointers retain their declared shape, but include
+                // null until every constructor path assigns them.
+            case TypeNil tn -> tn.nullable() ? con(Type.NIL) : con(t.meet(Type.NIL));
+            case TypeInteger ti -> _code.ZERO;
             case TypeFloat tf -> con(TypeFloat.FZERO);
             // Bottom signals type inference: they must be initialized in
             // the constructor and that's when we'll discover the type.
             case Type tt -> { assert tt==Type.BOTTOM; yield con(tt); }
             };
-            // Nullable fields are set in the constructor, but remain shallow final.
-            // e.g. final pointer to a r/w array
-            if( t instanceof TypeNil tn && !tn.nullable() && !hasBang )
-                fld_final = true;
+            // Every non-null pointer without a default is constructor-required.
+            // Without `!` it is also shallow-final; mutability and definite
+            // initialization are independent properties.
+            if( t instanceof TypeNil tn && !tn.nullable() ) {
+                uninit = true;
+                if( !hasBang ) fld_final = true;
+            }
         }
 
         // Lift expression, based on type
-        Node lift = liftExpr(expr, t, xfinal, true);
-        // Rebuild the deep RO 't', not returned from liftExpr
-        if( xfinal && t instanceof TypeMemPtr tmp )
-            t = tmp.makeRO();
-
-        // Lift type to the declaration.  This will report as an error later if
-        // we cannot lift the type.
-        if( !lift._type.isa(t) )
-            lift = peep(new CastNode(t.widen(),null,lift));
+        // Do not let an authoritative Convert hide the nullable
+        // not-yet-initialized state from constructor-local type flow.
+        Node lift = uninit ? expr : convertExpr(expr, t);
+
         // Define a new name
         if( !_scope.define(name,t,xfinal || fld_final,lift, loc) )
             throw error("Redefining name '" + name + "'", loc);
+        _scope.lookup(name)._uninit = uninit;
         return lift;
     }
 
@@ -840,59 +1128,132 @@ public class Parser {
      *
      * @return zero
      */
-    private String _nestedType;
-    private Node parseStruct() {
-        // "struct" already parsed, so expect the struct name next.
-        String old = _nestedType;
+    private Node parseStruct( ) {
+        // keyword "struct" already parsed, so expect the struct name next.
         String typeName = requireId();
-        if( old!=null ) typeName = old+"."+typeName;
-        _nestedType = typeName;
-        // New declared or forward-ref type
-        TypeStruct ts = TYPES.get(typeName) instanceof TypeMemPtr tmp ? tmp._obj : TypeStruct.open(typeName);
-        TYPES.put(typeName,TypeMemPtr.make(ts));
-
-        // A Block scope parse, and inspect the scope afterward for fields.
-        _scope.push(new Kind.Define(TypeMemPtr.make(ts)));
         require("{");
-        int lexlen = _scope._kinds.last()._lexSize, nvar=lexlen;
-        while (!peek('}') && !_lexer.isEOF()) {
-            parseStatement().isKill();
-            while( nvar < _scope._vars._len ) {
-                Var v = _scope.var(nvar++);
-                if( !v.isFRef() ) {
-                    ts = ts.add( Field.make( v._name, v.type(), _code.getALIAS(), v._final, v._final && _scope.in( v._idx )._type != Type.TOP ) );
-                    TYPES.put( typeName, TypeMemPtr.make( ts ) );
-                }
-            }
-        }
 
-        // Count struct declarations
-        int varlen = _scope._vars._len;
-        ts = ts.close();
-        TYPES.put(typeName,TypeMemPtr.make(ts));
+        // create type class:NESTED.typeName; no fields.
 
-        // Generate an initializing struct
-        StructNode s = new StructNode(ts);
-        for( int i=lexlen; i<varlen; i++ )
-            if( !_scope.var(i).isFRef() ) // Promote to outer scope, not defined here
-                s.addDef(_scope.in(i)); // Keep the program code to generate instance
+        String old = _nestedType;
+        String fullName = _scope.depth()==1 && _nestedType.endsWith(typeName) ? old : (old+"."+typeName).intern();
+        _nestedType = fullName; // Recursive structs start with this as their basename
 
-        // Save instance default constructor
-        s.setType(s.compute()); // Do not call peephole, in case the entire struct is a big plain constant
-        INITS.put(typeName,s.keep());
+        ReturnNode ret = parseStruct( false, fullName );
 
-        // Having finalized the struct, upgrade all the 'self' pointers
-        for( Node n : s._inputs )
-            if( n._type instanceof TypeFunPtr tfp && _code.link(tfp) instanceof FunNode fun )
-                _code.addAll( fun._outputs );
+        _nestedType = old;
 
+        // Insert a field into class:NESTED.typeName of "val typeName = fcn-ptr-to-init"
+        // Function does malloc internally.
+        // Future self: means subtyping has to deal with "who does the malloc"
+        String clzName = addClzPrefix(fullName);
+        TypeFunPtr sig = ret.fun().sig();
+        TypeStruct ts = (TypeStruct)TYPES.get(clzName);
+        String initName = initFieldName(fullName);
+        Field oldFld = ts==null ? null : ts.field(initName);
+        Field fld = oldFld==null
+            ? Field.make(initName,sig,_code.alias(_ref._cname),true)
+            : oldFld.makeFrom(sig);
+        Field ctorFld = ts==null ? null : ts.field("<ctor>");
+        ts = ctorFld==null
+            ? TypeStruct.make(clzName,false,fld)
+            : TypeStruct.make(clzName,false,fld,ctorFld);
+        TYPES.put(clzName,ts);
+
+        // Insert a field in the containing class with the nested class type.
+        // This is basically sugar for "val CLZNAME = <init>"
+        // and is a nicer version of updateSelfAsFieldsDiscovered.
+        _scope.define(typeName, sig, true, new FunPtrNode(sig,_code._start,ret).peephole(), loc());
 
-        // Done with struct/block scope
-        _nestedType = old;
         require("}");
-        require(";");
-        _scope.pop();
-        return ZERO;
+        return require(_code.ZERO,";");
+    }
+
+    // Parse a struct declaration (not an allocation); file-level is a class-init, and scope structs are normal
+    private ReturnNode parseStruct( boolean isClz, String typeName ) {
+        // Record & restore global state set during parsing the <init> code
+        Node oldCtrl= _scope.ctrl().keep();
+        Node oldMem = _scope.mem ().keep();
+
+        // Make the future clazz/instance struct.
+        TypeStruct tself = (TypeStruct)TYPES.get(typeName);
+        if( tself==null )
+            TYPES.put(typeName, tself = TypeStruct.make(typeName,true));
+        else {
+            assert tself._open;
+            TYPES.put(typeName,tself = tself.defined());
+        }
+
+        // Signature of the default constructor
+        TypeFunPtr sig = structInitSig(isClz,tself);
+        // Function and argument names of default constructor
+        String fname = (typeName + (isClz ? ".<clinit>" : ".<init>")).intern();
+        String[] ids = new String[]{"self", isClz ? "arg" : "#selfMem"};
+
+        // Struct decls look like function bodies.  Parse function body normally.
+        ReturnNode ret = _parseFunctionBody(fname,sig,loc(),ids);
+        // Unwind global state.
+        ctrl(oldCtrl.unkeep());
+        mem (oldMem .unkeep());
+        return ret;
+    }
+
+        // <cl/init> signature: { self arg/selfMem -> BOT/selfMem }
+        // Self-memory is the rare *private* (never aliased) memory for the new object.
+    private TypeFunPtr structInitSig( boolean isClz, TypeStruct tself ) {
+        // Private uninitialized memory from new object, no escaped values.
+        TypeMem privMem = isClz ? null : TypeMem.make(1,tself,true,isClz,false,null,null);
+        Type targ = isClz ? TypeInteger.BOT : privMem;
+        // Return for private memory has to name all escaped fields, which are not known yet.
+        // Escape ALL fields, and sharpen later.
+        Type tret = isClz ? Type.BOTTOM     : TypeMem.makePrivate(tself);
+        Type[] targs = new Type[]{ TypeMemPtr.make((byte)2,tself,isClz), targ };
+        // FIDX for FREFs is in the global namespace, needs the correct clz name.
+        String clzBare = tself._name;
+        int order = 3; // 3 is always the <init> order, 2nd in the file just behind the <clinit>
+        if( isClz ) {
+            assert startsClzPrefix( clzBare );
+            clzBare = clzBare.substring(clzPrefix.length()).intern();
+            order = 2; // 2 is always the <clinit> order, first in file and skipping reserved #1
+        }
+        return TypeFunPtr.make1((byte)2, true, targs, tret, _code.fidx(clzBare,order));
+    }
+
+    // A class type carries the constructor function as a required final field.
+    private TypeStruct classStruct( String typeName, TypeFunPtr init, boolean open ) {
+        return TypeStruct.make(addClzPrefix(typeName),open,Field.make(initFieldName(typeName),init,_code.alias(_ref._cname),true));
+    }
+
+    private static String initFieldName( String typeName ) {
+        if( startsClzPrefix(typeName) )
+            typeName = typeName.substring(clzPrefix.length());
+        int idx = typeName.lastIndexOf('.');
+        return (idx == -1 ? typeName : typeName.substring(idx+1)).intern();
+    }
+
+    private TypeStruct latestStruct( TypeStruct ts ) {
+        Type t = TYPES.get(ts._name);
+        return t instanceof TypeStruct ts2 ? ts2 : ts;
+    }
+
+    private Field fieldOrOpen( TypeStruct ts, String name, boolean xfinal ) {
+        ts = latestStruct(ts);
+        Field fld = ts.field(name);
+        if( fld != null ) return fld;
+        if( !ts._open || !ts._fref ) return null;
+        fld = Field.make(name,Type.BOTTOM,_code.alias(_ref._cname),xfinal);
+        TYPES.put(ts._name,ts = ts.add(fld));
+        if( _ctorOpenStruct != null && _ctorOpenStruct._name == ts._name )
+            _ctorOpenStruct = ts;
+        return fld;
+    }
+
+    private Var defineOpenConstructorField( String name ) {
+        if( _ctorOpenStruct==null ) return null;
+        Field fld = fieldOrOpen(_ctorOpenStruct,name,true);
+        if( fld == null ) return null;
+        _scope.define(name,fld._t,fld._final,con(Type.TOP),loc());
+        return _scope.lookup(name);
     }
 
 
@@ -902,48 +1263,146 @@ public class Parser {
     // ref type position.
 
     // t = int|i8|i16|i32|i64|u8|u16|u32|u64|byte|bool | flt|f32|f64 | val | var | struct[?]
+
+    // Structs have nested names, and can be discovered with a partial name
+    // match.  Example, searching for a type name "C.D" in the namespace "A.B".
+    // This will match "A.B.C.D", then "A.C.D", then "C.D".
+
+    // Will also match external names like "sys.io" or "externModule.subtype.subtype"
+
     private Type type() {
-        int old1 = pos();
         // Only type with a leading `{` is a function pointer...
         if( peek('{') ) return typeFunPtr();
 
         // Otherwise you get a type name
+        int old1 = pos();
         String tname = _lexer.matchId();
         if( tname==null ) return null;
 
         // Convert the type name to a type.
-        Type t0 = TYPES.get(tname);
+        Type t0 = TYPES.get(tname), t1 = t0;
         // No new types as keywords
-        if( t0 == null && KEYWORDS.contains(tname) )
-            return posT(old1);
-        if( t0 == Type.BOTTOM || t0 == Type.TOP ) return t0; // var/val type inference
+        if( KEYWORDS.contains(tname) ) {
+            if( t0 == null ) return posT(old1);
+            // Something like "int" or "f64" or "var".
+            // Can be "int[]" so still need to check array-ness
+        } else {
+            if( t0 == Type.BOTTOM || t0 == Type.TOP ) return t0; // var/val type inference
+
+            if( t0 != null ) {
+                while( true ) {
+                    int old2 = pos();
+                    if( !match(".") ) break;
+                    String sname = matchId();
+                    if( sname==null ) { pos(old2); break; }
+                    sname = tname+"."+sname;
+                    Type t = TYPES.get(sname);
+                    if( t==null ) { pos(old2); break; }
+                    tname = sname;
+                    t0 = t;
+                }
+            } else {
+                // Type A.B.C starts with just A.  Search our nested type path,
+                // e.g. path "X.Y.Z", in order:
+
+                // If A==X its now a local type.
+                //   If another dot, repeat for B==Y then C==Z
+                //   Else if AX.B exists, done
+                //   Else AX.B is a local forward ref.
+                //
+                // Else its a short cut form, one of:
+                //   X.Y.Z.A
+                //   X.Y.A
+                //   X.A
+                // Else this all failed, assume a forward ref with A as an external symbol:
+                //   A
+
+                String root = _nestedType;
+                int ridx = root.indexOf('.');
+                if( ridx != -1 ) root = root.substring(0,ridx);
+                if( tname.equals(root) ) {
+                    boolean localForward = false;
+                    while( true ) {
+                        int old2 = pos();
+                        if( !match(".") ) break;
+                        String sname = matchId();
+                        if( sname==null ) { pos(old2); break; }
+                        sname = tname+"."+sname;
+                        Type t = TYPES.get(sname);
+                        if( t==null && !(_nestedType.equals(tname) || _nestedType.startsWith(tname+".")) && !localForward ) {
+                            pos(old2);
+                            break;
+                        }
+                        tname = sname;
+                        t0 = t;
+                        localForward |= t==null;
+                    }
+                } else {
+                    String nest = _nestedType, fullq = tname;
+                    while( true ) {
+                        fullq = nest+"."+tname; // Full qualified name
+                        t0 = TYPES.get(fullq);
+                        if( t0 != null )
+                            { tname = fullq; break; } // Search succeeded
+                        // Subtract a layer from nested typenames
+                        int idx = nest.lastIndexOf('.');
+                        if( idx== -1 ) break; // Search failed; leave as an external symbol
+                        nest = nest.substring(0,idx);
+                    }
+                    if( t0==null ) {
+                        CompUnit cu = ParseAll.findCompUnit(_code,_ref,tname);
+                        if( cu != null ) {
+                            tname = cu._cname;
+                            t0 = TYPES.get(tname);
+                        }
+                        while( true ) {
+                            int old2 = pos();
+                            if( !match(".") ) break;
+                            String sname = matchId();
+                            if( sname==null ) { pos(old2); break; }
+                            tname = tname+"."+sname;
+                            t0 = TYPES.get(tname);
+                        }
+                    } else {
+                        while( true ) {
+                            int old2 = pos();
+                            if( !match(".") ) break;
+                            String sname = matchId();
+                            if( sname==null ) { pos(old2); break; }
+                            sname = tname+"."+sname;
+                            Type t = TYPES.get(sname);
+                            if( t==null ) { pos(old2); break; }
+                            tname = sname;
+                            t0 = t;
+                        }
+                    }
+                }
+            }
+
+            tname = tname.intern();
+            // Still no type found?  Assume forward reference
+            t1 = t0 == null
+                ? TypeStruct.forward(tname) // Null: assume a forward ref type
+                : t0;
+        }
+
+        // Structs are always actually references
+        if( t1 instanceof TypeStruct ts1 )
+            t1 = TypeMemPtr.make(ts1);
 
-        // Check for subtype.
-        while( true ) {
-            int old2 = pos();
-            if( !match(".") )  break;
-            String sname = _lexer.matchId();
-            if( sname==null ) { pos(old2); break; }
-            String tsname = tname+"."+sname;
-            t0 = TYPES.get(tsname);
-            if( t0==null ) { pos(old2); t0 = TYPES.get(tname); break; }
-            tname = tsname;
-        }
-
-        // Still no type found?  Assume forward reference
-        Type t1 = t0 == null ? TypeMemPtr.make(TypeStruct.open(tname)) :t0; // Null: assume a forward ref type
         // Nest arrays and '?' as needed
         Type t2 = t1;
         while( true ) {
             if( match("?") ) {
-                if( !(t2 instanceof TypeMemPtr tmp) )
+                if( t2 instanceof TypeMemPtr tmp ) {
+                    if( tmp.nullable() ) throw error("Type "+t2+" already allows null");
+                    t2 = tmp.makeNullable();
+                } else
                     throw error("Type "+t0+" cannot be null");
-                if( tmp.nullable() ) throw error("Type "+t2+" already allows null");
-                t2 = tmp.makeNullable();
             } else if( match("[~]") ) {
-                t2 = typeAry(t2,true);
+                t2 = TypeMemPtr.make(typeAry(t2,true));
             } else if( match("[]") ) {
-                t2 = typeAry(t2,false);
+                t2 = TypeMemPtr.make(typeAry(t2,false));
             } else
                 break;
         }
@@ -955,28 +1414,63 @@ public class Parser {
         int old2 = pos();
         match("!");
         String id = _lexer.matchId();
-        if( !(peek(',') || peek(';') || match("->")) || id==null )
+        if( !(peek(',') || peek(';') || peek('=') || match("->")) || id==null )
             return posT(old1);  // Reset lexer to reparse
         pos(old2);              // Reset lexer to reparse
         // Yes a forward ref, so declare it
-        TYPES.put(tname,t1);
+        forwardRefType(tname,(TypeStruct)((TypeMemPtr)t1)._obj);
         // Return the (array, final) type
         return t2;
     }
 
-    // Make an array type of t
-    private TypeMemPtr typeAry( Type t, boolean efinal ) {
+    private TypeMemPtr forwardRefType( String tname, TypeStruct tself ) {
+        TYPES.put(tname,tself);
+        String clzName = addClzPrefix( tname );
+        TYPES.put(clzName, classStruct(tname,structInitSig(false,tself),true));
+        return TypeMemPtr.make(tself);
+    }
+
+    private TypeMemPtr forwardRefType( String tname ) {
+        tname = fullTypeName(tname);
+        return forwardRefType(tname,TypeStruct.forward(tname));
+    }
+
+    private String fullTypeName( String tname ) {
+        String nest = _nestedType, fullq;
+        while( true ) {
+            fullq = nest+"."+tname;
+            if( TYPES.get(fullq) != null )
+                return fullq.intern();
+            int idx = nest.lastIndexOf('.');
+            if( idx== -1 ) return fullq.intern();
+            nest = nest.substring(0,idx);
+        }
+    }
+
+    // Make an array type of t.  Always record a mutable version,
+    // but return the requested version.
+    private TypeStruct typeAry( Type t, boolean efinal ) {
         if( t instanceof TypeMemPtr tmp && tmp.notNull()  )
             throw error("Arrays of reference types must always be nullable");
-        String tname = "[]"+t.str();
-        TypeMemPtr ta = (TypeMemPtr)TYPES.get(tname);
-        if( ta==null )
-            // Remember final version
-            TYPES.put(tname, ta = TypeMemPtr.make( TypeStruct.makeAry(tname,TypeInteger.U32,_code.getALIAS(),t,_code.getALIAS(),true) ));
-        Field elem = ta._obj.field("[]");
-        if( elem._final == efinal )
-            return ta;
-        return TypeMemPtr.make( ta._obj.replace(elem.makeFrom(efinal)));
+        String tname = ("[]"+t.str()).intern();
+        TypeStruct ta = (TypeStruct)TYPES.get(tname);
+        if( ta==null ) {
+            // Primitive arrays use the null compunit
+            String rcname = TYPES.get(t) instanceof TypeStruct ? _ref._cname : ("_."+t).intern();
+            ta = TypeStruct.makeAry(tname,TypeInteger.U32,_code.alias(rcname),t,_code.alias(rcname), false );
+            TYPES.put(tname,ta);
+        }
+        if( !efinal ) return ta;
+        // Already have the aliases, just efinal is wrong
+        return TypeStruct.makeAry(tname,TypeInteger.U32,ta._fields[0]._alias,t,ta._fields[1]._alias,true );
+    }
+
+    private Type implicitSelfType() {
+        TypeStruct self = _scope.constructorSelf();
+        // Ordinary instance methods accept the declared object shape.  The
+        // constructor-only receiver starts at the low/default field values,
+        // and is built explicitly by constructorFunc().
+        return self == null ? TypePtr.PTR : TypeMemPtr.make(self);
     }
 
     // A function type is `{ type... -> type }` or `{ type }`.
@@ -985,16 +1479,19 @@ public class Parser {
         match("{");             // Skip already-peeked '{'
         Type t0 = type();       // Either return or first arg
         if( t0==null ) return posT(old); // Not a function
-        if( match("}") )                 // No-arg function { -> type }
-            return TypeFunPtr.make(match("?"),false,TypeFunPtr.TEMPTY,t0);
         Ary<Type> ts = new Ary<>(Type.class);
+        // Always reserve a receiver slot.  Outside constructor scopes it is
+        // broad and unused, so call sites can uniformly pass their self.
+        ts.push(implicitSelfType());
+        if( match("}") )                 // No-arg function { -> type }
+            return TypeFunPtr.make(match("?"),ts.asAry(),t0);
         ts.push(t0);            // First argument
         while( true ) {
             if( match("->") ) { // End of arguments, parse return
                 Type ret = type();
                 if( ret==null || !match("}") )
                     return posT(old); // Not a function
-                return TypeFunPtr.make(match("?"),false,ts.asAry(),ret);
+                return TypeFunPtr.make(match("?"),ts.asAry(),ret);
             }
             Type t1 = type();
             if( t1==null ) return posT(old); // Not a function
@@ -1070,7 +1567,7 @@ public class Parser {
             else if( !match("!=") ) break;
             lhs.keep();
             Node rhs = parseComparison();
-            lhs = peep(new BoolNode.EQ(lhs.unkeep(),rhs).widen());
+            lhs = peep(new BoolNode.EQ(lhs.unkeep(),rhs));
             if( !eq ) lhs = peep(new NotNode(lhs));
         }
         return lhs;
@@ -1087,46 +1584,64 @@ public class Parser {
      */
     private Node parseComparison() {
         Node lhs = parseShift();
-        int dir = 0;
-
-        while( true ) {
-            int dir0;
-            if( false ) ;
-            else if( match("<=" ) ) dir0 = -1;
-            else if( match(">=" ) ) dir0 = -2;
-            else if( match("<"  ) ) dir0 =  1;
-            else if( match(">"  ) ) dir0 =  2;
-            else break;
-            lhs.keep();
-            // Check and record direction
-            if( dir==0 ) {
-                dir = Math.abs(dir0);
-                Node rhs = parseShift();
-                lhs = makeCompBool(dir0,lhs.unkeep(),rhs); // Convert to a bool
-            } else if( dir == Math.abs(dir0) ) {
-                // e0 < lhs < ???
-                Node ifNode = new IfNode(ctrl(), lhs).peephole();
-                Node ifT = new CProjNode(ifNode.  keep(), 0, "True" ).peephole();
-                Node ifF = new CProjNode(ifNode.unkeep(), 1, "False").peephole();
-                // False side does nothing
-                ScopeNode fScope = _scope.dup();
-                fScope.ctrl(ifF);
-                // True side executes next part of range
-                ctrl(ifT);
-                _scope.addGuards(ifT,lhs,false);
-                Node rhs = parseShift();
-                _scope.removeGuards(ifT); // TODO: I think should remain true as long as possible
-                Node next = makeCompBool(dir0, lhs, rhs).keep();
-                // Merge result
-                RegionNode r = ctrl(_scope.mergeScopes(fScope, loc()));
-                assert next._type.meet(lhs._type).isa( TypeInteger.BOOL );
-                lhs = peep(new PhiNode("",TypeInteger.BOOL,r,next.unkeep(),lhs.unkeep()));
-                r.peephole();
-            } else {
+        int dir = parseCompDir();
+        // No compare
+        if( dir==0 ) return lhs;
+
+        // Compare
+        Node rhs = parseShift().keep();
+        Node cmp = makeCompBool(dir,lhs,rhs); // Convert to a bool
+
+        // Stacked compares?
+        int dir0 = parseCompDir();
+        if( dir0 == 0 ) {
+            rhs.unkeep();
+            if( rhs != cmp ) rhs.isKill();
+            return cmp;
+        }
+
+        // rhs is keeped() and becomes lhs
+        // cmp is NOT keeped() and is the last test
+        Node ifNode = new IfNode(ctrl(), cmp).peephole();
+        Node ifT = new CProjNode(ifNode.  keep(), 0, "True" ).peephole();
+        Node ifF = new CProjNode(ifNode.unkeep(), 1, "False").peephole();
+        // False side does nothing but capture memory & side-effects
+        ScopeNode fail = _scope.dup();
+        fail.ctrl(ifF);
+
+        // Loop over stacked compares.  Each loop moves the old RHS to become
+        // the new LHS, so e.g. (a < b < c < d) compares (LHS:a < RHS:b) then
+        // compares (LHS:b < RHS:c) then (LHS:c < RHS:d), etc.
+        while( dir0 != 0 ) {
+            if( Math.abs(dir) != Math.abs(dir0) )
                 throw error("Mixing relational directions in a chained relational test");
-            }
-        }
-        return lhs;
+            // True side parses next arm of test
+            ctrl(ifT);
+            lhs = rhs;          // lhs is keeped() and is old RHS
+            rhs = parseShift().keep();
+            cmp = makeCompBool(dir,lhs.unkeep(),rhs); // Convert to a bool
+            ifNode = new IfNode(ctrl(), cmp).peephole();
+            ifT = new CProjNode(ifNode.  keep(), 0, "True" ).peephole();
+            ifF = new CProjNode(ifNode.unkeep(), 1, "False").peephole();
+            // Merge result into the fail case
+            ctrl(ifF);
+            fail.mergeScopes(_scope.dup(), loc()).peephole();
+            // Check next stacked compare
+            dir0 = parseCompDir();
+        }
+        rhs.unkill();
+        ctrl(ifT);
+        RegionNode r = fail.mergeScopes(_scope, loc()).init();
+        _scope = fail;
+        return new PhiNode("", r,_code.ZERO,con(1)).peephole();
+    }
+
+    private int parseCompDir() {
+        if( match("<=") ) return -1; // Negative for "equals-or-less"
+        if( match(">=") ) return -2; // 1 for <, 2 for >
+        if( match("<" ) ) return  1; // Positive for just "less"
+        if( match(">" ) ) return  2;
+        return 0;
     }
 
     private Node makeCompBool( int dir0, Node lhs, Node rhs ) {
@@ -1134,10 +1649,9 @@ public class Parser {
         if( Math.abs(dir0)==2 ) // Swap direction
             { Node tmp = lhs; lhs = rhs; rhs = tmp; }
         lhs = peep(dir0 < 0 ? new BoolNode.LE(lhs,rhs) : new BoolNode.LT(lhs,rhs));
-        return peep(lhs.widen());
+        return peep(lhs);
     }
 
-
     /**
      * Parse an additive expression
      *
@@ -1158,7 +1672,7 @@ public class Parser {
             ParseException err;
             if( (err=lhs.err()) != null )
                 throw err;
-            lhs = peep(lhs.widen());
+            lhs = peep(lhs);
         }
         return lhs;
     }
@@ -1179,7 +1693,7 @@ public class Parser {
             else if( match("-") ) lhs = new SubNode(lhs,null);
             else break;
             lhs.setDef(2,parseMultiplication());
-            lhs = peep(lhs.widen());
+            lhs = peep(lhs);
         }
         return lhs;
     }
@@ -1200,7 +1714,7 @@ public class Parser {
             else if( match("/") ) lhs = new DivNode(lhs,null);
             else break;
             lhs.setDef(2,parseUnary());
-            lhs = peep(lhs.widen());
+            lhs = peep(lhs);
         }
         return lhs;
     }
@@ -1217,16 +1731,14 @@ public class Parser {
         // Pre-dec/pre-inc
         int old = pos();
         if( match("--") || match("++") ) {
-            int delta = _lexer.peek(-1)=='+' ? 1 : -1; // Pre vs post
+            int delta = _lexer.peek(-1)=='+' ? 1 : -1; // Inc vs Dec
             String name = _lexer.matchId();
             if( name!=null ) {
                 Var n = _scope.lookup(name);
                 if( n != null && !(n.type() instanceof TypeMemPtr) ) {
                     if( n._final )
                         throw error("Cannot reassign final '"+n._name+"'");
-                    Node expr = n.type() instanceof TypeFloat
-                        ?        peep(new AddFNode(_scope.in(n),con(TypeFloat.constant(delta))))
-                        : zsMask(peep(new  AddNode(_scope.in(n),con(delta))),n.type());
+                    Node expr = zsMask(peep(new AddNode(_scope.in(n),con(delta))),n.type());
                     _scope.update(n,expr);
                     return expr;
                 }
@@ -1234,7 +1746,7 @@ public class Parser {
             // Reset, try again
             pos(old);
         }
-        if (match("-")) return peep(new MinusNode(parseUnary()).widen());
+        if (match("-")) return peep(new MinusNode(parseUnary()));
         if (match("!")) return peep(new   NotNode(parseUnary()));
         // Else be a primary expression
         return parsePrimary();
@@ -1246,7 +1758,7 @@ public class Parser {
      * <pre>
      *     primaryExpr : integerLiteral | "string" | 'char' | true | false | null |
      *                   new Type | '(' expression ')' | Id['++','--'] |
-     *                   [static.]* Id
+     *                   type['.' Id]*
      * </pre>
      * @return a primary {@link Node}, never {@code null}
      */
@@ -1254,95 +1766,113 @@ public class Parser {
         if( _lexer.isNumber(_lexer.peek()) ) return parseLiteral();
         if( _lexer.peek('"') ) return newString(parseString());
         if( matchx("true" ) ) return con(1);
-        if( matchx("false") ) return ZERO;
-        if( matchx("null" ) ) return NIL;
+        if( matchx("false") ) return _code.ZERO;
+        if( matchx("null" ) ) return con(Type.NIL);
         if( match ("'"    ) ) return parseChar();
         if( match ("("    ) ) return parsePostfix(require(parseAsgn(), ")"));
         if( matchx("new"  ) ) return parsePostfix(alloc());
         if( match ("{"    ) ) return parsePostfix(require(func(),"}"));
 
-        // Parse static variable lookup: `type.fld` in the type namespace
-        // CNC: not a full type parse, just a typename parse
         int pos = pos();
-        Type t = type();
-        if( t!=null ) {
-            if( peek('.') )
-                return parsePostfix(con(t));
-            //pos(pos); // TODO: not a `type.fld`
-            //return null;
-            throw Utils.TODO();
-        }
-
         // Expect an identifier now
-
-        // - if null, make fref, normal var handling
-        // - if final constant, normal var handling
-        // - if method var, scan skipping blocks & methods, must hit correct struct no fcns
-        // - if normal var, scan skipping blocks, allowing last fcn
-        // - NO fcns nested in methods, NO methods nested in fcns
-
         String id = _lexer.matchId();
         if( id == null || KEYWORDS.contains(id) )
             throw errorSyntax("an identifier or expression");
+        int pos2 = pos();
+        // Attempt a local var lookup first
         Var var = _scope.lookup(id);
-
         if( var==null ) {
-            // If missing, assume a forward reference
-            _scope.define(id, FRefNode.FREF_TYPE, true, XCTRL, loc());
-            var = _scope.lookup(id);
-        }
+            // Not a local var, try again as a type name
+            pos(pos);
+            Type t = type();
+            if( t!=null ) {
+                // Static <clinit> typename lookup
+                if( peek('.') ) // type.fld, which is really a field lookup in the class object
+                    return parsePostfix(con(t));
+                // Direct reference to a <clinit> type.  Convert the instance
+                // type to a class type name
+                if( !(t instanceof TypeMemPtr tmp) ) {
+                    //return new FRefNode(addClzPrefix(tmp._obj._name), loc()).peephole();
+                    // Not a local var, but yes a bare type... disallow a local
+                    // FREF and return null, not-a-primary parse.
+                    pos(pos);
+                    return null;
+                }
+            }
 
-        // If a method var, allow nested blocks and methods, but not fcns or other structs.
-        // Else safety check for accessing fields out of function scope.
-        if( instance(var) ) {
-            Node self = _scope.in(_scope.lookup("self")); // Insert self reference
-            return parsePostfixName(self,id);
+            // Insert FREF outside enclosing Kind.Func scope.
+            pos(pos2);
+            t = FRefNode.FREF_TYPE;
+            // Check if this is a class.
+            CompUnit cu = ParseAll.findCompUnit(_code,_ref,id);
+            if( cu!=null ) {
+                // Must be a final class-type
+                String clzName = addClzPrefix(cu._cname);
+                TypeStruct clz = (TypeStruct)TYPES.get(clzName);
+                if( clz == null )
+                    TYPES.put(clzName,clz = TypeStruct.make(clzName,true));
+                t = TypeMemPtr.make((byte)2,clz,true);
+            }
+            // Define the FRef
+            var = _scope.defineFRef(id,t,cu!=null,loc());
         }
 
         // Load local value
         Node rvalue = _scope.in(var);
-        if( rvalue._type == Type.BOTTOM )
-            if( rvalue instanceof FRefNode )
-                return parsePostfix(rvalue);
-            else throw error("Cannot read uninitialized field '"+id+"'");
+        if( var._fref )
+            return parsePostfix(rvalue);
+        // Required constructor fields begin as their declared pointer type
+        // widened to include null.  Inside the explicit constructor, any read
+        // before all paths replace that value observes a partially initialized
+        // object.  Ordinary methods run only after construction is complete;
+        // their enclosing declaration scope still carries the same Var marker.
+        if( inExplicitConstructor() && var._uninit && rvalue._type instanceof TypeNil tn && tn.nullable() )
+            throw error("Field '"+id+"' might not be initialized",var._loc);
+
+        // Check for an instance field load
+        int kx = _scope.kindx(var); // Declaration scope
+        int fx = _scope.enclosingFunction(); // Enclosing function scope
+        Kind kk = _scope._kinds.at(kx);
+        Kind fk = _scope._kinds.at(fx);
+        // Access instance field from 'self'
+        if( kx+1 == fx && kk instanceof Kind.Func inst && FunNode.isInstance(inst._name) && fk instanceof Kind.Func method )
+            return parsePostfixName(_scope.in(method._lexSize),id);
+
+        // Check for a function-escaping variable; these require true
+        // closures.  Final constants are OK; final vars require a hidden var
+        // argument; not-final fields can just use an explicit struct arg.
+        if( kx < fx &&          // Out of scope
+            !(var._final && rvalue._type.isConstant()) ) { // Not a final constant
+            if( kx > 0  ) // Global scope is OK, only ever one of these (not one per function invoke)
+                throw error("Variable '"+var._name+"' is out of function scope and must be a final constant");
+
+            // var.idx==2 is self argument, 3 is args, 4 or more are now static globals
+            if( var._idx >= 4 ) {
+                // Read from global scope.
+                // Surely a nicer way to get the top-level scope compile name?
+                Var clzptr = _scope.var( 2 );
+                // Get the most recent sharpen global
+                TypeStruct clz = (TypeStruct) TYPES.get( ((TypeMemPtr) clzptr.type())._obj._name );
+                TypeMemPtr clztmp = TypeMemPtr.make( (byte) 2, clz, true );
+                return parsePostfixName( con( clztmp ), id );
+                //return parsePostfixName(_scope.in(2),id);
+            }
+        }
 
         // Check for assign-update, x += e0;
         char ch = _lexer.matchOperAssign();
-        if( ch==0  )            // Normal primary, check for postfix updates
-            return parsePostfix(rvalue);
+        if( ch==0  ) {          // Normal primary, check for postfix updates
+            int selfx = _scope.kindFcn(var)._lexSize;
+            // Might be a method call from inside a method, so no explicit "self".
+            // Pass the in-scope "self"
+            return parsePostfixMethod(rvalue,_scope.in(selfx));
+        }
         // Assign-update direct into Scope
         Node op = opAssign(ch,rvalue, var.type() );
         _scope.update(var,op);
         return postfix(ch) ? rvalue.unkeep() : op;
     }
 
-    // true if instance variable lookup (var is in any number of nested blocks,
-    // then an instance function then inside a struct declaration).
-    private boolean instance(Var var ) {
-        // If a method var, allow nested blocks and methods, but not fcns or other structs
-        Kind kind = _scope.kind(var);
-        if( kind instanceof Kind.Define ) {
-            for( int i = _scope.depth()-1; i>=0 && var._idx < _scope._kinds.at(i)._lexSize; i-- ) {
-                Kind xkind = _scope._kinds.at(i);
-                if( xkind instanceof Kind.Block ) continue;
-                if( xkind instanceof Kind.Func ) {
-                    if( _scope._kinds.at(i-1)==kind )
-                        return true; // Instance variable: lookup in a method in a decl
-                }
-                throw Utils.TODO();
-            }
-        } else {
-            // If a normal var, allow any nested blocks, and a last fcn -
-            // but not functions further out (which involves capture).
-            Node def = _scope.in(var._idx);
-            for( int i = _scope.depth()-1; i>=0 && var._idx < _scope._kinds.at(i)._lexSize; i-- )
-                if( _scope._kinds.at(i) instanceof Kind.Func &&
-                    !(def instanceof FRefNode) && !(var._final && def._type.isConstant()) )
-                    throw error("Variable '"+var._name+"' is out of function scope and must be a final constant");
-        }
-        return false;
-    }
-
     // Check for assign-update, "x += e0".
     // Returns "x + e0"; the caller assigns value.
     // if ch is postfix, then lhs is kept and caller will unkeep and return it.
@@ -1365,11 +1895,11 @@ public class Parser {
         case '-' -> new SubNode(lhs,rhs);
         case '*' -> new MulNode(lhs,rhs);
         case '/' -> new DivNode(lhs,rhs);
-        default  -> throw Utils.TODO();
+        default  -> throw TODO();
         };
         // Convert to float ops, or narrow int types; error if not declared type.
         // Also, if postfix LHS is still keep()
-        return liftExpr(peep(op.widen()),t,false,true);
+        return convertExpr(peep(op),t.glb(false));
     }
 
 
@@ -1378,124 +1908,163 @@ public class Parser {
      */
     private Node alloc() {
         Type t = type();
-        if( t==null ) throw error("Expected a type");
+        if( t==null ) {
+            String tname = _lexer.matchId();
+            if( tname==null || KEYWORDS.contains(tname) )
+                throw error("Expected a type");
+            t = forwardRefType(tname);
+        }
         // Parse ary[ length_expr ]
         if( match("[") ) {
             if( !t.makeZero().isa(t) )
-                throw error("Cannot allocate a non-nullable, since arrays always zero/null fill");
-            Node len = parseAsgn();
-            if( !(len._type instanceof TypeInteger) )
-                throw error("Cannot allocate an array with length "+len._type);
+                throw error("Cannot allocate a non-nullable, since arrays are always zero/null filled");
+            Node len = parseAsgn().keep();
             require("]");
-            TypeMemPtr tmp = typeAry(t,false);
-            return newArray(tmp._obj,len);
-        }
-
-        if( !(t instanceof TypeMemPtr tmp) )
-            throw error("Cannot allocate a "+t.str());
-
-        // Parse new struct { default_initialization }
-        StructNode s = INITS.get(tmp._obj._name);
-        if( s==null ) throw error("Unknown struct type '" + tmp._obj._name + "'");
-
-        Field[] fs = s._ts._fields;
-        // if the object is fully initialized, we can skip a block here.
-        // Check for constructor block:
-        boolean hasConstructor = match("{");
-        Ary<Node> init=s._inputs;  int idx=0;
-        if( hasConstructor ) {
-            idx = _scope.nIns();
-            // Push a scope, and pre-assign all struct fields.
-            _scope.push(new Kind.Block());
-            Lexer loc = loc();
-            for( int i=0; i<fs.length; i++ )
-                // An initial TOP means the field needs to be initialized.  We
-                // store a BOT initially; any partial init will fall to BOT
-                // (merge BOT and the partial) and be obviously only a partial
-                // init.  To be initialized the field needs a full clobber.
-                _scope.define(fs[i]._fname, fs[i]._t, fs[i]._final, s.in(i)._type==Type.TOP ? con(Type.BOTTOM) : s.in(i), loc);
-            // Parse the constructor body
-            require(parseBlock(new Kind.Alloc(tmp)),"}");
-            init = _scope._inputs;
-        }
-        // Check that all fields are initialized
-        for( int i=idx; i<init.size(); i++ )
-            if( init.at(i)._type == Type.TOP || init.at(i)._type == Type.BOTTOM )
-                throw error("'"+tmp._obj._name+"' is not fully initialized, field '" + fs[i-idx]._fname + "' needs to be set in a constructor");
-        Node ptr = newStruct(tmp._obj, off(tmp._obj, " len"), idx, init );
-        if( hasConstructor )
-            _scope.pop();
-        return ptr;
+            return allocArray(typeAry(t,false),len);
+        } else {
+            if( !(t instanceof TypeMemPtr tmp) )
+                throw error("Cannot allocate a "+t.str());
+            return allocStruct(tmp._obj);
+        }
     }
 
+    private Node allocStruct(TypeStruct ts) {
+        Ary<Node> ctorArgs = constructorArgs(); // CNC TODO- BAD THREADING SELF-MEM
+        Node size = off(ts, " len");
+
+        // Build a NewNode; takes in ctrl and size.
+        // Produces a ptr and a private mem.
+        NewNode nnn = new NewNode(ts, ctrl(), size ).init();
+        ProjNode self = new ProjNode(nnn,0,ts.str()).init().keep();
+        ProjNode smem = new ProjNode(nnn,1,"#selfMem").init();
+
+        // Find a "class:XXX" struct, with field "XXX" function ptr as the <init>
+        TypeStruct clz = (TypeStruct)TYPES.get(addClzPrefix(ts._name));
+        if( clz==null )
+            throw error("Unknown struct type '" + ts._name + "'");
+        TypeFunPtr init = (TypeFunPtr)clz.field(initFieldName(ts._name))._t;
+
+        // Call construct <init>($ctrl,$mem,NewNode.self,NewNode.#selfMem) and
+        // encourage inlining
+        Node initSelf = self._type.isa(init.arg(0)) ? self : peep(new CheckCastNode(init.arg(0),ctrl(),self));
+        Ary<Node> args = new Ary<>(Node.class){{add(ctrl()); add(mem()); add(initSelf); add(smem); add(ConstantNode.seed(init)); }};
+        Node selfMem = functionCall( args );
+        // The returned value is a merge of private *Memory* and NOT some Scalar
+
+        // Optional user constructor; same as the default constructor; private
+        // memory going in and out.
+        Field ctor = clz.field("<ctor>");
+        if( ctor != null )
+            selfMem = constructorCall((TypeFunPtr)ctor._t,self,selfMem,ctorArgs);
+        else if( !ctorArgs.isEmpty() )
+            throw error("Constructor arguments for '" + ts._name + "' but no constructor is defined");
+        if( match("{") )
+            throw error("Inline constructor blocks are no longer supported; define a constructor in '" + ts._name + "'");
+
+        // Might be TOP if parsing in dead/unreachable code
+        if( selfMem._type == Type.TOP ) {
+            _code.add(selfMem);
+            return self.unkeep();
+        }
+
+        // Escape all new aliases.  EscapeNode inputs are the self pointer, the
+        // merged private memory, then all the named public aliases.  The
+        // output is all the newly merged public aliases - but not actually
+        // bulk memory.
+        selfMem.keep();
+        for( Field fld : ts._fields ) {
+            Field fld2 = fld._final ? fld : (Field)fld.glb(true);
+            Node prior = mem();
+            Node esc = peep(new EscapeNode(fld2,self,selfMem,prior));
+            mem(mergeAlias(prior,fld._alias,esc));
+        }
+
+        if( selfMem.unkeep().isUnused() ) selfMem.kill();
+        else _code.add(selfMem);
+        return self.unkeep();
+    }
 
-    /**
-     * Return a NewNode initialized memory.
-     * @param obj is the declared type, with GLB fields
-     * @param init is a collection of initialized fields
-     */
-    private Node newStruct( TypeStruct obj, Node size, int idx, Ary<Node> init ) {
-        Field[] fs = obj._fields;
-        if( fs==null )
-            throw error("Unknown struct type '" + obj._name + "'");
-        int len = fs.length;
-        Node[] ns = new Node[2+len];
-        ns[0] = ctrl();         // Control in slot 0
-        // Total allocated length in bytes
-        ns[1] = size;
-        // Memory aliases for every field
-        for( int i = 0; i < len; i++ )
-            if( !fs[i]._one )
-                ns[2+i] = memAlias(fs[i]._alias);
-        Node nnn = new NewNode(TypeMemPtr.make(obj), ns).peephole().keep();
-        for( int i = 0; i < len; i++ )
-            if( !fs[i]._one )
-                memAlias(fs[i]._alias, new ProjNode(nnn,i+2,memName(fs[i]._alias)).peephole());
-        Node ptr = new ProjNode(nnn.unkeep(),1,obj._name).peephole().keep();
-
-        // Initial nonzero values for every field
-        for( int i = 0; i < len; i++ ) {
-            Node val = init.get( i + idx );
-            if( !fs[i]._one && val._type != val._type.makeZero() ) {
-                Node mem = memAlias(fs[i]._alias);
-                Node st = new StoreNode(loc(),fs[i]._fname,fs[i]._alias,fs[i]._t,mem,ptr,off(obj,fs[i]._fname),val,true).peephole();
-                memAlias(fs[i]._alias,st);
-            }
+    private Ary<Node> constructorArgs() {
+        Ary<Node> args = new Ary<>(Node.class);
+        if( !match("(") )
+            return args;
+        while( !peek(')') ) {
+            Node arg = parseAsgn();
+            if( arg==null ) break;
+            args.push(arg.keep());
+            if( !match(",") ) break;
         }
+        require(")");
+        return args;
+    }
+
+    // Constructors are called with two extra arguments: self and selfMem.
+    private Node constructorCall(TypeFunPtr ctor, Node self, Node selfMem, Ary<Node> ctorArgs) {
+        Ary<Node> args = new Ary<>(Node.class);
+        Node ctorSelf = self._type.isa(ctor.arg(0))
+            ? self
+            : peep(new CheckCastNode(ctor.arg(0),ctrl(),self));
+        args.add(ctrl());
+        args.add(mem());
+        args.add(ctorSelf);
+        args.add(selfMem);
+        for( Node arg : ctorArgs )
+            args.add(arg.unkeep());
+        args.add(ConstantNode.seed(ctor));
 
-        return ptr.unkeep();
+        CallNode call = (CallNode)new CallNode(loc(), args.asAry()).peephole();
+        CallEndNode cend = (CallEndNode)new CallEndNode(call,TypeRPC.constant(_code.rpc(_ref._cname))).peephole();
+        call.peephole();
+        cend = (CallEndNode)cend.keep().peephole();
+        ctrl(new CProjNode(cend,0,ScopeNode.CTRL).peephole());
+        mem (new  ProjNode(cend,1,ScopeNode.MEM0).peephole());
+        return new ProjNode(cend.unkeep(),2,"#selfMem").peephole();
     }
 
-    private static final Ary<Node> ALTMP = new Ary<>(Node.class);
-    private Node newArray(TypeStruct ary, Node len) {
-        ConFldOffNode base = off(ary, "[]");
-        int scale= ary.aryScale();
-        Node size = peep(new AddNode(base,peep(new ShlNode(null,len.keep(),con(scale)))));
-        ALTMP.clear();  ALTMP.add(len.unkeep()); ALTMP.add(con(ary._fields[1]._t.makeZero()));
-        return newStruct(ary,size,0,ALTMP);
+    private Node allocArray(TypeStruct ts, Node len) {
+        Field  lenFld = ts.field("#" );
+        Field bodyFld = ts.field("[]");
+
+        ConFldOffNode base = off(ts, "[]");
+        int scale = ts.aryScale();
+        Node size = peep(new AddNode(base,peep(new ShlNode(null,len,con(scale)))));
+
+        // Build a NewNode; takes in and puts out all aliases.
+        NewNode nnn = new NewNode(ts, ctrl(), size ).init();
+        ProjNode self = new ProjNode(nnn,0,ts.str()).init().keep();
+        ProjNode smem = new ProjNode(nnn,1,"#selfMem").init().keep();
+
+        // Store length.  Rest of array is zero'd via CALLOC during CodeGen.
+        // Length is casted to sanity.
+        // TODO: Needs runtime check.
+        Node st = peep(new StoreNode(null, "#", 1, TypeInteger.U32, null, smem, self, off(ts,"#"), len.unkeep(), true));
+
+        // TODO: Allow add-on "constructor" to init the array elements
+
+        Node prior = mem();
+        Node esc = peep(new EscapeNode(lenFld,self,st,prior));
+        mem(mergeAlias(prior,lenFld._alias,esc));
+        prior = mem();
+        esc = peep(new EscapeNode(bodyFld,self,smem,prior));
+        mem(mergeAlias(prior,bodyFld._alias,esc));
+        smem.unkeep();
+        return self.unkeep();
     }
+
     private Node newString(String s) {
-        TypeMemPtr tmp = typeAry(TypeInteger.U8,true);
-        int  lenAlias = tmp._obj.field("#" )._alias;
-        int elemAlias = tmp._obj.field("[]")._alias;
-        TypeConAryB con = TypeConAryB.make(s);
-        Type elem = con.elem();
+        TypeStruct ts = typeAry(TypeInteger.U8,true);
+        int  lenAlias = ts.field("#" )._alias;
+        int elemAlias = ts.field("[]")._alias;
+        TypeConAryB body = TypeConAryB.make(s);
+        TypeInteger slen = TypeInteger.constant(s.length());
         // Make a TMP, not-null (byte)2, singleton (true) (requires text
         // strings are hash-interned), with a TypeStruct having a constant
         // array body.
-        TypeMemPtr str = TypeMemPtr.make((byte)2,TypeStruct.makeAry("[]u8", TypeInteger.constant(s.length()), lenAlias, con, elemAlias, true),true);
+        TypeMemPtr str = TypeMemPtr.make((byte)2,TypeStruct.makeAry("[]u8", slen, lenAlias, body, elemAlias, true),true);
         assert str.isConstant();
         return con(str);
     }
 
-    // We set up memory aliases by inserting special vars in the scope these
-    // variables are prefixed by $ so they cannot be referenced in Simple code.
-    // Using vars has the benefit that all the existing machinery of scoping
-    // and phis work as expected
-    private Node memAlias(int alias         ) { return _scope.mem(alias    ); }
-    private void memAlias(int alias, Node st) {        _scope.mem(alias, st); }
-    public static String memName(int alias) { return ("$"+alias).intern(); }
-
     /**
      * Parse postfix expression; this can be a field expression, an array
      * lookup or a postfix operator like '#'
@@ -1508,17 +2077,34 @@ public class Parser {
      *     expr '(' [args,]* ')'              // Function call
      * </pre>
      */
+    private Node parsePostfixMethod(Node expr, Node self) {
+        // TODO: This is too broad because the parser lacks strong types here.
+        // Some normal functions can end up with a "self" argument.
+
+        // Self method call?  Self is a TMP-not-CLZ, then assume and pass self.
+        if( match("(") ) {
+            expr = parsePostfix(require(functionCall(expr,self),")"));
+        } else
+            self.isKill();      // Not a method call, no need for self
+        return parsePostfix(expr);
+    }
     private Node parsePostfix(Node expr) {
         String name;
         if( match(".") )      name = requireId();
         else if( match("#") ) name = "#";
         else if( match("[") ) name = "[]";
-        else if( match("(") ) return parsePostfix(require(functionCall(expr,null),")"));
+        // Can get here without an explicit receiver: "f()" or
+        // "self.method()(next)(next)(next)".  Pass the current function self.
+        else if( match("(") ) return parsePostfix(require(functionCall(expr,defaultSelf()),")"));
         else return expr;       // No postfix
 
         return parsePostfixName(expr,name);
     }
 
+    private Node defaultSelf() {
+        return _scope.in(_scope._kinds.at(_scope.enclosingFuncOrDecl())._lexSize);
+    }
+
     /**
      * Parse postfix expression; this can be a field expression, an array
      * lookup or a postfix operator like '#'
@@ -1529,97 +2115,96 @@ public class Parser {
      *     expr ('[' expr ']')* [ [op]= expr ] // Array reference
      * </pre>
      */
+
     private Node parsePostfixName(Node expr, String name) {
+        // Keep expr across possible updates
+        expr.keep();
 
-        if( expr._type==Type.NIL )
-            throw error("Accessing unknown field '" + name + "' from 'null'");
-
-        // Sanity check expr for being a reference
-        if( !(expr._type instanceof TypeMemPtr ptr) )
-            throw error( "Expected "+(name=="#" || name=="[]" ? "array" : "reference")+" but found " + expr._type.str() );
-
-        // Find the field from the Type.  Lookup in the base object field names.
-        TypeMemPtr ptr2 = (TypeMemPtr)TYPES.get(ptr._obj._name);
-        ptr = (TypeMemPtr)ptr.join(ptr2);// Upgrade to latest TYPES
-        TypeStruct base = ptr._obj;
-        int fidx = base.find(name);
-        if( fidx == -1 )
-            throw error("Accessing unknown field '" + name + "' from '" + ptr.str() + "'");
-
-        // Get field type and layout offset from base type and field index fidx
-        Field f = base._fields[fidx];  // Field from field index
-        Type tf = f._t;
-        if( tf instanceof TypeMemPtr ftmp && ftmp.isFRef() )
-            tf = ftmp.makeFrom(((TypeMemPtr)(TYPES.get(ftmp._obj._name)))._obj);
-        if( base.isAry() && tf instanceof TypeConAry con )
-            tf = con.elem();
+        // Get the best known TypeStruct from a pointer type.
+        TypeStruct ts = null, ts2;
+        if( expr._type instanceof TypeMemPtr tmp && (ts2=((TypeStruct)TYPES.get(tmp._obj._name))) != null )
+            ts = (TypeStruct)tmp._obj.join(ts2);
+        // A Load's flow type is intentionally not promised during parsing,
+        // but its declaring field type is still known.  Recover that static
+        // type for chained accesses such as `_grow(1).buf[len++]`; otherwise
+        // the array Store is parsed as alias #1 and can hide the independent
+        // side effect of the postfix `len++`.
+        if( ts==null && expr instanceof LoadNode load ) {
+            TypeStruct ots = load.off() instanceof ConFldOffNode coff ? coff._ts : null;
+            if( ots==null && load.ptr()._type instanceof TypeMemPtr owner ) {
+                Type owner0 = TYPES.get(owner._obj._name);
+                ots = owner0 instanceof TypeStruct obj ? obj : owner._obj;
+            }
+            if( ots != null ) {
+                Field loaded = ots.field(load._name);
+                if( loaded != null && loaded._t instanceof TypeMemPtr ltmp ) {
+                    Type loaded0 = TYPES.get(ltmp._obj._name);
+                    ts = loaded0 instanceof TypeStruct obj ? obj : ltmp._obj;
+                }
+            }
+        }
+
+        Field fld = ts==null ? null : ts.field(name);
+        if( fld==null && ts!=null )
+            fld = fieldOrOpen(ts,name,false);
+        // With no field, we will update the bulk memory
+        int alias = fld==null ?  1          : fld._alias;
+        Type decl = fld==null ? Type.BOTTOM : fld._t;
 
         // Field offset; fixed for structs, computed for arrays
-        Node off = (name.equals("[]")       // If field is an array body
-            // Array index math
-            ? peep(new AddNode(off(base,"[]"),peep(new ShlNode(null,require(parseAsgn(),"]"),con(base.aryScale())))))
-            // Struct field offsets are hardwired
-            : off(base,name)).keep();
+        Node off = (name=="[]"
+            // Array element math, with unknown base offset and shift amount.
+            ? peep(new AddNode(fldoff(expr,"[]"),peep(new ShlNode(null,require(parseAsgn(),"]"),fldoff(expr,"<<")))))
+            // Named field offset on an unknown struct type
+            : fldoff(expr,name)).keep();
 
         // Disambiguate "obj.fld==x" boolean test from "obj.fld=x" field assignment
         if( matchOpx('=','=') ) {
+            // Field assignment
             Node val = parseAsgn().keep();
-            Node lift = liftExpr( val, tf, f._final, false );
-
-            Node st = new StoreNode(loc(), name, f._alias, tf, memAlias(f._alias), expr, off.unkeep(), lift, false);
-            // Arrays include control, as a proxy for a safety range check.
-            // Structs don't need this; they only need a NPE check which is
-            // done via the type system.
-            if( base.isAry() )  st.setDef(0,ctrl());
-            memAlias(f._alias, st.peephole());
+            // Lift value for store
+            Node lift = fld==null ? val : new ConvertNode(fld._t,val).peephole();
+            // Memory for store, post assignment expression
+            Node mem = mem();
+            // Store to field
+            mem.keep();
+            Node st = new StoreNode(loc(), name, alias, decl, ctrl(), mem, expr.unkeep(), off.unkeep(), lift, false).peephole().keep();
+            storeMem(st,alias,mem);
+            st.unkeep();
+            mem.unkeep();
+
             return val.unkeep();        // "obj.a = expr" returns the expression while updating memory
         }
 
-        // Keep expr for possible store update
-        expr.keep();
+        // Memory for load
+        Node mem = mem();
+        // Loading from a constant array, the declared type is the
+        // meet-over-elements and not the array itself.
+        if( name=="[]" && decl instanceof TypeConAry conary )
+            decl = conary.elem();
+
         // Load field
-        Node load = f._one && INITS.containsKey( base._name )
-            ? INITS.get(base._name).in(base.find(name))
-            : new LoadNode(loc(),name, f._alias, tf, memAlias(f._alias), expr, off);
-        // Arrays include control, as a proxy for a safety range check
-        // Structs don't need this; they only need a NPE check which is
-        // done via the type system.
-        if( base.isAry() && !name.equals("#") ) load.setDef(0,ctrl());
-        load = peep(load);
+        Node load = peep(new LoadNode(loc(),name, alias, ctrl(), mem, expr, off));
 
         // Check for assign-update, "ptr.fld += expr" or "ary[idx]++"
         char ch = _lexer.matchOperAssign();
         if( ch!=0 ) {
-            Node op = opAssign(ch,load, tf );
-            Node st = new StoreNode(loc(), name, f._alias, tf, memAlias(f._alias), expr.unkeep(), off.unkeep(), op, false);
-            // Arrays include control, as a proxy for a safety range check.
-            // Structs don't need this; they only need a NPE check which is
-            // done via the type system.
-            if( base.isAry() )  st.setDef(0,ctrl());
-            memAlias(f._alias, peep(st));
+            if( fld!=null && decl==Type.BOTTOM )
+                throw error( "'" + ts._name + "' is not fully initialized, field '" + fld._fname + "' needs to be set in a constructor" );
+            Node op = opAssign(ch,load, decl );
+            mem.keep();
+            Node st = new StoreNode(loc(), name, alias, decl.glb(true), ctrl(), mem, expr.unkeep(), off.unkeep(), op, false).peephole().keep();
+            storeMem(st,alias,mem);
+            st.unkeep();
+            mem.unkeep();
+
             load = postfix(ch) ? load.unkeep() : op;
             // And use the original loaded value as the result
             return load;
-            //throw Utils.TODO(); // NO POSTFIX AFTER STORE, JUST RETURN
-        } else {
-            off.unkill();
-            // Method call: Loaded a function from a named field, AND the base
-            // field type is final.
-            if( load._type instanceof TypeFunPtr && name!="[]" &&
-                !(load instanceof ExternNode) &&
-                ((TypeMemPtr)TYPES.get(base._name))._obj.field(name)._final &&
-                // And calling a function
-                match("(") ) {
-                return parsePostfix(require(functionCall(load,expr),")"));
-            }
-
-            // Drop expr, keeping load alive
-            load.keep();
-            expr.unkill();
-            load.unkeep();
         }
-
-        return parsePostfix(load);
+        off.unkill();
+        // Might be a method call, so pass expr as 'self'
+        return parsePostfixMethod(load,expr.unkeep());
     }
 
 
@@ -1653,15 +2238,9 @@ public class Parser {
     private Node func() {
         Ary<Type> ts = new Ary<>(Type.class);
         Ary<String> ids = new Ary<>(String.class);
-
-        // Defined in constructor?  Add `self` argument.  "static" calls still
-        // add a `self` they just ignore it.
-        if( _scope._kinds.last() instanceof Kind.Define define ) {
-            // Upgrade defined struct to latest fields
-            TypeMemPtr tmp = (TypeMemPtr)TYPES.get(define._tmp._obj._name);
-            ts .push(tmp);
-            ids.push("self");
-        }
+        Type self = implicitSelfType();
+        ts.push(self);
+        ids.push(self == TypePtr.PTR ? "#self" : "self");
 
         // Parse other arguments
         _lexer.skipWhiteSpace();
@@ -1676,9 +2255,42 @@ public class Parser {
         }
         require("->");
         // Make a concrete function type, with a fidx
-        TypeFunPtr tfp = _code.makeFun(TypeFunPtr.make(false,false,ts.asAry(),Type.BOTTOM));
+        TypeFunPtr tfp = TypeFunPtr.make1((byte)2,true,ts.asAry(),Type.BOTTOM,_code.fidx(_ref._cname));
         ReturnNode ret = parseFunctionBody(tfp,loc,ids.asAry());
-        return con(ret._fun.sig());
+        return new FunPtrNode(tfp,_code._start,ret).peephole();
+    }
+
+    private Node constructorFunc(String name) {
+        require("{");
+        Ary<Type> ts = new Ary<>(Type.class);
+        Ary<String> ids = new Ary<>(String.class);
+        TypeStruct self = _scope.constructorSelf();
+        assert self != null;
+        ts.push(TypeMemPtr.make(constructorRecv(self)));
+        ids.push("self");
+        // Explicit constructors use the same hidden allocation arguments as
+        // <init>: public memory is the call memory edge (index 1), followed by
+        // self (index 2) and the private, unescaped object memory (index 3).
+        ts.push(TypeMem.makePrivate(self));
+        ids.push("#selfMem");
+
+        _lexer.skipWhiteSpace();
+        Lexer loc = loc();
+        while( true ) {
+            Type t = type();
+            if( t==null ) break;
+            String id = requireId();
+            ts .push(t );
+            ids.push(id);
+            match(",");
+        }
+        require("->");
+        TypeFunPtr tfp = TypeFunPtr.make1((byte)2,true,ts.asAry(),TypeMem.makePrivate(self),_code.fidx(_ref._cname));
+        Node[] preParse = _scope.save();
+        ReturnNode ret = _parseFunctionBody((self._name+"."+name).intern(),tfp,loc,ids.asAry());
+        _scope.restore(preParse);
+        require("}");
+        return new FunPtrNode(tfp,_code._start,ret).peephole();
     }
 
     /**
@@ -1690,15 +2302,13 @@ public class Parser {
     private Node functionCall(Node fcn, Node self) {
         if( fcn._type == Type.NIL )
             throw error("Calling a null function pointer");
-        if( !(fcn instanceof FRefNode) && !fcn._type.isa(TypeFunPtr.BOT) )
-            throw error("Expected a function but got "+fcn._type.glb(false).str());
         fcn.keep();            // Keep while parsing args
 
         Ary<Node> args = new Ary<>( Node.class );
         args.push(null);        // Space for ctrl,mem
         args.push(null);
         if( self != null )      // Method call has a self
-            args.push(self);
+            args.push(self.keep());
         while( !peek(')') ) {
             Node arg = parseAsgn();
             if( arg==null ) break;
@@ -1707,11 +2317,15 @@ public class Parser {
         }
         // Control & memory after parsing args
         args.set(0,ctrl().keep());
-        args.set(1,_scope.mem().merge().keep());
+        args.set(1,mem().keep());
         args.push(fcn);        // Function pointer
         // Unkeep them all
         for( Node arg : args )
             arg.unkeep();
+        return functionCall(args);
+    }
+
+    private Node functionCall( Ary<Node> args ) {
         // Dead into the call?  Skip all the node gen
         if( ctrl()._type == Type.XCONTROL ) {
             for( Node arg : args )
@@ -1723,17 +2337,16 @@ public class Parser {
         // Into the call
         CallNode call = (CallNode)new CallNode(loc(), args.asAry()).peephole();
         // Post-call setup
-        CallEndNode cend = (CallEndNode)new CallEndNode(call).peephole();
+        CallEndNode cend = (CallEndNode)new CallEndNode(call,TypeRPC.constant(_code.rpc(_ref._cname))).peephole();
         call.peephole();        // Rerun peeps after CallEnd, allows early inlining
+        cend = (CallEndNode)cend.keep().peephole(); // TODO: Might inline
         // Control from CallEnd
         ctrl(new CProjNode(cend,0,ScopeNode.CTRL).peephole());
         // Memory from CallEnd
-        MemMergeNode mem = new MemMergeNode(true);
-        mem.addDef(null);       // Alias#0
-        mem.addDef(new ProjNode(cend,1,ScopeNode.MEM0).peephole());
-        _scope.mem(mem);
+        Node mem = new ProjNode(cend,1,ScopeNode.MEM0).peephole();
+        mem(mem);
         // Call result
-        return new ProjNode(cend,2,"#2").peephole();
+        return new ProjNode(cend.unkeep(),2,"#2").peephole();
     }
 
     // Just after parsing "type foo = " can parse `"C"`
@@ -1745,10 +2358,14 @@ public class Parser {
         return false;
     }
     // External linked constant
-    private Node externDecl( String ex, Type t ) {
-        if( t instanceof TypeFunPtr tfp ) // Generic TFP from type parse
-            t  = _code.makeFun(tfp);      // Get a FIDX, becomes a constant
-        return new ExternNode(t,ex).peephole();
+    private ConstantNode externDecl( String ex, Type t ) {
+        if( t instanceof TypeFunPtr tfp ) {  // Generic TFP from type parse
+            int fidx = _code.fidx(_ref._cname); // Get a FIDX
+            tfp = tfp.makeFrom(fidx);           // Become a constant
+            _code.externFunc(fidx,ex);          // Map fidx to extern name
+            t = tfp;
+        }
+        return (ExternNode)(new ExternNode(t,ex).peephole());
     }
 
     /**
@@ -1756,13 +2373,20 @@ public class Parser {
      *
      * <pre>
      *     integerLiteral: [1-9][0-9]* | [0]
-     *     floatLiteral: [digits].[digits]?[e [digits]]?
+     *     floatLiteral: [digits].[digits]?[e [digits]]?[f]?
      * </pre>
      */
     private ConstantNode parseLiteral() { return con(_lexer.parseNumber()); }
-    public static Node con( long con ) { return con==0 ? ZERO : con(TypeInteger.constant(con));  }
-    public static ConstantNode con( Type t ) { return (ConstantNode)new ConstantNode(t).peephole();  }
-    public static ConFldOffNode off( TypeStruct base, String fname ) { return (ConFldOffNode)(new ConFldOffNode(base._name,fname).peephole()); }
+    ConstantNode con( long con ) { return _code.con(con); }
+    ConstantNode con( Type t   ) { return _code.con(t  ); }
+    // Field offset for a known type (but unknown offset)
+    public static ConFldOffNode off( TypeStruct ts, String fname ) {
+        return (ConFldOffNode)(new ConFldOffNode(ts,fname).peephole());
+    }
+    // Field offset for an unknown type
+    public Node fldoff( Node n, String name ) {
+        return new FldOffNode(n,name,loc()).peephole();
+    }
     public Node peep( Node n ) {
         // Peephole, then improve with lexically scoped guards
         return _scope.upcastGuard(n.peephole());
@@ -1772,11 +2396,27 @@ public class Parser {
     private String parseString() {
         if( !peek('"') ) return null;
         _lexer.inc();
-        int start = pos();
-        while( !_lexer.isEOF() && _lexer.nextChar()!= '"' ) ;
-        if( _lexer.isEOF() )
-            throw error("Unclosed string");
-        return new String(_lexer._input,start,pos()-start-1);
+        StringBuilder sb = new StringBuilder();
+        while( !_lexer.isEOF() ) {
+            char c = _lexer.nextChar();
+            if( c=='"' ) return sb.toString();
+            if( c!='\\' ) {
+                sb.append(c);
+                continue;
+            }
+            if( _lexer.isEOF() )
+                throw error("Unclosed string");
+            char esc = _lexer.nextChar();
+            sb.append(switch( esc ) {
+            case 'n'  -> '\n';
+            case 't'  -> '\t';
+            case 'r'  -> '\r';
+            case '\\' -> '\\';
+            case '"'  -> '"';
+            default -> throw error("Unknown string escape \\\\"+esc);
+            });
+        }
+        throw error("Unclosed string");
     }
 
     // Already parsed "'"
@@ -1784,6 +2424,14 @@ public class Parser {
         return require(con(TypeInteger.constant(_lexer.nextChar())),"'");
     }
 
+    private boolean noLowerCase(String s) {
+        for( int i=0; i<s.length(); i++ )
+            if( Character.isLowerCase(s.charAt(i)) )
+                return false;
+        return true;
+    }
+
+
     //////////////////////////////////
     // Utilities for lexical analysis
 
@@ -1856,6 +2504,11 @@ public class Parser {
         // Start of current line
         private int _line_start = 0;
 
+        /** True when this location precedes {@code that} in the same source. */
+        public boolean before(Lexer that) {
+            return that != null && _input == that._input && _position < that._position;
+        }
+
         /**
          * Record the source text for lexing
          */
@@ -2002,7 +2655,7 @@ public class Parser {
 
         // Used for errors
         String getAnyNextToken() {
-            if (isEOF()) return "";
+            if (isEOF()) return "EOF";
             if (isIdStart(peek())) return parseId();
             if (isNumber(peek())) return parseNumberString();
             if (isPunctuation(peek())) return parsePunctuation();
@@ -2016,17 +2669,26 @@ public class Parser {
         private Type parseNumber() {
             int old = _position;
             int len = isLongOrDouble();
+            boolean f32 = peek()=='f';
+            if( f32 ) nextChar();
+            int n = Math.abs(len);
+            if( f32 )
+                return TypeFloat.constant(Float.parseFloat(new String(_input,old,n)));
             if( len > 0 ) {
                 if( len > 1 && _input[old]=='0' )
                     throw error("Syntax error: integer values cannot start with '0'",this);
                 long i = Long.parseLong(new String(_input,old,len));
                 return TypeInteger.constant(i);
             }
-            return TypeFloat.constant(Double.parseDouble(new String(_input,old,-len)));
+            return TypeFloat.constant(Double.parseDouble(new String(_input,old,n)));
         }
         private String parseNumberString() {
             int old = _position;
             int len = Math.abs(isLongOrDouble());
+            if( peek()=='f' ) {
+                nextChar();
+                len++;
+            }
             return new String(_input,old,len);
         }
 
@@ -2056,7 +2718,7 @@ public class Parser {
         private String parseId() {
             int start = _position;
             while (isIdLetter(nextChar())) ;
-            return new String(_input, start, --_position - start);
+            return new String(_input, start, --_position - start).intern();
         }
 
         //
@@ -2085,9 +2747,9 @@ public class Parser {
         }
     }
 
-    ParseException errorSyntax(String syntax) { return _errorSyntax("expected "+syntax);  }
+    ParseException errorSyntax(String syntax) { return _errorSyntax("expected `"+syntax+"`");  }
     private ParseException _errorSyntax(String msg) {
-        return error("Syntax error, "+msg+": " + _lexer.getAnyNextToken());
+        return error("Syntax error, "+msg+" but found `" + _lexer.getAnyNextToken()+"`");
     }
     ParseException error(String msg) { return error(msg,_lexer); }
     public static ParseException error(String msg, Lexer loc) { return new ParseException(msg,loc); }
diff --git a/src/main/java/com/seaofnodes/simple/Var.java b/src/main/java/com/seaofnodes/simple/Var.java
index cf549cd6..1906ce15 100644
--- a/src/main/java/com/seaofnodes/simple/Var.java
+++ b/src/main/java/com/seaofnodes/simple/Var.java
@@ -1,6 +1,7 @@
 package com.seaofnodes.simple;
 
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.Utils;
 
 
 /**
@@ -15,6 +16,9 @@ public class Var {
     private Type _type;          // Declared type
     public boolean _final;       // Final field
     public boolean _fref;        // Forward ref
+    // Parser-only definite-initialization marker.  The current binding's
+    // nullable type carries the path-sensitive state through SSA merges.
+    public boolean _uninit;
     public Parser.Lexer _loc;    // Source location
 
     public Var(int idx, String name, Type type, boolean xfinal, Parser.Lexer loc ) {
@@ -28,12 +32,8 @@ public class Var {
         _fref = fref;
         _loc = loc;
     }
-    public Type type() {
-        if( !_type.isFRef() ) return _type;
-        // Update self to no longer use the forward ref type
-        Type def = Parser.TYPES.get(((TypeMemPtr)_type)._obj._name);
-        return (_type=_type.meet(def));
-    }
+    public Type  type() { return _type; }
+    public Type _type() { return _type; } // ScopeNode printer needs to have no side effects
 
     // Forward reference variables (not types) must be BOTTOM and
     // distinct from inferred variables
@@ -48,6 +48,6 @@ public class Var {
     }
 
     @Override public String toString() {
-        return _type.toString()+(_final ? " ": " !")+_name;
+        return (_fref ? "FREF " : "")+(_uninit ? "UNINIT " : "")+_type.toString()+(_final ? " ": " !")+_name;
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java b/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java
index e9b5eb2e..911e69f6 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java
@@ -14,9 +14,14 @@ abstract public class BuildLRG {
     // since it will not color, just split the conflicted ranges now).  Returns
     // true if no hard-conflicts, although we still might not color.
     public static boolean run(int round, RegAlloc alloc) {
-        for( Node bb : alloc._code._cfg )
+        FunNode fun = null;
+        for( Node bb : alloc._code._cfg ) {
+            if( bb instanceof FunNode fun2 )
+                fun = fun2;
             for( Node n : bb.outs() ) {
                 if( n instanceof PhiNode phi && !(phi._type instanceof TypeMem) ) {
+                    if( phi instanceof MachNode mach && mach.outregmap()==null )
+                        continue;
                     // All Phi inputs end up with the same LRG.
                     // Pass 1: find any pre-existing LRG, to avoid make-then-Union a LRG
                     LRG lrg = alloc.lrg(phi);
@@ -25,8 +30,8 @@ abstract public class BuildLRG {
                             if( (lrg = alloc.lrg(phi.in(i))) != null )
                                 break;
                     // If none, make one.
-                    if( lrg==null ) lrg = alloc.newLRG(n);
-                    if( phi instanceof MachNode ) defLRG(alloc,n);
+                    if( lrg==null ) lrg = alloc.newLRG(n,fun);
+                    if( phi instanceof MachNode ) defLRG(alloc,n,fun);
                     // Pass 2: everybody uses the same LRG
                     lrg=alloc.union(lrg,phi);
                     for( int i=phi instanceof ParmNode ? 2 : 1; i<n.nIns(); i++ )
@@ -40,13 +45,13 @@ abstract public class BuildLRG {
                         int uidx = n.out(0)._inputs.find(n);
                         RegMask mask1 = n.in (1) instanceof MachNode machx ? machx.outregmap() : alloc.lrg(n.in(1))._mask;
                         RegMask mask2 = n.in (2) instanceof MachNode machx ? machx.outregmap() : alloc.lrg(n.in(2))._mask;
-                        RegMask masko = n.out(0) instanceof MachNode machx ? machx.regmap(uidx): alloc.lrg(n      )._mask;
+                        RegMask masko = n.out(0) instanceof MachNode machx ? machx.regmap(uidx): mach.outregmap();
                         if( !mask1.overlap(masko) && mask2.overlap(masko) )
                             n.swap12();
                     }
 
                     // Define live range
-                    defLRG(alloc,n);
+                    defLRG(alloc,n,fun);
 
                     // Now, look in the opposite direction. How are incoming
                     // LRGs affected by this node: For all uses, make live lrgs
@@ -66,8 +71,9 @@ abstract public class BuildLRG {
                 if( n instanceof MultiNode && !(n instanceof CFGNode) )
                     for( Node proj : n.outs() )
                         if( proj instanceof MachNode )
-                            defLRG(alloc,proj);
+                            defLRG(alloc,proj,fun);
             }
+        }
 
         // Collect live ranges
         alloc.unify();
@@ -75,12 +81,12 @@ abstract public class BuildLRG {
         return alloc.success();
     }
 
-    private static void defLRG( RegAlloc alloc, Node n ) {
+    private static void defLRG( RegAlloc alloc, Node n, FunNode fun ) {
         MachNode mach = (MachNode)n;
         RegMask def_mask = mach.outregmap();
         if( def_mask == null ) return;
         LRG lrg = mach.twoAddress() == 0
-            ? alloc.newLRG(n)                  // Define a new LRG for N
+            ? alloc.newLRG(n,fun)              // Define a new LRG for N
             : alloc.lrg2(n,mach.twoAddress()); // Use the matching 2-adr input
         // Record mask and mach
         if( !lrg.machDef(mach,def_mask.size1()).and(def_mask) )
diff --git a/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java b/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
index 3715d015..85d8143b 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
@@ -5,78 +5,276 @@ import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.print.*;
 import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.*;
+import java.io.File;
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.*;
 
+
+// Compile Driver for a Compilation Unit
 @SuppressWarnings("unchecked")
 public class CodeGen {
-    public static final String PORTS = "com.seaofnodes.simple.node.cpus";
-    // Last created CodeGen as a global; used all over to avoid passing about a
-    // "context".
+
+    // Last created CodeGen as a global; used all over to avoid passing about a "context".
     public static CodeGen CODE;
 
+    // Location of built-in CPU ports
+    public static final String PORTS = "com.seaofnodes.simple.node.cpus";
+
+    // Compile phases
     public enum Phase {
         Parse,                  // Parse ASCII text into Sea-of-Nodes IR
+        Iter,                   // Pessimistic peepholes after parse
         Opto,                   // Run ideal optimizations
         TypeCheck,              // Last check for bad programs
         LoopTree,               // Build a loop tree; break infinite loops
+        Serialize,              // Serialize public IR for future compiles to link
+        Unlink,                 // Unlink call sites before machine code generation
         Select,                 // Convert to target hardware nodes
         Schedule,               // Global schedule (code motion) nodes
         LocalSched,             // Local schedule
         RegAlloc,               // Register allocation
         Encoding,               // Encoding
         Export,                 // Export
+        LastPhase               // After last phase
     }
     public Phase _phase;
+
+    /** True when tests deliberately randomize Iter worklist order. */
+    public static boolean iterSeedOverridden() { return System.getProperty("simple.iter.seed") != null; }
+
+    // ---------------------------
+    // Module Source Root
+    public final String _modDir;
+    // Module Build Root
+    public final String _buildDir;
+    // Search path from CWD for `.o` files containing external symbols and types.
+    // This can contain archives, zips and other .o file containers.
+    public final Ary<String> _externPaths;
+
+    // Dotted path from module root to file containing the source, sans ".smp".
+    // e.g. module root: "sys", nested source name "sys.io".
+    public final String _srcName;
+
+    // Only available for tests, otherwise source comes from the CompUnit
+    private final String _src;
+
+    // Current Working Directory; default module base
+    private final String _cwd;
+
+    // Compilation Units in this compile; one per source/object file
+    public HashMap<String,CompUnit> _compunits;
+    // Test shortcut for only one compilation unit
+    public CompUnit compunit() {
+        assert _compunits.size()==1;
+        for( CompUnit cu : _compunits.values() )
+            return cu;
+        throw Utils.TODO();
+    }
+
+    // True when fidx is published through a public field of a public class.
+    // TypeStruct.fidxs() already excludes private (underscore) fields.
+    public boolean publicFIDX(int fidx) {
+        // A public class initializer is itself an external root; unlike
+        // constructors and methods, it is not reached through a class field.
+        FunNode fun = _linker.atX(fidx);
+        if( fun != null && fun.isClz() && fun.isPublic() )
+            return true;
+        // Constructors and methods live on their class objects, including
+        // nested classes which do not have their own CompUnit.
+        for( Type t : Parser.TYPES.values() )
+            if( t instanceof TypeStruct clz &&
+                Parser.startsClzPrefix(clz._name) &&
+                Parser.isPublicClassName(clz._name) &&
+                resolvedClass(clz) &&
+                publicClassFIDX(clz,fidx) )
+                return true;
+        return false;
+    }
+
+    private static boolean publicClassFIDX(TypeStruct clz, int fidx) {
+        boolean hasCtor = clz.field("<ctor>") != null;
+        for( Field fld : clz._fields )
+            if( fld._fname.charAt(0)!='_' && fld._t instanceof TypeFunPtr tfp &&
+                // With a user constructor, class:N.N is the private <init>.
+                !(hasCtor && clz.hiddenInit(fld)) &&
+                XInt.bit(tfp._fidxs,fidx) )
+                return true;
+        return false;
+    }
+
+    public static boolean hasUserConstructor(TypeStruct self) {
+        Type t = Parser.TYPES.get(Parser.addClzPrefix(self._name));
+        return t instanceof TypeStruct clz && clz.field("<ctor>") != null;
+    }
+
+    // A forward reference gets a class object and constructor signature so
+    // parsing can proceed, but it has no callable definition yet.
+    private static boolean resolvedClass(TypeStruct clz) {
+        Type t = Parser.TYPES.get(clz._name.substring(Parser.CLZ.length()));
+        return !(t instanceof TypeStruct ts) || !ts._fref;
+    }
+
+    private int[] _publicFIDXs, _publicAliases;
+
+    /**
+     * Freeze the externally visible portion of the program after ParseAll has
+     * loaded every compilation unit and closed/upgraded all types.  Later
+     * optimization can remove linker entries and create inline-only fidxs;
+     * neither operation changes this interface.
+     */
+    void freezePublicInterface() {
+        assert _publicFIDXs==null && _publicAliases==null;
+        int[] fidxs = XInt.EMPTY;
+        for( int fidx=1; fidx<_linker._len; fidx++ )
+            if( publicFIDX(fidx) )
+                fidxs = XInt.make(fidxs,fidx);
+        int[] aliases = XInt.EMPTY;
+        for( Type t : Parser.TYPES.values() )
+            if( t instanceof TypeStruct clz &&
+                Parser.startsClzPrefix(clz._name) &&
+                Parser.isPublicClassName(clz._name) &&
+                resolvedClass(clz) ) {
+                boolean hasCtor = clz.field("<ctor>") != null;
+                for( Field fld : clz._fields )
+                    if( fld._fname.charAt(0)!='_' && fld._t!=Type.TOP &&
+                        !(hasCtor && clz.hiddenInit(fld)) )
+                        aliases = XInt.make(aliases,fld._alias);
+            }
+        _publicFIDXs = fidxs;
+        _publicAliases = aliases;
+    }
+
+    public int[] publicFIDXs()  { assert _publicFIDXs !=null; return _publicFIDXs;  }
+    public int[] publicAliases(){ assert _publicAliases!=null; return _publicAliases; }
+    public boolean publicInterfaceFrozen() { return _publicFIDXs != null; }
+
     // ---------------------------
-    // Compilation source code
-    public final String _src;
-    // Compile-time known initial argument type
-    public final TypeInteger _arg;
+
+    // Very common nodes, cached here
+    public final ConstantNode ZERO;
+    public final XCtrlNode XCTRL;
+
+    public Node constant( Type t ) {
+        assert _phase==null || _phase.ordinal() <= Phase.Opto.ordinal();
+        return ConstantNode.make(t).peephole();
+    }
+    public ConstantNode con( Type t ) { return (ConstantNode)constant(t); }
+    public ConstantNode con( long con ) { return con==0 ? ZERO : con(TypeInteger.constant(con));  }
+
 
     // ---------------------------
-    public CodeGen( String src ) { this(src, TypeInteger.BOT, 123L, true ); }
-    public CodeGen( String src, TypeInteger arg) { this(src, arg==null ? TypeInteger.BOT : arg, 123L, true ); }
+    // Test setup; no module nor file with specific argument
+    public CodeGen( String src ) { this(src, 126L ); }
+
+    // Test setup; no module nor file; can alter seed & argument; can re-run same CodeGen
+    public CodeGen( String src, Type arg ) {
+        this(null,null,null,null, src, 126L, arg);
+    }
+    // Test setup; no module nor file; can alter seed & argument; can re-run same CodeGen
+    public CodeGen( String src, long workListSeed ) {
+        this(null,null,null,null, src, workListSeed, TypeInteger.BOT);
+    }
 
-    public CodeGen( String src, TypeInteger arg, long workListSeed, boolean reset ) {
+    // Generic CodeGen, including full module setup
+    public CodeGen( String modDir, String buildDir, Ary<String> externPaths,
+                    String srcName, String src, long workListSeed, Type arg ) {
+        // Public singleton to avoid passing about this state to a huge count
+        // of places.  Probably becomes a TLS at some point.
         CODE = this;
-        if( reset ) Type.reset();
-        _main = makeFun(TypeFunPtr.MAIN);
-        _phase = null;
-        _callingConv = null;
-        _start = new StartNode(arg);
-        _stop = new StopNode(src);
+        Type.reset();           // Reset to recover from failed test
+
+        _cwd = System.getProperty("user.dir")+"/";
+        _modDir   =   modDir == null ? _cwd :   modDir;
+        _buildDir = buildDir == null ? _cwd : buildDir;
+        _externPaths = externPaths;
+        _srcName = srcName;
+        _callingConv = null;       // Calling convention
+        // Source code from test strings, not files
         _src = src;
-        _arg = arg;
-        _iter = new IterPeeps(workListSeed);
-        P = new Parser(this,arg);
+        // All the compilation units
+        _compunits = new HashMap<>();
+        _phase = null;
+        // Start GVN table
+        _gvn = new HashMap<>();
+        // Allow whole-suite worklist-order sweeps without rewriting the many
+        // explicit seeds used by tests and command-line compilation.
+        String iterSeed = System.getProperty("simple.iter.seed");
+        _iter = new IterPeeps(iterSeed == null ? workListSeed : Long.parseLong(iterSeed));
+        // End points of graph
+        _stop = new StopNode().init();
+        _start = new StartNode(null,_stop,arg).init();
+        ZERO  = con(TypeInteger.ZERO).keep();
+        XCTRL = new XCtrlNode().peephole().keep();
+        P = new Parser(this);
     }
 
 
-    // All passes up to Phase, except ELF
-    public CodeGen driver( Phase phase ) { return driver(phase,null,null); }
+    // Run requested phases.
+
+    // No code emission, just IR generation
+    public CodeGen driver( Phase phase ) { return driver(phase,null,null,false,false,0); }
+    // No object file writing, but code generation for a specific cpu/os pair (allows emulation)
     public CodeGen driver( Phase phase, String cpu, String callingConv ) {
-        if( _phase==null )                       parse();
-        int p1 = phase.ordinal();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.Opto      .ordinal() ) opto();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.TypeCheck .ordinal() ) typeCheck();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.LoopTree  .ordinal() ) loopTree();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.Select    .ordinal() && cpu != null ) instSelect(cpu,callingConv);
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.Schedule  .ordinal() ) GCM();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.LocalSched.ordinal() ) localSched();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.RegAlloc  .ordinal() ) regAlloc();
-        if( _phase.ordinal() < p1 && _phase.ordinal() < Phase.Encoding  .ordinal() ) encode();
+        if( phase.ordinal() < Phase.Export.ordinal() )
+            // No code outputted
+            return driver(phase,cpu,callingConv,false,false,0);
+        if( _srcName == null )
+            throw new RuntimeException("No source filename provided, so do not know how to name the obj file");
+        boolean emitEntrySymbol = !_srcName.contains(".");
+        return driver( phase, cpu, callingConv, false, emitEntrySymbol, 0 );
+    }
+    // Write an object file for a specific cpu/os pair
+
+    public CodeGen driver( String cpu, String callingConv, boolean inMemory, boolean emitEntrySymbol ) { return driver(Phase.Export,cpu,callingConv,inMemory,emitEntrySymbol,0); }
+    // Generic driver
+    public CodeGen driver( Phase phase, String cpu, String callingConv, boolean inMemory, boolean emitEntrySymbol, int dump ) {
+        int p1 = phase.ordinal(), p2 = _phase==null ? -1 : _phase.ordinal();
+        if( p2 < p1 && p2 <  Phase.Parse     .ordinal() ) { parse();     p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.Iter      .ordinal() ) { iter();      p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.Opto      .ordinal() ) { opto();      p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.TypeCheck .ordinal() ) { typeCheck(); p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.LoopTree  .ordinal() ) { loopTree();  p2 = dump(dump); }
+        if( p2 < p1 && p1 >= Phase.Encoding  .ordinal() ) { unlinkImports(); p2 = dump(dump); }
+        if( p2 < p1 && p1 >= Phase.Encoding  .ordinal() ) { serialize(); p2 = dump(dump); } // Include ideal graph in object file
+        if( p2 < p1 && p2 <  Phase.Unlink    .ordinal() ) { unlink();    p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.Select    .ordinal() && cpu != null ) { instSelect(cpu,callingConv); p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.Schedule  .ordinal() ) { GCM();       p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.LocalSched.ordinal() ) { localSched();p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.RegAlloc  .ordinal() ) { regAlloc();  p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.Encoding  .ordinal() ) { encode();    p2 = dump(dump); }
+        if( p2 < p1 && p2 <  Phase.Export    .ordinal() ) { exportELF(inMemory,emitEntrySymbol); p2 = dump(dump); }
         return this;
     }
 
-    // Run all the phases through final ELF emission
-    public CodeGen driver( String cpu, String callingConv, String obj ) throws IOException {
-        return driver(Phase.Encoding,cpu,callingConv).exportELF(obj);
+    public String entryClinitName() {
+        return Parser.addClzPrefix(_srcName==null ? "Test" : _srcName)+".<clinit>";
     }
 
+    // Verbose printing during compilation
+    private int dump(int dump) {
+        int p2 = _phase.ordinal();
+        if( (dump & (1<<p2)) == 0 ) return p2;
+        if( (dump & (1<<29)) != 0 ) {
+            String fn = ""+p2+"-"+_phase+".dot";
+            try {
+                Files.writeString(Path.of(fn),
+                                  new GraphVisualizer().generateDotOutput(compunit(), null, null));
+            } catch(IOException e) { throw Utils.TODO("Cannot write DOT file"); }
+            return p2;
+        }
+
+        if( (dump & (1<<30)) != 0 )
+            System.err.println("After "+_phase+":");
+        System.err.println(IRPrinter.prettyPrint(this));
+        return p2;
+    }
+
+
+    // Record times by phase
+    public final long[] _times = new long[Phase.LastPhase.ordinal()];
 
     // ---------------------------
     /**
@@ -89,9 +287,39 @@ public class CodeGen {
         return _uid++;
     }
 
-    // Next available memory alias number
-    private int _alias = 2; // 0 is for control, 1 for memory
-    public  int getALIAS() { return _alias++; }
+
+    // These next fields all 2-way map some *global* program feature to a
+    // local dense index, suitable for packing in BitSets.  The mapping takes a
+    // global value - always a {source file/class} name, and an order number
+    // counting up per feature in the same file.  The dense local index can be
+    // different in different compilations.
+
+    // The global info allows loading the same remote class info from different
+    // paths and aligning them.  Example: Compiling A loads pre-compiled B and
+    // C, both of which load pre-compiled D.  The 2 different D loads unify via
+    // this global info.
+
+    // These mappings are all trivial identities when compiling one file; they
+    // only become complex when loading separately compiled code.
+
+    // Compute local function index (FIDX) from global function info.  This is
+    // called *in order* during parsing, and that order is part of the global
+    // unique mapping
+    public final GlobalBits _aliases = new GlobalBits();
+    public int alias(String clz) { return _aliases.next(clz); }
+
+    // Compute local function index (FIDX) from global function info.  This is
+    // called *in order* during parsing, and that order is part of the global
+    // unique mapping
+    public final GlobalBits _fidxs = new GlobalBits();
+    // Return local index for specific global file & order.  Used to find fidxs for e.g. FREF class <init> fcns
+    public int fidx( String clz, int order ) { return _fidxs.next(clz, order); }
+    // New fidx in the current file
+    public int fidx( String clz ) { return fidx(clz, -1); }
+
+    // Compute local RPC index from global RPC info, one per call
+    public final GlobalBits _rpcs = new GlobalBits();
+    public int rpc( String clz ) { return _rpcs.next(clz); }
 
 
     // idepths are cached and valid until *inserting* CFG edges (deleting is
@@ -116,30 +344,21 @@ public class CodeGen {
     public final BitSet _visit = new BitSet();
     public BitSet visit() { assert _visit.isEmpty(); return _visit; }
 
-    // Start and stop; end points of the generated IR
+    // Start and Stop; end points of the generated IR
     public StartNode _start;
     public StopNode  _stop;
 
     // Global Value Numbering.  Hash over opcode and inputs; hits in this table
     // are structurally equal.
-    public final HashMap<Node,Node> _gvn = new HashMap<>();
+    public final HashMap<Node,Node> _gvn;
 
-    // Source of unique function indices
-    private int _fidx =0;
-    public TypeFunPtr makeFun( TypeFunPtr fun ) {
-        int fidx = _fidx++;
-        assert fidx<64;         // TODO: need a larger FIDX space
-        return fun.makeFrom(fidx);
-    }
-    // Signature for MAIN
-    public TypeFunPtr _main;
-    public void setMain(FunNode main) {
-        _main = main.sig();
-        link(main);
-    }
     // Reverse from a constant function pointer to the IR function being called.
     // Error to call with a non-constant TFP
     public FunNode link( TypeFunPtr tfp ) { return link(tfp.fidx());  }
+    // Read-only linker lookup, suitable for printers and debugger display.
+    // In particular, do not lazily remove a partially dead function.
+    public FunNode lookupFun(int fidx) { return _linker.atX(fidx); }
+    public FunNode lookupFun(TypeFunPtr tfp) { return lookupFun(tfp.fidx()); }
     // Return the FunNode from a fidx
     public FunNode link( int fidx ) {
         FunNode fun =_linker.atX(fidx);
@@ -158,20 +377,48 @@ public class CodeGen {
     // "Linker" mapping from constant TypeFunPtrs to heads of function.  These
     // TFPs all have exact single fidxs and their return is wiped to BOTTOM (so
     // the return is not part of the match).
-    final Ary<FunNode> _linker = new Ary<>(FunNode.class);
+    public final Ary<FunNode> _linker = new Ary<>(FunNode.class);
+
+    // Extern function declarations; input is the FIDX assigned to the name.
+    final HashMap<Integer,String> _externFunc = new HashMap<>();
+    public void externFunc(int fidx, String ex) {
+        assert !_externFunc.containsKey(fidx);
+        _externFunc.put(fidx,ex);
+    }
+    public String externFunc(int fidx) { return _externFunc.get(fidx); }
 
+    public String funcName(int fidx ) {
+        FunNode fun = link(fidx);
+        if( fun!=null ) return fun._name;
+        return externFunc(fidx);
+    }
+
+    public boolean owns(FunNode fun) {
+        return fun._compunit != null && fun._compunit._src != null;
+    }
+
+
+    // ---------------------------
     // Parser object
     public final Parser P;
 
     // Parse ASCII text into Sea-of-Nodes IR
-    public int _tParse;
     public CodeGen parse() {
         assert _phase == null;
         _phase = Phase.Parse;
         long t0 = System.currentTimeMillis();
 
-        P.parse();
-        _tParse = (int)(System.currentTimeMillis() - t0);
+        Parser.TYPES.clear();
+        Parser.TYPES.putAll(Parser.INIT_TYPES);
+        if( _src != null ) {
+            // No source file, just the source itself.
+            ParseAll.parseSource(this,_srcName==null ? "Test" : _srcName,_src);
+        } else {
+            // Path from module root to source file
+            ParseAll.parsePath(this,_srcName);
+        }
+
+        _times[Phase.Parse.ordinal()] = System.currentTimeMillis() - t0;
         JSViewer.show();
         return this;
     }
@@ -188,24 +435,64 @@ public class CodeGen {
     public void iterCnt() { if( !_midAssert ) _iter_cnt++; }
     public void iterNop() { if( !_midAssert ) _iter_nop_cnt++; }
 
+    // Pessimistic peepholes after parsing.  This lifts loaded and parsed
+    // types before the optimistic Opto pass resets types and lets them fall.
+    public CodeGen iter() {
+        assert _phase == Phase.Parse;
+        _phase = Phase.Iter;
+        long t0 = System.currentTimeMillis();
+
+        // The phase shift closes all parser-in-progress states and freezes
+        // unknown external inputs.  Imported nodes carry post-Opto escape
+        // precision, but Iter is a fresh pessimistic solve: non-singleton
+        // memory must restart at FULL so newly discovered private escapes can
+        // only be removed, never added.  Seed the complete graph once.
+        _start.walk(n -> {
+            n._type = iterEscapeReset(n._type);
+            add(n);
+            return null;
+        });
+        _iter.iterate(this);
+        assert Opto.fixedPointCheck(this);
+
+        _times[Phase.Iter.ordinal()] = System.currentTimeMillis() - t0;
+        return this;
+    }
+
+    private static Type iterEscapeReset(Type t) {
+        if( t instanceof TypeMem mem )
+            return mem._one ? mem : mem.makeFrom(XInt.FULL,XInt.FULL);
+        if( t instanceof TypeTuple tt ) {
+            TypeTuple rez = tt;
+            for( int i=0; i<tt._types.length; i++ ) {
+                Type tx = iterEscapeReset(tt._types[i]);
+                if( tx != tt._types[i] ) rez = rez.makeFrom(i,tx);
+            }
+            return rez;
+        }
+        return t;
+    }
+
+
     // Run ideal optimizations
-    public int _tOpto;
     public CodeGen opto() {
-        assert _phase == Phase.Parse;
+        if( _phase == Phase.Parse )
+            iter();
+        assert _phase == Phase.Iter;
         _phase = Phase.Opto;
         long t0 = System.currentTimeMillis();
 
         Opto.opto(this);
 
-        _tOpto = (int)(System.currentTimeMillis() - t0);
+        _times[Phase.Opto.ordinal()] = System.currentTimeMillis() - t0;
         return this;
     }
     public <N extends Node> N add( N n ) { return _iter.add(n); }
     public void addAll( Ary<Node> ary ) { _iter.addAll(ary); }
+    public void addAll( Node n ) { _iter.add(n); _iter.addAll(n._inputs); }
 
     // ---------------------------
     // Last check for bad programs
-    public int _tTypeCheck;
     public CodeGen typeCheck() {
         // Demand phase Opto for cleaning up dead control flow at least,
         // required for the following GCM.
@@ -213,33 +500,123 @@ public class CodeGen {
         _phase = Phase.TypeCheck;
         long t0 = System.currentTimeMillis();
 
-        Parser.ParseException err = _stop.walk( Node::err );
-        _tTypeCheck = (int)(System.currentTimeMillis() - t0);
-        if( err != null )
-            throw err;
+        final Ary<Node> errs = new Ary<>(Node.class);
+        _stop.walk( n -> {
+                    if( n.err() != null )
+                        errs.add(n);
+                    return null;
+            });
+        String unresolved = unresolvedTypeName();
+        _times[Phase.TypeCheck.ordinal()] = System.currentTimeMillis() - t0;
+        if( !errs.isEmpty() ) {
+            // Prefer an originating error over a secondary error caused by a
+            // BOTTOM input.  If all errors are downstream-poisoned, retain
+            // the old first-error behavior.
+            Node min = null;
+            for( Node n : errs )
+                if( noBottomInputs(n) ) {
+                    min = n;
+                    break;
+                }
+            if( min==null )
+                min = errs.at(0);
+            for( Node n : errs )
+                if( n!=min &&
+                    noBottomInputs(n) &&
+                    ((n   instanceof MemOpNode nmop &&
+                      min instanceof MemOpNode mmop &&
+                      nmop._loc.before(mmop._loc)) ||
+                     (n   instanceof CFGNode ncfg &&
+                      min instanceof CFGNode mincfg &&
+                      ncfg.idepth() < mincfg.idepth())) )
+                    min = n;
+            throw min.err();
+        }
+        if( unresolved != null )
+            throw Parser.error("Unknown struct type '"+unresolved+"'",null);
         return this;
     }
 
+    private static boolean noBottomInputs(Node n) {
+        for( Node def : n._inputs )
+            if( def!=null && !(def instanceof FldOffNode) && def._type==Type.BOTTOM )
+                return false;
+        return true;
+    }
+
+    // Forward-ref structs are open while parsing.  They must all be resolved
+    // to closed structs before leaving type checking.
+    private String unresolvedTypeName() {
+        String[] unresolved = new String[1];
+        _stop.walk(n -> {
+            TypeStruct ts = requiredStruct(n);
+            if( unresolved[0]==null && ts!=null && ts._fref )
+                unresolved[0] = ts._name;
+            return null;
+        });
+        return unresolved[0];
+    }
+
+    public static TypeStruct requiredStruct(Node n) {
+        if( n instanceof NewNode alloc ) return alloc._ts;
+        if( n instanceof ConFldOffNode off ) return off._ts;
+        if( n instanceof FldOffNode off && off.in(0)._type instanceof TypeMemPtr ptr ) return ptr._obj;
+        return null;
+    }
+
     // ---------------------------
     // Build the loop tree; break never-exit loops
-    public int _tLoopTree;
     public CodeGen loopTree() {
-        assert _phase.ordinal() <= Phase.TypeCheck.ordinal();
+        assert _phase.ordinal() <= Phase.Serialize.ordinal();
         _phase = Phase.LoopTree;
         long t0 = System.currentTimeMillis();
         // Build the loop tree, fix never-exit loops
-        _start.buildLoopTree(_start,_stop);
-        _tLoopTree = (int)(System.currentTimeMillis() - t0);
+        _start.buildLoopTree( _linker, _stop);
+        // Invariant theory: No more type or code changes after Opto.  The
+        // LoopTree stuff is used to do layouts now, but not core opts.  TODO:
+        // at some future date we'll do loop opts (e.g. peeling, unrolling)
+        // that will totally impact code shape, types and core opts - but this
+        // will be done in tandem with Opto changes.
+        //_iter.iterate(this);
+        _times[Phase.LoopTree.ordinal()] = System.currentTimeMillis() - t0;
         return this;
     }
 
     // ---------------------------
+    public BAOS _serial;
+    public void serialize() {
+        assert _phase.ordinal() <= Phase.Serialize.ordinal();
+        _phase = Phase.Serialize;
+        long t0 = System.currentTimeMillis();
+        // Does not change compiler phase; just records IR
+        Serialize.serialize(this);
+        _times[Phase.Serialize.ordinal()] = System.currentTimeMillis() - t0;
+    }
+
+    // Unlink imported function bodies before serialization.  Calls to them
+    // remain as normal calls through their function pointer, and codegen later
+    // turns them into external relocations.
+    private void unlinkImports() {
+        assert _phase.ordinal() <= Phase.Serialize.ordinal();
+        for( FunNode fun : _linker ) {
+            if( fun==null || fun.isDead() || owns(fun) )
+                continue;
+            for( int i=1; i<fun.nIns(); i++ )
+                if( fun.in(i) instanceof CallNode call )
+                    call.unlink(fun,i--);
+        }
+        //_iter.iterate(this);
+    }
+
+    // ---------------------------
     // Code generation CPU target
     public Machine _mach;
     // Chosen calling convention (usually either Win64 or SystemV)
     public String _callingConv;
+    public String _cCallingConv;
     // Callee save registers
     public RegMask _callerSave;
+    public RegMask _cCallerSave;
 
     // All returns have the following inputs:
     // 0 - ctrl
@@ -252,10 +629,9 @@ public class CodeGen {
     public RegMask _rpcMask;
 
     // Convert to target hardware nodes
-    public int _tInsSel;
     public CodeGen instSelect( String cpu, String callingConv ) { return instSelect(cpu,callingConv,PORTS); }
     public CodeGen instSelect( String cpu, String callingConv, String base ) {
-        assert _phase.ordinal() == Phase.LoopTree.ordinal();
+        assert _phase.ordinal() <= Phase.Unlink.ordinal();
         _phase = Phase.Select;
 
         _callingConv = callingConv;
@@ -267,12 +643,17 @@ public class CodeGen {
         try { _mach = ((Class<Machine>) Class.forName( clzFile )).getDeclaredConstructor(new Class[]{CodeGen.class}).newInstance(this); }
         catch( Exception e ) { throw new RuntimeException(e); }
 
+        _cCallingConv = _mach.cCallingConv(callingConv);
+
         // Build global copies of common register masks.
         long callerSave = _mach.callerSave();
+        long cCallerSave= _mach.callerSave(_cCallingConv);
         long  neverSave = _mach. neverSave();
         int maxReg = Math.min(64,_mach.regs().length);
         assert maxReg>=64 || (-1L << maxReg & callerSave)==0; // No stack slots in callerSave
+        assert maxReg>=64 || (-1L << maxReg & cCallerSave)==0; // No stack slots in cCallerSave
         _callerSave = new RegMask(callerSave);
+        _cCallerSave= new RegMask(cCallerSave);
 
         // Build a Return RegMask array.  All returns have the following inputs:
         // 0 - ctrl
@@ -292,12 +673,20 @@ public class CodeGen {
         _uid = 1;               // All new machine nodes reset numbering
         var map = new IdentityHashMap<Node,Node>();
         _instSelect( _stop, map );
-        _stop  = ( StopNode)map.get(_stop );
+        _stop  = (StopNode)map.get(_stop );
         StartNode start = (StartNode)map.get(_start);
         _start = start==null ? new StartNode(_start) : start;
         _instOuts(_stop,visit());
         _visit.clear();
-        _tInsSel = (int)(System.currentTimeMillis() - t0);
+
+        // Replace the CompUnit stop (and list of functions)
+        // with hardware-specific ones
+        for( CompUnit cu : _compunits.values() ) {
+            cu._start= (StartCUNode)map.get(cu._start);
+            cu._stop = (StopCUNode )map.get(cu._stop );
+        }
+
+        _times[Phase.Select.ordinal()] = System.currentTimeMillis() - t0;
         return this;
     }
 
@@ -319,11 +708,20 @@ public class CodeGen {
 
         // Produce a machine node from n; map it to flag as done so stops cycles.
         map.put(n, x=_mach.instSelect(n) );
+        // Carry loop-tree and pre-order info across the ideal->mach transition
+        if( n instanceof CFGNode ncfg && x instanceof CFGNode xcfg ) {
+            xcfg._ltree = ncfg._ltree;
+            xcfg._pre = ncfg._pre;
+        }
         // Walk machine op and replace inputs with mapped inputs
         for( int i=0; i < x.nIns(); i++ )
             x._inputs.set(i, _instSelect(x.in(i),map) );
-        if( x instanceof MachNode mach )
+        // Post selection action
+        if( x instanceof MachNode mach ) {
+            if( n instanceof ReturnNode ret )
+                ((ReturnNode)mach)._fun = (FunNode)map.get(ret._fun);
             mach.postSelect(this);  // Post selection action
+        }
 
         return x;
     }
@@ -335,14 +733,90 @@ public class CodeGen {
         for( Node in : n._inputs )
             if( in!=null ) {
                 in._outputs.push(n);
+                // CallNode special: outputs are partially ordered; CallEnd in slot 0
+                if( in instanceof CallNode call && n instanceof CallEndNode cend && call.out(0) != cend )
+                    call._outputs.swap(0,call.nOuts()-1);
                 _instOuts(in,visit);
             }
     }
 
+    // ---------------------------
+    public void unlink() {
+        assert _phase.ordinal() <= Phase.Select.ordinal();
+        _phase = Phase.Unlink;
+        long t0 = System.currentTimeMillis();
+
+    	// The remaining passes assume all calls are unlinked; i.e. we are throwing
+    	// away the Call Graph here.  Functions only reachable from internal calls
+    	// need to be re-hooked to stop/start less they go dead.
+        for( FunNode fun : _linker ) {
+            // Already linked to start, not going dead
+            if( fun==null || fun.isDead() || fun._type.isHigh() )
+                continue;
+
+            // Imported functions are not emitted by this object.  Unlink any
+            // concrete calls so they become normal external relocations.
+            if( !owns(fun) ) {
+                while( fun.nIns() > 1 ) {
+                    if( fun.in(1) instanceof CallNode call )
+                        call.unlink(fun,1);
+                    else
+                        fun.removeDeadPath(1);
+                }
+                StartCUNode start = fun._compunit._start;
+                StopCUNode  stop  = fun._compunit._stop;
+                // Unhook the Stop->Return edge also
+                ReturnNode ret = fun.ret();
+                int idx = stop._inputs.find(ret);
+                if( idx != -1 ) {
+                    stop._inputs.del(idx);
+                    ret.delUse(stop);
+                }
+                //
+                if( stop.nIns()==0 ) {
+                    idx = _stop._inputs.find(stop);
+                    if( idx != -1 )
+                        _stop.delDef(idx);
+                    if( start.nIns() > 0 && start.in(0) != null )
+                        start.setDef(0,null);
+                    if( start.nIns() > 1 && start.in(1) != null )
+                        start.setDef(1,null);
+                }
+                continue;
+            }
+
+            // Insert the post-Opto code-generation hook.  Unlike an Opto-time
+            // Start input, this no longer carries unknown-caller semantics.
+            ReturnNode ret = fun.ret();
+            StartNode start = fun._compunit._start;
+            assert start!=null;
+            if( fun.in(1) != start ) {
+                fun.insertDef(1,start);
+                for( Node use : fun._outputs )
+                    if( use instanceof ParmNode parm )
+                        parm.insertDef(1,ConstantNode.raw(parm._type));
+                if( fun._compunit._stop._inputs.find(ret) == -1 )
+                    fun._compunit._stop.addDef(ret);
+            }
+            // Unlink from Call
+            for( int i=2; i<fun.nIns(); i++ )
+                ((CallNode)fun.in(i)).unlink(fun,i--);
+            if( fun.rpc()==null ) { // Ensure valid RPC
+                // First make sure a valid RPC; single-call into multi-fun will have each
+                // function having a single call site, so the RPC becomes a constant and
+                // folds - but since multiple targets, the Call never inlines.  Recreate a
+                // valid RPC so codegen (and Eval2) understands the calling convention.
+                ParmNode rpc = new ParmNode( "$rpc", 0, ret.rpc()._type, fun );
+                rpc.addDef(ret.rpc());
+                ret.setDef( 3, rpc.init() );
+            }
+        }
+
+        _times[Phase.Unlink.ordinal()] = System.currentTimeMillis() - t0;
+    }
 
     // ---------------------------
     // Control Flow Graph in Reverse Post Order.
-    public int _tGCM;
     public Ary<CFGNode> _cfg = new Ary<>(CFGNode.class);
 
     // Global schedule (code motion) nodes
@@ -353,28 +827,26 @@ public class CodeGen {
         long t0 = System.currentTimeMillis();
 
         GlobalCodeMotion.buildCFG(this);
-        _tGCM = (int)(System.currentTimeMillis() - t0);
+        _times[Phase.Schedule.ordinal()] = System.currentTimeMillis() - t0;
         if( show )
-            System.out.println(new GraphVisualizer().generateDotOutput(_stop,null,null));
+            System.out.println(new GraphVisualizer().generateDotOutput(compunit(),null,null));
         return this;
     }
 
     // ---------------------------
     // Local (basic block) scheduler phase, a classic list scheduler
-    public int _tLocal;
     public CodeGen localSched() {
         assert _phase == Phase.Schedule;
         _phase = Phase.LocalSched;
         long t0 = System.currentTimeMillis();
         ListScheduler.sched(this);
-        _tLocal = (int)(System.currentTimeMillis() - t0);
+        _times[Phase.LocalSched.ordinal()] = System.currentTimeMillis() - t0;
         return this;
      }
 
 
     // ---------------------------
     // Register Allocation
-    public int _tRegAlloc;
     public RegAlloc _regAlloc;
     public CodeGen regAlloc() {
         assert _phase == Phase.LocalSched;
@@ -382,15 +854,14 @@ public class CodeGen {
         long t0 = System.currentTimeMillis();
         _regAlloc = new RegAlloc(this);
         _regAlloc.regAlloc();
-        _tRegAlloc = (int)(System.currentTimeMillis() - t0);
+        _times[Phase.RegAlloc.ordinal()] = System.currentTimeMillis() - t0;
         return this;
     }
 
-    // Human readable register name
-    public String reg(Node n) { return reg(n,null); }
-    public String reg(Node n, FunNode fun) {
+    // Human-readable register name
+    public String reg(Node n) {
         if( _phase.ordinal() >= Phase.RegAlloc.ordinal() ) {
-            String s = _regAlloc.reg(n,fun);
+            String s = _regAlloc.reg(n);
             if( s!=null ) return s;
         }
         return "N"+ n._nid;
@@ -399,50 +870,171 @@ public class CodeGen {
 
     // ---------------------------
     // Encoding
-    public int _tEncode;
-    public Encoding _encoding;   // Encoding object
-    public void preEncode() {  } // overridden by alternative ports
+    public Encoding _encoding;
     public CodeGen encode() {
         assert _phase == Phase.RegAlloc;
         _phase = Phase.Encoding;
         long t0 = System.currentTimeMillis();
-        _encoding = new Encoding(this);
-        preEncode();
-        _encoding.encode();
-        _tEncode = (int)(System.currentTimeMillis() - t0);
+
+        _encoding = new Encoding(this).encode();
+
+        _times[Phase.Encoding.ordinal()] = System.currentTimeMillis() - t0;
         return this;
     }
 
     // ---------------------------
     // Exporting to external formats
-    public CodeGen exportELF(String fname) throws IOException {
+    ElfWriter _elf;
+    public CodeGen exportELF( boolean inMemory, boolean emitEntrySymbol ) {
         assert _phase == Phase.Encoding;
         _phase = Phase.Export;
-        if( fname == null ) new LinkMem(this).link(); // In memory patching
-        else new ElfFile(this).export(fname); // External ELF file
+        long t0 = System.currentTimeMillis();
+        if( _encoding!=null ) {
+            if( inMemory )
+                new LinkMem(this).link(_encoding); // In memory patching
+            else
+                _elf = new ElfWriter(this).export(emitEntrySymbol);
+        }
+        _times[Phase.Export.ordinal()] = System.currentTimeMillis() - t0;
         return this;
     }
 
+
+    // ---------------------------
+
+    // Search a external path list, each path is recursively searched for .o
+    // files, which are partially loaded and searched for public symbols.
+
+    // This is a state machine which lazily searches down the set of search
+    // paths until the requested module is class is found.
+
+    // Map from external Strings to either partially read Simple ElfFile or ExternNode
+    public final HashMap<String,Object> _externSymbols = new HashMap<>();
+
+    // State machine elements; the outermost element is _externPaths
+    private int _extPathIdx;    // Search index into the extern path list
+    private final Ary<File> _files = new Ary<>(File.class);   // Files in the current extern path being searched
+    private int _extFileIdx;    // Index into _files
+
+    public ElfReader findExternalSimple( String name ) {
+        return findExternalSymbol(name) instanceof ElfReader elf ? elf : null;
+    }
+
+    public ExternNode findExternal( String name ) {
+        return findExternalSymbol(name) instanceof ExternNode extern ? extern : null;
+    }
+
+    // Search the search-path for the name; return an ElfReader if found in a
+    // Simple-made ELF; return an ExternNode if from another ELF, or null if
+    // not found.
+    private Object findExternalSymbol( String name ) {
+        // State Machine!
+
+        while( true ) {
+            // Check for an immediate hit
+            switch( _externSymbols.get(name) ) {
+
+            case ExternNode extern:
+                // Name maps to an ExternNode
+                return extern;
+
+            case ElfReader elf:
+                return elf;
+
+            case null:
+                // Name is unknown.  Advance the file-system search, pulling
+                // out new ELF files from the search directory list and loading
+                // their published symbols.
+
+                // The last directory was mined out, so get the next search
+                // directory and find all ELF-like files.
+                if( _extFileIdx >= _files._len ) {
+                    if( _externPaths==null || _extPathIdx >= _externPaths._len )
+                        return null; // A true miss in the whole search path
+                    loadExtPath();   // Load next batch file of files
+                    break;
+                }
+                // Load and parse an ELF header
+                ElfReader elf = getElf(_files.at(_extFileIdx++));
+                if( elf == null ) break; // Not an ELF
+                // Load public symbols from the ELF
+                elf.loadPublicSymbols();
+                if( elf._strs==null ) break; // No .simple section with strings
+                // Put public symbol in global table; first names shadow all others
+                // Map from symbol string to ELFReader; most lookups
+                // will miss and no need to unpack ElfReader types
+                _externSymbols.putIfAbsent(elf._strs[1],elf);
+                for( String str : elf._strs )
+                    if( str.startsWith(Parser.CLZ) )
+                        _externSymbols.putIfAbsent(str,elf);
+                break;
+
+            default: throw Utils.TODO("should not reach here");
+            }
+        }
+    }
+
+    // Load all the .o files in the next external path.
+    private void loadExtPath() {
+        _files.clear();
+        _extFileIdx = 0;
+        String extpath = _externPaths.at(_extPathIdx++);
+        File f = new File(extpath);
+        if( !f.isAbsolute() )
+            f = new File(_cwd+extpath);
+        fillExtFiles(f);
+    }
+
+    // Recursive search (TODO: gzip, archives) and gather all .o files.
+    private void fillExtFiles(File dir) {
+        if( dir.isDirectory() )
+            for( File f : dir.listFiles() )
+                fillExtFiles(f);
+        else if( dir.getName().endsWith(".o") )
+            _files.add(dir);
+    }
+
+    // Map from object file names to ElfReaders
+    public final HashMap<String,ElfReader> _elfs = new HashMap<>();
+    ElfReader getElf(File f) {
+        ElfReader elf = _elfs.get(f.getPath());
+        if( elf != null )
+            return elf;
+        _elfs.put(f.getPath(), elf = ElfReader.load(f,null));
+        return elf;
+    }
+
     // ---------------------------
     public boolean _asmLittle=true;
-    SB asm(SB sb) { return ASMPrinter.print(sb,this); }
     public String asm() { return asm(new SB()).toString(); }
+    SB asm(SB sb) {
+        ASMPrinter.print(sb,this);
+        return sb;
+    }
 
 
     // Testing shortcuts
-    public Node ctrl() { return _stop.ret().ctrl(); }
-    public Node expr() { return _stop.ret().expr(); }
-    public String print() { return _stop.print(); }
+    public Node ctrl() { return compunit()._stop.ret().ctrl(); }
+    public Node expr() { return compunit()._stop.ret().expr(); }
+    public String print() { return compunit()._stop.print(); }
 
     // Debugging helper
     @Override public String toString() {
-        return _phase.ordinal() > Phase.Schedule.ordinal()
-            ? IRPrinter._prettyPrint( this )
-            : _stop.p(9999);
+        if( _phase!=null && _phase.ordinal() > Phase.Schedule.ordinal() )
+            return IRPrinter.prettyPrint( this );
+        if( _stop == null )
+            return "No StopNode";
+        return _stop.p(4999);
     }
 
     // Debugging helper
-    public Node f(int idx) { return _stop.find(idx); }
+    public Node f(int idx) {
+        for( CompUnit cu : _compunits.values() ) {
+            Node n = (cu._stop == null ? _stop : cu._stop).find(idx);
+            if( n != null ) return n;
+        }
+        return null;
+    }
 
 
     String printCFG() {
@@ -461,28 +1053,4 @@ public class CodeGen {
         }
         System.out.println();
     }
-
-    public void print_as_hex() {
-        for (byte b : _encoding._bits.toByteArray()) {
-            System.out.print(String.format("%02X", b));
-        }
-        System.out.println();
-    }
-
-    //// Debug purposes for now
-//    public CodeGen printENCODING() {
-//        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-//
-//        for(Node bb : CodeGen.CODE._cfg) {
-//            for(Node n: bb.outs()) {
-//                if(n instanceof MachNode) {
-//                    ((MachNode) n).encoding(E);
-//                }
-//            }
-//        }
-//
-//        print_as_hex(outputStream);
-//        // Get the raw bytes from the output stream
-//        return this;
-//    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/CompUnit.java b/src/main/java/com/seaofnodes/simple/codegen/CompUnit.java
new file mode 100644
index 00000000..2681066e
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/CompUnit.java
@@ -0,0 +1,138 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeStruct;
+import com.seaofnodes.simple.util.*;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import static com.seaofnodes.simple.codegen.CodeGen.CODE;
+
+// A compilation-unit, which is an external reference and source and object
+// files.  These are mirrored over a file system tree (so form a tree), both
+// the source tree and build/object tree.
+public class CompUnit {
+    public final CompUnit _par;        // Parent, e.g. A/B
+    final String _fname;        // Full slashed file name starting from module root, e.g. A/B/C
+    final public String _cname; // Full dotted class name starting from module root, e.g. A.B.C
+    final String _name;         // Base name, e.g. C
+    final ExternNode _ext;      // Found in external libs; e.g. libc
+    final File _smp;            // Simple source file, e.g. module_root/A/B/C.smp
+    public final File _obj;            // ELF output file, e.g. build/A/B/C.o
+    final public String _src;   // Source code, from file or test case
+    //public Encoding _encoding;  // Encoding for output
+
+    public TypeStruct _clz; // The one TypeStruct being published
+    //BAOS _serial;           // Serialized IR for this ELF file
+    Ary<CompUnit> _deps;    // CompUnits that this CompUnit depends on
+
+    //// List of symbols exported by this compilation unit, and their Node
+    //// definitions.
+    //public HashMap<String,Node> _exported;
+    // Per-Compilation-Unit Start/StopNodes, keeping alive all exported Nodes.
+    // Null means no code loaded (yet).
+    public StartCUNode _start;
+    public StopCUNode  _stop ;
+
+
+    // Discovered source file.  Source is loaded if required to parse, and null
+    // otherwise.
+    CompUnit( CompUnit par, String fname, String cname, String name ) throws IOException {
+        _par  = par;
+        _fname= fname;
+        _cname= cname;
+        _name = name;
+        _ext  = null;
+        _smp  = new File( CODE.  _modDir + "/" + fname + ".smp");
+        _obj  = new File( CODE._buildDir + "/" + fname + ".o"  );
+
+        boolean mustCompile = _smp.exists() && // Has source to compile
+            ( !_obj.exists() ||                // No object file
+              _smp.lastModified() > _obj.lastModified() || // Out-of-date with source?
+              checkDependentObjs() );                      // Out-of-date with other objs?
+        _src  = mustCompile ? new String(Files.readAllBytes(_smp.toPath())) : null;
+    }
+
+    // Test case.  No source file.  Source code passed in as a String.  Fake
+    // class name.
+    CompUnit( String fname, String src ) {
+        _par  = null;
+        _name = fname;
+        _fname= fname;
+        _cname= fname;
+        _ext  = null;
+        _smp  = null;
+        _obj  = null;
+        _src  = src;
+    }
+
+    // External CompUnit, pulled in from an external library like libc
+    CompUnit( ExternNode ext, String symbol ) {
+        _par  = null;
+        _name = symbol;
+        _fname= _name;
+        _cname= null;
+        _ext  = ext;
+        _smp  = null;
+        _obj  = null;
+        _src  = null;
+    }
+
+    // External Simple object file, or namespace parent, found on an external search path.
+    CompUnit( File obj, CompUnit par, String fname, String cname, String name ) {
+        _par  = par;
+        _name = name;
+        _fname= fname;
+        _cname= cname;
+        _ext  = null;
+        _smp  = null;
+        _obj  = obj;
+        _src  = null;
+    }
+
+    // Return true if _obj is out-of-date relative to dependents.
+    private boolean checkDependentObjs() {
+        ElfReader elf = CODE.getElf(_obj);
+        elf.loadPublicSymbols();
+        for( String dep : elf._deps ) {
+            File obj = new File(CODE._buildDir+"/"+dep+".o");
+            if( obj.lastModified() > _obj.lastModified() ) // Out-of-date with deps?
+                return true;
+        }
+        return false;
+    }
+
+    // Add a discovered dependency, for later writing out in an ELF file, ".simple" section
+    void addDep(CompUnit dep) {
+        if( _deps == null ) _deps = new Ary<>(CompUnit.class);
+        _deps.add(dep);
+    }
+
+    public void addFun(CodeGen code, FunNode fun) {
+        assert fun.in(1)==_start;
+        _stop.addDef(fun.ret());
+        code.add(_stop);
+        _stop.addDep(fun);
+    }
+
+    void setStart(CodeGen code) {
+        _stop  = new  StopCUNode().init();
+        _start = new StartCUNode(code._start,_stop, Type.BOTTOM, _fname).init();
+        code._stop.addDef(_stop);
+    }
+
+
+    @Override public String toString() {
+        String x = "{"+_cname;
+        if( _smp!=null && _smp.exists()) x += ",hasSMP";
+        if( _obj!=null && _obj.exists()) x += ",hasObj";
+        if( _src!=null   ) x += ",hasSrc";
+        if( _ext != null ) x += ",isExt";
+        x += "}";
+        return x;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java b/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
deleted file mode 100644
index 8f9e2981..00000000
--- a/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
+++ /dev/null
@@ -1,381 +0,0 @@
-package com.seaofnodes.simple.codegen;
-
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.Encoding.BAOS;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.Ary;
-import java.io.*;
-import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
-import java.util.HashMap;
-import java.util.Map;
-
-public class ElfFile {
-
-    final CodeGen _code;
-    Ary<Section> _sections = new Ary<>(Section.class);
-
-    ElfFile( CodeGen code ) { _code = code; }
-
-    public static int writeCString(DataSection strtab, String name) {
-        // place name in the string table
-        int pos = strtab._contents.size();
-        byte[] name_bytes = name.getBytes();
-        strtab._contents.write(name_bytes, 0, name_bytes.length);
-        // the strings are null terminated
-        strtab._contents.write(0);
-        return pos;
-    }
-
-    public static void write4( ByteArrayOutputStream bits, int op ) {
-        bits.write(op    );
-        bits.write(op>> 8);
-        bits.write(op>>16);
-        bits.write(op>>24);
-    }
-    public static void write8( ByteArrayOutputStream bits, long i64 ) {
-        write4(bits, (int) i64     );
-        write4(bits, (int)(i64>>32));
-    }
-
-    public static final int SYMBOL_SIZE = 4+1+1+2+8+8;
-
-    public static final int SYM_BIND_LOCAL   = 0;
-    public static final int SYM_BIND_GLOBAL  = 1;
-    public static final int SYM_BIND_WEAK    = 2;
-
-    public static final int SYM_TYPE_NOTYPE  = 0;
-    public static final int SYM_TYPE_OBJECT  = 1;
-    public static final int SYM_TYPE_FUNC    = 2;
-    public static final int SYM_TYPE_SECTION = 3;
-
-    public static class Symbol {
-        String _name;
-        int _name_pos;
-
-        // index in the symbol table
-        int _index;
-
-        // which section is it in
-        int _parent;
-
-        // depends on the symbol type
-        //   TODO
-        int _value, _size;
-
-        // top 4bits are the "bind", bottom 4 are "type"
-        int _info;
-
-        // bind 1011
-        // 00001111
-        // 10110000
-
-        Symbol(String name, int parent, int bind, int type) {
-            _name = name;
-            _parent = parent;
-            _info = (bind << 4) | (type & 0xF);
-        }
-
-        void writeHeader(ByteBuffer out) {
-            out.putInt(_name_pos);         // name
-            out.put((byte) _info);         // info
-            // default visibility
-            out.put((byte) 0);             // other
-            out.putShort((short) _parent); // shndx
-            out.putLong(_value);           // value
-            out.putLong(_size);            // size
-        }
-    }
-
-    public static final int SHF_WRITE     = 1;
-    public static final int SHF_ALLOC     = 2;
-    public static final int SHF_EXECINSTR = 4;
-    public static final int SHF_STRINGS   = 32;
-    public static final int SHF_INFO_LINK = 64;
-
-    public static final int SECTION_HDR_SIZE = 64;
-    abstract public static class Section {
-        String _name;
-        int _index;
-
-        int _type, _flags;
-        int _link, _info;
-
-        // where's the name in the string table
-        int _name_pos;
-        int _file_offset;
-
-        Section(String name, int type) {
-            _name = name;
-            _type = type;
-        }
-
-        void writeHeader(ByteBuffer out) {
-            out.putInt(_name_pos);     // name
-            out.putInt(_type);         // type
-            out.putLong(_flags);       // flags
-            out.putLong(0);            // addr
-            out.putLong(_file_offset); // offset
-            out.putLong(size());       // size
-            out.putInt(_link);         // link
-            out.putInt(_info);         // info
-            out.putLong(16);           // addralign
-            if (_type == 2) {
-                out.putLong(SYMBOL_SIZE);// entsize
-            } else if (_type == 4) {
-                out.putLong(24);         // entsize
-            } else {
-                out.putLong(0);          // entsize
-            }
-        }
-
-        abstract void write(ByteBuffer out);
-        abstract int size();
-    }
-
-    public static class SymbolSection extends Section {
-        Ary<Symbol> _symbols = new Ary<>(Symbol.class);
-        Ary<Symbol> _loc = new Ary<>(Symbol.class);
-
-        SymbolSection(String name, int type) {
-            super(name, type);
-        }
-
-        @Override
-        void writeHeader(ByteBuffer out) {
-            // points to string table section
-            _link = 1;
-
-            // number of non-local symbols
-            _info = _loc.len() + 1;
-
-            super.writeHeader(out);
-        }
-
-        void push(Symbol s) {
-            if ((s._info >> 4) != SYM_BIND_LOCAL) {
-                _symbols.push(s);
-            } else {
-                _loc.push(s);
-            }
-        }
-
-        @Override
-        void write(ByteBuffer out) {
-            // Index 0 both designates the first entry in the table and serves as the undefined symbol index
-            for( int i = 0; i < SYMBOL_SIZE/4; i++ ) {
-                out.putInt(0);
-            }
-            // index is already set
-            for( Symbol s : _loc ) {
-                s.writeHeader(out);
-            }
-            for( Symbol s : _symbols ) {
-                s.writeHeader(out);
-            }
-        }
-
-        @Override
-        int size() {
-            return (1 + _symbols.len() + _loc.len()) * SYMBOL_SIZE;
-        }
-    }
-
-    public static class DataSection extends Section {
-        ByteArrayOutputStream _contents;
-
-        DataSection(String name, int type) {
-            super(name, type);
-            _contents = new ByteArrayOutputStream();
-        }
-
-        DataSection(String name, int type, ByteArrayOutputStream contents) {
-            super(name, type);
-            _contents = contents;
-        }
-
-        @Override
-            void write(ByteBuffer out) {
-            out.put(_contents.toByteArray());
-        }
-
-        @Override
-            int size() {
-            return _contents.size();
-        }
-    }
-
-    private void pushSection(Section s) {
-        _sections.push(s);
-        // ELF is effectively "1-based", due to the NULL section
-        s._index = _sections._len;
-    }
-
-    /* creates function and stores where it starts*/
-    private final HashMap<TypeFunPtr,Symbol> _funcs = new HashMap<>();
-    private void encodeFunctions(SymbolSection symbols, DataSection text) {
-        for( int i=0; i<_code._cfg._len; i++ ) {
-            if( !(_code._cfg.at(i) instanceof FunNode fun) ) continue;
-            // skip until the function ends
-            while( !(_code._cfg.at(i) instanceof ReturnNode ret) )
-                i++;
-            int end = _code._encoding._opStart[ret._nid] + _code._encoding._opLen[ret._nid];
-
-            Symbol func = new Symbol(fun._name, text._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
-            func._value = _code._encoding._opStart[fun._nid];
-            func._size = end - func._value;
-            symbols.push(func);
-            _funcs.put(fun.sig(), func);
-        }
-    }
-
-    public void export(String fname) throws IOException {
-        DataSection strtab = new DataSection(".strtab", 3 /* SHT_SYMTAB */);
-        // first byte is reserved for an empty string
-        strtab._contents.write(0);
-        pushSection(strtab);
-
-        // place all the symbols
-        SymbolSection symbols = new SymbolSection(".symtab", 2 /* SHT_STRTAB */);
-        pushSection(symbols);
-
-        // zero flag by default
-        // we've already constructed this entire section in the encoding phase
-        DataSection text = new DataSection(".text", 1 /* SHT_PROGBITS */, _code._encoding._bits);
-        text._flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR;
-        pushSection(text);
-
-        // Build and write constant pool
-        BAOS cpool = new BAOS();
-        Encoding enc = _code._encoding;
-        enc.writeConstantPool(cpool,false);
-        DataSection rdata = new DataSection(".rodata", 1 /* SHT_PROGBITS */, cpool);
-        rdata._flags = SHF_ALLOC;
-        pushSection(rdata);
-
-        // populate function symbols
-        encodeFunctions(symbols, text);
-
-        int idx = 1;
-        for( Section s : _sections ) {
-            Symbol sym = new Symbol(s._name, idx++, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
-            // we can reuse the same name pos from the actual section
-            sym._name_pos = s._name_pos;
-            sym._size = s.size();
-            symbols.push(sym);
-        }
-
-        // calculate local index
-        int num = 1;
-        for( Symbol s : symbols._loc )
-            s._index = num++;
-        // extra space for .rela.text
-        int start_global = num+1; // Add one to skip the final .rela.text local symbol
-        for( Symbol a: symbols._symbols )
-            a._index = start_global++;
-
-        // create .text relocations
-        DataSection text_rela = new DataSection(".rela.text", 4 /* SHT_RELA */);
-        for( Node n : enc._externals.keySet()) {
-            int nid    = n._nid;
-            String extern = enc._externals.get(n);
-
-            Symbol sym = new Symbol(extern, 0, SYM_BIND_GLOBAL, SYM_TYPE_NOTYPE);
-            sym._index = start_global++;
-            symbols.push(sym);
-
-            int offset = enc._opStart[nid] + enc._opLen[nid] - 4;
-
-            // u64 offset
-            write8(text_rela._contents, offset);
-            // u64 info
-            write8(text_rela._contents, ((long)sym._index << 32L) | 4L /* PLT32 */);
-            // i64 addend
-            write8(text_rela._contents, -4);
-        }
-
-        // Write relocations for the constant pool
-        for( Encoding.Relo relo : enc._bigCons.values() ) {
-            Symbol glob = new Symbol("CPOOL$"+start_global, rdata._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
-            glob._value = relo._target;
-            glob._size = relo._t.size();
-            glob._index = start_global++;
-            symbols.push(glob);
-            write8(text_rela._contents, relo._opStart+relo._off);
-            write8(text_rela._contents, ((long)glob._index << 32L) | relo._elf );
-            write8(text_rela._contents, -4);
-        }
-
-        text_rela._flags = SHF_INFO_LINK;
-        text_rela._link = 2;
-        text_rela._info = text._index;
-        pushSection(text_rela);
-
-        // Final .rela.text symbol
-        Symbol sym = new Symbol(text_rela._name, num++, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
-        sym._name_pos = text_rela._name_pos;
-        sym._size = text_rela.size();
-        symbols.push(sym);
-
-        // populate string table
-        for( Section s : _sections ) { s._name_pos = writeCString(strtab, s._name); }
-        for( Symbol s : symbols._symbols ) { s._name_pos = writeCString(strtab, s._name); }
-        for( Symbol s : symbols._loc ) { s._name_pos = writeCString(strtab, s._name); }
-
-        int size = 64; // ELF header
-        // size of all section data
-        for( Section s : _sections ) {
-            s._file_offset = size;
-            size += s.size();
-        }
-        // headers go at the very end
-        int shdr_offset = size;
-        // there's a "null" section at the start of the section headers
-        size += SECTION_HDR_SIZE*(1 + _sections.len());
-
-        // System.out.printf("Hello %d, %d, %s\n", size, shdr_offset);
-        ByteBuffer out = ByteBuffer.allocate(size);
-        out.order(ByteOrder.LITTLE_ENDIAN);
-
-        // ELF header
-        out.put(new byte[]{ 0x7F, 'E', 'L', 'F', 2, 1, 1, 0 });
-        out.put(new byte[8]);
-        out.putShort((short)1 /* ET_REL */); // type
-        out.putShort((short)62 /* AMD64 */); // machine
-        out.putInt(1);                // version
-        out.putLong(0);               // entry
-        out.putLong(0);               // phoff
-        out.putLong(shdr_offset);     // shoff
-        out.putInt(0);                // flags
-        out.putShort((short)64);      // ehsize
-        out.putShort((short)0);       // phentsize
-        out.putShort((short)0);       // phnum
-        out.putShort((short)64);      // shentsize
-        out.putShort((short) (1 + _sections.len())); // shnum
-        out.putShort((short)1);       // shstrndx
-
-        // raw section data
-        for( Section s : _sections ) {
-            s.write(out);
-        }
-
-        // "null" section
-        for( int i = 0; i < 16; i++ ) {
-            out.putInt(0);
-        }
-
-        for( Section s : _sections ) {
-            s.writeHeader(out);
-        }
-        assert out.position() == size;
-
-        File file = new File(fname);
-        if( file.getParentFile()!=null )
-          file.getParentFile().mkdirs();
-        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
-        bos.write(out.array());
-        bos.close();
-    }
-
-}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ElfReader.java b/src/main/java/com/seaofnodes/simple/codegen/ElfReader.java
new file mode 100644
index 00000000..534bb10f
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/ElfReader.java
@@ -0,0 +1,234 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.type.TypeMemPtr;
+import com.seaofnodes.simple.type.TypeStruct;
+import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
+import java.io.*;
+import java.nio.file.Files;
+import java.util.HashMap;
+
+public class ElfReader {
+
+    public final File _file;
+    public final byte[] _buf;
+    int _x;                     // Cursor into buffer
+    // ELF Header
+    public final ElfHeader _header;
+    // All sections
+    public final Section[] _sections;
+    // Simple section, if available
+    public final Section _simple;
+    // Byte array in/out stream - used as a reader
+    public final BAOS _bais;
+    // Compilation unit; written into FunNodes
+    public final CompUnit _compunit;
+
+    // Strings from the Simple section, either small public set or whole set
+    public String[] _strs;
+    // Dependent file names
+    public String[] _deps;
+    // Only published symbol this file
+    public TypeStruct _clz;
+    // Canonical named types, distinct from optimized same-named graph states.
+    public TypeStruct[] _pubTypes;
+    // Nodes read in this Elf
+    public Ary<Node> _nodes;
+
+    // Load an Elf file (mostly lazily)
+    public static ElfReader load( File f, CompUnit cu ) {
+        try { return new ElfReader(f,cu); }
+        catch( IOException ioe ) { return null; }
+    }
+
+    // Load the Simple section from the ELF file
+    private ElfReader( File f, CompUnit cu ) throws IOException {
+        _file = f;
+        _compunit = cu;
+        _buf = Files.readAllBytes(f.toPath());
+        _header = new ElfHeader();
+        // No attempt is made to parse the program header table.
+        _sections = new Section[_header._shnum];
+        for( int i=0; i<_header._shnum; i++ )
+            _sections[i] = new Section(i);
+
+        // Load section names
+        Section secstr = _sections[_header._shstrndx];
+        for( Section sec : _sections )
+            if( sec._type != 0 )
+                sec._name = secstr.str(sec._noff);
+
+        Section simple = null;
+        for( Section sec : _sections )
+            if( ".simple".equals(sec._name) )
+                simple = sec;
+        _simple = simple;
+        _bais = new BAOS(_buf, (int)_simple._offset);
+    }
+
+    // For Serialize self-test
+    ElfReader( BAOS bais ) {
+        _file = null;
+        _compunit = null;
+        _buf = bais.buf();
+        _header = null;
+        _sections = null;
+        _simple = null;
+        _bais = bais;
+    }
+
+    // Load the public symbols and dependent objs, but not the whole IR
+    void loadPublicSymbols() {
+        // Check already loaded and cached
+        if( _strs == null && _simple != null )
+            // Read only the published public strings, for speed purposes when
+            // scanning a large count of ELF files but getting hits in only a
+            // few of them.  i.e. optimizing (prematurely?) for the traditional
+            // case of linking a small file against a large library
+            Serialize.read_public_strs(this);
+    }
+
+    // Loads the entire IR
+    public TypeStruct loadSimple(CodeGen code) {
+        Serialize.readAll(code, this, code._aliases, code._fidxs, code._rpcs);
+        return _clz;
+    }
+
+    // Loads strings, mappings, and types, but not Nodes.  Used after the
+    // public-string scan finds a matching Simple ELF, so parsing can resolve
+    // imported field/array aliases before the full graph is linked in later.
+    public TypeStruct loadPublicTypes(CodeGen code) {
+        Serialize.readTypes(code, this, code._aliases, code._fidxs, code._rpcs);
+        return _clz;
+    }
+
+    int u1() { return _buf[_x++]&0xFF; }
+    int magic() {                         // Big endian
+        return (u1() << 24) | (u1() << 16) | (u1() << 8) | u1();
+    }
+    int u2() { return u1() | (u1()<<8); } // Little endian
+    int u4() {                  // Little endian
+        return u1() | (u1() << 8) | (u1() << 16) | (u1() << 24);
+    }
+    long u8() { return u4() | ((long)u4()<<32); }
+    void skip(int skip) { _x += skip; }
+
+
+    public class ElfHeader {
+        final int _magic;
+        final boolean _format32; // Format32 or format64
+        final byte _osabi;
+        final boolean _little;  // True if little endian, false if big endian
+        final char _type;
+        final char _machine;
+        final long _entry;      // Process entry point
+        final long _phoff;      // Program header table offset, from file start
+        final long _shoff;      // Section header table offset, from file start
+        final int _flags;       // Flags
+        final int _phnum;       // Number of program header entries
+        final int _shentsize;
+        final int _shnum;       // Number of section header entries
+        final int _shstrndx;    // Section header index contains section names
+
+
+        ElfHeader() throws IOException {
+            _x = 0;
+            if( (_magic = magic()) != 0x7F454C46 ) bad("magic number",_magic);
+            byte EI_CLASS = (byte)u1();
+            if( EI_CLASS != 1 && EI_CLASS != 2 ) bad("EI_CLASS",EI_CLASS);
+            _format32 = (EI_CLASS==1);
+            byte EI_DATA = (byte)u1();
+            if( EI_DATA != 1 && EI_DATA != 2 ) bad("EI_DATA",EI_DATA);
+            _little = EI_DATA == 1;
+            if( u1() != 1 )  bad("version",1);
+            if( (_osabi=(byte)u1()) != 0 )  bad("EI_VERSION",_osabi);
+            byte abiversion = (byte)u1();
+            if( abiversion != 0 ) bad("EI_ABIVERSION",abiversion);
+            skip(7);            // Pad
+
+            // Endian matters now
+            if( !_little ) throw new IOException("TODO: Big endian");
+            if( (_type = (char)u2()) != 1 )  bad("ET_REL",_type);
+            if( (_machine = (char)u2()) != 0x3E )  bad("AMD x86-64",_machine);
+            int ver = u4();
+            if( ver != 1 ) bad("Version",ver);
+            // Format32 matters now
+            if( _format32 ) bad("Format",1);
+            _entry = u8();      // Process entry point
+            _phoff = u8();      // Program header table offset
+            _shoff = u8();      // Section header table offset
+            _flags = u4();      // Flags
+            int ehsize = u2();
+            if( ehsize != 0x40 ) bad("EHSIZE",ehsize);
+            int phentsize = u2();
+            if( phentsize != 0x38 && phentsize != 0 ) bad("PHENTSIZE",phentsize);
+            _phnum = u2();
+            _shentsize = u2();
+            if( _shentsize != 0x40 ) bad("SHENTSIZE",_shentsize);
+            _shnum = u2();
+            // String section
+            _shstrndx = u2();
+            assert _x == ehsize;
+        }
+    }
+
+    public class Section {
+        final int _noff;        // Offset in string section for name
+        final int _type;        // Section type
+        final long _flags;
+        final long _addr;       // Offset in virtual mem, if loaded
+        final long _offset;     // Offset in file
+        final long _size;       // Size in bytes
+        final int _link;        // Associated section index, varies
+        final int _info;        // Varies
+        final byte _align;      // Log2 alignment
+        final int _esize;       // Element size, if non-zero
+        String _name;
+
+        Section(int sidx) throws IOException {
+            _x = (int)(_header._shoff + (sidx * _header._shentsize));
+            _noff  = u4();
+            _type  = u4();
+            _flags = u8();
+            _addr  = u8();
+            _offset= u8();
+            _size  = u8();
+            _link  = u4();
+            _info  = u4();
+            long align = u8();
+            if( align==0 ) align=1;
+            _align = (byte)Long.numberOfTrailingZeros(align);
+            if( (1L << _align ) != align )
+                throw new IOException("Bad section alignment: "+align);
+            _esize = (int)u8();
+        }
+
+        String str(int off) {
+            assert _type == 3/*SHT_STRTAB*/; // String table section header
+            int start = (int)(_offset+off);
+            int x = start;
+            while( _buf[x++] !=0 ) ;
+            return new String(_buf,start,x-start-1);
+        }
+    }
+
+    private static void bad(String msg, int val) throws IOException {
+        throw new IOException("Bad "+msg+": "+val);
+    }
+
+
+
+    //public TypeMemPtr lookup( String name ) {
+    //    if( _simple == null ) return null;
+    //    BAOS baos = new BAOS(_buf, (int)_simple._offset);
+    //    Ary<String> strs = Serialize.read_strs(baos);
+    //
+    //
+    //
+    //    Ary<Node> nodes = Serialize.read_types(baos);
+    //
+    //    throw Utils.TODO("Elf load symbol "+name);
+    //}
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ElfWriter.java b/src/main/java/com/seaofnodes/simple/codegen/ElfWriter.java
new file mode 100644
index 00000000..508cdcca
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/ElfWriter.java
@@ -0,0 +1,387 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeStruct;
+import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.BAOS;
+import java.io.*;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.HashMap;
+
+public class ElfWriter {
+
+    final CodeGen _code;
+    Ary<Section> _sections;
+    StringSection _strtab;
+
+    ElfWriter( CodeGen code ) {
+        _code = code;
+    }
+
+    // ------------------------------------------------------------------------
+    abstract public class Section {
+        static final int SHT_NULL    = 0;
+        static final int SHT_PROGBITS= 1;
+        static final int SHT_SYMTAB  = 2;
+        static final int SHT_STRTAB  = 3;
+        static final int SHT_RELA    = 4;
+        static final int SHT_SIMPLE  = 10; // Simple section
+
+        final String _name;
+        final int _type, _entsize, _index, _name_pos, _flags;
+        int _link, _info;
+        int _file_offset;
+
+        Section(String name, int type, int entsize, int flags) {
+            _name = name;
+            _type = type;
+            _entsize = entsize;
+            _flags = flags;
+            _index = _sections._len;
+            _sections.push(this);
+            _name_pos = name.isEmpty()
+                    ? 0  // Null section
+                    : _strtab == null
+                    ? 1  // StringSection
+                    // All the other sections
+                    : _strtab.writeCString(name);
+        }
+
+        void writeHeader(ByteBuffer out) {
+            out.putInt(_name_pos);     // name
+            out.putInt(_type);         // type
+            out.putLong(_flags);       // flags
+            out.putLong(0);            // addr
+            out.putLong(_file_offset); // offset
+            out.putLong(size());       // size
+            out.putInt(_link);         // link
+            out.putInt(_info);         // info
+            out.putLong(16);           // addralign
+            out.putLong(_entsize);     // Fixed-size element size
+        }
+
+        abstract void write(ByteBuffer out);
+        abstract int size();
+    }
+
+    // ------------------------------------------------------------------------
+    // Generic data sections; carries about a BAOS for bits
+    public class DataSection extends Section {
+        static final int SHF_WRITE     = 1;
+        static final int SHF_ALLOC     = 2;
+        static final int SHF_EXECINSTR = 4;
+        static final int SHF_INFO_LINK = 64;
+
+        final BAOS _contents;
+
+        DataSection( String name, int type, int flags, int entsize ) { this(name, type, flags, entsize, new BAOS() ); }
+        DataSection( String name, int type, BAOS contents, int flags ) { this(name, type, flags, 0, contents ); }
+        private DataSection( String name, int type, int flags, int entsize, BAOS contents ) {
+            super(name, type, entsize, flags);
+            _contents = contents;
+        }
+
+        @Override void write(ByteBuffer out) { out.put(_contents.toByteArray()); }
+        @Override int size() { return _contents.size(); }
+        public void write2( int op ) {
+            _contents.write(op    );
+            _contents.write(op>> 8);
+        }
+        public void write4( int op ) {
+            _contents.write(op    );
+            _contents.write(op>> 8);
+            _contents.write(op>>16);
+            _contents.write(op>>24);
+        }
+        public void write8( long i64 ) {
+            write4( (int) i64     );
+            write4( (int)(i64>>32));
+        }
+
+    }
+
+    // ------------------------------------------------------------------------
+    // Section to collect and de-dup strings
+    public class StringSection extends DataSection {
+        final HashMap<String,Integer> _dedup = new HashMap<>();
+
+        StringSection() {
+            super(".strtab",SHT_STRTAB, 0, 0 );
+            int emptyoff = writeCString("");   // Always empty string at offset 0
+            assert emptyoff == 0;
+            int namepos = writeCString(".strtab");
+            assert namepos == _name_pos;
+        }
+
+        public int writeCString(String name) {
+            if( name==null ) return 0; // Anonymous functions have no name
+            Integer ii = _dedup.get(name);
+            if( ii != null ) return ii;
+            // place name in the string table
+            int pos = _contents.size();
+            _dedup.put(name,pos);
+            byte[] name_bytes = name.getBytes();
+            _contents.write(name_bytes);
+            // the strings are null terminated
+            _contents.write(0);
+            return pos;
+        }
+    }
+
+    // ------------------------------------------------------------------------
+    // The relocations; 3 words per relocation
+    public class ReloSection extends DataSection {
+        ReloSection( int info ) {
+            super(".rela.text", SHT_RELA, SHF_INFO_LINK, 24/*entsize*/);
+            _link = 2;
+            _info = info;
+        }
+
+        void writeReloOffPlus(int offset, int symidx, byte relo) {
+            assert symidx > 0;
+            write8(offset);
+            write8(((long)symidx << 32L) | relo);
+            write8(-4);
+        }
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Symbols section; emit the symbols into the data section directly
+    public class SymbolSection extends DataSection {
+        public static final int SYMBOL_SIZE = 4+1+1+2+8+8;
+        final BAOS _globals;
+        final int _nlocals;
+
+        SymbolSection(int nlocals) {
+            super(".symtab", SHT_SYMTAB, 0/*flags*/, SYMBOL_SIZE);
+            _globals = new BAOS();
+            _nlocals = nlocals;
+        }
+
+        // Global symbol index
+        int gidx() { return _nlocals+(_globals.size()/SYMBOL_SIZE); }
+
+        public int symbol( String name, int shndx, int bind, int type, long value, long size ) {
+            int gidx = gidx();  // Global index before I write to _globals
+            BAOS baos = bind==SYM_BIND_GLOBAL ? _globals : _contents;
+            write4(baos,_strtab.writeCString(name));
+            int info = (bind << 4) | (type & 0xF);
+            baos.write(info);
+            baos.write(0);      // other/visibility
+            write2(baos,shndx); // section index
+            write8(baos,value);
+            write8(baos,size);
+            return bind==SYM_BIND_GLOBAL ? gidx : -99;
+        }
+
+        public int symbol( String name, int shndx, int bind, int type ) {
+            return symbol(name,shndx,bind,type,0,0);
+        }
+
+        // creates function and stores where it starts.
+        // Filters to just this class.obj file.
+        void encodeFunctions(StopNode stop, Encoding enc, int text_idx) {
+            for( Node stopcu : stop._inputs ) {
+                for( Node ret : stopcu._inputs ) {
+                    FunNode fun = ((ReturnNode)ret).fun();
+                    if( !_code.owns(fun) )
+                        continue;
+                    int end = enc.opStart(fun.ret()) + enc.opLen(fun.ret());
+                    long value = enc.opStart(fun);
+                    long size = end - value;
+                    if( fun._name != null ) // Anonymous functions have no name
+                        symbol(fun._name, text_idx, SYM_BIND_GLOBAL, SYM_TYPE_FUNC, value, size);
+                }
+            }
+        }
+
+        // Insert a default-main for top-level compilations, if the top-level
+        // does not declare a main.
+        void symbolEntryClinit(int text_idx, Encoding enc) {
+            FunNode clinit = null;
+            String entryName = _code.entryClinitName();
+            for( FunNode fun : _code._linker )
+                if( fun != null && _code.owns(fun) ) {
+                    if( "main".equals(fun._name) )
+                        return; // Top-level declared a main, take the existing one
+                    if( entryName.equals(fun._name) )
+                        clinit = fun; // Keep top-level entry, if we don't find an explicit main
+                }
+            // No top-level main, so the top-level clinit becomes a default main
+            if( clinit != null ) {
+                assert enc.opStart(clinit) == 0;
+                symbol("main",text_idx, SYM_BIND_GLOBAL, SYM_TYPE_FUNC, enc.opStart(clinit), 0);
+                return;
+            }
+            throw new IllegalStateException("Missing entry <clinit> "+entryName);
+        }
+
+        static void write2( BAOS bits, int op ) {
+            bits.write(op    );
+            bits.write(op>> 8);
+        }
+        static void write4( BAOS bits, int op ) {
+            bits.write(op    );
+            bits.write(op>> 8);
+            bits.write(op>>16);
+            bits.write(op>>24);
+        }
+        static void write8( BAOS bits, long i64 ) {
+            write4(bits, (int) i64     );
+            write4(bits, (int)(i64>>32));
+        }
+
+        @Override
+        void writeHeader(ByteBuffer out) {
+            // points to string table section
+            _link = _strtab._index;
+            _info = _nlocals;
+            super.writeHeader(out);
+        }
+
+        @Override void write(ByteBuffer out) {
+            out.put(_contents.toByteArray());
+            out.put(_globals .toByteArray());
+        }
+        @Override int size() {
+            return _contents.size() + _globals.size();
+        }
+    }
+
+    public static final int SYM_BIND_LOCAL   = 0;
+    public static final int SYM_BIND_GLOBAL  = 1;
+
+    public static final int SYM_TYPE_NOTYPE  = 0;
+    public static final int SYM_TYPE_OBJECT  = 1;
+    public static final int SYM_TYPE_FUNC    = 2;
+    public static final int SYM_TYPE_SECTION = 3;
+
+    public static final int SECTION_HDR_SIZE = 64;
+
+    // ------------------------------------------------------------------------
+    public class SimpleSection extends DataSection {
+        SimpleSection(BAOS serial) { super(".simple", SHT_SIMPLE, serial, 0); }
+    }
+
+
+    // ------------------------------------------------------------------------
+
+    public ElfWriter export(boolean emitEntrySymbol) {
+        // Sections are created in the order they are emitted.
+        _sections = new Ary<>(Section.class);
+
+        // Null section
+        Section nullSection = new DataSection("",Section.SHT_NULL,0,0);
+
+        // String section next; written out early and available to record/dedup
+        // strings for all remaining sections
+        _strtab = new StringSection();
+
+        // place all the symbols
+        int nlocals = 1/*null*/+7/*number of sections*/+1/*Simple section*/;
+        SymbolSection symbols = new SymbolSection(nlocals);
+
+        // we've already constructed these entire sections in the encoding phase
+        Encoding enc = _code._encoding;
+        DataSection text   = new DataSection(".text"  , Section.SHT_PROGBITS, enc._bits , DataSection.SHF_ALLOC | DataSection.SHF_WRITE | DataSection.SHF_EXECINSTR );
+        // Constant pool
+        DataSection rodata = new DataSection(".rodata", Section.SHT_PROGBITS, enc._cpool, DataSection.SHF_ALLOC );
+        // Static/global pool
+        DataSection rwdata = new DataSection(".data"  , Section.SHT_PROGBITS, enc._sdata, DataSection.SHF_ALLOC | DataSection.SHF_WRITE );
+
+
+        // populate function symbols
+        symbols.encodeFunctions(_code._stop, _code._encoding, text._index);
+        // Export the source compilation unit <clinit> as the C runtime "main".
+        // Encoding keeps this function at text offset zero.
+        if( emitEntrySymbol )
+            symbols.symbolEntryClinit(text._index,enc);
+
+        // create external .text relocations
+        ReloSection relocations = new ReloSection(text._index);
+
+        for( Node n : enc._externals.keySet()) {
+            String extern = enc._externals.get(n);
+            int symidx = symbols.symbol(extern, 0, SYM_BIND_GLOBAL, SYM_TYPE_NOTYPE);
+            int offset = enc.opStart(n) + enc.opLen(n) - 4;
+            relocations.writeReloOffPlus(offset, symidx, (byte)4/*PLT32*/);
+        }
+
+        // Write relocations for the constant pool
+        for( Encoding.Relo relo : enc._bigCons.values() ) {
+            boolean ro = !(relo._t instanceof TypeStruct ts) || ts.isConstant();
+            DataSection data = ro ? rodata : rwdata;
+            int symidx = symbols.symbol("CPOOL$"+symbols.gidx(), data._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC, relo._target, relo._t.size());
+            relocations.writeReloOffPlus(relo._opStart+relo._off, symidx, relo._elf );
+        }
+
+        // Create a "Simple" section for Simple types and ir
+        SimpleSection simple = new SimpleSection(_code._serial);
+
+        // Write the local section header symbols
+        assert nlocals == 1+_sections._len;
+        symbols.symbol("",0,0,0); // Null symbol at index 0
+        for( Section s : _sections )
+            symbols.symbol(s._name, s._index, SYM_BIND_LOCAL, SYM_TYPE_SECTION, 0, s.size());
+
+        int size = 64; // ELF header size
+        // size of all section data
+        for( Section s : _sections ) {
+            s._file_offset = size;
+            size += s.size();
+        }
+        // headers go at the very end
+        int shdr_offset = size;
+        size += SECTION_HDR_SIZE*_sections.len();
+
+        ByteBuffer out = ByteBuffer.allocate(size);
+        out.order(ByteOrder.LITTLE_ENDIAN);
+
+        // ELF header
+        out.put(new byte[]{ 0x7F, 'E', 'L', 'F', 2, 1, 1, 0 });
+        out.put(new byte[8]);
+        out.putShort((short)1 /* ET_REL */); // type
+        out.putShort((short)62 /* AMD64 */); // machine
+        out.putInt(1);                // version
+        out.putLong(0);               // entry
+        out.putLong(0);               // phoff
+        out.putLong(shdr_offset);     // shoff
+        out.putInt(0);                // flags
+        out.putShort((short)64);      // ehsize
+        out.putShort((short)0);       // phentsize
+        out.putShort((short)0);       // phnum
+        out.putShort((short)64);      // shentsize
+        out.putShort((short) _sections.len()); // shnum
+        out.putShort((short) _strtab._index);  // shstrndx
+
+        // raw section data
+        for( Section s : _sections )
+            s.write(out);
+
+        // Section headers
+        for( Section s : _sections )
+            s.writeHeader(out);
+
+        assert out.position() == size;
+
+        String objName = _code._buildDir + "/" + _code._srcName + ".o";
+        File file = new File(objName);
+        if( file.getParentFile()!=null )
+            file.getParentFile().mkdirs();
+        try {
+            BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
+            bos.write(out.array());
+            bos.close();
+        } catch( IOException ioe ) {
+            // Caller does not want to deal, but it is a failed compilation in any case
+            throw new RuntimeException(ioe);
+        }
+        // Reset for next ELF
+        _sections = null;
+        _strtab = null;
+        return this;
+    }
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Encoding.java b/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
index e3684445..4c7475fd 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
@@ -1,12 +1,10 @@
 package com.seaofnodes.simple.codegen;
 
+import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.print.IRPrinter;
 import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.util.*;
 import java.util.*;
 
 
@@ -24,11 +22,14 @@ public class Encoding {
     // Top-level program graph structure
     public final CodeGen _code;
 
+    // CFG Nodes in RPO order, per-encoding.
+    public Ary<CFGNode> _cfg;
+
     // Instruction bytes.  The registers are encoded already.  Relocatable data
     // is in a fixed format depending on the kind of relocation.
 
     // - RIP-relative offsets into the same chunk are just encoded with their
-    //   check relative offsets; no relocation info is required.
+    //   chunk relative offsets; no relocation info is required.
 
     // - Fixed address targets in the same encoding will be correct for a zero
     //   base; moving the entire encoding requires adding the new base address.
@@ -36,17 +37,10 @@ public class Encoding {
     // - RIP-relative to external chunks have a zero offset; the matching
     //   relocation info will be used to patch the correct value.
 
-    public static class BAOS extends ByteArrayOutputStream {
-        public byte[] buf() { return buf; }
-        void set( byte[] buf0, int count0 ) { buf=buf0; count=count0; }
-    };
-    final public BAOS _bits = new BAOS();
-
-    public int [] _opStart;     // Start  of opcodes, by _nid
-    public byte[] _opLen;       // Length of opcodes, by _nid
-
-    // Function headers now padded when printing
-    public boolean _padFunHeads;
+    public final BAOS _bits  = new BAOS(); // Instructions / encodings
+    public final BAOS _cpool = new BAOS(); // Constant r/o pool
+    public final BAOS _sdata = new BAOS(); // Static   r/w pool
+    public final HashMap<Node,Relo> _bigCons = new HashMap<>();
 
     // Big Constant relocation info.
     public static class Relo {
@@ -54,15 +48,16 @@ public class Encoding {
         public final Type _t;          // Constant type
         public final byte _off;        // Offset from start of opcode
         public final byte _elf;        // ELF relocation type, e.g. 2/PC32
-        public int _target;      // Where constant is finally placed
-        public int _opStart;     // Opcode start
+        public int _target;            // Where constant is finally placed
+        public int _opStart;           // Opcode start
         Relo( Node op, Type t, byte off, byte elf ) {
             _op=op;  _t=t;  _off=off; _elf=elf;
         }
     }
-    public final HashMap<Node,Relo> _bigCons = new HashMap<>();
 
-    Encoding( CodeGen code ) { _code = code; }
+    Encoding( CodeGen code ) {
+        _code = code;
+    }
 
     // Shortcut to the defining register
     public short reg(Node n) {
@@ -103,14 +98,6 @@ public class Encoding {
     }
 
     // Convenience for writing log-N
-    static void addN( int log, Type t, BAOS bits ) {
-        long x = t instanceof TypeInteger ti
-            ? ti.value()
-            : log==3
-            ? Double.doubleToRawLongBits(    ((TypeFloat)t).value())
-            : Float.floatToRawIntBits((float)((TypeFloat)t).value());
-        addN(log,x,bits);
-    }
     static void addN( int log, long x, BAOS bits ) {
         for( int i=0; i < 1<<log; i++ ) {
             bits.write((int)x);
@@ -123,48 +110,88 @@ public class Encoding {
     public Encoding add4( int op ) { addN(2,op,_bits); return this; }
     public Encoding add8(long op ) { addN(3,op,_bits); return this; }
 
+    private final static int SENTINEL = -1;
+    private final IntHashMap _opStart = new IntHashMap(SENTINEL);
+    private final IntHashMap _opLen   = new IntHashMap(SENTINEL);
+
+
+    // Read op start for n
+    public int opStart(Node n) { return _opStart.get(n._nid); }
+    // Read op length for n
+    public byte opLen (Node n) { return (byte)_opLen.get(n._nid); }
+
+    // Set op start for n
+    public void opStart(Node n, int off) {
+        assert off != SENTINEL;
+        _opStart.put(n._nid,off);
+    }
+
+    // Set op start for n
+    public void opStartAdd(Node n, int off) {
+        if( off==0 ) return;
+        int old = _opStart.get(n._nid);
+        assert old != SENTINEL && old+off != SENTINEL;
+        _opStart.put(n._nid,old+off);
+    }
+
+    // Set op length for n
+    public void opLen(Node n, byte len) {
+        assert len != SENTINEL;
+        _opLen.put(n._nid,len);
+    }
 
     // Nodes need "relocation" patching; things done after code is placed.
     // Record src and dst Nodes.
     private final HashMap<Node,CFGNode> _internals = new HashMap<>();
     // Source is a Call, destination in the Fun.
     public Encoding relo( CallNode call ) {
-        _internals.put(call,_code.link(call.tfp()));
+        FunNode fun = _code.link(call.tfp());
+        if( fun != null && !_code.owns(fun) )
+            _externals.put(call,fun._name);
+        else
+            _internals.put(call,fun);
         return this;
     }
-    public Encoding relo( ConstantNode con ) {
-        TypeFunPtr tfp = (TypeFunPtr)con._con;
-        _internals.put(con,_code.link(tfp));
+    // Code address as a constant
+    public Encoding relo( FunPtrNode fptr ) {
+        TypeFunPtr tfp = (TypeFunPtr)fptr._type;
+        FunNode fun = _code.link(tfp);
+        if( fun != null && !_code.owns(fun) )
+            _externals.put(fptr,fun._name);
+        else
+            _internals.put(fptr,fun);
         return this;
     }
+    // Local jump
     public void jump( CFGNode jmp, CFGNode dst ) {
         _internals.put(jmp,dst.uctrlSkipEmpty());
     }
 
-
-    final HashMap<Node,String> _externals = new HashMap<>();
+    // External references only located by Strings a link-time
+    public final HashMap<Node,String> _externals = new HashMap<>();
     public Encoding external( Node n, String extern ) {
         _externals.put(n,extern);
         return this;
     }
 
     // Store t as a 32/64 bit constant in the code space; generate RIP-relative
-    // addressing to load it
+    // addressing to load it.  Type is stored in either the .rodata or .data.
     public void largeConstant( Node relo, Type t, int off, int elf ) {
-        assert t.isConstant();
+        // TODO: Any-old struct in the cpool
+        assert t.isConstant() || (t instanceof TypeStruct ts && Parser.startsClzPrefix(ts._name));
         assert (byte)off == off;
         assert (byte)elf == elf;
         _bigCons.put(relo,new Relo(relo,t,(byte)off,(byte)elf));
     }
 
     // --------------------------------------------------
-    void encode() {
+    Encoding encode( ) {
         // Basic block layout: negate branches to keep blocks in-order; insert
         // unconditional jumps.  Attempt to keep backwards branches taken,
         // forwards not-taken (this is the default prediction on most
         // hardware).  Layout is still Reverse Post Order but with more
         // restrictions.
-        basicBlockLayout();
+        basicBlockLayout( );
 
         // Write encoding bits in order into a big byte array.
         // Record opcode start and length.
@@ -174,8 +201,15 @@ public class Encoding {
         // encodings and compact the code, changing all the offsets.
         compactShortForm();
 
+        // Write the constant pool
+        writeConstantPool(_cpool,true );
+        // Write the static memory
+        writeConstantPool(_sdata,false);
+
         // Patch RIP-relative and local encodings now.
         patchLocalRelocations();
+
+        return this;
     }
 
     // --------------------------------------------------
@@ -183,29 +217,48 @@ public class Encoding {
     // unconditional jumps.  Attempt to keep backwards branches taken, forwards
     // not-taken (this is the default prediction on most hardware).  Layout is
     // still Reverse Post Order but with more restrictions.
-    private void basicBlockLayout() {
+    private void basicBlockLayout( ) {
         IdentityHashMap<LoopNode,Ary<CFGNode>> rpos = new IdentityHashMap<>();
-        Ary<CFGNode> rpo = new Ary<>(CFGNode.class);
-        rpos.put(_code._start.loop(),rpo);
+        _cfg = new Ary<>(CFGNode.class);
+        rpos.put(_code._start.loop(),_cfg);
         BitSet visit = _code.visit();
-        rpo.add(_code._stop);
-        FunNode main = _code.link(_code._main);
-        for( Node n : _code._start._outputs )
-            if( n instanceof FunNode fun && fun != main ) {
-                int x = rpo._len;
-                _rpo_cfg(fun, visit, rpos );
-                assert rpo.at(x) instanceof ReturnNode;
+
+        // Do them all except the <clinit>s
+        Ary<FunNode> clinits = new Ary<>(FunNode.class);
+        FunNode entry = null;
+        String entryName = _code.entryClinitName();
+        for( FunNode fun : _code._linker ) {
+            if( fun != null && !fun.isDead() && _code.owns(fun) ) {
+                if( fun.isClz() ) {
+                    if( fun._name.equals(entryName) )
+                        entry = fun;
+                    else
+                        clinits.add(fun);
+                } else {
+                    int x = _cfg._len;
+                    _rpo_cfg(fun,visit,rpos);
+                    assert _cfg.at(x) instanceof ReturnNode;
+                }
             }
-        // Do any main function last... so it lands at offset 0 in the RPO
-        if( main!=null )
-            _rpo_cfg(main, visit, rpos );
-        rpo.add(_code._start);
+        }
+        // Now the <clinit>s last, so when reversed they become first.  The
+        // program entry <clinit> is last of all, so it lands at offset zero.
+        for( FunNode clinit : clinits ) {
+            int x = _cfg._len;
+            _rpo_cfg(clinit,visit,rpos);
+            assert _cfg.at(x) instanceof ReturnNode;
+        }
+        if( entry != null ) {
+            int x = _cfg._len;
+            _rpo_cfg(entry,visit,rpos);
+            assert _cfg.at(x) instanceof ReturnNode;
+        }
+
 
         // Reverse in-place
-        for( int i=0; i< rpo.size()>>1; i++ )
-            rpo.swap(i,rpo.size()-1-i);
+        for( int i=0; i< _cfg.size()>>1; i++ )
+            _cfg.swap(i,_cfg.size()-1-i);
         visit.clear();
-        _code._cfg = rpo;       // Save the new ordering
     }
 
 
@@ -279,7 +332,7 @@ public class Encoding {
     private static boolean shouldInvert(CFGNode t, CFGNode f, int bld) {
         int tld = t.loopDepth(), fld = f.loopDepth();
         // These next two are symmetric and can happen in any order; if `tld <
-        // bld` is true, the `fld < bld` must be false, or else both directions
+        // bld` is true, then `fld < bld` must be false, or else both directions
         // exit the loop... and the IF test would not be in the loop.
 
         // true to exit a loop usually (and false falls into Yet Another Loop
@@ -324,24 +377,26 @@ public class Encoding {
     // --------------------------------------------------
     // Write encoding bits in order into a big byte array.
     // Record opcode start and length.
-    public FunNode _fun;        // Currently encoding function
+
+    // Current function is used by the spill-op encodings to query the stack
+    // frame layout and get the spill offsets.
     private void writeEncodings() {
-        _opStart= new int [_code.UID()];
-        _opLen  = new byte[_code.UID()];
-        for( CFGNode bb : _code._cfg ) {
+        for( CFGNode bb : _cfg ) {
             if( !(bb instanceof MachNode mach0) )
-                _opStart[bb._nid] = _bits.size();
-            else if( bb instanceof FunNode fun ) {
-                _fun = fun;     // Currently encoding function
-                _opStart[bb._nid] = _bits.size();
+                opStart(bb, _bits.size());
+            else if( bb instanceof FunNode ) {
+                opStart(bb, _bits.size());
                 mach0.encoding( this );
-                _opLen[bb._nid] = (byte) (_bits.size() - _opStart[bb._nid]);
+                opLen(bb, (byte) (_bits.size() - opStart(bb)));
             }
             for( Node n : bb._outputs ) {
-                if( n instanceof MachNode mach && !(n instanceof FunNode) ) {
-                    _opStart[n._nid] = _bits.size();
+                if( n instanceof MachNode mach && !(n instanceof FunNode) &&
+                    // FunPtrs are encoding in the block of their control, not
+                    // the block of the ReturnNode input - which is also a CFG.
+                    !(n instanceof FunPtrNode && bb instanceof ReturnNode) ) {
+                    opStart(n, _bits.size());
                     mach.encoding( this );
-                    _opLen[n._nid] = (byte) (_bits.size() - _opStart[n._nid]);
+                    opLen(n, (byte) (_bits.size() - opStart(n)));
                 }
             }
         }
@@ -351,10 +406,10 @@ public class Encoding {
     // Short-form RIP-relative support: replace short encodings with long
     // encodings and expand the code, changing all the offsets.
     private void compactShortForm() {
-        int len = _code._cfg._len;
+        int len = _cfg._len;
         int[] oldStarts = new int[len];
         for( int i=0; i<len; i++ )
-            oldStarts[i] = _opStart[_code._cfg.at(i)._nid];
+            oldStarts[i] = opStart(_cfg.at(i));
 
         // TODO: Rewrite this algo to use the small "_jmps" list of just the
         // jumps instead of walking all blocks.
@@ -368,24 +423,27 @@ public class Encoding {
         while( slide != 0) {    // While no fails
             slide = 0;
             for( int i=0; i<len; i++ ) {
-                CFGNode bb = _code._cfg.at(i);
-                _opStart[bb._nid] += slide;
+                CFGNode bb = _cfg.at(i);
+                opStartAdd(bb, slide);
                 // Slide down all other (non-CFG) ops in the block
                 for( Node n : bb._outputs )
-                    if( n instanceof MachNode && !(n instanceof CFGNode) )
-                        _opStart[n._nid] += slide;
+                    if( n instanceof MachNode && !(n instanceof CFGNode) &&
+                        // Match writeEncodings(): FunPtrs are encoded in the
+                        // block of their control, not again at the Return.
+                        !(n instanceof FunPtrNode && bb instanceof ReturnNode) )
+                        opStartAdd(n, slide);
                 if( bb instanceof RIPRelSize riprel ) {
                     CFGNode target = (bb instanceof IfNode iff ? iff.cproj(0) : (CFGNode)bb.out(0)).uctrlSkipEmpty();
                     // Delta is from opStart to opStart.  X86 at least counts
                     // the delta from the opEnd, but we don't have the end until
                     // we decide the size - so the encSize has to deal
-                    int delta = _opStart[target._nid] - _opStart[bb._nid];
+                    int delta = opStart(target) - opStart(bb);
                     byte opLen = riprel.encSize(delta);
                     // Recorded size is smaller than the current size?
-                    if( _opLen[bb._nid] < opLen ) {
+                    if( opLen(bb) < opLen ) {
                         // Start sliding the code down; record slide amount and new size
-                        slide += opLen - _opLen[bb._nid];
-                        _opLen[bb._nid] = opLen;
+                        slide += opLen - opLen(bb);
+                        opLen(bb, opLen);
                     }
                 }
             }
@@ -396,21 +454,21 @@ public class Encoding {
         // short-jumps span function headers, the padding will not make any
         // short jumps fail.
         for( int i=0; i<len; i++ ) {
-            CFGNode bb = _code._cfg.at(i);
+            CFGNode bb = _cfg.at(i);
             // Functions pad to align 16
             if( bb instanceof FunNode ) {
-                int newStart = _opStart[bb._nid]+slide;
+                int newStart = opStart(bb)+slide;
                 slide += (newStart+15 & -16)-newStart;
             }
-            _opStart[bb._nid] += slide;
+            opStartAdd(bb, slide);
             for( Node n : bb._outputs )
-                if( n instanceof MachNode && !(n instanceof CFGNode) )
-                    _opStart[n._nid] += slide;
+                if( n instanceof MachNode && !(n instanceof CFGNode) &&
+                    !(n instanceof FunPtrNode && bb instanceof ReturnNode) )
+                    opStartAdd(n, slide);
         }
-        _padFunHeads = true;
 
         // Copy/slide the bits to make space for all the longer branches
-        int grow = _opStart[_code._cfg.at(len-1)._nid] - oldStarts[len-1];
+        int grow = opStart(_cfg.at(len-1)) - oldStarts[len-1];
         if( grow > 0 ) {        // If no short-form ops, nothing to do here
             int end = _bits.size();
             byte[] bits = new byte[end+grow];
@@ -418,7 +476,7 @@ public class Encoding {
                 int start = oldStarts[i];
                 if( start==0 && i>1 ) continue;
                 int oldStart = oldStarts[i];
-                int newStart = _opStart[_code._cfg.at(i)._nid];
+                int newStart = opStart(_cfg.at(i));
                 System.arraycopy(_bits.buf(),oldStart,bits,newStart,end-start);
                 end = start;
             }
@@ -433,22 +491,28 @@ public class Encoding {
     void patchLocalRelocations() {
         // Walk the local code-address relocations
         for( Node src : _internals.keySet() ) {
-            int start  = _opStart[src._nid];
+            int start = opStart(src);
             Node dst =  _internals.get(src);
-            int target = _opStart[dst._nid];
-            ((RIPRelSize)src).patch(this, start, _opLen[src._nid], target - start);
+            // If function is entirely dead, only the function pointer remains
+            // and, it can only be used to test against zero or equals to
+            // another function pointer... i.e., there Is No Code Here.
+            int target = dst == null ? start : opStart(dst);
+             ((RIPRelSize)src).patch(this, start, opLen(src), target - start);
         }
     }
 
     // --------------------------------------------------
     // Write the constant pool into the BAOS and optionally patch locally
-    void writeConstantPool( BAOS bits, boolean patch ) {
+    void writeConstantPool( BAOS bits, boolean ro ) {
         padN(16,bits);
 
         // radix sort the big constants by alignment
         Ary<Relo>[] raligns = new Ary[5];
         for( Node op : _bigCons.keySet() ) {
             Relo relo = _bigCons.get(op);
+            // non-constant structs in the r/w data, everything else in r/o data
+            if( (relo._t instanceof TypeStruct ts && !ts.isConstant()) == ro )
+                continue;
             int align = relo._t.alignment();
             Ary<Relo> relos = raligns[align]==null ? (raligns[align]=new Ary<>(Relo.class)) : raligns[align];
             relos.add(relo);
@@ -459,7 +523,7 @@ public class Encoding {
         HashMap<Type,Integer> targets = new HashMap<>();
 
         // By alignment
-        for( int align = 4; align >= 0; align-- ) {
+        for( int align = raligns.length-1; align >= 0; align-- ) {
             Ary<Relo> relos = raligns[align];
             if( relos == null ) continue;
             for( Relo relo : relos ) {
@@ -469,30 +533,37 @@ public class Encoding {
                     targets.put(relo._t,target = bits.size());
                     // Write constant into constant pool
                     switch( relo._t ) {
-                    case TypeTuple  tt -> cpool(align,bits,tt);
-                    case TypeStruct ts -> cpool(bits,ts);
-                    // Simple primitive (e.g. larger int, float)
+                    case TypeTuple  tt -> throw Utils.TODO("no tuples here, use structs instead");
+                    case TypeStruct ts -> addStruct(bits,ts);
+                    // Simple primitive (e.g. larger int, float, function ptr)
                     default -> addN(align,relo._t,bits);
                     }
                 }
-                // Record target address and opcode start
+                // Record target address and opcode start.
+                // Target is relative to the cpool/sdata start.
                 relo._target = target;
-                relo._opStart= _opStart[relo._op._nid];
-                // Go ahead and locally patch in-memory
-                if( patch )
-                    ((RIPRelSize)relo._op).patch(this, relo._opStart, _opLen[relo._op._nid], relo._target - relo._opStart);
+                relo._opStart= opStart(relo._op);
             }
         }
+
     }
 
-    // Constant tuples put all entries at same alignment
-    private void cpool(int align, BAOS bits, TypeTuple tt) {
-        for( Type tx : tt._types )
-            addN(align,tx,bits);
+    // Emit a single scalar as bits
+    static void addN( int log, Type t, BAOS bits ) {
+        long x = switch( t ) {
+        case TypeInteger ti -> ti.value();
+        case TypeFloat tf -> log==3
+        ? Double.doubleToRawLongBits(    tf.value())
+        : Float.floatToRawIntBits((float)tf.value());
+        case TypeFunPtr tfp -> 0; // These need to be relocated
+        case TypeMemPtr tmp -> 0; // These need to be relocated
+        default -> { if( t==Type.NIL ) yield 0; else throw Utils.TODO(); }
+        };
+        addN(log,x,bits);
     }
 
     // Structs use internal field layout
-    private void cpool( BAOS bits, TypeStruct ts ) {
+    private void addStruct( BAOS bits, TypeStruct ts ) {
         // Field order by offset
         int[] layout = ts.layout();
         int off=0; // offset in the struct
@@ -507,7 +578,7 @@ public class Encoding {
                 off += ((TypeConAry)f._t).len();
             } else {
                 int log = f._t.log_size();
-                addN(log,f._t,bits);
+                addN(log,f._t.isConstant() ? f._t : f._t.makeZero(),bits);
                 off += 1<<log;
             }
         }
@@ -522,14 +593,14 @@ public class Encoding {
 
     void patchGlobalRelocations() {
         for( Node src : _externals.keySet() ) {
-            int start  = _opStart[src._nid];
+            int start  = opStart(src);
             String dst =  _externals.get(src);
             int target = switch( dst ) {
             case "calloc" -> SENTINEL_CALLOC;
             case "write"  -> SENTINEL_WRITE ;
             default -> throw Utils.TODO();
             };
-            ((RIPRelSize)src).patch(this, start, _opLen[src._nid], target - start);
+            ((RIPRelSize)src).patch(this, start, opLen(src), target - start);
         }
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/GlobalBits.java b/src/main/java/com/seaofnodes/simple/codegen/GlobalBits.java
new file mode 100644
index 00000000..b0060024
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/GlobalBits.java
@@ -0,0 +1,171 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.util.*;
+import java.util.HashMap;
+import java.util.Arrays;
+import java.util.Objects;
+
+
+// This utility 2-way maps some *global* program feature to a local dense
+// index, suitable for packing in BitSets.  The mapping takes a global value -
+// always a {source file/class} name and an order number counting up per
+// feature in the same file.  The dense local index can be different in
+// different compilations.
+
+// The global info allows loading the same remote class info from different
+// paths and aligning them.  Example: Compiling A loads pre-compiled B and C,
+// both of which load pre-compiled D.  The 2 different D loads unify via this
+// global info.
+
+// These mappings are all trivial identities when compiling one file; they
+// only become complex when loading seperately compiled code.
+
+public class GlobalBits {
+    public static final int RESERVED = 2;
+    private final HashMap<String,int[]> _clzOrder2Local = new HashMap<>();
+    private final Ary<String> _local2Clz = new Ary<>(String.class);
+    private final AryInt _local2Order = new AryInt();
+    // Local dense index
+    private int _local;
+
+    GlobalBits() {
+        _local = RESERVED;
+        // Reserved null-class bits are global identities and are never
+        // remapped.
+        int[] xs = new int[RESERVED];
+        xs[0] = RESERVED;       // Per-class next order counter
+        for( int i=0; i<RESERVED; i++ ) {
+            if( i > 0 ) xs[i] = i;
+            _local2Clz  .setX(i,null);
+            _local2Order.setX(i,i);
+        }
+        _clzOrder2Local.put(null,xs);
+    }
+
+    // Get a next local index for this clz
+    int next( String clz ) { return next(clz,-1); }
+
+    // Given a clz and order, return an existing local index or make a new
+    // mapping and return that.
+    int next(String clz, int order ) {
+        // Get the per-clz Order->Local mapping
+        int[] xs = _clzOrder2Local.get(clz);
+        if( xs == null )
+            xs = new int[]{RESERVED,1}; // Make, if it does not exist
+        // Caller does not have an order in mind, just take the next one stored
+        // in xs[0]
+        if( order == -1 )
+            order = xs[0]++;
+        // Order exists from prior compilation, but not recorded locally
+        else if( order >= xs[0] )
+            xs[0] = order+1;
+        // Grow as needed
+        while( xs.length <= order )
+            xs = Arrays.copyOf(xs,xs.length*2);
+        // Have a local mapping already?
+        if( xs[order] != 0 )
+            return xs[order];
+        int local = _local++;
+        bind(local,clz,order);
+        return local;        // The dense local index
+    }
+
+    // Bind a specific dense local index to {clz,order}.  Used by both fresh
+    // allocation and deserialization, where local indexes must not compact
+    // across holes because XInt bitsets are serialized against this space.
+    private void bind( int local, String clz, int order ) {
+        if( _local <= local )
+            _local = local+1;
+        _local2Clz  .setX(local,clz  );
+        _local2Order.setX(local,order);
+
+        // Inline-only fidx holes are represented as {null,0}.  They need the
+        // reverse mapping above, but no forward map because xs[0] is the
+        // per-class next-order counter.
+        if( clz==null && order==0 )
+            return;
+
+        int[] xs = _clzOrder2Local.get(clz);
+        if( xs == null )
+            xs = new int[]{RESERVED,1};
+        if( order >= xs[0] )
+            xs[0] = order+1;
+        while( xs.length <= order )
+            xs = Arrays.copyOf(xs,xs.length*2);
+        _clzOrder2Local.put(clz,xs);
+        xs[order] = local;
+    }
+
+    // A file-local function that will inline, and never write to disk
+    public int nextInline( ) {
+        int local = _local++;
+        _local2Clz  .setX(local,null);
+        _local2Order.setX(local,0);
+        return local;
+    }
+    // Get a next local index for the same clz as this old index
+    public int next( int old ) { return next(_local2Clz.at(old));  }
+
+    // Map a file-local dense index to this compilation unit's local dense index.
+    public int map( GlobalBits fileBits, int fileLocal ) {
+        if( fileLocal >= fileBits._local2Clz.size() )
+            throw new ArrayIndexOutOfBoundsException(""+fileLocal+" >= "+fileBits._local2Clz.size());
+        return findOrNext(fileBits._local2Clz.at(fileLocal), fileBits._local2Order.at(fileLocal));
+    }
+
+    // Map a global {clz,order} to a local one; keep any existing mapping or
+    // make a new one as needed.
+    private int findOrNext(String clz, int order ) {
+        // Reserved null-class identities are not represented in xs[order],
+        // because xs[0] is the next-order counter.
+        if( clz==null && order < _local2Clz.size() && _local2Order.at(order)==order && _local2Clz.at(order)==null )
+            return order;
+        int[] xs = _clzOrder2Local.get(clz);
+        if( xs != null && order < xs.length ) {
+            int local = xs[order];
+            if( local < _local2Clz.size() && _local2Order.at(local)==order && Objects.equals(_local2Clz.at(local),clz) )
+                return local;
+        }
+        return next(clz,order);
+    }
+
+    // Write out to BAOS enough bits to unwind the local back to global index
+    void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        // Unwind a local index to the clz.
+        baos.packed2(_local2Clz.size());
+        for( int i=RESERVED; i<_local2Clz.size(); i++ ) {
+            String clz = _local2Clz.at(i);
+            baos.packed2(clz==null ? 0 : strs.get(clz));
+            baos.packed2( _local2Order.at(i) );
+        }
+    }
+
+    void gather( HashMap<String,Integer> strs ) {
+        for( int i=RESERVED; i<_local2Clz.size(); i++ )
+            Serialize.gather(strs,_local2Clz.at(i));
+    }
+
+    // Read in the BAIS bits needed to make a file-local -> global mapping
+    static GlobalBits packed( BAOS bais, String[] strs ) {
+        var gb = new GlobalBits();
+        int n = bais.packed2();
+        for( int i=RESERVED; i<n; i++ ) {
+            int sx = bais.packed2();
+            String clz = strs[sx];
+            if( clz.isEmpty() ) clz = null;
+            int order = bais.packed2();
+            gb.bind(i,clz,order);
+        }
+        return gb;
+    }
+
+    @Override public String toString() {
+        SB sb = new SB().p('[');
+        for( int i=0; i<_local2Clz.size(); i++ ) {
+            if( i > 0 ) sb.p(',');
+            sb.p(i).p(" <-> ").p(_local2Clz.at(i)).p('#').p(_local2Order.at(i));
+        }
+        return sb.p(']').toString();
+    }
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java b/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
index d9c7a6ad..5d8ed03c 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
@@ -24,10 +24,10 @@ public abstract class GlobalCodeMotion {
         schedEarly(code);
 
         // Break up shared global constants by functions
-        breakUpGlobalConstants(code._start);
+        breakUpGlobalConstants(code._start );
 
         code._visit.clear();
-        schedLate (code);
+        schedLate(code);
     }
 
     // Post-Order of CFG
@@ -45,45 +45,91 @@ public abstract class GlobalCodeMotion {
 
     // Break up shared global constants by functions
     private static void breakUpGlobalConstants( Node start ) {
+
         // For all global constants
         for( int i=0; i< start.nOuts(); i++ ) {
             Node con = start.out(i);
-            if( con instanceof MachNode mach && mach.isClone() ) {
-                breakUpGlobalConstants(con);
-                // While constant has users in different functions
-                while( true ) {
-                    // Find a function user, and another function
-                    FunNode fun = null;
-                    boolean done=true;
-                    for( Node use : con.outs() ) {
-                        FunNode fun2 = use instanceof ReturnNode ret ? ret.fun() : use.cfg0().fun();
-                        if( fun==null || fun==fun2 ) fun=fun2;
-                        else { done=false; break; }
-                    }
-                    // Single function user, so this constant is not shared
-                    if( done ) {
-                        if( con.in(0)==start ) i--;
-                        con.setDef(0,fun);
-                        break;
-                    }
-                    // Move function users to a private constant
-                    Node con2 = mach.copy();  // Private constant clone
-                    con2._inputs.set(0,null); // Preserve edge invariants from clone
-                    con2.setDef(0,fun);
-                    // Move function users to this private constant
-                    for( int j=0; j<con._outputs._len; j++ ) {
-                        Node use = con.out(j);
-                        FunNode fun2 = use.cfg0().fun();
-                        if( fun2==fun ) {
-                            use.setDef(use._inputs.find(con),con2);
-                            j--;
-                        }
-                    }
+            // Instruction selection can expand one shared TypeNode constant
+            // into a constant-valued machine expression.  Split either form
+            // before scheduling, since separate functions have no CFG LCA.
+            if( !(con instanceof CFGNode) &&
+                ((con._type.isHighOrConst() && con.isConst()) ||
+                 con instanceof MachNode mach && mach.isClone() && con._type.isConstant()) ) {
+                breakUpGlobalConstantSingle( con );
+                i--;        // Removed a global constant, re-run same index
+            }
+        }
+    }
+
+
+    private static void breakUpGlobalConstantSingle( Node con ) {
+        // While constant has users in different functions
+        while( true ) {
+            // Find a function user, and another function
+            FunNode fun = null;
+            boolean done=true;
+            for( Node use : con.outs() ) {
+                if( use == null ) continue;
+                FunNode fun2 = useFun(use);
+                if( fun2==null || !CodeGen.CODE.owns(fun2) ) continue;
+                if( fun==null || fun==fun2 ) fun=fun2;
+                else { done=false; break; }
+            }
+            // Single function user, so this constant is not shared
+            if( done ) {
+                con.setDef(0,fun);
+                return;
+            }
+            // Move function users to a private constant
+            Node con2 = con.copy();   // Private constant clone
+            // Node copies made through Node(Node) carry unregistered inputs,
+            // while some machine copies construct fresh registered edges.
+            // Detach correctly in either case before pinning to the function.
+            Node old = con2.in(0);
+            if( old != null && old._outputs.find(con2) != -1 )
+                con2.setDef(0,null);
+            else
+                con2._inputs.set(0,null);
+            con2.setDef(0,fun);
+            // Move function users to this private constant
+            for( int j=0; j<con._outputs._len; j++ ) {
+                Node use = con.out(j);
+                if( use == null ) continue;
+                FunNode fun2 = useFun(use);
+                if( fun2==null || !CodeGen.CODE.owns(fun2) ) continue;
+                if( fun2==fun ) {
+                    use.setDef(use._inputs.find(con),con2);
+                    j--;
                 }
             }
         }
     }
 
+    private static FunNode useFun(Node use) {
+        if( use instanceof ReturnNode ret )
+            return ret.fun();
+        if( use instanceof ParmNode parm )
+            return parm.fun();
+        CFGNode cfg = use.cfg0();
+        if( cfg==null ) return null;
+        FunNode fun = cfg.fun();
+        // Use itself is not in a function... which makes it a 2-part
+        // constant such as happens on some chips where large constants have
+        // to be built up in parts.  PtrToInt followed by the array-body Add is
+        // another zero-code/global-value chain, so walk through any number of
+        // single-use pieces until reaching the function-owned use.
+        if( fun==null ) {
+            do {
+                assert use.nOuts()==1;
+                use = use.out(0);
+                cfg = use.cfg0();
+                fun = cfg==null ? null : cfg.fun();
+            } while( fun==null );
+        }
+        return fun;
+    }
+
+
     // ------------------------------------------------------------------------
     // Visit all nodes in CFG Reverse Post-Order, essentially defs before uses
     // (except at loops).  Since defs are visited first - and hoisted as early
@@ -252,6 +298,8 @@ public abstract class GlobalCodeMotion {
     // Block of use.  Normally from late[] schedule, except for Phis, which go
     // to the matching Region input.
     private static CFGNode use_block(Node n, Node use, CFGNode[] late) {
+        if( use instanceof ParmNode parm && n.cfg0().fun()==parm.fun() )
+            return late[use._nid];
         if( !(use instanceof PhiNode phi) )
             return late[use._nid];
         CFGNode found=null;
@@ -286,6 +334,12 @@ public abstract class GlobalCodeMotion {
                     lca = anti_dep( load, late[mem._nid], mem.cfg0(), lca, st );
                 }
                 break; // Loads do not cause anti-deps on other loads
+            case EscapeNode esc:
+                if( load._alias == esc.fld()._alias ) {
+                    assert late[mem._nid] != null;
+                    lca = anti_dep( load, late[mem._nid], mem.cfg0(), lca, mem );
+                }
+                break;
             case CallNode call:
                 assert late[call._nid]!=null;
                 lca = anti_dep(load,late[call._nid],call.cfg0(),lca,call);
diff --git a/src/main/java/com/seaofnodes/simple/codegen/IFG.java b/src/main/java/com/seaofnodes/simple/codegen/IFG.java
index 6dd6fbf1..1d88597c 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/IFG.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/IFG.java
@@ -68,9 +68,9 @@ abstract public class IFG {
         // Reset all to empty
         resetBBLiveOut();
         resetIFG();
+        WORK.clear();
 
         // Last block has nothing live out
-        assert WORK.isEmpty();
         for( CFGNode bb : alloc._code._cfg )
             if( bb.blockHead())
                 WORK.push( bb );
@@ -231,7 +231,9 @@ abstract public class IFG {
         selfConflict(alloc,n,lrg,TMP.get(lrg));
     }
     private static void selfConflict(RegAlloc alloc, Node n, LRG lrg, Node prior) {
-        if( prior!=null && prior != n ) {
+        // Casts never produce a *new* value, just lift our understanding of the value.
+        // They do not force self-conflicts.
+        if( prior!=null && prior != n && !(n instanceof CheckCastNode) ) {
             lrg.selfConflict(prior);
             lrg.selfConflict(n);
             alloc.fail(lrg); // 2 unrelated values live at once same live range; self-conflict
@@ -402,6 +404,7 @@ abstract public class IFG {
             swap(color_stack,sptr,bidx); // Pick best at sptr
     }
 
+    // Returns true if 'lrg' is better than 'best'
     private static boolean betterLRG( LRG best, LRG lrg ) {
         // If single-def varies, keep the not-single-def
         if( best.size1() != lrg.size1() )
@@ -409,6 +412,10 @@ abstract public class IFG {
         // If hasSplit varies, keep the hasSplit
         if( best.hasSplit() != lrg.hasSplit() )
             return lrg.hasSplit();
+        // If both are single register (so both sizes are 1),
+        // return a multi-use over a multi-def
+        if( best.size1() )
+            return !best._multiUse && lrg._multiUse;
         // Keep large register count
         return best.size() < lrg.size();
     }
@@ -438,7 +445,7 @@ abstract public class IFG {
     private static int pickRiskyScore( LRG lrg ) {
         // Pick single-def clonables that are not right next to their single-use.
         // Failing to color these will clone them closer to their uses.
-        if( !lrg._multiDef && lrg._machDef.isClone() ) {
+        if( !lrg._multiDef && lrg._machDef.isClone() && lrg._machUse != null ) {
             Node def = ((Node)lrg._machDef);
             Node use = ((Node)lrg._machUse);
             CFGNode cfg = def.cfg0();
@@ -458,7 +465,7 @@ abstract public class IFG {
 
         // TODO: cost/benefit model.  Perhaps counting loop-depth (freq) of def/use for cost
         // and "area" for benefit
-        return 1000;
+        return 1000 + (lrg._multiUse ? -100 : 0);
     }
 
     private static short biasColor( RegAlloc alloc, LRG lrg, short reg, RegMask mask ) {
diff --git a/src/main/java/com/seaofnodes/simple/codegen/LRG.java b/src/main/java/com/seaofnodes/simple/codegen/LRG.java
index 009ddcdb..3a4596fe 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/LRG.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/LRG.java
@@ -56,6 +56,10 @@ public class LRG {
     // Adjacent Live Range neighbors.  Only valid during coloring
     Ary<LRG> _adj;
 
+    // Function fully containing the live range; used to find the stack frame
+    // layout, for spill op offsets.
+    final public FunNode _fun;
+
     public int nadj() { return _adj==null ? 0 : _adj._len; }
 
     void addNeighbor(LRG lrg) {
@@ -78,7 +82,7 @@ public class LRG {
     // More registers than neighbors
     boolean lowDegree() { return nadj() < _mask.size(); }
 
-    LRG( short lrg ) { _lrg = lrg; _reg = -1; }
+    LRG( short lrg, FunNode fun ) { _lrg = lrg; _reg = -1; _fun = fun; }
 
     boolean leader() { return _leader == null; }
 
@@ -114,6 +118,7 @@ public class LRG {
     }
     // Union `this` and `lrg`, folding together all stats.
     private LRG _union( LRG lrg ) {
+        assert _fun == lrg._fun;
         // Set U-F leader
         lrg._leader = this;
         // Fold together stats
diff --git a/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java b/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
index 2415203d..e0b59395 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
@@ -1,6 +1,8 @@
 package com.seaofnodes.simple.codegen;
 
 import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.type.TypeStruct;
+import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 // In-memory linking
@@ -8,15 +10,23 @@ public class LinkMem {
     final CodeGen _code;
     LinkMem( CodeGen code ) { _code = code; }
 
-    public CodeGen link() {
-        Encoding enc = _code._encoding;
-
+    public CodeGen link(Encoding enc) {
         // Patch external calls internally
         enc.patchGlobalRelocations();
 
-        // Write any large constants into a constant pool; they
-        // are accessed by RIP-relative addressing.
-        enc.writeConstantPool(enc._bits,true);
+        // Place constant pool after code, static data after constants
+        int code  = 0;                     // Code start
+        int cpool = (enc._bits .size() + code  + 15) & -16;  // pad to 16
+        int sdata = (enc._cpool.size() + cpool + 15) & -16;
+
+
+        // Patch local ops, e.g. loading float constants from the constant pool
+        for( Node op : enc._bigCons.keySet() ) {
+            Encoding.Relo relo = enc._bigCons.get(op);
+            boolean ro = !(relo._t instanceof TypeStruct ts) || ts.isConstant();
+            int target = relo._target+(ro ? cpool : sdata);
+            ((RIPRelSize)relo._op).patch(enc, relo._opStart, enc.opLen(relo._op), target - relo._opStart);
+        }
 
         return _code;
     }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java b/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java
index ddf5a679..b6b3a22c 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java
@@ -28,7 +28,7 @@ public abstract class ListScheduler {
         }
         void free() { _n = null; FREE.push(this); }
 
-        static XSched get(Node n) { return n==null ? null : XS.get(n instanceof ProjNode && !(n.in(0) instanceof CallEndNode) ? n.in(0) : n); }
+        static XSched get(Node n) { return n==null ? null : XS.get(n instanceof ProjNode && !(n.in(0) instanceof CFGNode) ? n.in(0) : n); }
 
         private XSched init(CFGNode bb, Node n) {
             _n = n;
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Machine.java b/src/main/java/com/seaofnodes/simple/codegen/Machine.java
index 2766414f..91d07d57 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/Machine.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/Machine.java
@@ -6,28 +6,42 @@ import com.seaofnodes.simple.type.TypeFunPtr;
 abstract public class Machine {
     // Human readable machine name.  Something like "x86-64" or "arm" or "risc5"
     public abstract String name();
+
     // Default opcode size for printing; 4 bytes for most 32-bit risc chips
     public int defaultOpSize() { return 4; }
+
     // Human-readable name for a register number, e.g. "RAX" or "R0"
     public abstract String[] regs();
-    // Create a split op; any register to any register, including stack slots
-    public abstract SplitNode split( String kind, byte round, LRG lrg);
+
+    // Create a split op; any register to any register, including stack slots.
+    // The FunNode holds the stack layout after RegAlloc, which in turn
+    // dictates the stack slot (the frame offset) for stack splits.
+    public abstract SplitNode split( LRG lrg, String kind, byte round );
+
     // List of caller-save registers, as a 64bit mask
     public abstract long callerSave();
+    public long callerSave(String conv) { return callerSave(); }
+
     // List of never-save registers, e.g. RSP or a ZERO register if you have one
     public abstract long neverSave();
+
     // Call Argument Mask.  Passed in the function signature and argument
     // number (2-based; 0 is for control and 1 for memory).  Also passed in a 0
     // for the function itself, or for *outgoing* calls, the maximum stack slot
     // given to the incoming function arguments (stack slots reserved for
     // incoming arguments).
     public abstract RegMask callArgMask(TypeFunPtr tfp, int arg, int maxArgSlot);
+    public RegMask callArgMask(TypeFunPtr tfp, int arg, int maxArgSlot, String conv) { return callArgMask(tfp,arg,maxArgSlot); }
+
     // Return register mask, based on signature (GPR vs FPR)
     public abstract RegMask retMask(TypeFunPtr tfp);
+
     // Return PC register
     public abstract int rpc();
+
     // Return a MachNode unconditional branch
     public abstract CFGNode jump();
+
     // Instruction select from ideal nodes
     public abstract Node instSelect( Node n );
 
@@ -93,5 +107,9 @@ Pre-alloc               Post-Alloc    SP+48   RPC
     // shadow slots if defined in the ABI, even if all arguments are passed in
     // registers.
     public abstract short maxArgSlot(TypeFunPtr tfp);
+    public short maxArgSlot(TypeFunPtr tfp, String conv) { return maxArgSlot(tfp); }
+
+    // Calling convention used for external C symbols.
+    public String cCallingConv(String callingConv) { return callingConv; }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Module.java b/src/main/java/com/seaofnodes/simple/codegen/Module.java
new file mode 100644
index 00000000..a5d85dbc
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/Module.java
@@ -0,0 +1,98 @@
+package com.seaofnodes.simple.codegen;
+
+
+/***
+    Modules!?!?!?
+
+    Goal: under no circumstances can you load from an uninitialized variable
+    (although you can see default inits for fields that have defaults).
+    Goal: nested tree-structured name spaces, to control complexity.
+    Goal: field decl order within a file is fairly flexible.
+
+    A Module a root-level SMP file, and the full file path must be provided on
+    the command line.  All other Simple structs are relative to this file.
+
+    Example: "simple /user/Dave/hello.smp"
+
+    Defines a module "hello" in directory "/user/Dave", compiles and produces
+    a `hello` or `hello.exe` output file, and runs it.
+
+    A SMP file has some <finit> file-init code which is static-global.
+    This code is executed on "first touch" of the file (defined below).
+
+    Example: hello.smp contains:
+        sys.io.p("Hello World!");
+    On first-touch, will print "Hello World!".
+
+    A SMP file is a lexical scope, and code inside it can reference those names.
+
+    Example: hello.smp contains:
+        val greet = "Hello World!"; // Declare file-scoped variable
+        sys.io.p(greet);            // Reference file-scoped variable
+
+    Static code is NOT allowed to have forward-references AND be executed
+    before the <finit> finishes initializing all variables.  After var
+    initialization, a singleton instance of the implied file struct is made,
+    and then <finit> code can call anything.
+
+    Example:
+        sys.io.p(greet); // Illegal forward reference
+        val greet = "Oops!";
+
+    Example:
+        val delay = { -> greet };    // Legal forward ref, but cannot execute (yet)
+        val greet = "Hello World!";  // Ref is resolved
+        sys.io.p(delay());           // Allowed to call delay()
+        val nprimes = { N ->
+          // compute number of primes < N
+        }
+        // Can otherwise execute any code in a <finit>
+        sys.io.p(nprimes(100));
+
+    Inside a directory, you can have sibling SMP files:
+    File hello.smp contains:
+        sys.io.p(I9A.GREETING);  // File hello references sibling file I9A static globals
+    File I9A.smp contains:
+        val GREETING = translate("Hello World!");
+        val translate = { str msg -> ... };
+
+    <finit> code cannot reference sibling files (nor child files, see below)
+    until all static variables are initialized.  This prevents cyclic
+    initialization bugs, where file A uses vars from file B and vice-versa.
+
+    File Chicken.smp contains:
+        val lay = Egg.hatch; // Illegal, defining var 'lay' after calling sibling Egg
+    File Egg.smp contains:
+        val hatch = Chicken.lay; // Illegal
+
+    You can make cross references, if they get delayed until after all fields
+    are declared.
+
+    File Chicken.smp contains:
+        int lay = 2;
+        lay = Egg.egg;
+
+    File Egg.smp contains:
+        int egg = 3;
+        egg = Chicken.lay;
+
+    The problem here, of course, is that you need to touch one of Chicken or
+    Egg first.
+
+
+    Inside a SMP file, you can define structs; structs are also a lexical
+    scope.  Bare code in the struct is part of the struct's <init> and only
+    runs when an instance is created.  Structs do not have static <clinit> (nor
+    <finit>).  Structs <init> cannot have any forward references, and locally
+    declared functions cannot have both forward references and be executed (or
+    passed along to a possibly-executing function).
+
+    In the same directory as a SMP file, Simple allows other directories with
+    names matching SMP files.  Inside these dirs can be more SMP files that are
+    lexically nested, similar to embedded structs.
+
+
+*/
+
+public abstract class Module {
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Opto.java b/src/main/java/com/seaofnodes/simple/codegen/Opto.java
index f8ce1e54..b88067c4 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/Opto.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/Opto.java
@@ -1,10 +1,12 @@
 package com.seaofnodes.simple.codegen;
 
-import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
 import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.Utils;
+
 import java.util.Arrays;
+import java.util.BitSet;
 
 // Optimistic Algorithm
 abstract public class Opto {
@@ -24,34 +26,10 @@ abstract public class Opto {
     // get a fairly precise set of Call Graph edges between CallNodes and
     // FunNodes.
     public static void opto(CodeGen code) {
-
-        // Pessimistic peephole optimization on a worklist - this completes
-        // whatever peepholes can run after parsing.
-        code._iter.iterate(code);
-
         // Reset Types before running the worklist algorithm
         Ary<Type> oldTypes = new Ary<>(Type.class); // Used for asserts only
         resetToTop(code,oldTypes);
-
-        // The whole-world assumption: we use it if compiling `main`, and not otherwise.
-        // The assumption is no unknown callers into functions:
-        // - during or past an Opto phase (but not before, since parse through
-        //   pessimistic must assume somebody calls an unknown function which
-        //   calls everybody).
-        // - Have a `main` to start tracing the Call Graph from
-        // - - True for most test cases
-        // - - False for lacking a main; we assume the linker will call all public functions
-
-        // True if we can make the "whole world" assumption, which means we are
-        // compiling the program entry: `main`.
-        boolean wholeWorld = code.link(code._main) != null;
-
-
-        // If wholeWorld, remove the Start inputs to functions - they are not
-        // called unless they get linked (hence go dead and can be removed).
-        // If not wholeWorld, keep only public methods (and not the std lib).
-        unlinkStart(wholeWorld,code);
-
+        unlinkStart(code);
 
         // OPTIMISTIC INTERPROCEDURAL SCCP
         sccp(code, oldTypes);
@@ -60,6 +38,11 @@ abstract public class Opto {
         // peepholes can make more progress.
         moveChangesToWorklist(code, oldTypes);
 
+        // SCCP can leave a recursive numeric component at BOTTOM with no
+        // arithmetic mode selected.  Resolve the whole component from all
+        // available int/float evidence before IterPeeps consumes the types.
+        resolveNumericModes(code);
+
         // Progress with improved types.  E.g. since we have a full Call Graph
         // here, we might do better inlining.
         code._iter.iterate(code);
@@ -73,15 +56,23 @@ abstract public class Opto {
         // Propagate field size constants
         code._iter.iterate(code);
 
-        // Throw away the Call Graph
 
-        // The remaining passes assume all calls are unlinked; i.e. we are
-        // throwing away the Call Graph here.  Functions only reachable from
-        // internal calls need to be re-hooked to stop/start less they go dead.
-        removeCallGraph(code);
+        // Retain surviving functions in their CompUnits for later code
+        // emission.  Start inputs are semantic: they mean unknown callers.
+        for( FunNode fun : code._linker )
+            if( fun != null && !fun.isDead() && !fun._type.isHigh() )
+                keepInCompUnit(code,fun);
+
+        for( CompUnit cu : code._compunits.values() ) {
+            ProjNode mem = cu._start.proj(1);
+            if( mem != null ) mem.unkeep();
+        }
 
         // To help with testing, sort StopNode Returns by NID
-        Arrays.sort(code._stop._inputs._es,0,code._stop.nIns(),(x,y) -> x._nid - y._nid );
+        for( Node stop : code._stop._inputs )
+            Arrays.sort(stop._inputs._es,0,stop.nIns(),
+                        (x,y) -> ((((ReturnNode)x).fun().isClz() ? -1 : x._nid) -
+                                  (((ReturnNode)y).fun().isClz() ? -1 : y._nid) ));
     }
 
     // Reset Types before running the worklist algorithm
@@ -90,9 +81,6 @@ abstract public class Opto {
                 oldTypes.setX(x._nid,x._type); // Record original types for asserts
                 x._type = Type.TOP;            // Reset all Nodes to TOP
                 code._iter.add(x); // Visit everybody at least once; most Nodes produce better than TOP
-                // Unlink all existing (conservative) linkages.
-                if( x instanceof CallNode call )
-                    call.unlink_all();
                 return null;
             } );
     }
@@ -101,41 +89,49 @@ abstract public class Opto {
     // If wholeWorld, remove the Start inputs to functions - they are not
     // called unless they get linked (hence go dead and can be removed).  If
     // not wholeWorld, keep only public methods (and not the std lib).
-    private static void unlinkStart(boolean wholeWorld, CodeGen code) {
-        for( FunNode fun : code._linker ) {
-            if( fun != null && !fun.isDead() && !funIsPublic(code,wholeWorld,fun) ) {
-                assert fun.in(1)==code._start; // Start always in slot 1
-                fun.removeDeadPath(1);
-                // By same logic, remove stop->return linkage, without
-                // remove the (now dead) ReturnNode; it awaits in limbo
-                // for the opto phase to link to some valid call
-                code._stop._inputs.del(code._stop._inputs.find(fun.ret()));
-                fun.ret().delUse(code._stop);
-            }
+    private static void unlinkStart(CodeGen code) {
+        // Keep the Start & Start.ProjMem alive even as we remove all uses
+        for( CompUnit cu : code._compunits.values() ) {
+            ProjNode mem = cu._start.proj(1);
+            if( mem!=null ) mem.keep();
         }
-    }
 
-    // Function is public (callable from Start directly).
-    // - Always true for main
-    // - Never true for stdlib, or anonymous functions
-    // - Named functions use `!wholeWorld`
-    private static boolean funIsPublic( CodeGen code, boolean wholeWorld, FunNode fun ) {
-        // Always true for main
-        if( fun.sig().fidx() == code._main.fidx() ) return true;
-        // Never true for stdlib or anonymous functions
-        if( fun._name == null || fun._name.startsWith("sys.") )
-            return false;
-        // Named functions (and not stdlib) are callable if not whole-world.
-        return !wholeWorld;
+        // Iterate the Stop-of-Stops
+        for( Node stop : code._stop._inputs ) {
+            for( int i=0; i<stop.nIns(); i++ ) {
+                ReturnNode ret = (ReturnNode)stop.in(i);
+                FunNode fun = ret.fun();
+                // Start is a semantic unknown-caller edge.  Public functions
+                // keep it; closed-world functions must be reached by a
+                // concrete Call edge discovered during SCCP.
+                if( !(code.owns(fun) && fun.isClz()) &&
+                    !code.publicFIDX(fun.sig().fidx()) &&
+                    fun.in(1) instanceof StartNode ) {
+                    fun.removeDeadPath(1);
+                    // Unhook from Stop without treating the ReturnNode as
+                    // DEAD.  It stays in limbo until Opto links when a caller
+                    // is discovered (or not, and the function is really dead).
+                    stop._inputs.del(i--);
+                    ret.delUse(stop);
+                }
+                // Unlink the existing conservative call linkages.
+                for( int j=1; j<fun.nIns(); j++ )
+                    if( fun.in(j) instanceof CallNode call )
+                        call.unlink(fun,j--);
+            }
+        }
     }
 
     // As part of building a CallGraph, when opto finds a function ptr flowing
     // into a Call, link the Call and Fun.
     private static void linkCG(CodeGen code, TypeFunPtr tfp, CallNode call) {
         if( tfp.nargs() != call.nargs() ) return; // Error calls hit this
-        for( long fidxs=tfp.fidxs(); fidxs!=0; fidxs=TypeFunPtr.nextFIDX(fidxs) ) {
-            int fidx = Long.numberOfTrailingZeros(fidxs);
-            FunNode fun = code.link(fidx);
+        int[] fidxs = tfp.fidxs();
+        for( int fidx = XInt.next(fidxs,0); fidx >=0; fidx = XInt.next(fidxs,fidx) ) {
+            // unlinkStart deliberately leaves uncalled functions in a
+            // temporarily dead limbo.  A newly discovered call revives them;
+            // do not use the cleanup lookup which removes dead linker entries.
+            FunNode fun = code.lookupFun(fidx);
             // null here means an external function; i.e. this Call
             // calls to an outside library and all its arguments escape.
             if( fun != null && !call.linked(fun) ) {
@@ -146,6 +142,55 @@ abstract public class Opto {
         }
     }
 
+    // Start added some FIDXs, the same functions now can be reached from start
+    // and called by anybody.  Add the CG edges.
+    private static void linkStart( CodeGen code, TypeTuple tt  ) {
+        TypeMem tmem = (TypeMem)tt._types[1];
+        int[] fidxs = tmem._escFs;
+        if( XInt.isHigh(fidxs) ) {
+            // A scalar BOTTOM can flow into memory while compiling an error
+            // program.  It exposes all public functions, not private fields.
+            for( FunNode fun : code._linker )
+                if( fun != null && code.publicFIDX(fun.sig().fidx()) )
+                    linkStart(code,fun);
+            return;
+        }
+        for( int fidx = XInt.next(fidxs,0); fidx >=0; fidx = XInt.next(fidxs,fidx) ) {
+            FunNode fun = code._linker.atX(fidx);
+            if( fun==null )  assert code._externFunc.containsKey(fidx);
+            else             linkStart(code,fun);
+        }
+    }
+
+    // Function is now reachable by unknown callers through Start.  The
+    // default inputs must therefore use conservative declared types.
+    private static void linkStart( CodeGen code, FunNode fun ) {
+        assert !fun.isDead();
+        StartCUNode start = fun._compunit._start;
+        if( fun.nIns() < 2 || fun.in(1) != start ) {
+            assert !start.isDead();
+            keepInCompUnit(code,fun);
+            // Function is reachable by any *remote* caller who gets the pointer!
+            fun.insertDef(1,start);
+            code._iter.add(fun);
+            for( Node p : fun._outputs )
+                if( p instanceof ParmNode parm ) {
+                    Node defalt = parm._idx==1 ? start.proj(1) : ConstantNode.seed(parm._declaredType).peephole();
+                    parm.insertDef(1,defalt);
+                    code.add(parm);
+                }
+        }
+    }
+
+    // Keep a surviving function rooted in its compilation unit without
+    // claiming that it has unknown callers.
+    private static void keepInCompUnit(CodeGen code, FunNode fun) {
+        StopCUNode stop = fun._compunit._stop;
+        if( stop._inputs.find(fun.ret()) == -1 )
+            code.add(stop).addDef(fun.ret());
+    }
+
+
     // The core SCCP algorithm
     private static void sccp( CodeGen code, Ary<Type> oldTypes ) {
         // Iter workList is empty at this point
@@ -157,108 +202,159 @@ abstract public class Opto {
             count++;
             Type oval = n._type, nval = n.compute();
             if( oval == nval ) continue;
-            assert oval.isa(nval);    // Types start high and always fall
-            Type pesiVal = oldTypes.at(n._nid);
-            assert nval.isa(pesiVal); // Never fall worse than the pessimistic pass
+            assert oval.isa(nval) : "Non-monotonic SCCP: "+n.getClass().getSimpleName()+"#"+n._nid+" "+n+" old="+oval+" new="+nval;    // Types start high and always fall
+            Type pesiVal = oldTypes.atX(n._nid);
+            assert pesiVal==null || nval.isa(pesiVal) : "SCCP below pessimistic type: "+n.getClass().getSimpleName()+"#"+n._nid+" "+n+" pessimistic="+pesiVal+" new="+nval; // Never fall worse than the pessimistic pass
             n._type = nval;
 
-            // If a TFP adds a new function input to a call, link to the new Fun
+            // Now we have a series of stanzas where we lazily create the Call
+            // Graph - adding graph edges between every call site and called
+            // function, including external (unknown) callers.  These edges are
+            // not in from the start because they are *too many*; we would get
+            // O(n^2) edges.  So all along we have been treating them as
+            // "virtual" CFG edges - a FunNode taking a Start input is treated
+            // as if every call on the planet might call it.  Now we make these
+            // CG edges *concrete*, adding them back as we discover that a call
+            // calls a particular function.
+
+            // If a TFP adds a new function input to a call, link to the new
+            // Fun.  This adds new edges to the graph allowing argument values
+            // to flow from calls into functions.  The added edges are
+            // effectively a refined Call Graph.
             if( nval instanceof TypeFunPtr tfp ) {
                 for( Node use : n._outputs )
                     if( !use._type.isHigh() && use instanceof CallNode call && call.fptr() == n )
                         linkCG(code,tfp,call);
             }
 
-            // Link a Call which becomes alive
+            // Link a Call which becomes alive.  Like above, adds new Call
+            // Graph edges to the graph.
             if( n instanceof CallNode call && oval.isHigh() && !nval.isHigh() && call.fptr()._type instanceof TypeFunPtr )
                 linkCG(code,call.tfp(),call);
 
+            // If an otherwise-dead function pointer escapes, any future linked
+            // caller might find and call it.  Force the function to be alive
+            // and called by Start.
+            if( n instanceof StartNode && n._type instanceof TypeTuple tt )
+                linkStart(code,tt);
+
+
             // Since n._type changed, visit all output neighbors
             code._iter.addAll(n._outputs);
             n.moveDepsToWorklist(code._iter);
             // Quadratic (expensive) small-step assert
-            assert check(code);
+            assert worklistCheck(code);
         }
     }
 
-    // Quadratic (expensive) small-step assert
-    private static boolean check(CodeGen code) {
-        code._start.walk( x -> {
+    // Quadratic (expensive) fixed-point assert
+    public static boolean fixedPointCheck(CodeGen code) {
+        return fixedPointCheck(code,code._stop);
+    }
+    public static boolean fixedPointCheck(CodeGen code, Node root) {
+        root.walk( x -> {
                 Type xval = x.compute();
-                assert xval == x._type || (x._type.isa( xval ) && code._iter._work.on( x ));
+                assert xval == x._type;
                 return null;
             });
         return true;
     }
 
+    // Quadratic (expensive) small-step assert for SCCP, where changed nodes
+    // may already be on the worklist.
+    private static boolean worklistCheck(CodeGen code) {
+        code._midAssert = true;
+        Node root = code._start;
+        root.walk( x -> {
+                Type xval = x.compute();
+                assert xval == x._type || (x._type.isa( xval ) && code._iter._work.on( x ))
+                    : "Non-monotonic or missed SCCP work: "+x.getClass().getSimpleName()+"#"+x._nid+" "+x+" old="+x._type+" new="+xval;
+            return null;
+            });
+        code._midAssert = false;
+        return true;
+    }
+
     // After SCCP add everything changed to the worklist and see if peepholes
     // can make more progress.
     private static void moveChangesToWorklist(CodeGen code, Ary<Type> oldTypes) {
         code._start.walk( x -> {
                 assert x.compute() == x._type;      // Hit the fixed point
                 assert x._nid >= oldTypes._len || x._type.isa(oldTypes.at(x._nid)); // Hit at least the bottom-up type
-                code._iter.add(x);
+                code.add(x);
                 return null;
             });
     }
 
+    // Resolve arithmetic modes which are ambiguous only because they belong to
+    // a recursive component.  Float wins because integer operands can be
+    // converted to float.
+    private static void resolveNumericModes(CodeGen code) {
+        final BitSet visited = new BitSet();
+        code._stop.walk(n -> {
+            if( n instanceof ModeNode modeNode && modeNode.mode()==0 ) {
+                visited.clear();
+                visited.set(n._nid); // Inspect inputs, not Bool's integer result
+                int mode = 0;
+                for( int i=1; i<n.nIns(); i++ )
+                    mode |= numericEvidence(n.in(i),visited);
+                if( mode != 0 )  {
+                    // If both evidence, FP wins
+                    modeNode.setMode((byte)((mode&2)==2 ? 2 : 1)).init();
+                    code.add(n);
+                }
+            }
+            return null;
+        });
+    }
+
+    // Gather numeric evidence through Phi and interprocedural return cycles.
+    // The visited set makes self- and mutually-recursive calls finite.
+    private static int numericEvidence(Node n, BitSet visited) {
+        if( n==null || visited.get(n._nid) ) return 0;
+        visited.set(n._nid);
+
+        Type t = n._type;
+        if( t instanceof TypeFloat   ) return 2;
+        if( t instanceof TypeInteger ) return 1;
+        if( t!=Type.BOTTOM && !(t instanceof TypeTuple) )
+            return 0; // Something unrelated, like a ptr
+
+        int evidence = 0;
+        switch( n ) {
+        case ModeNode modeNode -> evidence = modeNode.mode();
+        case PhiNode phi -> {}
+        case ReturnNode ret -> {}
+        case ProjNode proj when proj._idx==2 && proj.in(0) instanceof CallEndNode cend -> {
+            for( int i=1; i<cend.nIns(); i++ )
+                evidence |= numericEvidence(cend.in(i),visited);
+        }
+        case ConvertNode convert -> {
+            Type dst = convert.dst();
+            evidence = dst instanceof TypeFloat   ? 2 :
+                       dst instanceof TypeInteger ? 1 : 0;
+        }
+        default -> { return 0; }
+        }
+        for( int i=1; i<n.nIns(); i++ )
+            evidence |= numericEvidence(n.in(i),visited);
+
+        return evidence;
+    }
+
+
     // Freeze field sizes; do struct layouts; convert field offsets into
     // constants.
     private static void fieldSizes( CodeGen code ) {
         for( int i=0; i<code._start.nOuts(); i++ ) {
             Node use = code._start.out(i);
             if( use instanceof ConFldOffNode off ) {
-                TypeMemPtr tmp = (TypeMemPtr) Parser.TYPES.get(off._name);
-                off.subsume( off.asOffset(tmp._obj) );
-                i--;
-            }
-        }
-    }
-
-    // The remaining passes assume all calls are unlinked; i.e. we are throwing
-    // away the Call Graph here.  Functions only reachable from internal calls
-    // need to be re-hooked to stop/start less they go dead.
-    private static void removeCallGraph(CodeGen code) {
-        code._start.walk( x -> {
-                // Unlink all existing (conservative) linkages.
-                if( x instanceof CallNode call ) {
-                    for( Node y : call._outputs ) {
-                        // Keep function alive and hooked to Start so it gets
-                        // codegen'd.  Function is callable by this call via
-                        // TFP, although perhaps not by any other means.
-                        if( y instanceof FunNode fun && !(fun.in(1) instanceof StartNode) ) {
-                            ParmNode rpc = fun.rpc();
-                            if( rpc==null ) // Ensure valid RPC
-                                rpc = makeRPC(fun);
-                            // Insert a hook to Start and Stop
-                            fun.insertDef(1,code._start);
-                            for( Node use : fun._outputs )
-                                if( use instanceof ParmNode parm )
-                                    parm.insertDef(1,ConstantNode.make(parm._type).peephole());
-                            code._stop.addDef(fun.ret());
-                        }
-                    }
-                    call.unlink_all();
+                Node con = off.asOffset();
+                if( con != null ) { // Can be null for trying to reference missing field
+                    off.subsume( con );
+                    i--;
                 }
-                return null;
-            } );
-
-    }
-
-    // Make a valid Parm RPC.
-    // First make sure a valid RPC; single-call into multi-fun will have each
-    // function having a single call site, so the RPC becomes a constant and
-    // folds - but since multiple targets, the Call never inlines.  Recreate a
-    // valid RPC so codegen (and Eval2) understands the calling convention.
-    private static ParmNode makeRPC( FunNode fun ) {
-        ParmNode rpc = new ParmNode("$rpc",0,fun.ret().rpc()._type,fun);
-        for( int i=1; i<fun.nIns(); i++ ) {
-            CallEndNode cend = ((CallNode)fun.in(i)).cend();
-            rpc.addDef(ConstantNode.make(cend._rpc).peephole());
+            }
         }
-        fun.ret().setDef(3,rpc.init());
-        return rpc;
     }
-
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ParseAll.java b/src/main/java/com/seaofnodes/simple/codegen/ParseAll.java
new file mode 100644
index 00000000..191016be
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/ParseAll.java
@@ -0,0 +1,379 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.IterPeeps;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.print.*;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.*;
+import java.io.File;
+import java.io.IOException;
+import java.util.*;
+
+// Parse a given file, and all its dependencies
+public abstract class ParseAll {
+
+    // Worklist of symbols to search and files to parse
+    private static final Ary<CompUnit> WORK = new Ary<>(CompUnit.class);
+
+    private static final Ary<CompUnit> NEEDS_LOAD = new Ary<>(CompUnit.class);
+
+    // Return a compilation unit (cached or new).  If new, it does not necessarily
+    // need to be compiled.
+    public static CompUnit makeCUnit( CodeGen code, CompUnit par, String name ) throws IOException {
+        return makeCUnit(code,par,name,null,false);
+    }
+
+    private static CompUnit makeCUnit( CodeGen code, CompUnit par, String name, File obj ) throws IOException {
+        return makeCUnit(code,par,name,obj,obj!=null);
+    }
+
+    private static CompUnit makeCUnit( CodeGen code, CompUnit par, String name, File obj, boolean external ) throws IOException {
+        // Slashed file name?  Move leading parts into parent CUs.
+        int idx = name.indexOf("/");
+        if( idx >= 0 ) {
+            String head = name.substring(0,idx);
+            CompUnit sub = makeCUnit(code,par,head,external ? externalObj(code,par,head) : null,external);
+            return makeCUnit(code,sub,name.substring(idx+1).intern(),obj,external);
+        }
+
+        String fname = par==null ? name : (par._fname + "/" + name).intern();
+        CompUnit cunit = code._compunits.get(fname);
+        if( cunit != null ) return cunit;
+        String cname = par==null ? name : (par._cname + "." + name).intern();
+        code._compunits.put(fname, cunit = external ? new CompUnit(obj,par,fname,cname,name) : new CompUnit(par,fname,cname,name));
+        return cunit;
+    }
+
+    // Parse a top-level string, used for e.g. testing
+    static void parseSource( CodeGen code, String src ) {
+        parseSource(code,"Test",src);
+    }
+
+    // Parse a top-level string with an explicit compilation-unit name.
+    static void parseSource( CodeGen code, String fname, String src ) {
+        CompUnit cunit = new CompUnit(fname,src);
+        code._compunits.put(cunit._fname,cunit);
+        parseAll(code,cunit);
+    }
+
+    // module_root/.../src.smp is source file name.
+    static void parsePath(CodeGen code, String fname) {
+        try {
+            // Split and build the parent-path down to the source file.
+            CompUnit cu = makeCUnit( code, null, fname );
+            // Compile this CompUnit
+            parseAll(code,cu);
+        } catch( IOException ioe ) {
+            throw new RuntimeException(ioe);
+        }
+    }
+
+    private static void parseAll(CodeGen code, CompUnit cunit) {
+        WORK.clear();           // Cleanup from prior tests
+        NEEDS_LOAD.clear();
+        // Prime the pump with the first CompUnit
+        WORK.add(cunit);
+        // Work through all unparsed compilation units and parse
+        while( !WORK.isEmpty() ) {
+            CompUnit cu = WORK.remove(0);
+            // No source code?  Means we do not need to parse, but instead need to load the symbols as-if we parsed
+            if( cu._src==null || cu._src.isEmpty() )
+                loadDeps(code,cu); // Load recursive dependents
+            else
+                parseOne( code, cu ); // Parse
+        }
+
+        // Load all pre-compiled CompUnits
+        for( CompUnit cu : NEEDS_LOAD )
+            loadCompUnit(code,cu);
+        if( !NEEDS_LOAD.isEmpty() )
+            code._stop.walk(n -> {
+                if( n instanceof CallNode )
+                    code.add(n);
+                return null;
+            });
+
+        // Many types will have been declared cyclically either internally or
+        // across multiple compilation units.
+
+        // Close over all recursive types, and upgrade TYPES
+        Ary<TypeStruct> ary = new Ary<>(TypeStruct.class);
+        for( Type t : Parser.TYPES.values() )
+            if( t instanceof TypeStruct ts )
+                ary.add(ts);
+        TypeStruct[] tss = Type.closeOver(ary.asAry(),Parser.TYPES);
+        for( TypeStruct ts : tss )
+            Parser.TYPES.put(ts._name,ts);
+        for( CompUnit cu : code._compunits.values() )
+            if( cu._ext==null )
+                cu._clz = (TypeStruct)Parser.TYPES.get(Parser.addClzPrefix(cu._cname));
+
+        // Walk over all Nodes, and upgrade the internal constants to the
+        // closed-over types.
+        code._stop.walk( (Node n) -> {
+                n.upgradeType(Parser.TYPES);
+                if( n instanceof FRefNode fref ) {
+                    TypeStruct clz = (TypeStruct)Parser.TYPES.get(fref._name);
+                    if( clz == null )
+                        return null;
+                    // Class pointer:
+                    TypeMemPtr clzptr = TypeMemPtr.make((byte)2,clz,true);
+                    // Class pointer constant:
+                    ConstantNode clzCon = code.con(clzptr);
+                    // Replace and optimize
+                    fref.addDef(clzCon);
+                    code.add(fref);
+                }
+                // Adds sort by NIDs, which just got shuffled
+                if( n instanceof AddNode add )
+                    code.add(add);
+                return null;
+            } );
+
+        // The complete public interface is now known.  Keep this independent
+        // of later graph/linker liveness so SCCP computations remain local and
+        // monotonic.
+        code.freezePublicInterface();
+    }
+
+    // Parse one Simple source code file.  Add all the FRefs produced to the worklist.
+    private static void parseOne( CodeGen code, CompUnit cunit ) {
+        cunit.setStart(code);
+        // Parse a source file, return missing external references
+        Ary<FRefNode> frefs = code.P.parse(cunit);
+
+        // Find all missing external references, or complain.  This can trigger more parses.
+        while( !frefs.isEmpty() ) {
+            FRefNode fref = frefs.remove(0);
+            // Symbol not found in source code (or we would not be here).
+            // Search the module for the fref
+            try {
+                CompUnit xcunit = findCUnitModule(code,cunit,fref._name);
+                if( xcunit == null )
+                    xcunit = findCUnitExternalSimple(code,fref._name);
+                if( xcunit != null ) {
+                    // Replace the FRef with the discovered class name.
+                    fref._name = Parser.addClzPrefix(xcunit._cname);
+                    cunit.addDep(xcunit);
+                } else {
+                    throw new RuntimeException("Undefined name '" + fref._name +"'");
+                }
+            } catch( IOException ioe ) {
+                throw new RuntimeException(ioe);
+            }
+        }
+        addRequiredTypes(code,cunit);
+    }
+
+    private static void addRequiredTypes(CodeGen code, CompUnit cunit) {
+        LinkedHashSet<String> required = new LinkedHashSet<>();
+        code._stop.walk(n -> {
+            TypeStruct ts = CodeGen.requiredStruct(n);
+            if( ts!=null && ts._fref ) required.add(ts._name);
+            return null;
+        });
+        for( String typeName : required ) {
+            try {
+                CompUnit xcunit = findRequiredType(code,cunit,typeName);
+                if( xcunit != null )
+                    cunit.addDep(xcunit);
+            } catch( IOException ioe ) {
+                throw new RuntimeException(ioe);
+            }
+        }
+    }
+
+    private static CompUnit findRequiredType(CodeGen code, CompUnit cunit, String typeName) throws IOException {
+        for( CompUnit cu = cunit; cu != null; cu = cu._par ) {
+            String symbol = typeName.startsWith(cu._cname+".")
+                ? typeName.substring(cu._cname.length()+1)
+                : typeName;
+            CompUnit xcunit = findCUnitModule(code,cu,symbol);
+            if( xcunit != null )
+                return xcunit;
+        }
+        return findCUnitExternalSimple(code,typeName);
+    }
+
+    // Load the public symbols for this CompUnit, and add dependent CompUnits to the NEEDS_LOAD list.
+    private static void loadDeps(CodeGen code, CompUnit cunit) {
+        // Load IR after parsing
+        if( NEEDS_LOAD.find(cunit) != -1 )
+            return;             // Already on the to-be-loaded list?
+        try {
+            NEEDS_LOAD.add(cunit);
+            // Load dependent classes
+            ElfReader elf = ElfReader.load(cunit._obj,cunit);
+            elf.loadPublicSymbols();
+            for( String fname : elf._deps ) {
+                // Check CompUnit for being up to date
+                CompUnit sub = makeCUnit(code,null,fname,null/*depObj(code,cunit,fname)*/);
+                // If not seen before or out of date, parse the new nested cunit
+                if( sub._clz == null && sub._par == null )
+                    WORK.add(sub);
+            }
+        } catch( IOException ioe ) {
+            throw new RuntimeException(ioe);
+        }
+    }
+
+    private static File depObj(CodeGen code, CompUnit cunit, String fname) {
+        if( cunit._smp != null )
+            return null;
+        ElfReader elf = code.findExternalSimple(Parser.addClzPrefix(fname.replace('/','.')));
+        if( elf == null )
+            throw new RuntimeException("Cannot find external Simple dependency '"+fname+"'");
+        return elf._file;
+    }
+
+    private static File externalObj(CodeGen code, CompUnit par, String name) {
+        String cname = par==null ? name : par._cname + "." + name;
+        ElfReader elf = code.findExternalSimple(Parser.addClzPrefix(cname));
+        return elf == null ? null : elf._file;
+    }
+
+    private static void loadCompUnit(CodeGen code, CompUnit cunit) {
+        // Expecting a previously compiled object file
+        assert cunit._obj != null;
+        // Extract published symbols and put them in the internal tables;
+        // cross-references will pick them up there.
+        ElfReader elf = ElfReader.load(cunit._obj,cunit);
+        cunit._clz = elf.loadSimple(code);
+        StartNode lstart = (StartNode)elf._nodes.at(0);
+        StopNode  lstop  = ( StopNode)elf._nodes.last();
+
+        // Add all new loaded functions to the linker table
+        for( Node n : lstop._inputs ) {
+            StopCUNode  stop = (StopCUNode)n;
+            StartCUNode start = stop.start();
+            CompUnit cu = code._compunits.get(start._fname);
+            cu._start = start;
+            cu._stop  = stop ;
+
+            for( Node ret : stop._inputs ) {
+                FunNode fun = ((ReturnNode)ret).fun();
+                code.link(fun);
+            }
+        }
+
+        // Hook the new code into the existing code graph
+        for( Node lstopcu : lstop._inputs )
+            code._stop.addDef(lstopcu);
+        lstart.subsume(code._start);
+
+        // Add the new top-level loaded class
+        Parser.TYPES.put(cunit._clz._name,cunit._clz);
+        Field inst = cunit._clz.field(cunit._name);
+        if( inst != null ) // Also the instance type, if a constructor exists
+            Parser.TYPES.put(cunit._cname, ((TypeMem)((TypeFunPtr)inst._t)._ret)._t);
+    }
+
+    // Symbol not found in source code (or we would not be here).
+    // Search the module for the fref
+    public static CompUnit findCompUnitOrThrow(CodeGen code, CompUnit cu, String symbol) {
+        CompUnit cu2 =  findCompUnit(code,cu,symbol);
+        if( cu2 != null ) return cu2;
+        throw new RuntimeException("Undefined name '" + symbol +"'");
+    }
+
+    public static CompUnit findCompUnit(CodeGen code, CompUnit cu, String symbol) {
+        // Symbol not found in source code (or we would not be here).
+        // Search the module for the fref
+        try {
+            CompUnit local = findCUnitModule(code,cu,symbol);
+            if( local != null )
+                return local;
+            return findCUnitExternalSimple(code,symbol);
+        } catch( IOException ioe ) {
+            throw new RuntimeException(ioe);
+        }
+    }
+
+    // Find the symbol in module, starting from cunit.  This searches up the nested
+    // class chain and sideways 1 step, so that any prefix of the class chain can
+    // be skipped as a shortcut.  Symbol can have dotted names, which then go
+    // down into classes.  e.g.
+    //   A/X/Y exists.
+    //   A/B contains X.Y, which is a shortcut for A.X.Y
+
+    // However if A/B contains "Y", the search would be for A.B.Y then A.Y both of
+    // which do not exist.
+    private static CompUnit findCUnitModule( CodeGen code, CompUnit cunit, String symbol ) throws IOException {
+        if( cunit == null )     // Ran off top of module scope?
+            return null;        // Failed search
+
+        // Check self
+        if( cunit._name.equals(symbol) )
+            return cunit;
+
+        // If symbol is itself nested (has embedded dots), move the leading part
+        // over to the CompUnit path.  So e.g.:
+        //   CompUnit{A.B}, Symbol="X.Y"
+        // becomes
+        //   CompUnit{A.B.X}, Symbol="Y"
+        int dotIdx = symbol.indexOf(".");
+        if( dotIdx != -1 ) {
+            String pre = symbol.substring(0,dotIdx);
+            String rest = symbol.substring(dotIdx+1 );
+            String fname = cunit._fname + "/" + pre;
+            File f = new File( code._modDir + "/" + fname + ".smp" );
+            if( f.exists() ) {
+                CompUnit sub = makeCUnit(code,cunit,pre);
+                // Note that "sub" itself is not put on the to-be-parsed-list.  We're
+                // referring to a child class and do not need to parse the middles.
+                CompUnit dcunit = findCUnitModule(code,sub,rest);
+                if( dcunit != null )
+                    return dcunit; // Nested dot search found cunit
+            }
+        }
+
+        // Look in mod / fname / name / symbol.smp
+        String fname = cunit._fname + "/" + symbol;
+        File f = new File( code._modDir + "/" + fname + ".smp" );
+        if( f.exists() ) {
+            CompUnit sub = makeCUnit(code,cunit,symbol);
+            // If not seen before or out of date, parse the new nested cunit
+            if( sub._clz == null && WORK.find(sub) == -1 )
+                WORK.add(sub);
+            return sub;
+        }
+
+        // Look up the scope
+        return findCUnitModule( code, cunit._par, symbol );
+    }
+
+    // Search external Simple objects only.  C linkage uses explicit "C"
+    // declarations, which produce ExternNodes and are resolved by the linker.
+    public static CompUnit findCUnitExternalSimple( CodeGen code, String symbol ) {
+        String clzName = symbol.startsWith(Parser.CLZ) ? symbol : Parser.addClzPrefix(symbol);
+        String cname = clzName.substring(Parser.CLZ.length());
+        String fname = cname.replace('.','/');
+
+        CompUnit cunit = code._compunits.get(fname);
+        if( cunit != null )
+            return cunit;
+
+        ElfReader elf = code.findExternalSimple(clzName);
+        if( elf == null )
+            return null;
+
+        try {
+            cunit = makeCUnit(code,null,fname,elf._file);
+        } catch( IOException ioe ) {
+            throw new RuntimeException(ioe);
+        }
+        ElfReader typedElf = ElfReader.load(cunit._obj,cunit);
+        TypeStruct clz = typedElf == null ? null : typedElf.loadPublicTypes(code);
+        if( clz != null )
+            Parser.TYPES.put(clz._name,clz);
+        else
+            clz = (TypeStruct)Parser.TYPES.get(clzName);
+        if( clz == null )
+            Parser.TYPES.put(clzName,clz = TypeStruct.make(clzName,true));
+        cunit._clz = clz;
+        if( WORK.find(cunit) == -1 && NEEDS_LOAD.find(cunit) == -1 )
+            WORK.add(cunit);
+        return cunit;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java b/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java
index 777182dc..48319006 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java
@@ -3,7 +3,7 @@ package com.seaofnodes.simple.codegen;
 // This Node rip-relative encodings has sizes that vary by delta
 public interface RIPRelSize {
     // delta is the distance from the opcode *start* to the target start.  Each
-    // hardware target adjusts as needed, X86 measures from the opcode *end*
+    // hardware target adjusts as needed.  X86 measures from the opcode *end*
     // and small jumps are 2 bytes, so they'll need to subtract 2.
     byte encSize(int delta);
 
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java b/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java
index da521082..4c00391c 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java
@@ -56,6 +56,8 @@ public class RegAlloc {
 
     public int _spills, _spillScaled;
 
+    private boolean _done;
+
     // -----------------------
     // Live ranges with self-conflicts or no allowed registers
     private final IdentityHashMap<LRG,String> _failed = new IdentityHashMap<>();
@@ -64,6 +66,7 @@ public class RegAlloc {
         _failed.put(lrg,"");
     }
     boolean success() { return _failed.isEmpty(); }
+    public boolean done() { return _done; }
 
 
     // -----------------------
@@ -72,16 +75,16 @@ public class RegAlloc {
     short _lrg_num;
 
     // Define a new LRG, and assign n
-    LRG newLRG( Node n ) {
+    LRG newLRG( Node n, FunNode fun ) {
         LRG lrg = lrg(n);
         if( lrg!=null ) return lrg;
-        lrg = new LRG(_lrg_num++);
+        lrg = new LRG(_lrg_num++, fun);
         LRG old = _lrgs.put(n,lrg); assert old==null;
         return lrg;
     }
 
     // LRG for n
-    LRG lrg( Node n ) {
+    public LRG lrg( Node n ) {
         LRG lrg = _lrgs.get(n);
         if( lrg==null ) return null;
         LRG lrg2 = lrg.find();
@@ -130,18 +133,19 @@ public class RegAlloc {
     }
 
     // Printable register number for node n
-    String reg( Node n ) { return reg(n,null); }
-    String reg( Node n, FunNode fun ) {
+    String reg( Node n ) {
         LRG lrg = lrg(n);
-        if( lrg==null ) return null;
+        return lrg==null ? null : reg(lrg);
+    }
+    String reg( LRG lrg ) {
         // No register yet, use LRG
         if( lrg._reg == -1 ) return "V"+lrg._lrg;
         // Chosen machine register unless stack-slot and past RA
         String[] regs = _code._mach.regs();
-        if( lrg._reg < regs.length || _code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() || fun==null )
+        if( lrg._reg < regs.length || _code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() || lrg._fun==null )
             return RegMask.reg(regs,lrg._reg);
         // Stack-slot past RA uses the frame layout logic
-        return "[rsp+"+fun.computeStackOffset(_code,lrg._reg)+"]";
+        return "[rsp+"+lrg._fun.computeStackOffset(_code,lrg._reg)+"]";
     }
 
     // -----------------------
@@ -177,6 +181,7 @@ public class RegAlloc {
             round++;
         }
         postColor();                       // Remove no-op spills
+        _done = true;
     }
 
     private boolean graphColor(byte round) {
@@ -245,6 +250,8 @@ public class RegAlloc {
         // single-register.  Split after the def and before the use.  Does not
         // require a full pass.
 
+        // Compute def nOuts *before* replacing those uses with a split
+        int defNouts = ((Node)lrg._machDef).nOuts();
         // Split just after def
         if( lrg._1regDefCnt==1 && !lrg._machDef.isClone() )
             // Force must-split, even if a prior split same block because register
@@ -256,7 +263,7 @@ public class RegAlloc {
             //   st4 [V1],len - No good, must split around
             insertAfterAndReplace( makeSplit("def/empty1",round,lrg), (Node)lrg._machDef, false/*true*/);
         // Split just before use
-        if( lrg._1regUseCnt==1 || (lrg._1regDefCnt==1 && ((Node)lrg._machDef).nOuts()==1) )
+        if( lrg._machUse!=null && (lrg._1regUseCnt==1 || (lrg._1regDefCnt==1 && defNouts==1)) )
             insertBefore((Node)lrg._machUse,lrg._uidx,"use/empty1",round,lrg);
         return true;
     }
@@ -483,8 +490,8 @@ public class RegAlloc {
     void findAllLRG( LRG lrg ) {
         _ns.clear();
         int wd = 0;
-        _ns.push((Node)lrg._machDef);
-        _ns.push((Node)lrg._machUse);
+        if( lrg._machDef != null ) _ns.push((Node)lrg._machDef);
+        if( lrg._machUse != null ) _ns.push((Node)lrg._machUse);
         while( wd < _ns._len ) {
             Node n = _ns.at(wd++);
             if( lrg(n)!=lrg ) continue;
@@ -543,12 +550,12 @@ public class RegAlloc {
         // Clone simple constants if possible
         Node split = def instanceof MachNode mach && mach.isClone() && (umask==null || mach.outregmap().overlap(umask))
             ? mach.copy()
-            : _code._mach.split(kind,round,lrg);
+            : _code._mach.split(lrg,kind,round);
         _lrgs.put(split,lrg);
         return split;
     }
     private SplitNode makeSplit( String kind, byte round, LRG lrg ) {
-        SplitNode split = _code._mach.split(kind,round,lrg);
+        SplitNode split = _code._mach.split(lrg,kind,round);
         _lrgs.put(split,lrg);
         return split;
     }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RegMask.java b/src/main/java/com/seaofnodes/simple/codegen/RegMask.java
index c7dda1da..81e47e8e 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/RegMask.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/RegMask.java
@@ -33,7 +33,6 @@ public class RegMask {
     public RegMask(long bits ) { _bits0 = bits; }
     public RegMask(long bits0, long bits1 ) { _bits0 = bits0; _bits1 = bits1; }
     public RegMask(RegMask r) { _bits0 = r._bits0; _bits1 = r._bits1; }
-    private RegMask() { _bits0 = _bits1 = 0; }
 
     // AND, with copy-on-write if changing
     RegMask and( RegMask mask ) {
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Serialize.java b/src/main/java/com/seaofnodes/simple/codegen/Serialize.java
new file mode 100644
index 00000000..8014bb2c
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/Serialize.java
@@ -0,0 +1,617 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.*;
+import java.util.*;
+
+abstract public class Serialize {
+
+    static void serialize( CodeGen code ) {
+
+        // Get all Nodes in a sane order
+        Ary<Node> nodes = nodeOrder(code);
+
+        // Array of dependent file names
+        HashSet<String> xdeps = new HashSet<>();
+        for( CompUnit cu : code._compunits.values() ) {
+            if( cu._deps != null )
+                for( CompUnit cudep : cu._deps )
+                    xdeps.add(cudep._fname);
+        }
+        String[] deps = xdeps.toArray(new String[xdeps.size()]);
+
+        // Top-level clazz being reported
+        String topName = code._srcName == null ? "Test" : code._srcName;
+        CompUnit top = code._compunits.get(topName);
+        TypeStruct clz = top._clz;
+
+        // Preserve which same-named structs are the source-level declarations.
+        // Optimized graph types can carry sharper field states (e.g. len==0),
+        // and cannot be used to reconstruct this mapping during loading.
+        TreeMap<String,TypeStruct> named = new TreeMap<>();
+        for( Type type : Parser.TYPES.values() )
+            if( type instanceof TypeStruct ts )
+                named.put(ts._name,ts);
+        TypeStruct[] pubTypes = named.values().toArray(new TypeStruct[0]);
+
+        // Compress into bytes
+        BAOS baos = write(nodes, clz, pubTypes, deps, code._aliases, code._fidxs, code._rpcs, code._externFunc);
+
+        // --- Expensive bijection assert
+        if( false ) {
+            // Inflate into POJOs; renumbers everything
+            ElfReader elf = new ElfReader(new BAOS(baos.toByteArray()));
+            readAll(code,elf, code._aliases, code._fidxs, code._rpcs);
+            BAOS baos2 = write(elf._nodes,elf._clz,elf._pubTypes,elf._deps, code._aliases, code._fidxs, code._rpcs, code._externFunc);
+
+            // Bi-jection
+            for( int i=0; i<baos.size(); i++ )
+                assert baos.buf()[i]==baos2.buf()[i] : "bijection mismatch at "+i+": "+(baos.buf()[i]&0xFF)+" != "+(baos2.buf()[i]&0xFF);
+            assert baos.size()==baos2.size() : "bijection size mismatch: "+baos.size()+" != "+baos2.size();
+        }
+        // --- Expensive bijection assert
+
+        // Record serialized IR for later ELF writing
+        code._serial = baos;
+    }
+
+    // --------------------------------------------------
+    static BAOS write(Ary<Node> nodes, TypeStruct clz, TypeStruct[] pubTypes, String[] depobjs, GlobalBits aliases, GlobalBits fidxs, GlobalBits rpcs, HashMap<Integer,String> externFunc) {
+        // Initialize the mapping from bits/tags to types
+        Type.TAGOFFS();
+
+        BAOS baos = new BAOS();
+        // A - Print a header
+        baos.write('C').write('0').write('D').write('E');
+
+        // Count unique Types
+        var types = new HashMap<Type,Integer>();
+        // Count published types *first*, so can align with published strings
+        types.put(Type.TOP,0);
+        types.put( clz, types.size() );
+        // Have to visit the innards specially, since they did not get the
+        // normal recursive visit when first touching a type, because the
+        // published types are packed early to align with their string names so
+        // lookup in ElfReader can be fast.
+        for( int i=0; i<clz.nkids(); i++ )
+            clz.at(i).gather(types);
+        // Gather types from all sources
+        for( Node n : nodes ) {
+            n._type.gather(types);
+            if( n instanceof CallEndNode cend ) cend._rpc.gather(types);
+            if( n instanceof  FunNode fun ) fun.sig().gather(types);
+            if( n instanceof ParmNode parm ) parm._declaredType.gather(types);
+            if( n instanceof TypeNode con ) con._con .gather(types);
+        }
+        // Only record canonical declarations already reachable from this
+        // object's graph.  Pulling unrelated parser types into this closure
+        // can include open or partially built types from other units.
+        Ary<TypeStruct> writtenPubs = new Ary<>(TypeStruct.class);
+        for( TypeStruct ts : pubTypes )
+            if( types.containsKey(ts) )
+                writtenPubs.add(ts);
+        // Radix sort by Type ID#
+        Type[] atypes = new Type[types.size()];
+        for( Type t : types.keySet() )
+            atypes[types.get(t)] = t;
+
+        // Count all unique Strings
+        var strs = new HashMap<String,Integer>();
+        strs.put("",0);         // Null string is always 0
+        // Find and count *published* Strings first
+        gather(strs,clz._name);
+        // Find and count dependent object file string names
+        if( depobjs != null )
+            for( String fname : depobjs )
+                gather(strs,fname);
+        // Count strings from all types
+        for( Type t : atypes ) {
+            if( t instanceof Field fld     ) gather(strs,fld._fname);
+            if( t instanceof TypeStruct ts ) gather(strs,ts . _name);
+        }
+        // Count strings used by local->global bit mappings.
+        aliases.gather(strs);
+        fidxs  .gather(strs);
+        rpcs   .gather(strs);
+        for( String extern : externFunc.values() )
+            gather(strs,extern);
+        // Count strings from nodes
+        for( Node n : nodes )
+            n.gather(strs);
+        // Radix sort by string ID#
+        String[] astrs = new String[strs.size()];
+        for( String s : strs.keySet() )
+            astrs[strs.get(s)] = s;
+
+        // Check that published strings and types align
+        assert astrs[1] == ((TypeStruct)atypes[1])._name;
+        if( depobjs != null )
+            for( int i=0; i<depobjs.length; i++ )
+                assert astrs[1+i+1] == depobjs[i];
+
+
+        // B - Write unique strings
+        baos.packed4(depobjs==null ? 0 : depobjs.length);
+        baos.packed4(strs.size());
+        // Write in ID# order; the first depobjs.length of these are dependent strings
+        for( String s : astrs )
+            baos.packedS(s);
+
+        // B.2 - Write the local->global mappings
+        aliases.packed(baos,strs);
+        fidxs  .packed(baos,strs);
+        rpcs   .packed(baos,strs);
+        ArrayList<Integer> externFidxs = new ArrayList<>(externFunc.keySet());
+        Collections.sort(externFidxs);
+        baos.packed2(externFidxs.size());
+        for( int fidx : externFidxs ) {
+            baos.packed2(fidx);
+            baos.packed2(strs.get(externFunc.get(fidx)));
+        }
+
+        // C - Write unique Types
+        baos.packed4(atypes.length);
+        baos.packed2(writtenPubs._len);
+        for( TypeStruct ts : writtenPubs )
+            baos.packed4(types.get(ts));
+        // Write Types in ID# order, no children
+        for( Type t : atypes )
+            t.packed(baos,strs);
+        // Write Types in ID# order, only child IDs
+        for( Type t : atypes ) {
+            int nkids = t.nkids();
+            for( int i=0; i<nkids; i++ )
+                baos.packed4(types.get(t.at(i)));
+        }
+
+
+        // D - Write the nodes.  Since this is expected to be the bulk of the
+        // data, we might want to explore various options.
+
+        // How many nodes?
+        baos.packed4(nodes._len);
+
+        // Radix sort by Node ID#, new compressed NIDs
+        IdentityHashMap<Node,Integer> anodes = new IdentityHashMap<>();
+        for( Node n : nodes )
+            anodes.put(n,anodes.size()+1); // +1 bias, reserve 0 for null
+
+        // First cut: 1 byte opcode, optional per-node info, includes variable nIns
+        for( Node n : nodes ) {
+            baos.packed1(n.serialTag().ordinal());
+            baos.packed2(types.get(n._type));
+            n.packed(baos,strs,types,anodes);
+        }
+        // Write out the input indices packed.
+        for( Node n : nodes ) {
+            for( int j=0; j<n.nIns(); j++ ) {
+                Node def = n.in(j);
+                Integer idx = def==null ? Integer.valueOf(0) : anodes.get(def);
+                assert idx != null : "Missing serialized input for "+n+" input "+j+" def "+def;
+                baos.packed2(idx);
+            }
+            if( n instanceof FunNode fun )
+                baos.packed2(anodes.get(fun.ret()));
+        }
+
+        return baos;
+    }
+    public static <T> void gather( HashMap<T,Integer> strs, T s) {
+        if( s!=null && !strs.containsKey(s) )
+            strs.put(s,strs.size());
+    }
+    public static void gather( AryInt is, int s) {
+        if( is.atX(s)==0 ) {
+            int cnt=0;
+            for( int i=1; i<is._len; i++ )
+                if( is._es[i] != 0 )
+                    cnt++;
+            is.setX(s,cnt+1);
+        }
+    }
+
+    // Returned array of *public* strings only.
+    static void read_public_strs(ElfReader elf) {
+        BAOS bais = elf._bais;
+        Type.TAGOFFS();
+
+        // A - Read a header
+        if( bais.read()!='C' || bais.read()!='0' || bais.read()!='D' || bais.read()!='E' )
+            throw new IllegalArgumentException("Missing magic word");
+
+        // B - Packed read of #strings, then strings
+        int ndependents = bais.packed4(); // Number of dependent object files
+        int nstrs = bais.packed4();       // Total number of strings
+        String[] strs = new String[nstrs];
+        for( int i=0; i<nstrs; i++ )
+            strs[i] = bais.packedS();
+        elf._strs = strs;
+
+        // Collect dependent file names
+        elf._deps = new String[ndependents];
+        for( int i=0; i<ndependents; i++ )
+            elf._deps[i] = strs[1+i+1];
+    }
+
+    // --------------------------------------------------
+    record TypeRead(Type[] types, String[] strs, GlobalBits fileAliases, GlobalBits fileFidxs, GlobalBits fileRpcs) {}
+
+    static TypeRead readTypes( CodeGen code, ElfReader elf, GlobalBits aliases, GlobalBits fidxs, GlobalBits rpcs ) {
+        BAOS bais = elf._bais;
+        // Initialize the mapping from bits/tags to types
+        Type.TAGOFFS();
+
+        // If not read the strings already, read them now
+        String[] strs = elf._strs;
+        if( strs == null ) {
+            // A - Read a header
+            if( bais.read() != 'C' || bais.read() != '0' || bais.read() != 'D' || bais.read() != 'E' )
+                throw new IllegalArgumentException( "Missing magic word" );
+
+            // B - Packed read of #strings, then strings
+            int ndependents = bais.packed4(); // Number of dependent object files
+            int nstrs = bais.packed4();       // Total number of strings
+            elf._strs = strs = new String[nstrs];
+            for( int i = 0; i < nstrs; i++ )
+                strs[i] = bais.packedS();
+
+            // Collect dependent file names
+            elf._deps = new String[ndependents];
+            for( int i = 0; i < ndependents; i++ )
+                elf._deps[i] = strs[1 + i + 1];
+        }
+
+        // B.2 - Read the local->global mappings.  Further down we will map
+        // Elf file-local -> global, then global -> CodeGen.CODE local
+        GlobalBits fileAliases = GlobalBits.packed(bais,strs);
+        GlobalBits fileFidxs   = GlobalBits.packed(bais,strs);
+        GlobalBits fileRpcs    = GlobalBits.packed(bais,strs);
+        int nexterns = bais.packed2();
+        for( int i=0; i<nexterns; i++ ) {
+            int fileFidx = bais.packed2();
+            String extern = strs[bais.packed2()];
+            int fidx = fileFidx < GlobalBits.RESERVED ? fileFidx : fidxs.map(fileFidxs,fileFidx);
+            String old = code.externFunc(fidx);
+            if( old == null )
+                code.externFunc(fidx,extern);
+            else
+                assert old.equals(extern);
+        }
+
+
+        // C - Packed read of #types, then types
+        int ntypes = bais.packed4();
+        int npubTypes = bais.packed2();
+        int[] pubTypeIds = new int[npubTypes];
+        for( int i=0; i<npubTypes; i++ )
+            pubTypeIds[i] = bais.packed4();
+        Type[] types = Type.packed(bais,strs,ntypes, Parser.TYPES,
+                                   fileAliases,aliases,
+                                   fileFidxs  ,fidxs,
+                                   fileRpcs   ,rpcs);
+
+        // aliases.set(0,0);
+        // Check and collect first published symbols map to TypeStructs
+        elf._clz = (TypeStruct)types[1/*skip zero*/];
+        assert elf._clz._name==strs[1/*skip null ptr*/];
+        for( Type type : types )
+            if( type instanceof TypeStruct ts )
+                Parser.TYPES.put(ts._name,ts);
+        for( Type type : types ) {
+            if( !(type instanceof TypeStruct ts) || !Parser.startsClzPrefix(ts._name) )
+                continue;
+            String cname = ts._name.substring(Parser.CLZ.length());
+            int dot = cname.lastIndexOf('.');
+            String name = dot == -1 ? cname : cname.substring(dot+1);
+            Field inst = ts.field(name.intern());
+            if( inst != null && inst._t instanceof TypeFunPtr tfp && tfp._ret instanceof TypeMem mem && mem._t instanceof TypeStruct its )
+                Parser.TYPES.put(cname,its);
+        }
+        elf._pubTypes = new TypeStruct[npubTypes];
+        for( int i=0; i<npubTypes; i++ ) {
+            TypeStruct ts = elf._pubTypes[i] = (TypeStruct)types[pubTypeIds[i]];
+            Parser.TYPES.put(ts._name,ts);
+        }
+        return new TypeRead(types,strs,fileAliases,fileFidxs,fileRpcs);
+    }
+
+    static void readAll( CodeGen code, ElfReader elf, GlobalBits aliases, GlobalBits fidxs, GlobalBits rpcs ) {
+        BAOS bais = elf._bais;
+        TypeRead tread = readTypes(code, elf, aliases, fidxs, rpcs);
+        Type[] types = tread.types();
+        String[] strs = tread.strs();
+        GlobalBits fileAliases = tread.fileAliases();
+
+        // D - Read the nodes
+
+        // Number of nodes
+        int num = bais.packed4();
+        // Packed array of nodes
+        Ary<Node> nodes = new Ary<>(Node.class);
+        CompUnit cu = null;
+        for( int i=0; i<num; i++ ) {
+            Node.Tag tag = Node.Tag.VALS[bais.packed1()];
+            Type t = types[bais.packed2()];
+            Node n = tag.make(bais,strs,types,fileAliases,aliases);
+            n._type = t;
+            nodes.push(n);
+            // A little extra for FunNodes
+            if( n instanceof StartCUNode startcu ) {
+                cu = code._compunits.get(startcu._fname==null ? (code._srcName==null ? "Test" : code._srcName) : startcu._fname);
+                assert cu != null;
+            }
+            if( n instanceof StopCUNode stopcu ) {
+                cu = null;
+            }
+            if( n instanceof FunNode fun ) {
+                assert cu != null;
+                fun._compunit = cu;
+            }
+            if( n instanceof ExternNode ext && ext._con instanceof TypeFunPtr tfp && tfp.isConstant() ) {
+                String old = code.externFunc(tfp.fidx());
+                if( old == null )
+                    code.externFunc(tfp.fidx(), ext._extern);
+                else
+                    assert old.equals(ext._extern);
+            }
+        }
+
+        // Node edges
+        for( Node n : nodes ) {
+            int len = n.nIns();
+            for( int i=0; i<len; i++ ) {
+                int idx = bais.packed2();
+                Node def = idx==0 ? null : nodes.at(idx-1);
+                // MemMerge precise aliases are encoded by their input slot.
+                // Remap populated file-local slots into this compilation's
+                // local alias numbering; null holes carry no identity.
+                int local = n instanceof MemMergeNode && i >= GlobalBits.RESERVED && def != null
+                    ? aliases.map(fileAliases,i)
+                    : i;
+                n.setDefX(local,def);
+                // Call's output[0] is always the CallEnd
+                if( n instanceof CallEndNode cend && i==0 ) {
+                    var outs = cend.call()._outputs;
+                    outs.swap(0,outs._len-1);
+                }
+            }
+            // A little extra for FunNodes
+            if( n instanceof FunNode fun ) {
+                // Return is hooked like an edge
+                ReturnNode ret = (ReturnNode)nodes.at(bais.packed2()-1);
+                fun.setRet(ret);
+                ret._fun = fun;
+            }
+        }
+        // Add edge from Start to Stop
+        StartNode start = (StartNode)nodes.at(0);
+        StopNode stop = (StopNode)nodes.last();
+        start.setDef(1,stop);
+
+        assert check(code,nodes);
+        elf._nodes = nodes;
+    }
+
+    // Check loaded types and nodes are consistent
+    private static boolean check( CodeGen code, Ary<Node> nodes ) {
+        // Loaded nodes are complete, unlike nodes still being built by the
+        // parser.  Recompute them with post-parse semantics.  The compilation-
+        // unit Stop is the exception: its escape type depends on the complete
+        // program's public interface, which ParseAll freezes only after every
+        // compilation unit has been loaded.
+        boolean good = true;
+        CodeGen.Phase phase = code._phase;
+        code._phase = CodeGen.Phase.Opto;
+        try {
+            for( Node n : nodes ) {
+                if( n instanceof StopCUNode && !code.publicInterfaceFrozen() )
+                    continue;
+                Type nval = n.compute();
+                if( nval != n._type ) {
+                    System.err.println("Node "+n+" read in as "+n._type+" but computes as "+nval);
+                    good = false;
+                }
+            }
+        } finally {
+            code._phase = phase;
+        }
+        return good;
+    }
+
+    // --------------------------------------------------
+    public static Ary<Node> nodeOrder( CodeGen code, CompUnit cu ) {
+        assert code._start._ltree != null; // Uses loop tree
+        BitSet visit = code.visit();
+        Ary<Node> nodes = new Ary<>(Node.class);
+        visit.set(code._stop._nid);
+        // Walk all listed functions, in this single compilation unit
+        for( FunNode fun : code._linker )
+            if( fun!=null && !fun.isDead() && fun._compunit == cu )
+                _funWalk(fun,nodes,visit);
+
+        // Just constants used by the listed functions
+        Ary<Node> cons = new Ary<>(Node.class);
+        cons.add(code._start);
+        for( Node n : code._start._outputs ) {
+            if( n instanceof ConstantNode con && !visit.get(con._nid) ) {
+                for( Node use : con.outs() ) {
+                    // Special case for Cast:BOT which is basically a double-indirect constant
+                    if( use instanceof CheckCastNode cast && cast.in(0)==null )
+                        for( Node useuse : cast.outs() )
+                            conUsed(cast,useuse,visit,cons);
+                    // PtrToInt is another zero-code value rooted at a global
+                    // constant.  Its array-body Add is the value used by the
+                    // function, so include that extra link in the ownership
+                    // test as well.
+                    if( use instanceof PtrToIntNode ptr )
+                        for( Node add : ptr.outs() ) {
+                            for( Node addUse : add.outs() )
+                                conUsed(add,addUse,visit,cons);
+                            conUsed(ptr,add,visit,cons);
+                        }
+                    // Constant used by somebody, so flag for output
+                    conUsed(con,use,visit,cons);
+                }
+            }
+        }
+        // StartCU and memory projection
+        cons.add(cu._start);
+        for( Node n : cu._start._outputs )
+            if( n instanceof ProjNode ) cons.add(n);
+        // All the innards of functions
+        cons.addAll(nodes);
+        // StopCU, Stop
+        cons.add(cu._stop);
+        cons.add(code._stop);
+        visit.clear();
+        return cons;
+    }
+
+    private static void conUsed( Node con, Node use, BitSet visit, Ary<Node> cons ) {
+        if( use == null || !visit.get(use._nid) || visit.get(con._nid) ) return;
+        cons.add(con);
+        visit.set(con._nid);
+    }
+
+    // --------------------------------------------------
+    public static Ary<Node> nodeOrder( CodeGen code ) {
+        assert code._start._ltree != null; // Uses loop tree
+        Ary<Node> nodes = new Ary<>(Node.class);
+        BitSet visit = code.visit();
+        nodes.add(code._start);
+
+        // All the global constants
+        for( Node n : code._start._outputs ) {
+            if( n.isConst() ) {
+                visit.set( n._nid );
+                nodes.add( n );
+                // Special for Cast:BOT
+                for( Node cast : n._outputs )
+                    if( cast != null && cast.nIns() == 2 && cast.in( 0 ) == null ) {
+                        visit.set( cast._nid );
+                        nodes.add( cast );
+                        // Array pointer conversion adds the body offset after
+                        // the zero-code PtrToInt.  Both nodes are global-value
+                        // descendants of the constant and otherwise have no
+                        // function-local root from which to walk them.
+                        if( cast instanceof PtrToIntNode )
+                            for( Node add : cast.outs() )
+                                if( add instanceof AddNode && !visit.get(add._nid) ) {
+                                    visit.set(add._nid);
+                                    nodes.add(add);
+                                }
+                    }
+            }
+        }
+
+        // All the CompUnits
+        for( CompUnit cu : code._compunits.values() ) {
+            // Whole CompUnits have no users, went dead
+            if( cu._start != null && !cu._start.isDead() ) {
+                nodes.add(cu._start);
+                // Memory proj
+                nodes.add(cu._start.proj(1));
+                // All the functions, including internal ones, in comp-unit order
+                for( FunNode fun : code._linker )
+                    if( fun!=null && !fun.isDead() && fun._compunit == cu )
+                        _funWalk(fun,nodes,visit);
+                nodes.add(cu._stop);
+            }
+        }
+
+        nodes.add(code._stop);
+        visit.clear();
+        return nodes;
+    }
+
+    // Walk and print whole functions at a time, in CG order
+    private static void _funWalk( FunNode fun, Ary<Node> rpo, BitSet visit ) {
+        int start = rpo._len;
+        _funRPO(fun,rpo,visit);
+        int len = rpo._len - start;
+        for( int i=0; i< len>>1; i++ )
+            rpo.swap(start+i,start+len-1-i);
+    }
+
+    // Walk and gather RPO nodes.
+    private static void _funRPO(Node n, Ary<Node> rpo, BitSet visit ) {
+        if( visit.get(n._nid) ) return; // Been there, done that
+        visit.set(n._nid);              // Stop recursion
+        // Walk outputs ordered
+        if( n instanceof CFGNode ncfg ) {
+            // If nodes walk outer loops before inner, so they hit the
+            // Return first, so Return is at the bottom of the RPO.
+            if( n instanceof IfNode iff ) {
+                CProjNode c0 = iff.cproj(0);
+                CProjNode c1 = iff.cproj(1);
+                if( c0._ltree.depth() > c1._ltree.depth() )
+                    { c0 = c1; c1 = iff.cproj(0); }
+                _funRPO(c0,rpo,visit);
+                _funRPO(c1,rpo,visit);
+            } else if( n instanceof StopNode ) {
+                // nothing
+            } else {
+                // CFG to CFG before CFG to data
+                for( Node use : n._outputs )
+                    if( use instanceof CFGNode usecfg && !ncfg.skip(usecfg) ) // Do not walk from Call to Fun
+                        _funRPO(use,rpo,visit);
+            }
+            // Walk CFG to data eventually
+            for( Node use : n._outputs )
+                if( !(use instanceof CFGNode) )
+                    _funRPO(use,rpo,visit);
+        } else {
+            // Do not walk from a non-CFG to a CFG; CFGs walk to CFGs to
+            // preserve CFG order.  Do not walk *into* Phis; wait for the
+            // Region to walk the Phis (otherwise you visit some of the
+            // Phis ahead of others forcing the Phis to be spread around).
+            for( Node use : n._outputs ) {
+                if( use!=null && !(use instanceof CFGNode) && !(use instanceof PhiNode) )
+                    _funRPO(use,rpo,visit);
+            }
+        }
+
+        // If parent is a Multi, do not add (yet).
+        // If self   is a Multi, add self and children.
+        if( multiChild(n) || n instanceof CallEndNode ) {
+            // nothing; delay until Multi-head or CallNode
+        } else if( n instanceof MultiNode ) {
+            // Now lump all multi/projections together
+            printMulti(n,rpo);
+        } else if( n instanceof CallNode call ) {
+            printMulti(call.cend(),rpo);
+            rpo.add(call);
+        } else if( n instanceof RegionNode ) {
+            // Now lump all Phis together
+            int old = rpo._len;
+            for( Node use : n._outputs )
+                if( use instanceof PhiNode )
+                    rpo.add(use);
+            // Sort by label?  Want Phis before control outputs
+            Arrays.sort( rpo._es, old, rpo._len, (x,y) -> y.label().compareTo(x.label()) );
+            rpo.add(n);
+        } else if( n instanceof StopNode ) {
+            // nothing
+        } else {
+            rpo.add(n);         // Post-order add
+        }
+    }
+
+    private static boolean multiChild(Node n) {
+        return n instanceof Proj || n instanceof PhiNode;
+    }
+
+    private static void printMulti(Node n, Ary<Node> rpo) {
+        // Now lump all multi/projections together
+        for( Node use : n._outputs )
+            rpo.add(use);
+        // Sort by projection order
+        if( !(n instanceof StartNode) )
+            Arrays.sort( rpo._es,rpo._len-n.nOuts(),rpo._len,
+                         (x,y) -> x instanceof ProjNode px && y instanceof ProjNode py ? (py.idx() - px.idx()) : (y._nid - x._nid) );
+        rpo.add(n);
+    }
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/AddFNode.java b/src/main/java/com/seaofnodes/simple/node/AddFNode.java
deleted file mode 100644
index 4ad02dbb..00000000
--- a/src/main/java/com/seaofnodes/simple/node/AddFNode.java
+++ /dev/null
@@ -1,31 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-import java.util.BitSet;
-
-public class AddFNode extends ArithFNode {
-    public AddFNode(Node lhs, Node rhs) { super(lhs, rhs); }
-
-    @Override public String label() { return "AddF"; }
-
-    @Override public String glabel() { return "+"; }
-
-    @Override double doOp( double x, double y ) { return x+y; }
-
-    @Override
-    public Node idealize() {
-        // Add of 0.
-        Type t2 = in(2)._type;
-        if ( t2.isConstant() && t2 instanceof TypeFloat i && i.value()==0 )
-            return in(1);
-
-        // Move constants to RHS: con+arg becomes arg+con
-        if ( in(1)._type.isConstant() && !t2.isConstant() )
-            return swap12();
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new AddFNode(lhs,rhs); }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/AddNode.java b/src/main/java/com/seaofnodes/simple/node/AddNode.java
index c7fd4daa..46607c23 100644
--- a/src/main/java/com/seaofnodes/simple/node/AddNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/AddNode.java
@@ -1,16 +1,19 @@
 package com.seaofnodes.simple.node;
 
+import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.*;
 
-import static com.seaofnodes.simple.Parser.con;
-
 public class AddNode extends ArithNode {
+    @Override boolean allowFloat() { return true; }
     public AddNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
+    public AddNode(Node lhs, Node rhs, byte mode) { super(null, lhs, rhs, mode); }
+    @Override public Tag serialTag() { return Tag.Add; }
 
     @Override public String label() { return "Add"; }
     @Override public String op() { return "+"; }
 
-    @Override long doOp( long x, long y ) { return x + y; }
+    @Override long   doOp( long  x,  long  y ) { return x + y; }
+    @Override double doOp(double x, double y ) { return x + y; }
     @Override TypeInteger doOp(TypeInteger x, TypeInteger y) {
         // Fold ranges like {0-1} + {2-3} into {2-4}.
         if( !overflow(x._min,y._min) &&
@@ -21,6 +24,11 @@ public class AddNode extends ArithNode {
 
     @Override
     public Node idealize () {
+        // Settle the one-shot arithmetic mode before applying family-specific
+        // algebraic identities.
+        if( _mode==0 )
+            return super.idealize();
+
         Node lhs = in(1);
         Node rhs = in(2);
         if( rhs instanceof AddNode add && add.err()!=null )
@@ -33,8 +41,8 @@ public class AddNode extends ArithNode {
             return lhs;
 
         // Add of same to a multiply by 2
-        if( lhs==rhs )
-            return new ShlNode(null,lhs,con(1));
+        if( lhs==rhs && _mode==1 )
+            return new ShlNode(null,lhs,CodeGen.CODE.con(1));
 
         // Goal: a left-spine set of adds, with constants on the rhs (which then fold).
 
@@ -44,7 +52,7 @@ public class AddNode extends ArithNode {
 
         // x+(-y) becomes x-y
         if( rhs instanceof MinusNode minus )
-            return new SubNode(lhs,minus.in(1));
+            return new SubNode(lhs,minus.in(1),_mode);
 
         // Now we might see (add add non) or (add non non) or (add add add) but never (add non add)
 
@@ -52,18 +60,21 @@ public class AddNode extends ArithNode {
         // Swap to    (x + y) + z
         // Rotate (add add add) to remove the add on RHS
         if( rhs instanceof AddNode add )
-            return new AddNode(new AddNode(lhs,add.in(1)).peephole(), add.in(2));
+            return copy(copy(lhs,add.in(1)).peephole(), add.in(2));
 
         // Now we might see (add add non) or (add non non) but never (add non add) nor (add add add)
-        if( !(lhs instanceof AddNode) )
+        if( !(lhs instanceof AddNode) ) {
             // Rotate; look for (add (phi cons) con/(phi cons))
-            return spine_cmp(lhs,rhs,this) ? swap12() : phiCon(this,true);
+            if( spine_cmp(lhs,rhs,this) ) return swap12();
+            Node n = phiCon(this,true);
+            return n == null ? super.idealize() : n;
+        }
 
         // Now we only see (add add non)
 
         // Dead data cycle; comes about from dead infinite loops.  Do nothing,
         // the loop will peep as dead after a bit.
-        if( lhs.in(1) == lhs )
+        if( lhs.nIns()>=2 && lhs.in(1) == lhs )
             return null;
 
         // Do we have (x + con1) + con2?
@@ -73,7 +84,7 @@ public class AddNode extends ArithNode {
         // because if it later became a constant then we could make this
         // transformation.
         if( addDep(lhs.in(2))._type.isConstant() && rhs._type.isConstant() )
-            return new AddNode(lhs.in(1),new AddNode(lhs.in(2),rhs).peephole());
+            return copy(lhs.in(1),copy(lhs.in(2),rhs).peephole());
 
 
         // Do we have ((x + (phi cons)) + con) ?
@@ -87,13 +98,13 @@ public class AddNode extends ArithNode {
         // Do we rotate (x + y) + z
         // into         (x + z) + y ?
         if( spine_cmp(lhs.in(2),rhs,this) )
-            return new AddNode(new AddNode(lhs.in(1),rhs).peephole(),lhs.in(2));
+            return copy(copy(lhs.in(1),rhs).peephole(),lhs.in(2));
 
         return super.idealize();
     }
 
     // Rotation is only valid for associative ops, e.g. Add, Mul, And, Or, Xor.
-    // Do we have ((phi cons)|(x + (phi cons)) + con|(phi cons)) ?
+    // Do we have ((phi cons)|(x + (phi cons)) + con|(phi cons)|(op y con)) ?
     // Push constant up through the phi: x + (phi con0+con0 con1+con1...)
     static Node phiCon(Node op, boolean rotate) {
         Node lhs = op.in(1);
@@ -126,7 +137,7 @@ public class AddNode extends ArithNode {
         for( int i=1; i<ns.length; i++ )
             ns[i] = op.copy(lphi.in(i), rhs instanceof PhiNode ? rhs.in(i) : rhs).peephole();
         String label = lphi._label + (rhs instanceof PhiNode rphi ? rphi._label : "");
-        Node phi = new PhiNode(label,lphi._minType.meet(op._type),ns).peephole();
+        Node phi = new PhiNode(label,ns).peephole();
         // Rotate needs another op, otherwise just the phi
         return lhs==lphi ? phi : op.copy(lhs.in(1),phi);
     }
@@ -164,6 +175,5 @@ public class AddNode extends ArithNode {
         return lo._nid > hi._nid;
     }
 
-    @Override Node copy(Node lhs, Node rhs) { return new AddNode(lhs,rhs); }
-    @Override Node copyF() { return new AddFNode(null,null); }
+    @Override Node copy(Node lhs, Node rhs) { return new AddNode(lhs,rhs,_mode); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/AndNode.java b/src/main/java/com/seaofnodes/simple/node/AndNode.java
index 70b57d6d..083a9a8c 100644
--- a/src/main/java/com/seaofnodes/simple/node/AndNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/AndNode.java
@@ -5,9 +5,9 @@ import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
 public class AndNode extends ArithNode {
-    public AndNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs); }
+    public AndNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs, (byte)1); }
+    @Override public Tag serialTag() { return Tag.And; }
 
-    @Override public String label() { return "And"; }
     @Override public String op() { return "&"; }
     @Override public String glabel() { return "&"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/ArithFNode.java b/src/main/java/com/seaofnodes/simple/node/ArithFNode.java
deleted file mode 100644
index 7fa428c6..00000000
--- a/src/main/java/com/seaofnodes/simple/node/ArithFNode.java
+++ /dev/null
@@ -1,32 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-import java.util.BitSet;
-
-public abstract class ArithFNode extends Node {
-    public ArithFNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override
-    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        in(1)._print0(sb.append("("), visited);
-        in(2)._print0(sb.append(glabel()), visited);
-        return sb.append(")");
-    }
-
-    abstract double doOp(double x, double y);
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeFloat.TOP;
-        if( t1 instanceof TypeFloat f1 &&
-            t2 instanceof TypeFloat f2 ) {
-            if( f1.isConstant() && f2.isConstant() )
-                return TypeFloat.constant(doOp(f1.value(),f2.value()));
-        }
-        return t1.meet(t2);
-    }
-
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/ArithNode.java b/src/main/java/com/seaofnodes/simple/node/ArithNode.java
index f2beaacb..8c21aef7 100644
--- a/src/main/java/com/seaofnodes/simple/node/ArithNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ArithNode.java
@@ -1,16 +1,26 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
 
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
-public abstract class ArithNode extends Node {
+public abstract class ArithNode extends Node implements ModeNode {
     // Source location for late reported errors
     Parser.Lexer _loc;
+    // Mode is 0 for unknown, 1 for int, 2 for flt
+    byte _mode;
 
     public ArithNode( Parser.Lexer loc, Node lhs, Node rhs) { super(null, lhs, rhs); _loc = loc; }
+    public ArithNode( Parser.Lexer loc, Node lhs, Node rhs, byte mode) { this(loc,lhs,rhs); _mode=mode; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes) {
+        baos.packed1(_mode);
+    }
     @Override public String glabel() { return op(); }
     abstract String op();
 
@@ -23,20 +33,93 @@ public abstract class ArithNode extends Node {
 
     abstract long doOp(long x, long y);
     abstract TypeInteger doOp(TypeInteger x, TypeInteger y);
+    double doOp(double x, double y) { throw Utils.TODO(); }
+
+    @Override public byte mode() { return _mode; }
+    @Override public Node setMode(byte mode) {
+        assert _mode==0 && (mode==1 || mode==2);
+        unlock();               // _mode participates in GVN hash and equality
+        _mode = mode;
+        return this;
+    }
+    static byte mode( Type t1, Type t2 ) {
+        if( t1 instanceof TypeFloat   || t2 instanceof TypeFloat   )  return 2;
+        if( t1 instanceof TypeInteger && t2 instanceof TypeInteger )  return 1;
+        if( t1 instanceof TypeMemPtr  && t2 instanceof TypeMemPtr  )  return 1;
+        if( t1 instanceof TypeFunPtr  && t2 instanceof TypeFunPtr  )  return 1;
+        return 0;
+    }
+
+    // Check that a settled mode agrees with all data inputs.  Takes the Node
+    // instead of a varargs list both to avoid allocation and to keep this ready
+    // to become shared mode-aware Node behavior later.
+    static Parser.ParseException nodeErr(Node n, Parser.Lexer loc, String op, byte mode, boolean allowFloat) {
+        Type bad = null;
+        for( int i=1; i<n.nIns(); i++ ) {
+            Type t = n.in(i)._type;
+            if( t.isHigh() )
+                return null;
+            // A weak input is not evidence of a bad mode while the graph is
+            // still being built.  Loop Phis commonly await their backedge.
+            if( CodeGen.CODE._phase.ordinal() < CodeGen.Phase.Opto.ordinal() && t == Type.BOTTOM )
+                return null;
+            bad = switch( t ) {
+            case TypeInteger ti -> mode==1 ? null : t;
+            case TypeMemPtr  ti -> mode==1 ? null : t;
+            case TypeFunPtr  ti -> mode==1 ? null : t;
+            case TypeFloat   tf -> mode==2 ? null : t;
+            default -> t;
+            };
+            if( bad != null ) break;
+        }
+        boolean unsupportedFloat = false;
+        if( !allowFloat )
+            for( int i=1; i<n.nIns(); i++ )
+                if( n.in(i)._type instanceof TypeFloat ) {
+                    bad = n.in(i)._type;
+                    unsupportedFloat = true;
+                    break;
+                }
+        if( bad == null )
+            return null;
+        if( unsupportedFloat || n instanceof BoolNode )
+            return Parser.error("Cannot '"+op+"' "+bad,loc);
+        if( n.nIns()==3 )
+            return Parser.error("Cannot "+n.in(1)._type+" "+op+" "+n.in(2)._type,loc);
+        return Parser.error("Cannot '"+op+"' "+bad,loc);
+    }
+
+    // Arithmetic subclasses which have a floating-point interpretation override.
+    boolean allowFloat() { return false; }
 
     // Generic airthmetic op math: high returns high; low returns low; 2
     // constants fold; only 2 non-constants call specialized math.
     @Override
-    public final TypeInteger compute() {
+    public final Type compute() {
         Type t1 = in(1)._type, t2 = in(2)._type;
         if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger x &&
-            t2 instanceof TypeInteger y )
-            return x.isConstant() && y.isConstant()
-                ? con(x,y)
-                : doOp(x,y).makeWide( (byte)Math.max(x._widen,y._widen) );
-        return TypeInteger.BOT;
+            return _mode==0 ? Type.TOP :
+                _mode==1 ? TypeInteger.TOP :
+                TypeFloat.F64.dual();
+        byte mode = _mode==0 ? mode(t1,t2) : _mode;
+        if( mode==0 )
+            return Type.BOTTOM;
+        if( mode==1 ) {
+            if( t1 instanceof TypeInteger x &&
+                t2 instanceof TypeInteger y )
+                return x.isConstant() && y.isConstant()
+                    ? con(x,y)
+                    : doOp(x,y).makeWide( (byte)Math.max(x._widen,y._widen) );
+            return TypeInteger.BOT;
+        }
+        // FP handling
+        if( t1 instanceof TypeFloat f1 &&
+            t2 instanceof TypeFloat f2 ) {
+            if( f1.isConstant() && f2.isConstant() )
+                return TypeFloat.constant(doOp(f1.value(),f2.value()));
+            return t1.meet(t2);
+        }
+        return TypeFloat.F64;
     }
 
     private TypeInteger con( Type t1, Type t2 ) {
@@ -49,36 +132,50 @@ public abstract class ArithNode extends Node {
     // push-down peephole cycle because the constants all fold first.
     // Returns "Phi(op(con,con),op(x,y))".
 
-    // This check is slightly different from the
-
     // Expected to be called after other ideal checks are done.
     @Override public Node idealize() {
+        Type t1 = in(1)._type, t2 = in(2)._type;
+
+        // Can we decide int vs flt?
+        if( _mode==0 ) {
+            byte mode = mode(t1,t2);
+            if( mode!=0 ) return setMode(mode).init();
+        }
+        if( _mode==2 ) {
+            if( t1 instanceof TypeInteger ) return copy(new ToFloatNode(in(1)).peephole(),in(2));
+            if( t2 instanceof TypeInteger ) return copy(in(1),new ToFloatNode(in(2)).peephole());
+        }
+
         if( in(1) instanceof PhiNode lhs &&
             in(2) instanceof PhiNode rhs &&
             lhs.nIns() >= 2 && !lhs.inProgress() &&
-            lhs.region()==rhs.region() && !(lhs.region() instanceof FunNode) &&
-            lhs.nIns()>2 && // A 1-input Phi will collapse already
             // Disallow with self-looping phi; these will collapse
-            (lhs.in(2)!=lhs && rhs.in(2)!=rhs) ) {
-            // Profit check: only 1 instance of `this` will remain, all the
-            // others will fold to constants.
-            int cnt=0;
-            for( int i=1; i<lhs.nIns(); i++ )
-                if( isCon(lhs,rhs,i) )
-                    cnt++;
-            if( lhs.nIns()-1 - cnt <= 1 ) {
-                // Profit!  Push up-phi and fold
-                Node[] ns = new Node[lhs.nIns()];
-                ns[0] = lhs.in(0);
-                for( int i=1; i<lhs.nIns(); i++ ) {
-                    ns[i] = isCon(lhs,rhs,i)
-                        ? new ConstantNode(con(lhs.in(i)._type, rhs.in(i)._type)).peephole()
-                        : copy(lhs.in(i), rhs.in(i)).peephole();
+            (lhs.nIns() > 2 && lhs.in(2)!=lhs && rhs.nIns() > 2 && rhs.in(2)!=rhs) ) {
+            Node r = lhs.region();
+            if( r==rhs.region() && !(r instanceof FunNode) &&
+                // For loops, the backedge *must* fold away, lest we unroll forever
+                (!(r instanceof LoopNode) || isCon(lhs,rhs,2)) ) {
+                // Profit check: only 1 instance of `this` will remain, all the
+                // others will fold to constants.  For loops, *all* must fold away
+                int cnt=0;
+                for( int i=1; i<lhs.nIns(); i++ )
+                    if( isCon(lhs,rhs,i) )
+                        cnt++;
+                if( lhs.nIns()-1 - cnt <= 1 ) {
+                    // Profit!  Push up-phi and fold
+                    Node[] ns = new Node[lhs.nIns()];
+                    ns[0] = lhs.in(0);
+                    for( int i=1; i<lhs.nIns(); i++ ) {
+                        ns[i] = isCon(lhs,rhs,i)
+                            ? ConstantNode.make(con(lhs.in(i)._type, rhs.in(i)._type)).peephole()
+                            : copy(lhs.in(i), rhs.in(i)).peephole();
+                    }
+                    String label = lhs._label==rhs._label ? lhs._label : lhs._label + rhs._label;
+                    return new PhiNode(label, ns).peephole();
                 }
-                String label = lhs._label==rhs._label ? lhs._label : lhs._label + rhs._label;
-                return new PhiNode(label,lhs._minType,ns).peephole();
             }
         }
+
         return null;
     }
 
@@ -88,14 +185,14 @@ public abstract class ArithNode extends Node {
 
 
     static boolean overflow( long x, long y ) {
-        if( (x ^    y ) < 0 ) return false; // unequal signs, never overflow
+        if(    (x ^    y   ) < 0 ) return false; // unequal signs, never overflow
         return (x ^ (x + y)) < 0; // sum has unequal signs, so overflow
     }
 
     @Override public Parser.ParseException err() {
-        if( in(1)._type.isHigh() || in(2)._type.isHigh() ) return null;
-        if( !(in(1)._type instanceof TypeInteger) ) return Parser.error("Cannot '"+op()+"' " + in(1)._type,_loc);
-        if( !(in(2)._type instanceof TypeInteger) ) return Parser.error("Cannot '"+op()+"' " + in(2)._type,_loc);
-        return null;
+        return nodeErr(this,_loc,op(),_mode,allowFloat());
     }
+
+    @Override public boolean eq( Node n ) { return _mode==((ArithNode)n)._mode; }
+    @Override public int hash() { return _mode; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/BoolNode.java b/src/main/java/com/seaofnodes/simple/node/BoolNode.java
index 2765c308..c8722f67 100644
--- a/src/main/java/com/seaofnodes/simple/node/BoolNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/BoolNode.java
@@ -1,23 +1,29 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 import static com.seaofnodes.simple.type.TypeInteger.*;
 
-abstract public class BoolNode extends Node {
+abstract public class BoolNode extends Node implements ModeNode {
 
-    public BoolNode(Node lhs, Node rhs) {
-        super(null, lhs, rhs);
+    // Mode is 0 for unknown, 1 for int, 2 for flt
+    byte _mode;
+
+    public BoolNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
+    public BoolNode(Node lhs, Node rhs, byte mode) { super(null, lhs, rhs); _mode = mode; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes) {
+        baos.packed1(_mode);
     }
 
     abstract public String op(); // String opcode name
 
     @Override
-    public String label() { return getClass().getSimpleName(); }
-
-    @Override
     public String glabel() { return op(); }
 
     @Override
@@ -37,9 +43,17 @@ abstract public class BoolNode extends Node {
         if( in(1)==in(2) )
             // LT fails, both EQ and LE succeed
             return this instanceof LT ? FALSE : TRUE;
-        if( t1 instanceof TypeInteger i1 &&
-            t2 instanceof TypeInteger i2 )
-            return doOp(i1,i2);
+        byte mode = _mode==0 ? ArithNode.mode(t1,t2) : _mode;
+        if( mode==0 )
+            return BOOL;
+        // Handle integer compares
+        if( mode==1 ) {
+            if( t1 instanceof TypeInteger i1 &&
+                t2 instanceof TypeInteger i2 )
+                return doOp(i1,i2);
+            return BOOL;
+        }
+        // Floating compare.  Mixed inputs are converted in idealize().
         if( t1 instanceof TypeFloat f1 &&
             t2 instanceof TypeFloat f2 &&
             f1.isConstant() && f2.isConstant() )
@@ -49,22 +63,39 @@ abstract public class BoolNode extends Node {
 
     TypeInteger doOp(TypeInteger t1, TypeInteger t2) { throw Utils.TODO(); }
     boolean doOp(double lhs, double rhs) { throw Utils.TODO(); }
-    Node copyF(Node lhs, Node rhs) { return null; }
-    public boolean isFloat() { return false; }
+    public boolean isFloat() { assert _mode!=0; return _mode==2; }
+    @Override public byte mode() { return _mode; }
+    @Override public Node setMode(byte mode) {
+        assert _mode==0 && (mode==1 || mode==2);
+        unlock();               // _mode participates in GVN hash and equality
+        _mode = mode;
+        return this;
+    }
 
     @Override
     public Node idealize() {
         // Compare of same
         if( in(1)==in(2) )
-            return this instanceof LT ? Parser.ZERO : new ConstantNode(TRUE);
+            return this instanceof LT ? CodeGen.CODE.ZERO : ConstantNode.make(TRUE);
+        // Can we decide int vs flt?
+        Type t1 = in(1)._type, t2 = in(2)._type;
+        if( _mode==0 ) {
+            byte mode = ArithNode.mode(t1,t2);
+            if( mode!=0 ) return setMode(mode).init();
+        }
+        if( _mode==2 ) {
+            if( t1 instanceof TypeInteger ) return copy(new ToFloatNode(in(1)).peephole(),in(2));
+            if( t2 instanceof TypeInteger ) return copy(in(1),new ToFloatNode(in(2)).peephole());
+        }
+
 
         // Equals pushes constant to the right; 5==X becomes X==5.
         if( this instanceof EQ ) {
             if( !(in(2) instanceof ConstantNode) ) {
                 // con==noncon becomes noncon==con
                 if( in(1) instanceof ConstantNode || in(1)._nid > in(2)._nid )
-                // Equals sorts by NID otherwise: non.high == non.low becomes non.low == non.high
-                    return in(1)._type instanceof TypeFloat ? new EQF(in(2),in(1)) : new EQ(in(2),in(1));
+                    // Equals sorts by NID otherwise: non.high == non.low becomes non.low == non.high
+                    return new EQ(in(2),in(1));
             }
             // Equals X==0 becomes a !X
             if( (in(2)._type == ZERO || in(2)._type == Type.NIL) )
@@ -80,32 +111,44 @@ abstract public class BoolNode extends Node {
         return null;
     }
 
+    @Override public boolean eq( Node n ) { return _mode==((BoolNode)n)._mode; }
+    @Override public int hash() { return _mode; }
+    @Override public Parser.ParseException err() {
+        return ArithNode.nodeErr(this,null,op(),_mode,!(this instanceof ULT));
+    }
+
     public static class EQ extends BoolNode {
         public EQ(Node lhs, Node rhs) { super(lhs,rhs); }
+        public EQ(Node lhs, Node rhs, byte mode) { super(lhs,rhs, mode); }
+        @Override public Tag serialTag() { return Tag.EQ; }
         public String op() { return "=="; }
         TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
             if( i1==i2 && i1.isConstant() ) return TRUE;
             if( i1._max < i2._min || i1._min > i2._max ) return FALSE;
             return BOOL;
         }
-        Node copy(Node lhs, Node rhs) { return new EQ(lhs,rhs); }
-        Node copyF() { return new EQF(null,null); }
+        @Override boolean doOp(double lhs, double rhs) { return lhs==rhs; }
+        Node copy(Node lhs, Node rhs) { return new EQ(lhs,rhs,_mode); }
     }
 
     public static class NE extends BoolNode {
         public NE(Node lhs, Node rhs) { super(lhs,rhs); }
+        public NE(Node lhs, Node rhs, byte mode) { super(lhs,rhs,mode); }
+        @Override public Tag serialTag() { return Tag.NE; }
         public String op() { return "!="; }
         TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
             if( i1==i2 && i1.isConstant() ) return TRUE;
             if( i1._max < i2._min || i1._min > i2._max ) return FALSE;
             return BOOL;
         }
-        Node copy(Node lhs, Node rhs) { return new NE(lhs,rhs); }
-        Node copyF() { throw Utils.TODO(); }
+        @Override boolean doOp(double lhs, double rhs) { return lhs!=rhs; }
+        Node copy(Node lhs, Node rhs) { return new NE(lhs,rhs,_mode); }
     }
 
     public static class LT extends BoolNode {
         public LT(Node lhs, Node rhs) { super(lhs,rhs); }
+        public LT(Node lhs, Node rhs, byte mode) { super(lhs,rhs, mode); }
+        @Override public Tag serialTag() { return Tag.LT; }
         public String op() { return "<" ; }
         public String glabel() { return "&lt;"; }
         TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
@@ -113,12 +156,14 @@ abstract public class BoolNode extends Node {
             if( i1._min >= i2._max ) return FALSE;
             return BOOL;
         }
-        Node copy(Node lhs, Node rhs) { return new LT(lhs,rhs); }
-        Node copyF() { return new LTF(null,null); }
+        @Override boolean doOp(double lhs, double rhs) { return lhs<rhs; }
+        Node copy(Node lhs, Node rhs) { return new LT(lhs,rhs,_mode); }
     }
 
     public static class LE extends BoolNode {
         public LE(Node lhs, Node rhs) { super(lhs,rhs); }
+        public LE(Node lhs, Node rhs, byte mode) { super(lhs,rhs,mode); }
+        @Override public Tag serialTag() { return Tag.LE; }
         public String op() { return "<="; }
         public String glabel() { return "&lt;="; }
         TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
@@ -126,32 +171,18 @@ abstract public class BoolNode extends Node {
             if( i1._min >  i2._max ) return FALSE;
             return BOOL;
         }
-        Node copy(Node lhs, Node rhs) { return new LE(lhs,rhs); }
-        Node copyF() { return new LEF(null,null); }
-    }
-
-    public static class EQF extends EQ {
-        public EQF(Node lhs, Node rhs) { super(lhs,rhs); }
-        @Override boolean doOp(double lhs, double rhs) { return lhs == rhs; }
-        @Override public boolean isFloat() { return true; }
-        @Override Node copy(Node lhs, Node rhs) { return new EQF(lhs,rhs); }
-    }
-    public static class LTF extends LT {
-        public LTF(Node lhs, Node rhs) { super(lhs,rhs); }
-        @Override boolean doOp(double lhs, double rhs) { return lhs <  rhs; }
-        @Override public boolean isFloat() { return true; }
-        @Override Node copy(Node lhs, Node rhs) { return new LTF(lhs,rhs); }
-    }
-    public static class LEF extends LE {
-        public LEF(Node lhs, Node rhs) { super(lhs,rhs); }
-        @Override boolean doOp(double lhs, double rhs) { return lhs <= rhs; }
-        @Override public boolean isFloat() { return true; }
-        @Override Node copy(Node lhs, Node rhs) { return new LEF(lhs,rhs); }
+        @Override boolean doOp(double lhs, double rhs) { return lhs<=rhs; }
+        Node copy(Node lhs, Node rhs) { return new LE(lhs,rhs,_mode); }
     }
 
     // Unsigned less that, for range checks.  Not directly user writable.
     public static class ULT extends BoolNode {
-        public ULT(Node lhs, Node rhs) { super(lhs,rhs); }
+        public ULT(Node lhs, Node rhs) { super(lhs,rhs,(byte)1); }
+        public ULT(Node lhs, Node rhs, byte mode) {
+            super(lhs,rhs,(byte)1);
+            assert mode==1;
+        }
+        @Override public Tag serialTag() { return Tag.ULT; }
         public String op() { return "u<" ; }
         public String glabel() { return "u&lt;"; }
         TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
diff --git a/src/main/java/com/seaofnodes/simple/node/BulkMemPhiNode.java b/src/main/java/com/seaofnodes/simple/node/BulkMemPhiNode.java
new file mode 100644
index 00000000..cab85e44
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/BulkMemPhiNode.java
@@ -0,0 +1,333 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.GlobalBits;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeMem;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
+
+import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+/**
+ * A Phi for bulk memory.  It covers all aliases except {@link #_aliases};
+ * those aliases must be represented by parallel precise MemPhis at the same
+ * program slice.
+ */
+public class BulkMemPhiNode extends PhiNode {
+
+    private static final BitSet EMPTY = new BitSet();
+
+    // Excluded Aliases; empty means NO exclusions.
+    // Directly visible by design.  Empty sets share EMPTY; splitAlias performs
+    // copy-on-first-write and removes the node from GVN before mutation.
+    public BitSet _aliases;
+
+    public BulkMemPhiNode(String label, Node... inputs) {
+        this(label,EMPTY,inputs);
+    }
+
+    private BulkMemPhiNode(String label, BitSet aliases, Node... inputs) {
+        super(label, inputs);
+        _aliases = aliases;
+    }
+
+    public BulkMemPhiNode(BulkMemPhiNode phi) {
+        super(phi,phi._label);
+        _aliases = phi._aliases.isEmpty() ? EMPTY : (BitSet)phi._aliases.clone();
+    }
+
+    public BulkMemPhiNode(RegionNode r, Node sample) {
+        super(r,sample);
+        _aliases = EMPTY;
+    }
+
+    public boolean isSplit(int alias) { return _aliases.get(alias); }
+
+    /**
+     * Record that an alias has been split out.  The graph rewrite installing
+     * its parallel precise Phi must happen before this semantic change.
+     */
+    public void splitAlias(int alias) {
+        assert alias > 1;
+        if( _aliases.get(alias) ) return;
+        unlock();
+        if( _aliases==EMPTY )
+            _aliases = new BitSet();
+        _aliases.set(alias);
+    }
+
+    @Override public Tag serialTag() { return Tag.BulkMemPhi; }
+
+    @Override
+    public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types,
+                       IdentityHashMap<Node,Integer> anodes) {
+        super.packed(baos,strs,types,anodes);
+        baos.packed2(_aliases.cardinality());
+        for( int alias = _aliases.nextSetBit(0); alias >= 0; alias = _aliases.nextSetBit(alias+1) )
+            baos.packed2(alias);
+    }
+
+    static Node make(BAOS bais, String[] strs, Type[] types, GlobalBits fileAliases, GlobalBits aliases) {
+        Node[] ins = new Node[bais.packed1()];
+        String label = strs[bais.packed2()];
+        BitSet bits = new BitSet();
+        for( int i=bais.packed2(); i>0; i-- ) {
+            int alias = bais.packed2();
+            if( alias >= GlobalBits.RESERVED ) alias = aliases.map(fileAliases,alias);
+            bits.set(alias);
+        }
+        return new BulkMemPhiNode(label,bits.isEmpty() ? EMPTY : bits,ins);
+    }
+
+    @Override
+    public Type compute() {
+        Type t = super.compute();
+        return t instanceof TypeMem mem ? mem :
+            t==Type.BOTTOM ? TypeMem.BOT :
+            TypeMem.TOP;
+    }
+
+    @Override
+    public Node idealize() {
+        Node progress = super.idealize();
+        if( progress != null ) return progress;
+
+        if( !(region() instanceof RegionNode r ) )
+            return in(1);       // Input has collapse to e.g. starting control.
+        if( r.inProgress() || r.nIns()<=1 )
+            return null;        // Input is in-progress
+        if( nOuts()==0 ) return null;
+        if( nIns() <= 2 ) return null;
+
+        // "Peek through" a MemMerge that covers this alias set on its default
+        for( int i=1; i<nIns(); i++ )
+            if( in(i) instanceof MemMergeNode mmm && canPeek(mmm) ) {
+                setDef(i,mmm.in(1));
+                return this;
+            }
+
+        // If any input or output uses or defines a specific alias we cover,
+        // make a private MemPhi for it, and add it to the excluded list.
+        for( int i=1; i<nIns(); i++ ) {
+            int alias = inputAlias(in(i));
+            if( alias!=0 )
+                return slice(alias);
+        }
+
+        for( int i=0; i<nOuts(); i++ ) {
+            int alias = outputAlias(out(i));
+            if( alias!=0 )
+                return slice(alias);
+        }
+
+        return null;
+    }
+
+    static public boolean checkMem(Node n, int alias) {
+        for( Node m : n._inputs )
+            // Bulk memory supplies this alias
+            if( m instanceof BulkMemPhiNode bulk ) {
+                if( bulk._aliases.get(alias) )
+                    return false;
+            } else if( m instanceof MemMergeNode mmm &&
+                       mmm.in(1) instanceof BulkMemPhiNode bulk &&
+                       bulk._aliases.get(alias) &&
+                       (alias >= mmm.nIns() || mmm.in(alias)==null) )
+                return false;
+        return true;
+    }
+
+
+    // True if the MemMerge has no precise slice still covered by this Phi.
+    private boolean canPeek(MemMergeNode mmm) {
+        return missingAlias(mmm,false)==0;
+    }
+
+    // Return an alias required by an input but still covered by this Phi, or 0.
+    private int inputAlias(Node n) {
+        return switch(n) {
+        case ParmNode p -> { assert p._idx==1; yield 0; }
+        case ScopeNode scope -> 0;
+        case ReturnNode ret -> 0;
+        case ProjNode proj -> 0;
+        case ConstantNode con -> {
+            assert !(con._con instanceof TypeMem tmem && tmem._alias != 1);
+            yield 0;
+        }
+        case MemMergeNode mmm -> missingAlias(mmm,false);
+        case MemOpNode mem -> unsplit(mem._alias);
+        case BulkMemPhiNode bulk -> missingAlias(bulk);
+        default -> throw Utils.TODO();
+        };
+    }
+
+    // Return an alias required by a user but still covered by this Phi, or 0.
+    private int outputAlias(Node use) {
+        // This decision depends backwards on an immediate user's alias/set.
+        // Normal graph-neighbor enqueueing flows from defs to uses, so retain
+        // an explicit forward dependency to revisit this Phi when the user
+        // sharpens.
+        use = addDepForwards(use);
+        return switch(use) {
+        case ScopeNode scope -> 0;
+        case ParmNode parm -> 0;
+        case MemMergeNode mmm -> mmm.in(1)==this ? missingAlias(mmm,true) : 0;
+        case BulkMemPhiNode bulk -> missingAlias(bulk);
+        case MemOpNode mem -> unsplit(mem._alias);
+        case MemPhiNode phi -> unsplit(phi._alias);
+        case EscapeNode esc -> esc.pub()==this ? unsplit(esc.fld()._alias) : 0;
+        default -> {
+            assert use instanceof ReturnNode || use instanceof CallNode
+                : "Unexpected bulk-memory user "+use.getClass().getSimpleName()+"#"+use._nid+": "+use;
+            yield 0;
+        }
+        };
+    }
+
+    // Alias zero/one is bulk, and an already excluded precise alias cannot
+    // trigger another split of this Phi.
+    private int unsplit(int alias) {
+        return alias <= 1 || _aliases.get(alias) ? 0 : alias;
+    }
+
+    // First alias excluded by the neighboring bulk Phi but not by this one.
+    private int missingAlias(BulkMemPhiNode bulk) {
+        for( int alias = bulk._aliases.nextSetBit(0); alias >= 0; alias = bulk._aliases.nextSetBit(alias+1) )
+            if( !_aliases.get(alias) )
+                return alias;
+        return 0;
+    }
+
+    // First precise MemMerge slice still covered by this Phi.  When inspecting
+    // a user, ignore slots which point back to this Phi.
+    private int missingAlias(MemMergeNode mmm, boolean user) {
+        for( int alias=2; alias<mmm.nIns(); alias++ )
+            if( mmm.in(alias)!=null &&
+                mmm.alias(alias)!=mmm.in(1) &&
+                (!user || mmm.in(alias)!=this) &&
+                !_aliases.get(alias) )
+                return alias;
+        return 0;
+    }
+
+    // Slice out given alias
+    private MemMergeNode slice( int alias ) {
+        assert !_aliases.get(alias);
+        assert !hasDup(alias);
+        // Inputs are the same; MemPhi will sharpen his own inputs
+        MemPhiNode mphi = new MemPhiNode("$"+alias,alias);
+        for( int i=0; i<nIns(); i++ ) mphi.addDef(in(i));
+        Node mem = mphi.peephole();
+        assert ((TypeMem)mem._type)._alias==alias;
+        // The precise Phi is a new alias-sensitive user of every memory
+        // input.  Revisit those defs: a predecessor BulkMemPhi may now need
+        // to split this alias even though none of its inputs or types changed.
+        for( int i=1; i<mphi.nIns(); i++ )
+            CodeGen.CODE.add(mphi.in(i));
+
+        BitSet aliases = ((BitSet)_aliases.clone());
+        aliases.set(alias);
+        BulkMemPhiNode bphi = new BulkMemPhiNode(_label,aliases);
+        for( int i=0; i<nIns(); i++ )
+            bphi.addDef(in(i));
+        // Installing bphi creates a new bulk user with a different exclusion
+        // set.  Queue the original memory inputs before bphi itself can peep
+        // away and hide those neighbor relationships.
+        for( int i=1; i<bphi.nIns(); i++ )
+            CodeGen.CODE.add(bphi.in(i));
+        Node bulk = bphi.peephole();
+        CodeGen.CODE.add(bulk);
+        CodeGen.CODE.add(mphi);
+        return aggregate(bulk,alias,mem);
+    }
+
+    // Build aggregate memory over a bulk Phi, preserving every precise slice
+    // which the bulk has already excluded.  The named alias is newly supplied
+    // (or replaces its old slice).
+    MemMergeNode aggregate(Node bulk, int alias, Node precise) {
+        MemMergeNode mmm = new MemMergeNode(false,null,bulk);
+        for( int old = _aliases.nextSetBit(0); old >= 0; old = _aliases.nextSetBit(old+1) )
+            if( old != alias )
+                mmm.alias(old,precisePhi(old));
+        mmm.alias(alias,precise);
+        assert checkMerge(mmm);
+        mmm.init();
+        // Slicing changes representation, not the set of values in memory.
+        // Newly exposed precise inputs can carry conservative bulk escape
+        // summaries; do not let those invent escapes absent from this Phi.
+        if( _type instanceof TypeMem old && mmm._type instanceof TypeMem mem )
+            mmm._type = TypeMem.make(mem._alias,mem._t,mem._one,mem._clz,
+                                     mem._final,old._escFs,old._escAs);
+        return mmm;
+    }
+
+    // Find the precise Phi parallel to this bulk Phi at the same merge.
+    private Node precisePhi(int alias) {
+        Node found = null;
+        for( Node use : region().outs() )
+            if( use instanceof MemPhiNode mphi && mphi._alias==alias ) {
+                assert found==null;
+                found = mphi;
+            }
+        // The parallel Phi may already have collapsed to a common input.  Do
+        // not recover it from downstream MemMerges: they are distinct program
+        // points and can legitimately carry different values for this alias.
+        // Reconstruct from this Phi's merge inputs instead.  MemPhi selects
+        // the alias from each input MemMerge and collapses when, for example,
+        // the alias is loop-invariant here.
+        if( found==null ) {
+            MemPhiNode mphi = new MemPhiNode("$"+alias,alias);
+            mphi.addDef(region());
+            // Publishing the Phi on the Region makes it visible to recursive
+            // precisePhi lookups before all loop inputs have been installed.
+            // Give that recursion a valid lattice value until peephole computes
+            // the completed precise-memory Phi.
+            mphi.setType(TypeMem.BOT.makeFrom(alias));
+            for( int i=1; i<nIns(); i++ )
+                mphi.addDef(preciseInput(in(i),alias));
+            found = mphi.peephole();
+            // A newly reconstructed precise Phi also creates new users of
+            // its memory inputs.  In particular, a BulkMemPhi input may now
+            // need to split this alias, a backwards (user-to-def) change not
+            // covered by processing the new Phi itself.
+            for( int i=1; i<mphi.nIns(); i++ )
+                CodeGen.CODE.add(mphi.in(i));
+            CodeGen.CODE.add(found);
+        }
+        return found;
+    }
+
+    // Select an alias already split out of a predecessor's bulk memory.
+    private Node preciseInput(Node mem, int alias) {
+        if( mem instanceof MemMergeNode mmm )
+            return mmm.alias(alias);
+        if( mem instanceof BulkMemPhiNode bulk && bulk.isSplit(alias) )
+            return bulk.precisePhi(alias);
+        return mem;
+    }
+
+    // Every alias excluded by a bulk default must be supplied explicitly.
+    static boolean checkMerge(MemMergeNode mmm) {
+        if( !(mmm.in(1) instanceof BulkMemPhiNode bulk) ) return true;
+        for( int alias = bulk._aliases.nextSetBit(0); alias >= 0; alias = bulk._aliases.nextSetBit(alias+1) )
+            if( alias >= mmm.nIns() || mmm.in(alias)==null )
+                return false;
+        return true;
+    }
+
+    private boolean hasDup( int alias ) {
+        for( Node use : region().outs() )
+            if( use instanceof MemPhiNode mphi && mphi._alias==alias )
+                return true;
+        return false;
+    }
+
+    @Override public boolean eq(Node n) {
+        return _aliases.equals(((BulkMemPhiNode)n)._aliases) && super.eq(n);
+    }
+
+    @Override int hash() { return _aliases.hashCode(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/CFGNode.java b/src/main/java/com/seaofnodes/simple/node/CFGNode.java
index b9c70e5f..2b668da8 100644
--- a/src/main/java/com/seaofnodes/simple/node/CFGNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CFGNode.java
@@ -1,13 +1,11 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.*;
 import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.Utils;
+
 import java.util.BitSet;
-import java.util.HashMap;
-import java.util.HashSet;
+import java.util.IdentityHashMap;
 
 /** Control Flow Graph Nodes
  * <p>
@@ -100,8 +98,10 @@ public abstract class CFGNode extends Node {
     // Find nearest enclosing FunNode
     public FunNode fun() {
         CFGNode cfg = this;
-        while( !(cfg instanceof FunNode fun) )
+        while( !(cfg instanceof FunNode fun) ) {
+            if( cfg==null ) return null;
             cfg = cfg.idom();
+        }
         return fun;
     }
 
@@ -112,13 +112,13 @@ public abstract class CFGNode extends Node {
 
     public LoopTree _ltree;
     public int _pre;            // Pre-order numbers for loop tree finding
-    static class LoopTree {
-        LoopTree _par;
-        final LoopNode _head;
-        int _depth;
+    public static class LoopTree {
+        public LoopTree _par;
+        public final LoopNode _head;
+        public int _depth;
         LoopTree(LoopNode head) { _head = head; }
-        @Override public String toString() { return "LOOP"+_head._nid; }
-        int depth() {
+        @Override public String toString() { return label(_head); }
+        public int depth() {
             return _depth==0 ? (_par==null ? 0 : (_depth = _par.depth()+1)) : _depth;
         }
     }
@@ -127,73 +127,87 @@ public abstract class CFGNode extends Node {
     // Tag all CFG Nodes with their containing LoopNode; LoopNodes themselves
     // also refer to *their* containing LoopNode, as well as have their depth.
     // Start is a LoopNode which contains all at depth 1.
-    public void buildLoopTree(StartNode start, StopNode stop) {
-        // Unlink all linked calls.  This can remove RPC constants which
-        // shuffled the StartNode outputs so requires a while loop.
-        boolean done=false;
-        while(!done) {
-            done = true;
-            for( Node use : start._outputs )
-                if( use instanceof FunNode fun )
-                    for( Node c : fun._inputs )
-                        if( c instanceof CallNode call )
-                            { call.unlink_all(); done=false; }
+    public void buildLoopTree( Ary<FunNode> funs, StopNode stop) {
+        _ltree = stop._ltree = CodeGen.CODE.XCTRL._ltree = new LoopTree((StartNode)this);
+        Ary<FunNode> work = new Ary<>(FunNode.class);
+
+        BitSet post = new BitSet();
+        int pre = 1;
+        _pre = pre++;
+        for( FunNode fun : funs ) {
+            if( fun!=null && !fun.isDead() && !fun._type.isHigh() ) {
+                work.push(fun);
+                if(fun.in(1) instanceof StartCUNode start && start._pre==0 ) {
+                    start._pre = pre++;
+                    start._ltree = _ltree;
+                    post.set(start._nid);
+                }
+            };
         }
 
-        _ltree = stop._ltree = Parser.XCTRL._ltree = new LoopTree((StartNode)this);
-        _bltWalk(2,null,stop, new BitSet());
+        for( int i=0; i<work._len; i++ )
+            pre = work.at(i)._bltWalk(pre,work.at(i),stop, post, work);
     }
-    int _bltWalk( int pre, FunNode fun, StopNode stop, BitSet post ) {
+
+    int _bltWalk( int pre, FunNode fun, StopNode stop, BitSet post, Ary<FunNode> work ) {
         // Pre-walked?
         if( _pre!=0 ) return pre;
         _pre = pre++;
         // Pre-walk
         for( Node use : _outputs )
-            if( use instanceof CFGNode usecfg && !skip( usecfg ) )
-                pre = usecfg._bltWalk( pre, use instanceof FunNode fuse ? fuse : fun, stop, post );
-
-        // Post-order work: find innermost loop
-        LoopTree inner = null, ltree;
-        for( Node use : _outputs ) {
-            if( !(use instanceof CFGNode usecfg) ) continue;
-            if( skip(usecfg) ) continue;
-            if( usecfg._type == Type.XCONTROL ||       // Do not walk dead control
-                usecfg._type == TypeTuple.IF_NEITHER ) // Nor dead IFs
-                continue;
-            // Child visited but not post-visited?
-            if( !post.get(usecfg._nid) ) {
-                // Must be a backedge to a LoopNode then
-                ltree = usecfg._ltree = new LoopTree((LoopNode)usecfg);
-            } else {
-                // Take child's loop choice, which must exist
-                ltree = usecfg._ltree;
-                // If falling into a loop, use the target loop's parent instead
-                if( ltree._head == usecfg ) {
-                    if( ltree._par == null )
-                        // This loop never had an If test choose to take its
-                        // exit, i.e. it is a no-exit infinite loop.
-                        ltree._par = ltree._head.forceExit(fun,stop)._ltree;
-                    ltree = ltree._par;
-                }
+            if( use instanceof CFGNode usecfg ) {
+                if( skip( usecfg ) ) {
+                    if( usecfg._pre==0 && usecfg instanceof FunNode fun2 ) work.add( fun2 );
+                } else
+                    pre = usecfg._bltWalk( pre, use instanceof FunNode fuse ? fuse : fun, stop, post, work );
             }
-            // Sort inner loops.  The decision point is some branch far removed
-            // from either loop head OR either backedge so requires pre-order
-            // numbers to figure out innermost.
-            if( inner == null ) { inner = ltree; continue; }
-            if( inner == ltree ) continue; // No change
-            LoopTree outer = ltree._head._pre > inner._head._pre ? inner : ltree;
-            inner =          ltree._head._pre > inner._head._pre ? ltree : inner;
-            inner._par = outer;
+
+        if( this instanceof ReturnNode ret ) {
+            ret._ltree = stop._ltree;
+        } else {
+          // Post-order work: find innermost loop
+          LoopTree inner = null, ltree;
+          for( Node use : _outputs ) {
+              if( !(use instanceof CFGNode usecfg) ) continue;
+              if( skip(usecfg) ) continue;
+              if( usecfg._type == Type.XCONTROL ||       // Do not walk dead control
+                  usecfg._type == TypeTuple.IF_NEITHER ) // Nor dead IFs
+                  continue;
+              // Child visited but not post-visited?
+              if( !post.get(usecfg._nid) ) {
+                  // Must be a backedge to a LoopNode then
+                  ltree = usecfg._ltree = new LoopTree((LoopNode)usecfg);
+              } else {
+                  // Take child's loop choice, which must exist
+                  ltree = usecfg._ltree;
+                  // If falling into a loop, use the target loop's parent instead
+                  if( ltree._head == usecfg ) {
+                      if( ltree._par == null )
+                          // This loop never had an If test choose to take its
+                          // exit, i.e. it is a no-exit infinite loop.
+                          ltree._par = ltree._head.forceExit(fun,stop)._ltree;
+                      ltree = ltree._par;
+                  }
+              }
+              // Sort inner loops.  The decision point is some branch far removed
+              // from either loop head OR either backedge so requires pre-order
+              // numbers to figure out innermost.
+              if( inner == null ) { inner = ltree; continue; }
+              if( inner == ltree ) continue; // No change
+              LoopTree outer = ltree._head._pre > inner._head._pre ? inner : ltree;
+              inner =          ltree._head._pre > inner._head._pre ? ltree : inner;
+              inner._par = outer;
+          }
+          // Set selected loop
+          if( inner!=null )
+              _ltree = inner;
         }
-        // Set selected loop
-        if( inner!=null )
-            _ltree = inner;
         // Tag as post-walked
         post.set(_nid);
         return pre;
     }
 
-    private boolean skip(CFGNode usecfg) {
+    public boolean skip(CFGNode usecfg) {
         // Only walk control users that are alive.
         // Do not walk from a Call to linked Fun's.
         return usecfg instanceof XCtrlNode ||
@@ -201,8 +215,13 @@ public abstract class CFGNode extends Node {
                 (this instanceof ReturnNode && usecfg instanceof CallEndNode);
     }
 
-
-    public String label( CFGNode target ) {
-        return (target instanceof LoopNode ? "LOOP" : "L")+target._nid;
+    public static String label( CFGNode target ) {
+        return switch(target) {
+        case StartNode start -> start.label();
+        case FunNode fun -> fun.label();
+        case LoopNode loop -> "LOOP"+target._nid;
+        default -> "L"+target._nid;
+        };
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/CProjNode.java b/src/main/java/com/seaofnodes/simple/node/CProjNode.java
index d18f779b..b74619a3 100644
--- a/src/main/java/com/seaofnodes/simple/node/CProjNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CProjNode.java
@@ -1,13 +1,16 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Serialize;
 import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
 import com.seaofnodes.simple.type.TypeTuple;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.BAOS;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
-public class CProjNode extends CFGNode {
+public class CProjNode extends CFGNode implements Proj {
 
     // Which slice of the incoming multipart value
     public int _idx;
@@ -21,6 +24,14 @@ public class CProjNode extends CFGNode {
         _label = label;
     }
     public CProjNode(CProjNode c) { super(c); _idx = c._idx; _label = c._label; }
+    @Override public Tag serialTag() { return Tag.CProj; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed1(_idx);
+        baos.packed2(_label==null ? 0 : strs.get(_label));
+    }
+    static Node make( BAOS bais, String[] strs ) {
+        return new CProjNode(null, bais.packed1(), strs[bais.packed2()] );
+    }
 
     @Override public String label() { return _label; }
 
@@ -40,13 +51,13 @@ public class CProjNode extends CFGNode {
     public Node idealize() {
         if( ctrl()._type instanceof TypeTuple tt ) {
             if( tt._types[_idx]==Type.XCONTROL )
-                return Parser.XCTRL; // We are dead
+                return CodeGen.CODE.XCTRL; // We are dead
             if( ctrl() instanceof IfNode && tt._types[1-_idx]==Type.XCONTROL ) // Only true for IfNodes
                 return ctrl().in(0);               // We become our input control
         }
 
         // Flip a negating if-test, to remove the not
-        if( ctrl() instanceof IfNode iff && addDep(iff.pred()) instanceof NotNode not )
+        if( ctrl() instanceof IfNode iff && iff.pred() != null && addDep(iff.pred()) instanceof NotNode not )
             return new CProjNode(new IfNode(iff.ctrl(),not.in(1)).peephole(),1-_idx,_idx==0 ? "False" : "True");
 
         // Copy of some other input
@@ -65,4 +76,9 @@ public class CProjNode extends CFGNode {
     @Override
     int hash() { return _idx; }
 
+    @Override public int idx() { return _idx; }
+
+    @Override public void gather( HashMap<String,Integer> strs ) {
+        Serialize.gather(strs,_label);
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/CallEndMach.java b/src/main/java/com/seaofnodes/simple/node/CallEndMach.java
index d26ea33b..05707132 100644
--- a/src/main/java/com/seaofnodes/simple/node/CallEndMach.java
+++ b/src/main/java/com/seaofnodes/simple/node/CallEndMach.java
@@ -14,13 +14,15 @@ public class CallEndMach extends CallEndNode implements MachNode {
         _retMask = code._mach.retMask(call().tfp());
         // Kill mask is all caller-saves, and any mirror stack slots for args
         // in registers.
-        RegMaskRW kills = code._callerSave.copy();
+        RegMaskRW kills = (call().external() ? code._cCallerSave : code._callerSave).copy();
         // Start of stack slots
         int maxReg = code._mach.regs().length;
         // Incoming function arg slots, all low numbered in the RA
         int fslot = fun()._maxArgSlot;
         // Killed slots for this calls outgoing args
-        int xslot = code._mach.maxArgSlot(call().tfp());
+        int xslot = call().external()
+            ? code._mach.maxArgSlot(call().tfp(),code._cCallingConv)
+            : code._mach.maxArgSlot(call().tfp());
         _xslot = (maxReg+fslot)+xslot;
         for( int i=0; i<xslot; i++ )
             kills.set((maxReg+fslot)+i);
diff --git a/src/main/java/com/seaofnodes/simple/node/CallEndNode.java b/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
index a7e50c39..8e7f47f3 100644
--- a/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
@@ -1,9 +1,13 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
  *  CallEnd
@@ -11,16 +15,42 @@ import java.util.BitSet;
 public class CallEndNode extends CFGNode implements MultiNode {
 
     // When set true, this Call/CallEnd/Fun/Return is being trivially inlined
-    private boolean _folding;
+    boolean _folding;
     public final TypeRPC _rpc;
 
-    public CallEndNode(CallNode call) { super(new Node[]{call}); _rpc = TypeRPC.constant(_nid); }
+    public CallEndNode(CallNode call, TypeRPC rpc) {
+        super(new Node[]{call});
+        _rpc = rpc;
+    }
     public CallEndNode(CallEndNode cend) { super(cend); _rpc = cend._rpc; }
+    public CallEndNode(TypeRPC rpc) {
+        super(new Node[0]);
+        _rpc = TypeRPC.constant(CodeGen.CODE._rpcs.next(rpc.rpc()));
+    }
+    private CallEndNode(int nIns, TypeRPC rpc) {
+        super(new Node[nIns]);
+        _rpc = rpc;
+    }
+    @Override public Tag serialTag() { return Tag.CallEnd; }
+    public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed1(nIns());
+        // Linked CallEnds depend on Return types which depend on CallEnds;
+        // break the cycle
+        baos.packed2(types.get(_type));
+        baos.packed2(types.get(_rpc));
+    }
+    static Node make( BAOS bais, Type[] types )  {
+        int nIns = bais.packed1();
+        Type type = types[bais.packed2()];
+        Node cend = new CallEndNode(nIns,(TypeRPC)types[bais.packed2()]);
+        cend._type = type;
+        return cend;
+    }
 
-    @Override public String label() { return "CallEnd"; }
     @Override public boolean blockHead() { return true; }
 
     public CallNode call() { return (CallNode)in(0); }
+    boolean folding() { return _folding; }
 
     @Override public CFGNode idom(Node dep) {
         // Folding the idom is the one inlining Return
@@ -40,80 +70,100 @@ public class CallEndNode extends CFGNode implements MultiNode {
     @Override
     public Type compute() {
         if( !(in(0) instanceof CallNode call) || call._type != Type.CONTROL )
-            return TypeTuple.RET.dual();
-        // Mid-fold, just take the one single callers' return type
-        if( _folding ) return in(1)._type;
+            return TypeTuple.STATE.dual();
         // Grab the TFP and use the functions declared return type.
+        // If the call.fptr() is a FRef, return will be BOTTOM.
         Type ftype = addDep(call.fptr())._type;
-        Type ret = ftype.isHigh() ? Type.TOP : Type.BOTTOM;
-        if( ftype instanceof TypeFunPtr tfp ) {
-            ret = tfp.ret();
-            // Here, if I can figure out I've found *all* callers, then I can meet
-            // across the linked returns and join with the function return type.
-            if( 1+tfp.nfcns() == nIns() ) { // A linked function for every concrete function
+        if( !(ftype instanceof TypeFunPtr tfp) )
+            return ftype.isHigh() ? TypeTuple.STATE.dual() : TypeTuple.STATE;
+        // Mid-fold, just take the one single callers' return type
+        if( _folding ) {
+            TypeTuple tt = (TypeTuple)in(1)._type;
+            return tt.makeFrom(2,tt.ret().join(tfp._ret));
+        }
+
+        // Here, if I can figure out I've linked *all* callers, then I can meet
+        // across the linked returns and join with the function return type.
+
+        // External functions have an exact FIDX but deliberately no local
+        // FunNode/Return edge.  They conservatively crush public memory and
+        // produce their declared return type.  A missing non-external target
+        // is still an unresolved/error call.
+        int externs = 0;
+        if( !XInt.isHigh(tfp.fidxs()) )
+            for( int fidx = XInt.next(tfp.fidxs(),0); fidx >= 0; fidx = XInt.next(tfp.fidxs(),fidx) )
+                if( CodeGen.CODE.externFunc(fidx)!=null )
+                    externs++;
+        boolean hasExtern = externs != 0;
+
+        // If we have an error-call, e.g. wrong args, then we never link.
+        // Pre-Opto this looks like a missing target fcn, and we assume it will
+        // appear later - meanwhile, we use a conservative approx of memory
+        // effects.
+        if( (nIns()-1)+externs < tfp.nfcns() ) {
+            // If before SCCP, we might call extras or also the unknown target.
+            StartNode start = CodeGen.CODE._start;
+            addDep(start);
+            Type tmem = start._type instanceof TypeTuple tt ? tt._types[1] : (start._type.isHigh() ? TypeMem.TOP : TypeMem.BOT);
+            Type ret = tfp.ret();
+            // If during Opto, assume call won't be called and thus won't return anything.
+            if( CodeGen.CODE._phase.ordinal() >= CodeGen.Phase.Opto.ordinal() )
                 ret = Type.TOP;
-                for( int i=1; i<nIns(); i++ ) {
-                    Type tret = in(i)._type instanceof TypeTuple rtt ? rtt.ret() : in(i)._type;
-                    ret = ret.meet(tret);
-                }
-            }
+            return TypeTuple.make(Type.CONTROL,tmem,ret);
         }
-        return TypeTuple.make(call._type,TypeMem.BOT,ret);
+
+        // A linked function for every concrete function
+        TypeTuple state = hasExtern
+            ? TypeTuple.make(Type.CONTROL,TypeMem.BOT,tfp.ret())
+            : TypeTuple.STATE.dual();
+        for( int i=1; i<nIns(); i++ )
+            state = (TypeTuple)state.meet(in(i)._type);
+        // At least as good as the TFP
+        return state.makeFrom(2,state.ret().join(tfp.ret()));
     }
 
     @Override
     public Node idealize() {
 
-        // Trivial inlining: call site calls a single function; single function
-        // is only called by this call site.
+        // Worklist-based inlining.  Cannot inline if folding, or calling
+        // multiple targets or no CallNode (malformed because dying).
         if( !_folding && nIns()==2 && in(0) instanceof CallNode call ) {
             Node fptr = call.fptr();
-            if( fptr.nOuts() == 1 && // Only user is this call
-                fptr instanceof ConstantNode && // We have an immediate call
+            if( fptr.isConst() && // We have an immediate call
                 // Function is being called, and its not-null
-                fptr._type instanceof TypeFunPtr tfp && tfp.notNull() &&
+                fptr._type instanceof TypeFunPtr tfp && tfp.notNull() && !tfp.isHigh() &&
                 // Arguments are correct
-                call.err()==null ) {
+                call.nargs()==tfp.nargs() && goodArgs(call,tfp) ) {
                 ReturnNode ret = (ReturnNode)in(1);
                 FunNode fun = ret.fun();
-                // Expecting Start, and the Call
-                if( fun.nIns()==3 ) {
-                    assert fun.in(1) instanceof StartNode && fun.in(2)==call;
-                    // Disallow self-recursive inlining (loop unrolling by another name).
-                    // Disallow if still folding other things, as it makes other
-                    // dependency checks carry long chains of half-folded calls.
-                    CFGNode idom = call;
-                    while( true ) {
-                        idom = idom.idom();
-                        if( idom instanceof FunNode ) break;
-                        if( idom instanceof CallEndNode cend && cend._folding ) break;
-                    }
-                    // Inline?
-                    if( idom instanceof FunNode fun2 && fun2 != fun && !fun2._folding ) {
-                        // Trivial inline: rewrite
-                        _folding = true;
-                        // Rewrite Fun so the normal RegionNode ideal collapses
-                        fun._folding = true;
-                        fun.setDef(1,Parser.XCTRL); // No default/unknown StartNode caller
-                        fun.setDef(2,call.ctrl());  // Bypass the Call;
-                        fun.ret().setDef(3,null);   // Return is folding also
-                        CodeGen.CODE.addAll(fun._outputs);
-                        // Repeat defs 1 layer down, for users of Parm (Phis)
-                        for( Node parm : fun._outputs )
-                            if( parm instanceof ParmNode )
-                                CodeGen.CODE.addAll(parm._outputs);
-
-                        // Inlining immediately blows all cache idepth fields past the inline point.
-                        // Bump the global version number invalidating them en-masse.
-                        CodeGen.CODE.invalidateIDepthCaches();
-                        return this;
-                    } else {
-                        addDep(idom);
-                    }
-                } else {
-                    addDep(fun);
+                int isTrivial = trivialInlining( fptr, fun );
+
+                // Encouraged inlining because small size and constructor.
+                int maxSize = fun._name!=null && fun.isInit() && !fun.isClz() ? 200 : 100;
+                if( isTrivial==1 && fun._approxUIDs < maxSize ) {
+                    assert fun.sig().isa(tfp);
+                    assert !CodeGen.CODE._midAssert; // Triggered inlining
+                    CodeGen.CODE.add(fun);
+                    // Remove the existing function linkage
+                    call.unlink_all();
+                    // Clone the function body
+                    FunNode fun2 = fun.copyBody();
+                    // Call uses the unique new function
+                    Node fptr2 = new FunPtrNode(fun2.sig(),CodeGen.CODE._start,fun2.ret()).peephole();
+                    call.setDef(call.nIns()-1,fptr2);
+                    // Link to the new function
+                    call.link(fun2);
+                    fun = fun2;
+                    assert trivialInlining( fptr2, fun2 )==0;
+                    isTrivial = 0;
                 }
-            } else { // Function ptr has multiple users (so maybe multiple call sites)
+
+                // Trivial inlining: call site calls a single function; single function
+                // is only called by this call site.
+                if( isTrivial==0 )
+                    return doTrivialInlining(fun);
+
+            } else { // Function not (yet) a constant function pointer
                 addDep(fptr);
             }
         }
@@ -121,7 +171,105 @@ public class CallEndNode extends CFGNode implements MultiNode {
         return null;
     }
 
+    boolean goodArgs( CallNode call, TypeFunPtr tfp ) {
+        for( int i=0; i<tfp.nargs(); i++ ) {
+            Node arg = call.arg(i+2);
+            // The graph's function-pointer type can still contain open forward
+            // references here.  Compare against its recursively upgraded form,
+            // so deep mutability requirements participate before inlining.
+            Type formal = tfp.arg(i).upgradeType(Parser.TYPES);
+            if( !arg._type.isa(formal) )
+                { addDep(arg); return  false; }
+        }
+        return true;
+    }
+
+
+    // Check for trivial inlining: call only calls fun; fun only called by
+    // call.  Returns 0 for trivial, +1 for not-trivial because fptr/fun, and
+    // -1 for not-trivial because idoms.
+    public int trivialInlining( Node fptr, FunNode fun ) {
+        // Heuristic forced inlining off via name
+        if( fun._name != null &&
+            fun._name.endsWith("_noInline") )
+            return -1;
+
+        if( !fun.sig().isa(fptr._type) )
+            return -1; // Stall until these align
+
+        // Disallow self-recursive inlining (loop unrolling by another name).
+        for( int i=1; i < fun.nIns(); i++ )
+            if( fun.cfg(i).fun()==fun ) // Check for linked call input inside "fun"
+                { addDep(fun); return -1; }
+
+        CFGNode idom = call(), prior = this;
+        while( !(idom instanceof FunNode) ) {
+            if( idom==null ) {
+                addDep(prior);
+                if( prior instanceof RegionNode && !(prior instanceof StartNode) )
+                    for( int i=1; i<prior.nIns(); i++ )
+                        addDep(prior.in(i));
+                return -1;
+            }
+            prior = idom;
+            idom = idom.idom();
+        }
+
+
+        // If the *inlined* function is mid-collapse, also do not inline (yet)
+        idom = fun.ret();
+        while( idom != fun ) {
+            if( idom==null ) return -1; // Forced off, half-folded call
+            if( idom instanceof FunNode fun2 )
+                { addDep(fun2); return -1; }
+            if( idom instanceof CallEndNode cend && cend._folding )
+                { addDep(cend); return -1; }
+            idom = idom.idom();
+        }
+
+        // Only fun user is this call
+        if( fun.nIns() > 2 ) { addDep(fun); return 1; }
+        // Trivial inlining: call site calls a single function; single function
+        // is only called by this call site.
+        assert fun.in(1)==call();
+
+        return 0;
+    }
+
+
+    // Do trivial inlining.  Inlining does not need to clone code, merely
+    // triggers folding the Call/Fun and Return/CallEnd away.
+    private Node doTrivialInlining( FunNode fun ) {
+        assert !CodeGen.CODE._midAssert; // Triggered inlining
+        // Add the size heuristic to grow caller, preventing self-recursive
+        // functions from endlessly inlining.
+        fun()._approxUIDs += fun._approxUIDs;
+        // Trivial inline: rewrite
+        _folding = true;
+        // Rewrite Fun so the normal RegionNode ideal collapses
+        fun._folding = true;
+        fun.setDef(1,call().ctrl());// Bypass the Call;
+        fun.ret().setDef(3,null);   // Return is folding also
+
+        CodeGen.CODE.addAll(fun._outputs);
+        // Repeat defs 1 layer down, for users of Parm (Phis)
+        for( Node parm : fun._outputs )
+            if( parm instanceof ParmNode )
+                CodeGen.CODE.addAll(parm._outputs);
+
+        // Inlining immediately blows all cache idepth fields past the inline point.
+        // Bump the global version number invalidating them en-masse.
+        CodeGen.CODE.invalidateIDepthCaches();
+        return this;
+    }
+
+
     @Override public Node pcopy(int idx) {
         return _folding ? in(1).in(idx) : null;
     }
+
+    @Override public Node copy() {
+        return _folding ? super.copy() : new CallEndNode(_rpc);
+    }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/CallNode.java b/src/main/java/com/seaofnodes/simple/node/CallNode.java
index 47dfdf19..f2825650 100644
--- a/src/main/java/com/seaofnodes/simple/node/CallNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CallNode.java
@@ -1,12 +1,16 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.IterPeeps;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFunPtr;
+import com.seaofnodes.simple.type.TypeMem;
+import com.seaofnodes.simple.type.XInt;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
  *  Call
@@ -18,8 +22,9 @@ public class CallNode extends CFGNode {
 
     public CallNode(Parser.Lexer loc, Node... nodes) { super(nodes); _loc = loc; }
     public CallNode(CallNode call) { super(call); _loc = call._loc; }
-
-    @Override public String label() { return "Call"; }
+    @Override public Tag serialTag() { return Tag.Call; }
+    public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { baos.packed1(nIns()); }
+    static Node make( BAOS bais )  { return new CallNode(null,new Node[bais.packed1()]); }
 
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         String fname = name();
@@ -33,7 +38,7 @@ public class CallNode extends CFGNode {
     }
     public String name() {
         if( fptr()._type instanceof TypeFunPtr tfp && tfp.isConstant() ) {
-            FunNode fun = CodeGen.CODE.link(tfp);
+            FunNode fun = CodeGen.CODE.lookupFun(tfp);
             if( fun !=null ) return fun._name;
             if( fptr() instanceof ExternNode ex )  return ex._extern;
         }
@@ -97,14 +102,11 @@ public class CallNode extends CFGNode {
         Node progress = null;
         if( fptr()._type instanceof TypeFunPtr tfp && tfp.nargs() == nargs() ) {
             // If fidxs is negative, then infinite unknown functions
-            long fidxs = tfp.fidxs();
-            if( fidxs > 0 ) {
-                // Wipe out the return which matching in the linker table
-                // Walk the (63 max) bits and link
-                for( ; fidxs!=0; fidxs = TypeFunPtr.nextFIDX(fidxs) ) {
-                    int fidx = Long.numberOfTrailingZeros(fidxs);
-                    TypeFunPtr tfp0 = tfp.makeFrom(fidx);
-                    FunNode fun = CodeGen.CODE.link(tfp0);
+            int[] fidxs = tfp.fidxs();
+            if( !XInt.isHigh(fidxs) ) {
+                // Walk the bits and link
+                for( int fidx = XInt.next(fidxs,0); fidx > 0; fidx = XInt.next(fidxs,fidx) ) {
+                    FunNode fun = CodeGen.CODE.link(fidx);
                     if( fun!=null && !fun._folding && !linked(fun) )
                         progress = link(fun);
                 }
@@ -128,30 +130,43 @@ public class CallNode extends CFGNode {
         fun.addDef(this);
         for( Node use : fun._outputs )
             if( use instanceof ParmNode parm )
-                parm.addDef(parm._idx==0 ? new ConstantNode(cend()._rpc).peephole() : arg(parm._idx));
+                parm.addDef(parm._idx==0 ? ConstantNode.seed(cend()._rpc).peephole() : arg(parm._idx));
         // Call end points to function return
         CodeGen.CODE.add(cend()).addDef(fun.ret());
         return this;
     }
 
+    // Unlink a single function
+    public void unlink( FunNode fun, int path ) {
+        assert linked(fun);
+        for( Node use : fun._outputs )
+            if( use instanceof ParmNode )
+                use.delDef(path);
+        fun.delDef(path);
+        CodeGen.CODE.add(fun);
+        CallEndNode cend = cend();
+        ReturnNode ret = fun.ret().keep();
+        cend.delDef(cend._inputs.find(ret));
+        CodeGen.CODE.add(cend);
+        assert !linked(fun);
+        ret.unkeep();
+    }
+
+
     // Unlink all linked functions
     public void unlink_all() {
         for( int i=0; i<_outputs._len; i++ )
             if( out(i) instanceof FunNode fun ) {
-                assert linked(fun);
-                int idx = fun._inputs.find(this);
-                for( Node use : fun._outputs )
-                    if( use instanceof ParmNode )
-                        use.delDef(idx);
-                fun.delDef(idx);
-                cend().delDef(cend()._inputs.find(fun.ret()));
-                assert !linked(fun);
+                int path = fun._inputs.find(this);
+                unlink(fun,path);
                 i--;
             }
     }
 
     @Override
     public Parser.ParseException err() {
+        if( fptr()._type == Type.BOTTOM )
+            return null;        // Wrong, but failing earlier
         if( !(fptr()._type instanceof TypeFunPtr tfp) )
             throw Utils.TODO();
         if( !tfp.notNull() )
@@ -162,11 +177,13 @@ public class CallNode extends CFGNode {
         // Check for args
         for( int i=0; i<tfp.nargs(); i++ )
             if( !arg(i+2)._type.isa(tfp.arg(i)) ) {
-                cend().addDep(arg(i+2)); // Upgrading arg type may allow inlining
-                return Parser.error( "Argument #" + i + " isa " + arg(i+2)._type + ", but must be a " + tfp.arg(i), _loc );
+                // Constructors return private memory and carry hidden self and
+                // selfMem arguments ahead of the source-level arguments.
+                int argno = i - (tfp.ret() instanceof TypeMem ? 2 : 0);
+                return Parser.error( "Argument #" + argno + " isa " + arg(i+2)._type + ", but must be a " + tfp.arg(i), _loc );
             }
 
-        if( tfp.fidxs() < 0 )
+        if( tfp.isHigh() )
             throw Utils.TODO(); // Infinite unknown TFPs?  Should be fairly precise CG
 
         return null;
diff --git a/src/main/java/com/seaofnodes/simple/node/CastNode.java b/src/main/java/com/seaofnodes/simple/node/CastNode.java
deleted file mode 100644
index 6dc8e9fe..00000000
--- a/src/main/java/com/seaofnodes/simple/node/CastNode.java
+++ /dev/null
@@ -1,74 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import com.seaofnodes.simple.type.TypeMemPtr;
-import com.seaofnodes.simple.util.Utils;
-import java.util.BitSet;
-
-// Upcast (join) the input to a t.  Used after guard test to lift an input.
-// Can also be used to make a type-assertion if ctrl is null.
-public class CastNode extends Node {
-    public Type _t;
-    public CastNode(Type t, Node ctrl, Node in) {
-        super(ctrl, in);
-        _t = t;
-        setType(compute());
-    }
-
-    public CastNode(CastNode c) {
-        super(c.in(0), c.in(1)); // Call parent constructor
-        this._t = c._t;          // Copy the Type field
-        setType(compute());      // Ensure type is recomputed
-    }
-
-    @Override public String label() { return "("+_t.str()+")"; }
-
-    @Override
-    public String uniqueName() { return "Cast_" + _nid; }
-
-    @Override public boolean isPinned() { return true; }
-    @Override public boolean isConst() { return true; }
-
-    @Override
-    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        return in(1)._print0(sb.append(label()), visited);
-    }
-
-    @Override
-    public Type compute() {
-        // Cast array to int
-        Type t1 = in(1)._type;
-        if( _t == TypeInteger.BOT && t1 instanceof TypeMemPtr tmp && tmp._obj.isAry() )
-            return _t;
-        // Freeze if the join is high but both inputs are low
-        Type tj = t1.join(_t);
-        if( tj.isHigh() && !t1.isHigh() )
-            return _type==null ? _t : _type;
-
-        return tj;
-    }
-
-    @Override
-    public Node idealize() {
-        return in(1)._type.isa(_t) ? in(1) : null;
-    }
-
-    @Override
-    public boolean eq(Node n) {
-        CastNode cast = (CastNode)n; // Contract
-        return _t==cast._t;
-    }
-
-    @Override
-    int hash() { return _t.hashCode(); }
-
-    @Override
-    public Parser.ParseException err() {
-        // Has a condition to test, so OK
-        if( in(0) != null ) return null;
-        // No condition to test, so this must optimize away
-        return Parser.error( "Type " + in(1)._type.str() + " is not of declared type " + _t.str(), null );
-    }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/CastMach.java b/src/main/java/com/seaofnodes/simple/node/CheckCastMach.java
index e45898f5..9943c7b4 100644
--- a/src/main/java/com/seaofnodes/simple/node/CastMach.java
+++ b/src/main/java/com/seaofnodes/simple/node/CheckCastMach.java
@@ -3,17 +3,18 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.util.SB;
 
 /**
  * Cast a pointer to read-only
  */
-public class CastMach extends CastNode implements MachNode {
-    public CastMach( CastNode n ) { super(n); }
+public class CheckCastMach extends CheckCastNode implements MachNode {
+    public CheckCastMach( CheckCastNode n ) { super(n); }
     @Override public String op() { return label(); }
     @Override public RegMask regmap(int i) { assert i==1; return RegMask.FULL; }
     @Override public RegMask outregmap() { return RegMask.FULL; }
-    @Override public int twoAddress( ) { return 1; }
+    @Override public int twoAddress( ) { return in(1)._type==Type.BOTTOM ? 0 : 1; }
     @Override public void encoding( Encoding enc ) { }
     @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(in(1))); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/CheckCastNode.java b/src/main/java/com/seaofnodes/simple/node/CheckCastNode.java
new file mode 100644
index 00000000..900ee70e
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/CheckCastNode.java
@@ -0,0 +1,82 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+
+import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+// Upcast (join) the input to a t.  Used after guard test to lift an input.
+// Can also be used to make a type-assertion if ctrl is null.
+public class CheckCastNode extends TypeNode {
+    public CheckCastNode(Type t, Node ctrl, Node in) { super(t,ctrl, in); }
+
+    public CheckCastNode(CheckCastNode c) {
+        super(c);               // Call parent copy constructor
+        setType(compute());     // Ensure type is recomputed
+    }
+    @Override public Tag serialTag() { return Tag.CheckCast; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed2(types.get(_con)); // NPE if fails lookup
+    }
+    static Node make( BAOS bais, Type[] types)  { return new CheckCastNode(types[bais.packed2()], null, null); }
+
+    @Override public String label() { return "("+_con.str()+")"; }
+
+    @Override
+    public String uniqueName() { return "CheckCast_" + _nid; }
+
+    @Override public boolean isPinned() { return in(0)!=null; }
+
+    @Override
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        return in(1)._print0(sb.append(label()), visited);
+    }
+
+    @Override
+    public Type compute() {
+        // Cast array to int
+        Type t1 = in(1)._type;
+        if( _con == TypeInteger.BOT && t1 instanceof TypeMemPtr tmp && tmp._obj.isAry() )
+            return _con;
+
+        // If unconditional, it must collapse (or error)
+        if( in(0)==null )
+            return _con;
+        // If conditional, return the join.  The guard test ensures
+        // the join is correct.
+        return t1.join(_con);
+    }
+
+    @Override
+    public Node idealize() {
+        return in(1)._type.isa(_con) ? in(1) : null;
+    }
+
+    @Override
+    public Parser.ParseException err() {
+        // Has a condition to test, so OK
+        if( in(0) != null ) return null;
+        if( in(1)._type != Type.BOTTOM )
+            // No condition to test, so this must optimize away
+            return Parser.error( "Type " + in(1)._type.str() + " is not of declared type " + _con.str(), null );
+        // Only happens for un-initialized refs that must init.
+        // Allow uses of initializing stores, but other uses represent a
+        // partially initialized field, and should error
+        boolean bad = false;
+        StoreNode init=null;
+        for( Node use : _outputs )
+            if( (use instanceof StoreNode st && st._init && !((TypeMemPtr)st.ptr()._type)._obj._name.startsWith("class") ) )
+                init = st;
+            else if( (use instanceof StoreNode st && st.val() instanceof CheckCastNode cast && cast.in(1)._type == Type.BOTTOM) )
+                /*bogus init store in constructor*/;
+            else bad = true;
+        if( !bad ) return null;
+        if( init==null ) return null; // Error somewhere else
+        // Expecting an init store
+        TypeMemPtr ptr = (TypeMemPtr)init.ptr()._type;
+        throw Parser.error("'"+ptr._obj._name+"' is not fully initialized, field '" + init._name + "' is only partially set in the constructor", init._loc);
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/ConFldOffNode.java b/src/main/java/com/seaofnodes/simple/node/ConFldOffNode.java
index c54da2c4..11a16d28 100644
--- a/src/main/java/com/seaofnodes/simple/node/ConFldOffNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ConFldOffNode.java
@@ -1,11 +1,14 @@
 package com.seaofnodes.simple.node;
 
+import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 import com.seaofnodes.simple.type.TypeStruct;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
 
 /**
  * A field offset.  This becomes a constant *after* other optimizations which
@@ -14,12 +17,13 @@ import java.util.BitSet;
  */
 
 public class ConFldOffNode extends ConstantNode {
-    public final String _name;  // Struct name
+    public TypeStruct _ts;      // Struct holding field
     public final String _fname; // Field name
-    public ConFldOffNode( String name, String fname ) { super(TypeInteger.BOT); _name = name; _fname = fname; }
+    public ConFldOffNode( TypeStruct ts, String fname ) { super(TypeInteger.BOT); _ts = ts; _fname = fname; }
+    @Override public Tag serialTag() { throw Utils.TODO("should not reach here"); }
 
     @Override public String label() {
-        return _fname == " len" ? "sizeof("+_name+")" : "#"+_fname;
+        return _fname == " len" ? "sizeof("+_ts._name+")" : "#"+_fname;
     }
     @Override public String glabel() { return label(); }
     @Override public String uniqueName() { return "Off_" + _nid; }
@@ -29,15 +33,41 @@ public class ConFldOffNode extends ConstantNode {
         return sb.append(label());
     }
 
+    @Override public Node idealize() {
+        // Some array offsets are known early
+        if( _ts.isAry() ) {
+            // Length always at offset zero
+            if( _fname==" len" )
+                return CodeGen.CODE.ZERO;
+            // The shift depends on the element
+            if( _fname=="<<" )
+                return Node.con(_ts.aryScale());
+            // The base depends on the layout (alignment for large elements may
+            // involve padding) and MAY depend on the length if I go for
+            // smaller array lengths.
+        }
+        return null;
+    }
+
     // Convert field offset to an integer
-    public Node asOffset(TypeStruct ts) {
-        return new ConstantNode(TypeInteger.constant(ts.offset(_fname==" len" ? ts._fields.length : ts.find(_fname)))).peephole();
+    public Node asOffset() {
+        int fldx = _fname==" len" ? _ts._fields.length : _ts.find(_fname);
+        if( fldx == -1 ) return null;
+        return ConstantNode.make(TypeInteger.constant(_ts.offset(fldx))).peephole();
     }
 
+    // Upgrade the internal type
+    @Override boolean _upgradeType( HashMap<String,Type> TYPES) {
+        boolean progress = super._upgradeType(TYPES);
+        TypeStruct ts = (TypeStruct)_ts.upgradeType(TYPES);
+        if( ts == _ts ) return progress;
+        _ts = ts;
+        return true;
+    }
 
     @Override public boolean eq(Node n) {
         ConFldOffNode off = (ConFldOffNode)n; // Invariant
-        return _name.equals(off._name) && _fname.equals(off._fname) && super.eq(n);
+        return _ts._name==off._ts._name && _fname.equals(off._fname) && super.eq(n);
     }
-    @Override int hash() { return super.hash() * _name.hashCode() * _fname.hashCode(); }
+    @Override int hash() { return super.hash() * _ts._name.hashCode() * _fname.hashCode(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
index 22bf03c4..feed8c5c 100644
--- a/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
@@ -3,8 +3,11 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFunPtr;
-import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.BAOS;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
  * A Constant node represents a constant value.
@@ -16,28 +19,63 @@ import java.util.BitSet;
  * The Constant's value is the value stored in it.
  */
 
-public class ConstantNode extends Node {
-    public final Type _con;
+public class ConstantNode extends TypeNode {
     public ConstantNode( Type type ) {
-        super(new Node[]{CodeGen.CODE._start});
-        _con = _type = type;
+        this(type,false);
+    }
+    protected ConstantNode( Type type, boolean raw ) {
+        super(type,new Node[]{CodeGen.CODE._start});
+        assert raw || !(type instanceof TypeFunPtr tfp && tfp.isConstant()) :
+            "Unique function identities require a Return-linked FunPtrNode";
+        _type = type;
     }
-    public ConstantNode( ConstantNode con ) { super(con);  _con = con._type;  }
+    public ConstantNode( ConstantNode con ) { super(con); }
+    @Override public Tag serialTag() { return Tag.Con; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed2(types.get(_con)); // NPE if fails lookup
+    }
+    static Node make( BAOS bais, Type[] types)  { return raw(types[bais.packed2()]); }
 
+    // Semantic constant construction through Opto.  A unique internal
+    // function identity carries a lifetime edge to the function's Return.
     public static Node make( Type type ) {
         if( type==Type. CONTROL ) return new CtrlNode();
         if( type==Type.XCONTROL ) return new XCtrlNode();
+        if( CodeGen.CODE._phase != null &&
+            CodeGen.CODE._phase.ordinal() > CodeGen.Phase.Opto.ordinal() )
+            return raw(type);
+        if( type instanceof TypeFunPtr tfp && tfp.isConstant() ) {
+            FunNode fun = CodeGen.CODE.lookupFun(tfp);
+            if( fun != null )
+                return new FunPtrNode(tfp,CodeGen.CODE._start,fun.ret()).init();
+            // TODO: A singleton FIDX can also emerge after merging and
+            // guarding several function pointers.  Preserve that identity
+            // even if its internal Return is no longer available.
+            return raw(type);
+        }
         return new ConstantNode(type);
     }
 
+    // Exact construction for deserialization and graph-incomplete machine
+    // selection.  No semantic classification, compute, idealize, or GVN.
+    public static ConstantNode raw( Type type ) { return new ConstantNode(type,true); }
+    public static ConstantNode raw( ConstantNode con ) { return new ConstantNode(con); }
+
+    // Analysis input created from whole cloth, rather than a first-class
+    // runtime value.  In particular, a constructor call descriptor does not
+    // own the constructor function; the class FunPtr does.
+    public static ConstantNode seed( Type type ) { return new ConstantNode(type,true); }
+
     @Override public String  label() { return "#"+_con; }
     @Override public String glabel() { return "#"+_con.gprint(); }
     @Override public String uniqueName() { return "Con_" + _nid; }
+    @Override public Node copy() { return raw(this); }
+
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( _con instanceof TypeFunPtr tfp && tfp.isConstant() ) {
-            FunNode fun = CodeGen.CODE.link(tfp);
+            FunNode fun = CodeGen.CODE.lookupFun(tfp);
             if( fun!=null && fun._name != null )
                 return sb.append("{ ").append(fun._name).append("}");
         }
@@ -47,6 +85,4 @@ public class ConstantNode extends Node {
     @Override public boolean isConst() { return true; }
     @Override public Type compute() { return _con; }
     @Override public Node idealize() { return null; }
-    @Override public boolean eq(Node n) { return _con==((ConstantNode)n)._con; }
-    @Override int hash() { return _con.hashCode(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/ConvertNode.java b/src/main/java/com/seaofnodes/simple/node/ConvertNode.java
new file mode 100644
index 00000000..4e8e93ce
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/ConvertNode.java
@@ -0,0 +1,96 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+
+import java.util.BitSet;
+import java.util.HashMap;
+
+// Convert a value to an authoritative destination type.  The destination is
+// known structurally from a declaration; the source family might sharpen later.
+public class ConvertNode extends Node {
+    private Type _dst;
+
+    public ConvertNode(Type dst, Node val) {
+        super(null,val);
+        // Folding this conversion would replace the Return-linked FunPtrNode
+        // with an unhooked ConstantNode.
+        assert !(dst instanceof TypeFunPtr && val instanceof FunPtrNode);
+        _dst = dst;
+    }
+
+    public Type dst() { return _dst; }
+    public Node val() { return in(1); }
+
+    @Override public String label() { return "Convert_"+_dst.str(); }
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        return val()._print0(sb.append(label()).append("("),visited).append(")");
+    }
+
+    // The declaration fixes the result family during pessimistic parsing.
+    // Optimistic SCCP must retain stronger facts already inside that family.
+    @Override public Type compute() {
+        Type src = val()._type;
+        if( CodeGen.CODE._phase == CodeGen.Phase.Opto ) {
+            if( src.isHigh() ) return Type.TOP;
+            if( src.isa(_dst) ) return src;
+        }
+        return _dst;
+    }
+
+    @Override public Node idealize() {
+        Type src = val()._type;
+        if( src==Type.BOTTOM || src==Type.TOP ) return null;
+        if( src.isa(_dst) ) return val();
+
+        // Managed arrays are represented by an object pointer, while C wants
+        // the address of the first element.  The representation cast itself is
+        // zero-code; the Add skips the array header.
+        if( _dst==TypeInteger.BOT && src instanceof TypeMemPtr tmp && tmp._obj.isAry() )
+            return new AddNode(new PtrToIntNode(val()).peephole(),Parser.off(tmp._obj,"[]"));
+
+        // Integer (and nil-as-zero) to floating point.
+        if( (src instanceof TypeInteger || src==Type.NIL) && _dst instanceof TypeFloat )
+            return new ToFloatNode(val());
+
+        // Narrow integers produce the declared sign/zero extension.
+        if( src instanceof TypeInteger && _dst instanceof TypeInteger dst ) {
+            if( dst._min==0 )
+                return new AndNode(null,val(),con(dst._max));
+            int shift = Long.numberOfLeadingZeros(dst._max)-1;
+            Node shf = con(shift);
+            if( shf._type==TypeInteger.ZERO ) return val();
+            return new SarNode(null,new ShlNode(null,val(),shf.keep()).peephole(),shf.unkeep());
+        }
+
+        // Narrow f64 to f32.
+        if( src instanceof TypeFloat && _dst instanceof TypeFloat )
+            return new RoundF32Node(val());
+
+        // Wait for more source information, or report an error after Opto.
+        return null;
+    }
+
+    @Override boolean _upgradeType(HashMap<String,Type> TYPES) {
+        Type dst = _dst.upgradeType(TYPES);
+        if( dst==_dst ) return false;
+        unlock();
+        _dst = dst;
+        return true;
+    }
+
+    @Override public Parser.ParseException err() {
+        if( val()._type==Type.BOTTOM ||
+            val()._type instanceof TypeNil src && src.nullable() && _dst instanceof TypeNil dst && dst.notNull() ) {
+            Node out = out(0);
+            if( out instanceof PhiNode phi ) out = phi.out(0);
+            if( out instanceof StoreNode st )
+                return Parser.error( "'" + ((TypeMemPtr)st.ptr()._type)._obj._name + "' is not fully initialized, field '" + st._name + "' is only partially set in the constructor", null );
+        }
+        return Parser.error("Type "+val()._type.str()+" is not of declared type "+_dst.str(),null);
+    }
+
+    @Override public boolean eq(Node n) { return _dst==((ConvertNode)n)._dst; }
+    @Override int hash() { return _dst.hashCode(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/CtrlNode.java b/src/main/java/com/seaofnodes/simple/node/CtrlNode.java
index eda7d684..39c95aa4 100644
--- a/src/main/java/com/seaofnodes/simple/node/CtrlNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CtrlNode.java
@@ -7,6 +7,7 @@ import java.util.BitSet;
 
 public class CtrlNode extends CFGNode {
     public CtrlNode() { super(CodeGen.CODE._start); }
+    @Override public Tag serialTag() { throw com.seaofnodes.simple.util.Utils.TODO(); }
     @Override public String label() { return "Ctrl"; }
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append("Cctrl"); }
     @Override public boolean isConst() { return true; }
diff --git a/src/main/java/com/seaofnodes/simple/node/DivFNode.java b/src/main/java/com/seaofnodes/simple/node/DivFNode.java
deleted file mode 100644
index 0d037a30..00000000
--- a/src/main/java/com/seaofnodes/simple/node/DivFNode.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-import java.util.BitSet;
-
-public class DivFNode extends ArithFNode {
-    public DivFNode(Node lhs, Node rhs) { super(lhs, rhs); }
-
-    @Override public String label() { return "DivF"; }
-
-    @Override public String glabel() { return "/"; }
-
-    @Override double doOp( double x, double y ) { return x/y; }
-
-    @Override
-    public Node idealize() {
-        // Div of constant
-        if( in(2)._type instanceof TypeFloat f && f.isConstant() )
-            return new MulFNode(in(1),new ConstantNode(TypeFloat.constant(1.0/f.value())).peephole());
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new DivFNode(lhs,rhs); }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/DivNode.java b/src/main/java/com/seaofnodes/simple/node/DivNode.java
index 0de1c946..dcc9a27a 100644
--- a/src/main/java/com/seaofnodes/simple/node/DivNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/DivNode.java
@@ -2,15 +2,19 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeFloat;
 import java.util.BitSet;
 
 public class DivNode extends ArithNode {
+    @Override boolean allowFloat() { return true; }
     public DivNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
+    public DivNode(Node lhs, Node rhs, byte mode) { super(null, lhs, rhs, mode); }
+    @Override public Tag serialTag() { return Tag.Div; }
 
-    @Override public String label() { return "Div"; }
-    @Override public String op() { return "//"; }
+    @Override public String op() { return _mode==1 ? "//" : "/"; }
 
-    @Override long doOp( long x, long y ) { return y==0 ? 0 : x / y; }
+    @Override long   doOp( long  x,  long  y ) { return y==0 ? 0 : x / y; }
+    @Override double doOp(double x, double y ) { return            x / y; }
     @Override TypeInteger doOp(TypeInteger x, TypeInteger y) {
         return TypeInteger.BOT;
     }
@@ -20,9 +24,17 @@ public class DivNode extends ArithNode {
         // Div of 1.
         if( in(2)._type == TypeInteger.TRUE )
             return in(1);
+
+        // Div of constant
+        if( _mode==2 ) {
+            if( in(2)._type == TypeFloat.constant(1.) )
+                return in(1);
+            if( in(2)._type instanceof TypeFloat f && f.isConstant() )
+                return new MulNode(in(1),ConstantNode.make(TypeFloat.constant(1.0/f.value())).peephole(),_mode);
+        }
+
         return super.idealize();
     }
 
-    @Override Node copy(Node lhs, Node rhs) { return new DivNode(lhs,rhs); }
-    @Override Node copyF() { return new DivFNode(null,null); }
+    @Override Node copy(Node lhs, Node rhs) { return new DivNode(lhs,rhs,_mode); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/EscapeNode.java b/src/main/java/com/seaofnodes/simple/node/EscapeNode.java
new file mode 100644
index 00000000..df654291
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/EscapeNode.java
@@ -0,0 +1,114 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.*;
+import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+/**
+ *  Merge public and private aliases.
+ *  0 - control
+ *  1 - private pointer
+ *  2 - private alias
+ *  3 - public alias
+ */
+public class EscapeNode extends TypeNode {
+
+    public EscapeNode(Field fld, Node self, Node priv, Node pub ) {
+        super(fld,null,self,priv,pub);
+    }
+    public EscapeNode(EscapeNode esc ) {
+        super(esc);             // Copy constructor
+        // Except we do not want/need self ptr past Opto.
+        // *NOTE* the weird direct stomp; this is correct because this
+        // constructor does NOT set the backedges, because it is used to
+        // copy-construct an entire graph and ALL edges will get rewritten.
+        _inputs.set(1,null);
+        _con = esc._con;
+    }
+
+    // Pointer to some private (unescaped) memory from a NewNode
+    public Node self() { return in(1); }
+    public Node priv() { return in(2); }
+    public Node pub () { return in(3); }
+    public Field fld() { return (Field)_con; }
+
+    @Override public Tag serialTag() { return Tag.Escape; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed2(types.get(_con));
+    }
+    static Node make( BAOS bais, Type[] types)  {
+        return new EscapeNode((Field)types[bais.packed2()], null,null,null);
+    }
+
+    @Override
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        sb.append("Esc#").append(fld()._alias).append(" {");
+        if( self()==null ) sb.append("---");
+        else self()._print0(sb,visited).append(",");
+        priv()._print0(sb,visited).append("}, ");
+        pub ()._print0(sb,visited);
+        return sb;
+    }
+
+    @Override
+    public Type compute() {
+        if( priv()._type.isHigh() ) return TypeMem.TOP;
+        if( pub ()._type.isHigh() ) return TypeMem.TOP;
+        TypeMem mpriv = (TypeMem)priv()._type;
+        TypeMem mpub  = (TypeMem)pub ()._type;
+        // Private memory comes from an allocation or other non-aliased source.
+        // Public  memory comes from anywhere, might be bulk memory with a very weak mem type.
+        Field fld = fld();
+        assert mpriv._alias==1 || mpriv._alias==fld._alias;
+        assert mpub ._alias==1 || mpub ._alias==fld._alias;
+        Type tpriv = mpriv._t instanceof TypeStruct ts && ts.findAlias(fld._alias)!=-1
+            ? ts.at(ts.findAlias(fld._alias))._t
+            : mpriv._t;
+        assert !(mpub._t instanceof TypeStruct); // Never expect this, but if it starts to happen, need to optimize
+        Type tpub = mpub._t;
+
+        // t is meet of pub & priv.  Pub memory can be very weak (e.g. alias 1)
+        // and we're no worse than GLB of private
+        Type t = tpriv.meet(tpub).join(fld._t);
+        int[] fidxes  = XInt.meet(mpriv._escFs, mpub._escFs);
+        int[] aliases = XInt.meet(mpriv._escAs, mpub._escAs);
+        return TypeMem.make(fld._alias, t, false, false, fld._final, fidxes, aliases).escapesFrom(t);
+    }
+
+    @Override public Node idealize() {
+        // Sharpen private memory input
+        if( priv() instanceof MemMergeNode mmm ) {
+            setDef(2,mmm.alias(fld()._alias));
+            return this;
+        }
+        // Sharpen public memory input
+        if( pub() instanceof MemMergeNode mmm ) {
+            setDef(3,mmm.alias(fld()._alias));
+            return this;
+        }
+        // New allocation is dead
+        if( self()._type.isHigh() )
+            return pub();
+        return null;
+    }
+
+// Upgrade the internal type
+@Override boolean _upgradeType( HashMap<String,Type> TYPES) {
+    Type t = _con.upgradeType(TYPES);
+    if( t == _con ) return false;
+    unlock();               // Unlock before changing _con
+    _con = t;
+    return true;
+}
+
+    @Override public boolean eq(Node n) {
+        if( fld()._alias!=((EscapeNode)n).fld()._alias )
+            return false;
+        assert _con == ((EscapeNode)n)._con;
+        return true;
+    }
+
+    @Override int hash() { return _con.hashCode(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/ExternNode.java b/src/main/java/com/seaofnodes/simple/node/ExternNode.java
index a10bb84a..9768f41f 100644
--- a/src/main/java/com/seaofnodes/simple/node/ExternNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ExternNode.java
@@ -1,23 +1,40 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Serialize;
 import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFunPtr;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.SB;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
-   A constant with external linkage.
+    A constant with external linkage.
  */
 
 public class ExternNode extends ConstantNode {
     public final String _extern;
-    public ExternNode(Type t, String ex) { super(t); _extern = ex; }
+    // An exact external function identity has no local FunNode/Return to own.
+    // Its lifetime and eventual relocation are carried by the extern symbol
+    // and CodeGen's FIDX-to-extern mapping instead.
+    public ExternNode(Type t, String ex) { super(t,true); _extern = ex; }
+    @Override public Tag serialTag() { return Tag.Extern; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed2(types.get(_con   ));
+        baos.packed2( strs.get(_extern));
+    }
+    static Node make( BAOS bais, String[] strs, Type[] types)  {
+        return new ExternNode(types[bais.packed2()], strs[bais.packed2()]);
+    }
 
     @Override public String  label() { return "#"+_con+":"+_extern; }
     @Override public String glabel() { return _con.print(new SB().p("#"), new BitSet(), true).p(":").p(_extern).toString(); }
     @Override public String uniqueName() { return "Extern_" + _nid; }
 
     @Override public boolean eq(Node n) { return this==n; }
+    @Override public void gather( HashMap<String,Integer> strs ) {
+        Serialize.gather(strs,_extern);
+    }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/FRefNode.java b/src/main/java/com/seaofnodes/simple/node/FRefNode.java
index 6093b8a6..723e0007 100644
--- a/src/main/java/com/seaofnodes/simple/node/FRefNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/FRefNode.java
@@ -9,18 +9,28 @@ import java.util.BitSet;
  *  A Forward Reference.  Its any final constant, including functions.  When
  *  the Def finally appears its plugged into the forward reference, which then
  *  peepholes to the Def.
+
+ *  FRefs can be external references, to other Simple defined values in ELF
+ *  files, or external FFI/C libs.  If external, a file system lookup needs to
+ *  find it in another file, and the name (one time) change to match the found
+ *  location.
+ *
+ *  Example, a ambiguous name "foo" is looked up externally; it might resolve
+ *  to "A.B.foo" or "libc.foo" or the like; the name is changed to match.
  */
 public class FRefNode extends ConstantNode {
     public static final Type FREF_TYPE = Type.BOTTOM;
-    public final Var _n;
-    public FRefNode( Var n ) { super(FREF_TYPE); _n = n; }
+    public String _name;
+    public final Parser.Lexer _loc;    // Source location
+
+    public FRefNode( String name, Parser.Lexer loc ) { super(FREF_TYPE); _name = name; _loc = loc; }
 
-    @Override public String label() { return "FRef"+_n; }
+    @Override public String label() { return "FRef"+_name; }
 
     @Override public String uniqueName() { return "FRef_" + _nid; }
 
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        return sb.append("FRef_").append(_n);
+        return sb.append("FRef_").append(_name);
     }
 
     @Override public Node idealize() {
@@ -28,8 +38,8 @@ public class FRefNode extends ConstantNode {
         return nIns()==1 ? null : in(1);
     }
 
-    public Parser.ParseException err() { return Parser.error("Undefined name '"+_n._name+"'",_n._loc); }
+    public Parser.ParseException err() { return Parser.error("Undefined name '"+_name+"'",_loc); }
 
     @Override public boolean eq(Node n) { return this==n; }
-    @Override int hash() { return _n._idx; }
+    @Override int hash() { return _name.hashCode(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/FldOffNode.java b/src/main/java/com/seaofnodes/simple/node/FldOffNode.java
new file mode 100644
index 00000000..3a44f588
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/FldOffNode.java
@@ -0,0 +1,50 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
+import java.util.BitSet;
+import java.util.HashMap;
+
+/**
+ * A field offset.  This becomes a constant *after* other optimizations which
+ * determine field sizes - some fields might be dead, or hold only zeros or
+ * small values.
+ */
+
+public class FldOffNode extends TypeNode {
+    public final String _fname; // Field name
+    public final Parser.Lexer _loc;   //
+    public FldOffNode( Node base, String fname, Parser.Lexer loc ) { super(TypeInteger.BOT,base); _fname = fname; _loc=loc; }
+    @Override public Tag serialTag() { throw Utils.TODO("should not reach here"); }
+
+    @Override public String label() {
+        return _fname == " len" ? "sizeof()" : "#"+_fname;
+    }
+    @Override public String glabel() { return label(); }
+    @Override public String uniqueName() { return "Off_" + _nid; }
+
+    @Override
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        return sb.append(label());
+    }
+
+    @Override public Type compute() {
+        return Type.BOTTOM;
+    }
+
+    @Override public Node idealize() {
+        // When base() gets typed, this xforms into a ConFldOffNode
+        if( in(0)._type instanceof TypeMemPtr tmp )
+            return new ConFldOffNode(tmp._obj,_fname);
+        return null;
+    }
+
+    @Override public boolean eq(Node n) {
+        FldOffNode off = (FldOffNode)n; // Invariant
+        return _fname.equals(off._fname) && super.eq(n);
+    }
+    @Override int hash() { return super.hash() * _fname.hashCode(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/FunNode.java b/src/main/java/com/seaofnodes/simple/node/FunNode.java
index 2931b9ea..5018f5d6 100644
--- a/src/main/java/com/seaofnodes/simple/node/FunNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/FunNode.java
@@ -1,41 +1,68 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.Encoding;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import com.seaofnodes.simple.type.TypeTuple;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 import static com.seaofnodes.simple.codegen.CodeGen.CODE;
 
 public class FunNode extends RegionNode {
 
     // When set true, this Call/CallEnd/Fun/Return is being trivially inlined
-    boolean _folding;
+    public boolean _folding;
 
     private TypeFunPtr _sig;    // Initial signature
     private ReturnNode _ret;    // Return pointer
 
     public String _name;        // Debug name
 
-    public FunNode( Parser.Lexer loc, TypeFunPtr sig, String name, Node... nodes ) { super(loc,nodes); _name=name; _sig = sig; }
+    public int _approxUIDs;     // Approximate function size, used as a inlining heuristic
+    public CompUnit _compunit;  // Defined in source file
+    public final boolean _extern; // External function; no code, name only
+
+    private FunNode( Parser.Lexer loc, Node[] nodes, TypeFunPtr sig, String name, CompUnit compunit, boolean ext ) {
+        super(loc,nodes);
+        _name   = name;
+        _sig    = sig;
+        _extern = ext;
+        _compunit = compunit;
+    }
+    public FunNode( Parser.Lexer loc, TypeFunPtr sig, String name, CompUnit compunit, Node... nodes ) { this(loc,nodes,sig,name,compunit,false); }
+    public FunNode( TypeFunPtr sig, String name, boolean ext ) {
+        this(null,null,sig,name,null,ext);
+        assert ext;             // No need for ext
+        throw Utils.TODO();
+    }
     public FunNode( FunNode fun ) {
-        super( fun, fun==null ? null : fun._loc );
-        if( fun!=null ) {
-            _sig = fun.sig();
-            _name = fun._name;
-        } else {
-            _sig = TypeFunPtr.BOT;
-            _name = "";
-        }
+        super( fun, fun._loc );
+        _sig = fun.sig();
+        _name = fun._name;
+        _compunit = fun._compunit;
+        _extern = fun._extern;
+    }
+    @Override public Tag serialTag() { return Tag.Fun; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes ) {
+        assert !_folding;
+        baos.packed1(nIns());          // Number of linked calls
+        baos.packed2(types.get(_sig)); // NPE if fails lookup
+        baos.packed2(_name==null ? 0 : strs.get(_name));
+        baos.packed2(_approxUIDs);
+    }
+    static Node make( BAOS bais, String[] strs, Type[] types)  {
+        Node[] ins = new Node[bais.packed1()];
+        TypeFunPtr sig = (TypeFunPtr)types[bais.packed2()];
+        String name = strs[bais.packed2()];
+        FunNode fun = new FunNode(null,sig,name,null,ins);
+        fun._approxUIDs = bais.packed2();
+        return fun;
     }
 
-    @Override
-    public String label() { return _name == null ? "$fun"+_sig.fidx() : _name; }
+    @Override public String label() { return _name == null ? "$fun"+_sig.fidx() : _name; }
 
     // Find the one CFG user from Fun.  It's not always the Return, but always
     // the Return *is* a CFG user of Fun.
@@ -47,13 +74,14 @@ public class FunNode extends RegionNode {
         return null;
     }
 
-    public ParmNode rpc() {
-        ParmNode rpc = null;
+    public ParmNode parm(int idx) {
+        ParmNode pidx = null;
         for( Node n : _outputs )
-            if( n instanceof ParmNode parm && parm._idx==0 )
-                { assert rpc==null; rpc=parm; }
-        return rpc;
+            if( n instanceof ParmNode parm && parm._idx==idx )
+                { assert pidx==null; pidx=parm; }
+        return pidx;
     }
+    public ParmNode rpc() { return parm(0); }
 
     // Cannot create the Return and Fun at the same time; one has to be first.
     // So setting the return requires a second step.
@@ -66,13 +94,29 @@ public class FunNode extends RegionNode {
         assert sig.isa(_sig);
         if( _sig != sig ) {
             CODE.add(this);
+            // Changing the signature can allow more inlining
+            if( _ret != null )
+                for( Node use : ret().outs() )
+                    if( use instanceof CallEndNode || use instanceof FunPtrNode )
+                        CODE.add(use);
             _sig = sig;
+            unlock();
         }
     }
 
+    @Override boolean _upgradeType( HashMap<String,Type> TYPES) {
+        TypeFunPtr sig = (TypeFunPtr)_sig.upgradeType(TYPES);
+        if( sig == _sig ) return false;
+        unlock();
+        _sig = sig;
+        return true;
+    }
+
     public void setName( String name ) {
-        if( _name==null ) _name=name;
-        else _name += "."+name;
+        if( _name==null )
+            _name = _compunit==null || _compunit._cname==null || _compunit._cname.indexOf('.')==-1
+                ? name
+                : (_compunit._cname+"."+name).intern();
     }
 
     @Override
@@ -81,10 +125,10 @@ public class FunNode extends RegionNode {
         if( unknownCallers() )
             return Type.CONTROL;
         Type t = Type.XCONTROL;
-        for (int i = 1; i < nIns(); i++) {
-            // Since no unknown callers, we are not main and the Start input
-            // will be a Tuple with XControl, so ignore it.  Need to be called
-            // from someplace other than Start
+        for( int i = 1; i < nIns(); i++) {
+            // Since there are no unknown callers, the Start input is only a
+            // fake hook and will be a Tuple with XControl, so ignore it.  Need
+            // to be called from someplace other than Start.
             if( !(in(i) instanceof StartNode) )
                 t = t.meet(in(i)._type);
         }
@@ -94,28 +138,37 @@ public class FunNode extends RegionNode {
     @Override
     public Node idealize() {
 
-        // Some linked path dies, except main never kills Start
+        // Some linked path dies, except unknown caller hooks never kill Start.
         Node progress = deadPath(unknownCallers());
         if( progress!=null ) {
-            if( nIns()==3 && in(2) instanceof CallNode call )
-                CODE.add(call.cend()); // If Start and one call, check for inline
+            if( nIns()==2 && in(1) instanceof CallNode call )
+                CODE.add(call.cend()); // If no Start and one call, check for inline
             return progress;
         }
 
         // Upgrade inferred or user-written return type to actual
-        if( _ret!=null && _ret._type instanceof TypeTuple tt && tt.ret() != _sig.ret() ) {
+        if( _ret!=null && _ret._type instanceof TypeTuple tt &&
+            tt.ret() != _sig.ret() && tt.ret().isa(_sig.ret()) ) {
             setSig(_sig.makeFrom(tt.ret()));
             return this;
         }
 
+        // Attempt to get rid of the unknown caller.
+        // - Must be past pessimistic Iter, which discovers and links calls
+        //   through class-field loads and other initially imprecise values.
+        // - FIDX is not in the escape set
+        // - Not called anywhere else; post Opto called-not-escaped functions need to still be hooked to start
+        if( in(1) instanceof StartCUNode start ) {
+            boolean preOpto = CodeGen.CODE._phase == null ||
+                CodeGen.CODE._phase.ordinal() < CodeGen.Phase.Opto.ordinal();
+            if( !preOpto && !start.escapedFIDX(_sig.fidx()) && nIns()<=2 && _ret!=null ) {
+                _compunit._stop.delDef(_compunit._stop._inputs.find(ret()));
+                return removeDeadPath(1);
+            } else {
+                addDep(start);
+            }
+        }
 
-        // When can we assume no callers?  Or no other callers (except main)?
-        // In a partial compilation, we assume Start gets access to any/all
-        // top-level public structures and recursively what they point to.
-        // This in turn is valid arguments to every callable function.
-        //
-        // In a total compilation, we can start from Start and keep things
-        // more contained.
 
         // If no default/unknown caller, use the normal RegionNode ideal rules
         // to collapse
@@ -134,24 +187,58 @@ public class FunNode extends RegionNode {
     }
 
     // Bypass Region idom, always assume depth == 1, one more than Start,
-    // unless folding then just a ID on input#1
+    // unless folding
     @Override public int idepth() {
-        return _folding ? super.idepth() : CodeGen.CODE.iDepthAt(1);
+        if( _folding ) return super.idepth();
+        return CodeGen.CODE.iDepthAt(1);
     }
+
     // Bypass Region idom, always assume idom is Start
-    @Override public CFGNode idom(Node dep) { return _folding && nIns()==3 ? cfg(2) : (nIns()>1 ? cfg(1) : null); }
+    @Override public CFGNode idom(Node dep) {
+        return _folding ? cfg(1) : null;
+    }
 
     // Always in-progress until we run out of unknown callers
     public boolean unknownCallers() { return nIns()>=2 && in(1) instanceof StartNode; }
 
-    @Override public boolean inProgress() { return unknownCallers(); }
+    public boolean isModInit( ) {
+        // The one top-level <clinit> with no internal dots:
+        // "sys.<clinit>" is a module, but "sys.io.<clinit>" is not.
+        return isClz() && _name.indexOf('.')==_name.lastIndexOf('.');
+    }
+    public boolean isClz ( ) { return isClz (_name); }
+    public boolean isInit( ) { return isInit(_name); }
+    public boolean isInstance() { return isInstance(_name); }
+    public static boolean isClz (String name ) { return name!=null && name.endsWith(".<clinit>"); }
+    public static boolean isInit(String name ) { return name!=null && name.endsWith("init>"); }
+    public static boolean isInstance(String name ) { return name!=null && name.endsWith(".<init>"); }
+
+    // Function is public (callable from Start directly).
+    public boolean isPublic( ) {
+        // Never true for anonymous functions
+        if( _name == null ) return false;
+        // Only public for <clinit> and <init>, all others
+        // are found via field loads.  The <init> Start hook also supplies its
+        // conservative pre-Opto construction inputs; StopCU separately keeps
+        // its private-memory return from escaping as a public result.
+        if( !isInit() ) return false;
+        // Private class, has to be found via program text, not linker
+        if( _name.charAt(0)=='_' ) return false;
+
+        // No instances of "...clz1._clz2..." where the class name path
+        // includes a private class.
+        if( _name.indexOf("._") != -1 ) return false;
+
+        // Public class <cl/init>
+        return true;
+    }
 
-    // Add a new function exit point.
-    public void addReturn(Node ctrl, Node mem, Node rez) {  _ret.addReturn(ctrl,mem,rez);  }
+    @Override public boolean inProgress() {
+        return unknownCallers() && CodeGen.CODE._phase.ordinal() < CodeGen.Phase.Opto.ordinal();
+    }
 
-    // Build the function body
+    // Build the function body set
     public BitSet body() {
-
         // Reverse up (stop to start) CFG only, collect bitmap.
         BitSet cfgs = new BitSet();
         cfgs.set(_nid);
@@ -161,7 +248,13 @@ public class FunNode extends RegionNode {
         // If data use bottoms out in wrong CFG, returns false - but tries all outputs.
         // If any output hits an in-CFG use (e.g. phi), then keep node.
         BitSet body = new BitSet();
-        walkDown(this, cfgs, body, new BitSet());
+        BitSet visit = new BitSet();
+        int old;
+        do {
+            old = body.cardinality();
+            visit.clear();
+            walkDown(this, cfgs, body, visit);
+        } while( old != body.cardinality() );
         return body;
     }
 
@@ -175,20 +268,113 @@ public class FunNode extends RegionNode {
     }
 
     private static boolean walkDown( Node n, BitSet cfgs, BitSet body, BitSet visit ) {
+        if( n==null ) return false;
         if( visit.get(n._nid) ) return body.get(n._nid);
         visit.set(n._nid);
-
-        if( n instanceof CFGNode && !cfgs.get(n._nid) )
+        // Visit self as CFG outside the function
+        if( n instanceof CFGNode && !cfgs.get(n._nid) && unfolded( n ) )
             return false;
-        if( n.in(0)!=null && !cfgs.get(n.in(0)._nid) )
+        // Pretend the NewNode is a CFG, so its projections stay with it in loops
+        if( n instanceof NewNode nnn ) cfgs.set(n._nid);
+        // Visit n.cfg() outside of function
+        if( n.in(0)!=null && !cfgs.get(n.in(0)._nid) && unfolded( n.in( 0 ) ) )
             return false;
+        // Phis inside the function must have their body flag set BEFORE
+        // recursion walks around a loop and finds them again.
+        if( n instanceof PhiNode phi && cfgs.get(phi.in(0)._nid) )
+            body.set(phi._nid); // Find data cycles
         boolean in = n.in(0)!=null || n instanceof CFGNode;
-        for( Node use : n._outputs )
+        for( Node use : n._outputs ) {
+            // Will hit a backedge, so 'n' MUST be in the function, and must be
+            // set before the cyclic walk finds 'n' again.
+            if( use instanceof PhiNode puse && puse.in(0) instanceof LoopNode loop && puse.in(2)==n )
+                body.set(n._nid); // Set before walk
             in |= walkDown(use,cfgs,body,visit);
+        }
         if( in ) body.set(n._nid);
         return in;
     }
 
+    // A CFG is folding, and so is basically Data
+    private static boolean unfolded( Node cfg) {
+        if( cfg instanceof CallNode call && call.cend().folding() ) return false;
+        if( cfg instanceof CallEndNode cend && cend.folding() ) return false;
+        if( cfg instanceof FunNode fun && fun._folding ) return false;
+        if( cfg instanceof ReturnNode ret && ret._fun._folding ) return false;
+        return true;
+    }
+
+    // Clone function body.  Give function a new FIDX.
+    FunNode copyBody() {
+        // Build the function body BitSet
+        BitSet body = body();
+        assert body.cardinality() < 100;
+        // Walk the body, cloning
+        IdentityHashMap<Node,Node> map = new IdentityHashMap<>();
+        BitSet visit = CodeGen.CODE.visit();
+        bodyCopy( visit, body, map, this );
+        visit.clear();
+        bodyEdge( visit, body, map, this );
+        visit.clear();
+        assert map.size()==body.cardinality();
+
+        // New function/return cross-link each other
+        FunNode    fun2 = (FunNode   )map.get(this);
+        ReturnNode ret2 = (ReturnNode)map.get(_ret);
+        fun2._ret = ret2;
+        ret2._fun = fun2;
+
+        // Remove all callers - this is a private copy
+        while( fun2.nIns() > 1 )
+            if( fun2.in(1) instanceof CallNode call && body.get(call._nid) )
+                call.unlink(fun2,1); // Recursive calls unlink
+            else fun2.removeDeadPath(1); // Start and external calls can just be removed
+
+        // Flip to a new FIDX to avoid confusion with the old one.
+        // This is a non-monotonic (sideways) type move, only applicable
+        // because fun2 is new.  The fidx is also a purely local fiction,
+        // since this body will inline and the fidx goes dead.
+        fun2._sig = _sig.makeFrom(CodeGen.CODE._fidxs.nextInline());
+        return fun2;
+    }
+
+    // Clone small function
+    private void bodyCopy( BitSet visit, BitSet body, IdentityHashMap<Node,Node> map, Node n ) {
+        if( n==null ) return;
+        if( !body.get(n._nid) ) return; // Not part of the body
+        if( visit.get(n._nid) ) return; // Been there, done that
+        visit.set(n._nid);
+        Node m = n.copy();
+        CodeGen.CODE.add(m);
+        map.put(n,m);
+        m._type = n._type;
+        for( Node x : n._outputs )
+            bodyCopy(visit,body,map,x);
+    }
+    private void bodyEdge( BitSet visit, BitSet body, IdentityHashMap<Node,Node> map, Node n ) {
+        if( n==null ) return;
+        if( !body.get(n._nid) ) return; // Not part of the body
+        if( visit.get(n._nid) ) return; // Been there, done that
+        visit.set(n._nid);
+        Node m = map.get(n);
+        // The cloned Call should not clone any linked edges.
+        if( n instanceof CallEndNode cend && !cend._folding ) {
+            m.addDef( map.get(cend.call()) );
+        } else {
+            for( Node e : n._inputs ) {
+                Node x = e;
+                if( e != null ) {
+                    x = map.get(e);
+                    if( x == null ) x = e;
+                }
+                m.addDef(x);
+            }
+        }
+        for( Node x : n._outputs )
+            bodyEdge(visit,body,map,x);
+    }
+
+
     // FunNodes must match signature (equivalent: no 2 FunNodes are ever GVN'able)
     @Override public boolean eq( Node n ) {
         return _sig == ((FunNode)n)._sig;
@@ -245,4 +431,7 @@ public class FunNode extends RegionNode {
         return slotRotate*8;
     }
 
+    @Override public void gather( HashMap<String,Integer> strs ) {
+        Serialize.gather(strs,_name);
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java b/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java
new file mode 100644
index 00000000..33757640
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java
@@ -0,0 +1,65 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+
+import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+// Constant function pointer whose type follows the callee signature.
+public class FunPtrNode extends TypeNode {
+    public FunPtrNode(TypeFunPtr tfp, StartNode start, ReturnNode ret) {
+        super(tfp,start,ret);
+    }
+    public FunPtrNode(FunPtrNode fptr) { super(fptr); }
+    @Override public Tag serialTag() { return Tag.FunPtr; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes) {
+        baos.packed2(types.get(_con));
+    }
+    static Node make(BAOS bais, Type[] types) {
+        return new FunPtrNode((TypeFunPtr)types[bais.packed2()],null,null);
+    }
+    public ReturnNode ret() { return (ReturnNode)in(1); }
+    public FunNode fun() { return ret().fun(); }
+
+    @Override public String label() { return "#"+_con; }
+    @Override public String glabel() { return "#"+_con.gprint(); }
+    @Override public String uniqueName() { return "FunPtr_" + _nid; }
+    @Override public Node copy() {
+        FunPtrNode fptr = new FunPtrNode((TypeFunPtr)_con,null,null);
+        fptr._type = _type;
+        return fptr;
+    }
+
+    @Override
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        FunNode fun = CodeGen.CODE.lookupFun(((TypeFunPtr)_con).fidx());
+        return fun!=null && fun._name!=null
+            ? sb.append("{ ").append(fun._name).append("}")
+            : sb.append(_con);
+    }
+
+    @Override public boolean isConst() { return true; }
+    @Override public boolean isPinned() { return true; }
+    @Override public Type compute() {
+        ReturnNode ret = ret();
+        return ret == null ? _con : ret.fun().sig();
+    }
+    @Override public Node idealize() {
+        ReturnNode ret = ret();
+        if( ret==null ) return null;
+        // Function died (never executed), but fcn ptr is alive.
+        // Can be checked for null, or for unequals another FunPtr.
+        FunNode fun = addDep(ret.fun());
+        TypeFunPtr sig = fun.sig();
+        if( sig != _con )
+            { liftType(sig);  return this; }
+        // TODO: If the function body dies but this value remains live only as
+        // a null/equality sentinel, preserve the identity without the Return.
+        if( fun.isDead() )
+            { setDef(1,null); liftType(sig.makeFrom(Type.TOP)); return this; }
+        return null;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/GuardMach.java b/src/main/java/com/seaofnodes/simple/node/GuardMach.java
new file mode 100644
index 00000000..202b1ab8
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/GuardMach.java
@@ -0,0 +1,17 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.util.SB;
+
+public class GuardMach extends GuardNode implements MachNode {
+    public GuardMach(GuardNode guard) { super(guard); }
+    @Override public String op() { return label(); }
+    @Override public RegMask regmap(int i) { assert i==1; return RegMask.FULL; }
+    @Override public RegMask outregmap() { return RegMask.FULL; }
+    @Override public int twoAddress() { return in(1)._type==Type.BOTTOM ? 0 : 1; }
+    @Override public void encoding(Encoding enc) { }
+    @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(in(1))); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/GuardNode.java b/src/main/java/com/seaofnodes/simple/node/GuardNode.java
new file mode 100644
index 00000000..e3c6f0e2
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/GuardNode.java
@@ -0,0 +1,61 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeScalar;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
+
+import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+// A branch-proven refinement to zero/null or non-zero/non-null.  The value
+// family is deliberately taken from the input when it becomes known.
+public class GuardNode extends Node {
+    public final boolean _nonZero;
+
+    public GuardNode(boolean nonZero, Node ctrl, Node val) {
+        super(ctrl,val);
+        _nonZero = nonZero;
+    }
+
+    public GuardNode(GuardNode guard) {
+        super(guard);
+        _nonZero = guard._nonZero;
+    }
+
+    @Override public Tag serialTag() { return Tag.Guard; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes) {
+        baos.write(_nonZero ? 1 : 0);
+    }
+    static Node make(BAOS bais) { return new GuardNode(bais.read()!=0,null,null); }
+
+    @Override public String label() { return _nonZero ? "(!=0)" : "(==0)"; }
+    @Override public String uniqueName() { return "Guard_"+_nid; }
+    @Override public boolean isPinned() { return true; }
+
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        return in(1)._print0(sb.append(label()),visited);
+    }
+
+    @Override public Type compute() {
+        Type t = in(1)._type;
+        if( t==Type.BOTTOM || t==Type.TOP ) return t;
+        // The scalar envelope does not identify a value family.  Preserve it
+        // until SCCP learns whether this is an int, float, pointer, or fptr;
+        // choosing generic ptr here can be weaker than a later concrete type.
+        if( t==TypeScalar.BOT || t==TypeScalar.TOP ) return t;
+        Type t2 = _nonZero ? t.nonZero() : t.makeZero();
+        return t2==null ? (_type==null ? Type.TOP : _type) : t2; // No sane answer for e.g. not-zero of a zero
+    }
+
+    @Override public Node idealize() {
+        if( in(1)._type==Type.BOTTOM || in(1)._type==Type.TOP ) return null;
+        if( _type.isHighOrConst() && in(1)._type.isa(_type) )
+            return in(1);
+        return null;
+    }
+
+    @Override public boolean eq(Node n) { return _nonZero==((GuardNode)n)._nonZero; }
+    @Override int hash() { return _nonZero ? 1 : 0; }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/IfNode.java b/src/main/java/com/seaofnodes/simple/node/IfNode.java
index 5d751602..d8d72411 100644
--- a/src/main/java/com/seaofnodes/simple/node/IfNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/IfNode.java
@@ -12,9 +12,7 @@ public class IfNode extends CFGNode implements MultiNode {
         CodeGen.CODE.add(this); // Because idoms are complex, just add it
     }
     public IfNode(IfNode iff) { super(iff); }
-
-    @Override
-    public String label() { return "If"; }
+    @Override public Tag serialTag() { return Tag.If; }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
@@ -45,7 +43,7 @@ public class IfNode extends CFGNode implements MultiNode {
         // If constant is 0 then false branch is reachable
         // Else true branch is reachable
         if( t.isConstant() )
-            return (t==Type.NIL || t==TypeInteger.ZERO || (t instanceof TypeFunPtr tfp && tfp._fidxs==0) ) ? TypeTuple.IF_FALSE : TypeTuple.IF_TRUE;
+            return (t==Type.NIL || t==TypeInteger.ZERO || (t instanceof TypeFunPtr tfp && tfp._fidxs== XInt.EMPTY) ) ? TypeTuple.IF_FALSE : TypeTuple.IF_TRUE;
         // If adding a zero makes a difference, the predicate must not have a zero/null
         if( !t.makeZero().isa(t) )
             return TypeTuple.IF_TRUE;
@@ -58,15 +56,14 @@ public class IfNode extends CFGNode implements MultiNode {
         // Hunt up the immediate dominator tree.  If we find an identical if
         // test on either the true or false branch, that side wins.
         if( !pred()._type.isHighOrConst() )
-            for( CFGNode dom = idom(), prior=this; dom!=null;  prior = dom, dom = dom.idom() ) {
-                if( addDep(dom) instanceof IfNode iff && addDep(iff.pred())==pred() && prior instanceof CProjNode prj ) {
+            for( CFGNode dom = idom(), prior=this; dom!=null;  prior = dom, dom = dom.idom() )
+                if( addDep(dom) instanceof IfNode iff &&
+                    prior instanceof CProjNode prj &&
+                    (addDep(iff.pred())==pred() ||
+                     pred() instanceof GuardNode cast && cast._nonZero && iff.pred()==cast.in(1) ) ) {
                     setDef(1,con( prj._idx==0 ? 1 : 0 ));
                     return this;
                 }
-                if( dom instanceof RegionNode r )
-                    for( Node c : r._inputs )
-                        if( c!= null ) addDep(c); // If region loses input, idom changes
-            }
         return null;
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index 58dbfc81..f67f2b97 100644
--- a/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -2,7 +2,9 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.GlobalBits;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
 
@@ -20,9 +22,14 @@ public class LoadNode extends MemOpNode {
      * @param ptr   The ptr to the struct base from where we load a field
      * @param off   The offset inside the struct base
      */
-    public LoadNode(Parser.Lexer loc, String name, int alias, Type glb, Node mem, Node ptr, Node off) {
-        super(loc, name, alias, true, glb, mem, ptr, off);
+    public LoadNode(Parser.Lexer loc, String name, int alias, Node ctrl, Node mem, Node ptr, Node off) {
+        super(loc, name, alias, true, Type.BOTTOM, ctrl, mem, ptr, off);
     }
+    LoadNode( BAOS bais, String[] strs, Type[] types, GlobalBits fileAliases, GlobalBits aliases ) {
+        super(bais,strs,types,fileAliases,aliases,true);
+        _con = Type.BOTTOM;      // Serialized slot retained while MemOps share TypeNode
+    }
+    @Override public Tag serialTag() { return Tag.Load; }
 
     // GraphVis DOT code (must be valid Java identifiers) and debugger labels
     @Override public String  label() { return "ld_"+mlabel(); }
@@ -34,67 +41,110 @@ public class LoadNode extends MemOpNode {
 
     @Override
     public Type compute() {
-        Type tmem = mem()._type;
-        if( !(tmem instanceof TypeMem mem) )
-            return tmem; // No memory yet?  Assume TOP/BOT
-        assert !_declaredType.isFRef();
-        // No lifting if ptr might null-check
-        Type tptr = ptr()._type;
-        if( err() != null )
-            return _declaredType;
-        if( !(tptr instanceof TypeMemPtr tmp) )
-            return tptr; // No pointer yet?  Assume TOP/BOT
+        Type mem0 = aliasMem()._type;
+        Type ptr0 = ptr()._type;
+        // Validate argument types
+        if( ptr0.isHigh() )
+            return TypeScalar.TOP;
+        if( !(mem0 instanceof TypeMem mem) )
+            return mem0.isHigh() ? TypeScalar.TOP : TypeScalar.BOT;
+        if( ptr0 == Type.NIL )
+            return TypeScalar.TOP;
+        if( !(ptr0 instanceof TypeMemPtr ptr) )
+            return mem0.isHigh() ? TypeScalar.TOP : scalar(mem._t);
+
         // Load field from object
-        Field f = tmp._obj.field(_name);
+        TypeMemPtr tmp = ptr;
+        Field pfld = tmp._obj.field(_name);
         // No field?  Open objects might yet get the field when falling;
         // closed objects with missing field are an error.
-        if( f == null )
-            return tmp.isHigh() ? Type.TOP : _declaredType;
-        Type t = f._t;
+        if( pfld == null )
+            return tmp.isHigh() || tmp._obj.isHigh() ? TypeScalar.TOP : TypeScalar.BOT;
+
+        Type t = pfld._t;
         // Load member of constant array
         if( t instanceof TypeConAry ary )
             t = ary.elem();     // TODO: if offset is known, can peek the constant
-        // Lift from declared type and memory input
-        t = t.join(mem._t);
-        if( _declaredType.isFinal() )
-            t = t.makeRO(); // Deep final applied
-        // Pinch between declared type
-        t = t.join(_declaredType);
-        return t;
+
+        // Now, do the same for memory
+        if( mem._t instanceof TypeStruct ts ) {
+            assert ts._name==tmp._obj._name;
+            Field mfld = ts.field(_name);
+            // Lift from declared type and memory input
+            if( mfld != null )
+                t = t.join(mfld._t);
+        } else if( mem._alias==_alias ) {
+            t = t.join(mem._t);
+        } else if( mem._t == Type.TOP ) {
+            return TypeScalar.TOP;
+        }
+
+        // A deeply read-only base produces a deeply read-only value.  The
+        // generic declared field type must not cast this information away.
+        if( ptr0.isFinal() )
+            t = t.makeRO();
+        return scalar(t);
+    }
+
+    // Loads produce ordinary scalar values.  Field/memory joins can still
+    // expose the enclosing global lattice bounds through an uninitialized
+    // Type.TOP/BOTTOM field; keep those results inside the scalar envelope.
+    private static Type scalar(Type t) {
+        return t==Type.TOP ? TypeScalar.TOP : t==Type.BOTTOM ? TypeScalar.BOT : t;
     }
 
     @Override
     public Node idealize() {
         Node ptr = ptr();
-        Node mem = mem();
+        Node mem = aliasMem();
+
+        // Loads into structs do not need a ctrl edge, as null-ptr checking is
+        // baked into the type system.  Loads into arrays DO need the ctrl
+        // edge, at least until proper range-checking is in place.
+        if( in(0)!=null && ptr()._type instanceof TypeMemPtr tmp &&
+            // Never can be an array
+            (!tmp._obj._open || (tmp._obj._fields.length > 1 && tmp._obj._fields[0]._fname != "#")) ) {
+            setDef(0,null);
+            return this;
+        }
 
-        if( mem instanceof CastNode cast ) {
-            setDef(1,cast.in(1));
+        // Forward-ref loads eventually sharpen to a declared type
+        Field fld;
+        if( ptr()._type instanceof TypeMemPtr tmp &&
+            (fld=tmp._obj.field(_name)) != null &&
+            _alias != fld._alias) {
+            assert _alias==1 || _alias == fld._alias;
+            unlock();           // Alias participates in GVN semantics
+            _alias = fld._alias;
+            // Bulk memory may already have inspected this user.  Revisit it
+            // once the declaring shape is stable; an open forward reference
+            // can still change this Load's semantics.
+            if( !tmp._obj._open && !tmp._obj._fref )
+                CodeGen.CODE.add(mem());
             return this;
         }
+        // Must sharpen alias first
+        if( _alias == 1 )
+            return null;
 
         // Simple Load-after-Store on same address.
         if( mem instanceof StoreNode st &&
-            ptr == st.ptr() && off() == st.off() ) { // Must check same object
+            ptr == st.nnptr() &&
+            off() == st.off() ) { // Must check same object
             assert _name.equals(st._name); // Equiv class aliasing is perfect
             return extend(st.val());
         }
 
-        // Simple load-after-MemMerge to a known alias can bypass.  Happens when inlining.
-        if( mem instanceof MemMergeNode mem2 ) {
-            Node memA = mem2.alias(_alias);
-            for( Node ld : memA._outputs )
+        // Expose the same effective memory input already observed by compute.
+        if( mem != mem() ) {
+            for( Node ld : mem._outputs )
                 if( ld instanceof LoadNode )
                     CodeGen.CODE.add(ld);
-            setDef(1,memA);
+            if( mem instanceof BulkMemPhiNode ) CodeGen.CODE.add(mem);
+            setDef(1,mem);
             return this;
         }
 
-        // Simple Load-after-New on same address.
-        if( mem instanceof ProjNode p && p.in(0) instanceof NewNode nnn &&
-            ptr == nnn.proj(1) ) // Must check same object
-            return zero(nnn);   // Load zero from new
-
         // Uplift control to a prior dominating load.
         for( Node memuse : mem._outputs )
             // Find a prior load, has same mem,ptr,off but higher ctrl
@@ -115,8 +165,11 @@ public class LoadNode extends MemOpNode {
                     return extend(castRO(st.val())); // Proved equal
                 // Can we prove unequal?  Offsets do not overlap?
                 if( !off()._type.join(st.off()._type).isHigh() && // Offsets overlap
-                    !neverAlias(ptr,st.ptr()) )                   // And might alias
-                    break outer; // Cannot tell, stop trying
+                    !neverAlias(ptr,st.ptr()) ) {                 // And might alias
+                    addDep(   off());                             // Offsets can fold, proving unequal
+                    addDep(st.off());                             // Offsets can fold, proving unequal
+                    break outer;                                  // Cannot tell, stop trying
+                }
                 // Pointers cannot overlap
                 mem = st.mem(); // Proved never equal
                 break;
@@ -124,23 +177,32 @@ public class LoadNode extends MemOpNode {
                 // Assume related
                 addDep(phi);
                 break outer;
-            case ConstantNode top: break outer;  // Assume shortly dead
+            case ConstantNode con:
+                // Load from constant memory
+                if( con._con instanceof TypeMem tmem )
+                    return ConstantNode.make(tmem._t);
+                break outer;  // Assume shortly dead
             case ProjNode mproj: // Memory projection
                 switch( mproj.in(0) ) {
                 case NewNode nnn1:
-                    if( ptr instanceof ProjNode pproj && pproj.in(0) == mproj.in(0) )
-                        return zero(nnn1);
-                    if( !(ptr instanceof ProjNode pproj && pproj.in(0) instanceof NewNode) )
-                        break outer; // Cannot tell, ptr not related to New
-                    mem = nnn1.in(nnn1.findAlias(_alias));// Bypass unrelated New
-                    break;
+                    // Direct load from e.g. new array elements
+                    assert _name=="[]";
+                    Type decl = declaredType();
+                    return decl==Type.BOTTOM ? null : ConstantNode.make(decl.makeZero());
                 case StartNode  start: break outer;
-                case CallEndNode cend: break outer; // TODO: Bypass no-alias call
+                case CallEndNode cend: addDep(mproj); break outer; // TODO: Bypass no-alias call
                 default: throw Utils.TODO();
                 }
-                break;
-            case CastNode cast: mem = cast.in(1); break;
+            case CheckCastNode cast: mem = cast.in(1); break;
             case MemMergeNode merge:  mem = merge.alias(_alias);  break;
+            case EscapeNode esc:
+                if( esc.self()==ptr ) // Proved equal
+                    { mem = esc.priv(); break; }
+                // Two NewNodes are always unequal
+                if( esc.self().in(0) instanceof NewNode && ptr.in(0) instanceof NewNode )
+                    { mem = esc.pub(); break; }
+                // TODO: Can we prove unequal?
+                break outer;
 
             default:
                 throw Utils.TODO();
@@ -157,6 +219,8 @@ public class LoadNode extends MemOpNode {
         if( mem() instanceof PhiNode memphi && memphi.region()._type == Type.CONTROL && memphi.nIns()== 3 &&
             // Offset can be hoisted
             off() instanceof ConstantNode &&
+            // Not control dependent
+            in(0)==null &&
             // Pointer can be hoisted
             hoistPtr(ptr,memphi)  ) {
 
@@ -164,25 +228,34 @@ public class LoadNode extends MemOpNode {
             if( profit(memphi,2) ||
                 // Else must not be a loop to count profit on LHS.
                 (!(memphi.region() instanceof LoopNode) && profit(memphi,1)) ) {
+                // profit() peepholes inputs and can restore a required control
+                // edge.  Recheck before manufacturing control-free loads.
+                if( in(0)!=null )
+                    return null;
                 Node ld1 = ld(1);
                 Node ld2 = ld(2);
-                return new PhiNode(_name,_declaredType,memphi.region(),ld1,ld2);
+                PhiNode phi = new PhiNode(_name, memphi.region(),ld1,ld2);
+                phi.setType(phi.compute().join(_type));
+                return phi;
             }
         }
 
         return null;
     }
 
-    // Load a flavored zero from a New
-    private Node zero(NewNode nnn) {
-        TypeStruct ts = nnn._ptr._obj;
-        Type zero = ts._fields[ts.findAlias(_alias)]._t.makeZero();
-        return castRO(new ConstantNode(zero).peephole());
+    // Semantic memory input for this Load.  Compute defines behavior from
+    // this view; ideal merely exposes the same edge in the graph.
+    private Node aliasMem() {
+        Node mem = mem();
+        return _alias != 1 && mem instanceof MemMergeNode merge
+            ? merge.alias(_alias)
+            : mem;
     }
 
     private Node ld( int idx ) {
         Node mem = mem(), ptr = ptr();
-        return new LoadNode(_loc,_name,_alias,_declaredType,mem.in(idx),ptr instanceof PhiNode && ptr.in(0)==mem.in(0) ? ptr.in(idx) : ptr, off()).peephole();
+        assert in(0)==null;
+        return new LoadNode(_loc,_name,_alias,null,mem.in(idx),ptr instanceof PhiNode && ptr.in(0)==mem.in(0) ? ptr.in(idx) : ptr, off()).peephole();
     }
 
     private static boolean neverAlias( Node ptr1, Node ptr2 ) {
@@ -215,8 +288,14 @@ public class LoadNode extends MemOpNode {
     private boolean profit(PhiNode phi, int idx) {
         Node px = phi.in(idx);
         if( px==null ) return false;
-        if( px._type instanceof TypeMem mem && mem._t.isHighOrConst() ) return true;
-        if( px instanceof StoreNode st1 && ptr()==addDep(st1.ptr() )&& off()==st1.off() ) return true;
+        if( px._type instanceof TypeMem mem && mem._t.isHighOrConst() )
+            // To avoid cyclic pushing a Load up then down, getting here means
+            // the load *must* replace with the high/constant.
+            return true;
+        if( px instanceof StoreNode st1 && ptr()==addDep(st1.nnptr() )&& off()==st1.off() )
+            // To avoid cyclic pushing a Load up then down, getting here means
+            // the load *must* match against the Store
+            return true;
         addDep(px);
         return false;
     }
@@ -231,15 +310,25 @@ public class LoadNode extends MemOpNode {
     // When a load bypasses a store, the store might truncate bits - and the
     // load will need to zero/sign-extend.
     private Node extend(Node val) {
-        if( !(_declaredType instanceof TypeInteger ti) ) return val;
+        if( !(declaredType() instanceof TypeInteger ti) ) return val;
         if( ti._min==0 )        // Unsigned
             return new AndNode(null,val,con(ti._max));
         // Signed extension
         int shift = Long.numberOfLeadingZeros(ti._max)-1;
         Node shf = con(shift);
-        if( shf._type==TypeInteger.ZERO )
+        if( shf._type==TypeInteger.ZERO ) {
+            // A freshly exposed Store value can still be globally unknown.
+            // Revisit this Load when it settles instead of replacing a typed
+            // Load with the weaker transient value.
+            if( !val._type.isa(_type) ) {
+                addDep(val);
+                return null;
+            }
             return val;
+        }
         Node shl = new ShlNode(null,val,shf.keep()).peephole();
         return new SarNode(null,shl,shf.unkeep());
     }
+
+    @Override public int log_size() { return declaredType().log_size(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/src/main/java/com/seaofnodes/simple/node/LoopNode.java
index fc50e17f..44ca35d8 100644
--- a/src/main/java/com/seaofnodes/simple/node/LoopNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/LoopNode.java
@@ -3,23 +3,22 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
 import com.seaofnodes.simple.type.TypeMem;
-import com.seaofnodes.simple.util.Utils;
-import java.util.BitSet;
-import java.util.HashSet;
+import com.seaofnodes.simple.util.BAOS;
+
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 public class LoopNode extends RegionNode {
-    public LoopNode( Parser.Lexer loc, Node entry ) { super(loc,null,entry,null); }
+    public LoopNode( Parser.Lexer loc, Node xctrl, Node entry ) { super(loc,xctrl,entry,null); }
     public LoopNode( LoopNode loop ) { super(loop); }
+    @Override public Tag serialTag() { return Tag.Loop; }
+    public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { }
 
     public CFGNode entry() { return cfg(1); }
     public CFGNode back () { return cfg(2); }
 
     @Override
-    public String label() { return "Loop"; }
-
-    @Override
     public Type compute() {
         if( inProgress() ) return Type.CONTROL;
         return entry()._type;
@@ -48,7 +47,7 @@ public class LoopNode extends RegionNode {
             x = x.idom();
         }
         // Found a no-exit loop.  Insert an exit
-        NeverNode iff = (NeverNode)new NeverNode(back()).peephole(); // Ideal never-branch
+        NeverNode iff = (NeverNode)new NeverNode(1.2f,back()).peephole(); // Ideal never-branch
         CProjNode t = new CProjNode(iff,0,"True" ).init();
         CProjNode f = new CProjNode(iff,1,"False").init();
         setDef(2,t);            // True continues loop, False (never) exits loop
@@ -58,12 +57,14 @@ public class LoopNode extends RegionNode {
 
         // Now fold control into the exit.  Might have 1 valid exit, or an
         // XCtrl or a bunch of prior NeverNode exits.
-        Node top = new ConstantNode(Type.TOP).peephole();
+        Node top = ConstantNode.make(Type.TOP).peephole();
         Node memout = new MemMergeNode(false);
         memout.addDef(f); // placeholder for control
+        memout.addDef(top);
         for( Node u : _outputs )
             if( u instanceof PhiNode phi && phi._type.isa(TypeMem.BOT) )
                 memout.addDef(phi);
+        memout.init();
 
         Node ctrl = ret.ctrl(), mem = ret.mem(), expr = ret.expr();
         if( ctrl!=null && ctrl._type != Type.XCONTROL ) {
@@ -74,7 +75,7 @@ public class LoopNode extends RegionNode {
                 // Nope, insert an aligned exit layer
                 RegionNode r = new RegionNode(_loc,null,ctrl).init();
                 ctrl = r;  r._ltree = stop._ltree;
-                mem  = new PhiNode(r,mem ).init();
+                mem  = new BulkMemPhiNode(r,mem ).init();
                 expr = new PhiNode(r,expr).init();
             }
             // Append new Never exit
@@ -89,8 +90,12 @@ public class LoopNode extends RegionNode {
         ret.setDef(0,ctrl.unkeep());
         ret.setDef(1,mem .unkeep());
         ret.setDef(2,expr.unkeep());
-        ret._type = null; // This may LIFT the Return type, from [XCtrl,mem,expr] to [Ctrl,mem,expr]
-        ret.setType(ret.compute());
+        // Force sane types to exit; might locally break monotonicity
+        ret.init();
+        ret.out(0).init();
+        stop.init();
+        CodeGen.CODE.add(CodeGen.CODE._start);
+        CodeGen.CODE.add(mem);
 
         return stop;
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/MachNode.java b/src/main/java/com/seaofnodes/simple/node/MachNode.java
index c0b3af66..025b5dc4 100644
--- a/src/main/java/com/seaofnodes/simple/node/MachNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MachNode.java
@@ -55,6 +55,6 @@ public interface MachNode {
     // General form: "dst=src+src".
     default void asm(CodeGen code, SB sb) { throw Utils.TODO(); }
 
-    // Human readable opcode; e.g. "ld4" or "call".
+    // Human-readable opcode; e.g. "ld4" or "call".
     default String op() { throw Utils.TODO(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java b/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
index 9ab57714..a88748b5 100644
--- a/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
@@ -2,7 +2,10 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.*;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.Utils;
+
 import java.util.*;
 
 /**
@@ -12,18 +15,21 @@ import java.util.*;
 public class MemMergeNode extends Node {
 
     /*
-     *  In-Progress means this is being used by the Parser to track memory
-     *  aliases.  No optimizations are allowed.  When no longer "in progress"
-     *  normal peeps work.
+     *  In-Progress is the mutable construction form.  No optimizations are
+     *  allowed.  If not "in progress" then normal peeps work.
      */
     public final boolean _inProgress;
 
     public MemMergeNode( boolean inProgress) { _type = TypeMem.BOT; _inProgress = inProgress; }
+    public MemMergeNode( boolean inProgress, Node ...nodes) { super(nodes); _type = TypeMem.BOT; _inProgress = inProgress; }
     public MemMergeNode(MemMergeNode mem) { super(mem); _inProgress = false; }
+    @Override public Tag serialTag() { return Tag.MemMerge; }
+    public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { baos.packed1(nIns()); }
+    static Node make( BAOS bais )  { Node mem = new MemMergeNode(false); mem.setDefX(bais.packed1()-1,null); return mem; }
 
 
-    // If being used by a Scope, this is "in progress" from the Parser.
-    // Otherwise, it's a memory merge
+    // The mutable construction form is "in progress"; otherwise this is a
+    // graph-semantic memory merge.
     boolean inProgress() { return _inProgress; }
 
     @Override public String label() { return "ALLMEM"; }
@@ -61,29 +67,82 @@ public class MemMergeNode extends Node {
 
 
     @Override public Type compute() {
-        for( Node n : _inputs )
-            if( n != null && !n._type.isHigh() )
-                return TypeMem.BOT;
-        return TypeMem.TOP;
+        Type tmem = in(1)._type;
+        if( !(tmem instanceof TypeMem defmem) )
+            // A MemMerge is structurally memory even while its default input
+            // is a weak, not-yet-specialized Phi.
+            return tmem.isHigh() ? TypeMem.TOP : TypeMem.BOT;
+        // Is this a single private instance memory?
+        if( defmem._one ) {
+            if( !(defmem._t instanceof TypeStruct ts) )
+                return defmem;
+            // Perfect singleton memory, so all updates are parallel and
+            // independent and stack.
+            for( int i=2; i<nIns(); i++ ) {
+                Node in = in(i);
+                while( true ) {
+                    if( in !=null && in._type.isHigh() )
+                        return TypeMem.TOP;
+                    if( in instanceof MemMergeNode mem ) {
+                        in = mem.in(i);
+                    } else break;
+                }
+                if( in instanceof StoreNode st ) {
+                    Type val = ((TypeMem)st._type)._t;
+                    Field old = ts.field(st._name);
+                    // Lazy add an expected field for open structs.
+                    if( old == null && ts._open ) {
+                        old = Field.make(st._name,Type.BOTTOM,st._alias,st._init);
+                        ts = ts.add(old);
+                    }
+                    Field fld = old.makeFrom(val);
+                    // TODO: val leaks into perfect singleton memory, along with its fidxs and aliases
+                    ts = ts.replace(fld);
+                }
+            }
+            return TypeMem.makePrivate(ts);
+
+        } else {
+            // Default mixed mem is just BOT
+            TypeMem mem = defmem;
+            boolean progress = true;
+            while( progress ) {
+                progress = false;
+                for( int i=2; i<nIns(); i++ ) {
+                    // Has this alias escaped already?
+                    if( XInt.bit(mem._escAs,i) ) {
+                        Node n = in(i);
+                        if( n != null && !n._type.isHigh() ) {
+                            TypeMem mem2 = (TypeMem)mem.meet(n._type);
+                            // More escape aliases
+                            if( mem2 != mem )
+                                { mem = mem2; progress = true; }
+                        }
+                    }
+                }
+            }
+            return mem;
+        }
     }
 
     @Override public Node idealize() {
         if( inProgress() ) return null;
+        if( nIns()==0 ) return null;
 
         // Fold defaults into the default
         boolean progress=false, allDefault=true;
         for( int i=2; i<nIns(); i++ ) {
-            if( in(i) instanceof CastNode cast )
+            if( in(i) instanceof CheckCastNode cast )
                 { setDef(i,cast.in(1)); progress=true; }
-            if( in(1) == in(i) ) { setDef(i,null); progress=true; }
-            else                 { allDefault=false; }
+            if( in(1) == in(i) && in(1) != null ) { setDef(i,null); progress=true; }
+            else                                  { allDefault=false; }
         }
 
         // If not merging any memory (all memory is just the default)
         if( allDefault )
             return in(1);       // Become default memory
 
-        // Collapse stacked all-mem
+        // Collapse stacked merged-mem
         if( in(1) instanceof MemMergeNode mem ) {
             // Goal is to swap my default mem with mem's default mem
             for( int i=2; i<mem.nIns(); i++ ) {
@@ -93,6 +152,7 @@ public class MemMergeNode extends Node {
                         setDefX(i,mem.in(i));
                 }
             }
+            CodeGen.CODE.add(mem.in(1));
             setDef(1,mem.in(1));
             return this;
         }
@@ -104,13 +164,12 @@ public class MemMergeNode extends Node {
     public Node in( Var v ) { return in(v._idx); }
 
     public Node alias( int alias ) {
+        assert !(in(1) instanceof BulkMemPhiNode bulk && bulk.isSplit(alias) &&
+                 (alias >= nIns() || in(alias)==null));
         return alias < nIns() && in(alias)!=null ? in(alias) : in(1);
     }
 
-    Node alias( int alias, Node st ) {
-        while( alias >= nIns() ) addDef(null);
-        return setDef(alias,st);
-    }
+    public Node alias( int alias, Node st ) { return setDefX(alias,st); }
 
     // Read or update from memory.
     // A shared implementation allows us to create lazy phis both during
@@ -119,25 +178,19 @@ public class MemMergeNode extends Node {
         // Memory projections are made lazily; if one does not exist
         // then it must be START.proj(1)
         Node old = alias(alias);
-        if( old instanceof ScopeNode loop ) {
-            MemMergeNode loopmem = loop.mem();
-            Node memdef = loopmem.alias(alias);
-            // Lazy phi!
-            old = memdef instanceof PhiNode phi && loop.ctrl()==phi.region()
-                // Loop already has a real Phi, use it
-                ? memdef
-                // Set real Phi in the loop head
-                // The phi takes its one input (no backedge yet) from a recursive
-                // lookup, which might have insert a Phi in every loop nest.
-                : loopmem.alias(alias, new PhiNode(Parser.memName(alias), TypeMem.make(alias,Type.BOTTOM),loop.ctrl(),loopmem._mem(alias,null),null).peephole() );
-            alias(alias,old);
-        }
+        assert !(old instanceof ScopeNode); // Parser lazy memory is handled by ScopeNode
         // Memory projections are made lazily; expand as needed
         return st==null ? old : alias(alias,st); // Not lazy, so this is the answer
     }
 
+    // Remove lazy Phis on all aliases
+    public void removeLazyAll() {
+        for( int i = 1; i < nIns(); i++)
+            _mem(i,null);
+    }
 
-    void _merge( MemMergeNode that, RegionNode r) {
+    public void _merge( MemMergeNode that, RegionNode r) {
+        assert _inProgress;
         int len = Math.max(nIns(),that.nIns());
         for( int i = 1; i < len; i++)
             if( alias(i) != that.alias(i) ) { // No need for redundant Phis
@@ -145,13 +198,33 @@ public class MemMergeNode extends Node {
                 // by alias as it will trigger a phi creation
                 Node lhs = this._mem(i,null);
                 Node rhs = that._mem(i,null);
-                alias(i, new PhiNode(Parser.memName(i), lhs._type.meet(rhs._type).glb(true), r, lhs, rhs).peephole());
+                alias(i, new MemPhiNode(Parser.memName(i), i, r, lhs, rhs).peephole());
             }
     }
 
-    // Fill in the backedge of any inserted Phis
+    // Fill in the backedge of any inserted Phis.  Keep precise aliases for
+    // what is known at the loop head.  For aliases discovered in the loop
+    // body, gather them into a actual (not inProgress) MemMerge and merge into
+    // the default alias.
     void _endLoopMem( ScopeNode scope, MemMergeNode back, MemMergeNode exit ) {
+        assert _inProgress && back._inProgress && exit._inProgress;
         Node exit_def = exit.alias(1);
+        MemMergeNode more = null; // Dont often need the "more discovered" merge, make it lazy
+        int len = Math.max(nIns(),back.nIns());
+        for( int i=2; i<len; i++ ) {
+            if( !(i < this.nIns() && this.in(i)!=null) &&  // Alias is not known to loop head
+                 (i < back.nIns() && back.in(i)!=null) ) { // Alias IS     known to loop back
+                // Gather
+                if( more==null ) {
+                    more = new MemMergeNode(false);
+                    more.alias(1,back.in(1));
+                    back.alias(1,more);
+                }
+                more.alias(i,back.in(i));
+                back.setDef(i,null);
+            }
+        }
+
         for( int i=1; i<nIns(); i++ ) {
             if( in(i) instanceof PhiNode phi && phi.region()==scope.ctrl() ) {
                 assert phi.in(2)==null;
@@ -164,7 +237,7 @@ public class MemMergeNode extends Node {
 
     // Now one-time do a useless-phi removal
     void _useless( ) {
-        for( int i=2; i<nIns(); i++ ) {
+        for( int i=1; i<nIns(); i++ ) {
             if( in(i) instanceof PhiNode phi ) {
                 // Do an eager useless-phi removal
                 Node in = phi.peephole();
diff --git a/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
index ead82322..d824bc3a 100644
--- a/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -1,11 +1,15 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMemPtr;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.GlobalBits;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
 import java.lang.StringBuilder;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
  * Convenience common base for Load and Store.
@@ -16,84 +20,95 @@ import java.util.BitSet;
  * 3 - Offset, integer types
  * 4 - Value, for Stores only
  */
-public abstract class MemOpNode extends Node {
+public abstract class MemOpNode extends TypeNode {
 
     // The equivalence alias class
-    public final int _alias;
+    public int _alias;
 
     // True if load-like, false if store-like.
+    // Used on CPU-specific combined memory+arithmetic ops.
     //
     // Stores produce memory (maybe as part of a tuple with other things),
     // loads do not.
     //
-    // Loads might pick up anti-dependences on prior Stores, and never cause an
+    // Loads might pick up anti-dependencies on prior Stores, and never cause an
     // anti-dependence themselves.
     //
     // Stores must maximally sink to the least dominator use.  Loads can be
     // opportunistically hoisted.
     public final boolean _isLoad;
 
-    // Declared type; not final because it might be a forward-reference
-    // which will be lazily improved when the reference is declared.
-    public Type _declaredType;
-
-    // A debug name, no semantic meaning
+    // Field name.
     public final String _name;
     // Source location for late reported errors
     public final Parser.Lexer _loc;
 
-    public MemOpNode(Parser.Lexer loc, String name, int alias, boolean isLoad, Type glb, Node mem, Node ptr, Node off) {
-        super(null, mem, ptr, off);
+    public MemOpNode(Parser.Lexer loc, String name, int alias, boolean isLoad, Type glb, Node ctrl, Node mem, Node ptr, Node off) {
+        super(glb, ctrl, mem, ptr, off);
         _name  = name;
         _alias = alias;
-        _declaredType = glb;
         _loc = loc;
         _isLoad = isLoad;
     }
-    public MemOpNode(Parser.Lexer loc, String name, int alias, boolean isLoad, Type glb, Node mem, Node ptr, Node off, Node value) {
-        this(loc,name, alias, isLoad, glb, mem, ptr, off);
+    public MemOpNode(Parser.Lexer loc, String name, int alias, boolean isLoad, Type glb, Node ctrl, Node mem, Node ptr, Node off, Node value) {
+        this(loc, name, alias, isLoad, glb, ctrl, mem, ptr, off);
         addDef(value);
     }
-    public MemOpNode( Node mach, MemOpNode mop ) {
-        super(mach);
-        _name  = mop==null ? null : mop._name;
-        _alias = mop==null ? 0    : mop._alias;
-        _loc   = mop==null ? null : mop._loc;
-        _isLoad= mop==null ? true : mop._isLoad;
-        _declaredType = mop==null ? Type.BOTTOM : mop._declaredType;
-        if( mop==null )
-            throw Utils.TODO("Load or not");
+    public MemOpNode( Node ideal, MemOpNode mop ) {
+        super(ideal,mop instanceof LoadNode ld ? ld.declaredType() : mop._con);
+        _name  = mop._name;
+        _alias = mop._alias;
+        _loc   = mop._loc;
+        _isLoad= mop._isLoad;
+    }
+
+    MemOpNode( BAOS bais, String[] strs, Type[] types, GlobalBits fileAliases, GlobalBits aliases, boolean isLoad ) {
+        this(null,
+             strs[bais.packed2()],
+             mapAlias(bais,fileAliases,aliases),isLoad,
+             types[bais.packed2()],null,null,null,null);
+    }
+
+    private static int mapAlias( BAOS bais, GlobalBits fileAliases, GlobalBits aliases ) {
+        int alias = bais.packed2();
+        return alias < GlobalBits.RESERVED ? alias : aliases.map(fileAliases,alias);
     }
 
-    // Used by M2 when translating graph to Simple
-    public MemOpNode( boolean isLoad ) {
-        super((Node)null);
-        _name         = null;
-        _alias        = 0;
-        _loc          = null;
-        _isLoad       = isLoad;
-        _declaredType = Type.BOTTOM;
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed2(_name==null ? 0 : strs.get(_name));
+        baos.packed2(_alias);
+        baos.packed2(types.get(_con));                // NPE if fails lookup
+        assert _isLoad == this instanceof LoadNode; // No machine ops
     }
 
-    static String mlabel(String name) { return "[]".equals(name) ? "ary" : ("#".equals(name) ? "len" : name); }
+    static String mlabel(String name) { return "[]"==name ? "ary" : ("#"==name ? "len" : name); }
     String mlabel() { return mlabel(_name); }
 
     public Node mem() { return in(1); }
     public Node ptr() { return in(2); }
     public Node off() { return in(3); }
 
+    // Current declared field type.  This is deliberately a live lookup:
+    // cyclic/forward types can sharpen by replacing the pointer's struct.
+    public Type declaredType() {
+        if( !(ptr()._type instanceof TypeMemPtr tmp) )
+            return Type.BOTTOM;
+        Field fld = tmp._obj.field(_name);
+        return fld == null || fld._t == null ? Type.BOTTOM : fld._t;
+    }
+
     @Override public StringBuilder _print1( StringBuilder sb, BitSet visited ) { return _printMach(sb,visited);  }
     public StringBuilder _printMach( StringBuilder sb, BitSet visited ) { throw Utils.TODO(); }
-    public int log_size() { return _declaredType.log_size();  }
+    public int log_size() { return _con.log_size();  }
 
     @Override
     public boolean eq(Node n) {
         MemOpNode mem = (MemOpNode)n; // Invariant
-        return _alias==mem._alias;    // When comparing types error to use "equals"; always use "=="
+        return _alias==mem._alias && super.eq(mem);
     }
 
     @Override
-    int hash() { return _alias; }
+    int hash() { return _alias ^ super.hash(); }
 
     @Override
     public Parser.ParseException err() {
@@ -102,8 +117,15 @@ public abstract class MemOpNode extends Node {
         if( ptr == Type.BOTTOM ) return null;
         if( ptr.isHigh() ) return null; // Assume it will fall to not-null
         // Better be a not-nil TMP
-        if( ptr instanceof TypeMemPtr tmp && tmp.notNull() )
-            return null;
-        return Parser.error( "Might be null accessing '" + _name + "'",_loc);
+        if( !(ptr instanceof TypeMemPtr tmp && tmp.notNull()) )
+            return Parser.error( "Might be null accessing '" + _name + "'",_loc);
+        if( tmp._obj.field(_name)==null &&
+            CodeGen.CODE._phase.ordinal() > CodeGen.Phase.Opto.ordinal() )
+            return Parser.error("Accessing unknown field '"+_name+"' from '*"+tmp._obj._name+"'",_loc);
+        // Sane field
+        if( off() instanceof ConFldOffNode && CodeGen.CODE._phase.ordinal() > CodeGen.Phase.Opto.ordinal() )
+            return Parser.error("Accessing unknown field '"+_name+"' from '*"+tmp._obj._name+"'",_loc);
+        return null;
+
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/MemPhiNode.java b/src/main/java/com/seaofnodes/simple/node/MemPhiNode.java
new file mode 100644
index 00000000..e8e2592c
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/MemPhiNode.java
@@ -0,0 +1,72 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeMem;
+import com.seaofnodes.simple.codegen.GlobalBits;
+import com.seaofnodes.simple.util.BAOS;
+
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+/** A Phi for one precise memory alias. */
+public class MemPhiNode extends PhiNode {
+
+    public final int _alias;
+
+    public MemPhiNode(String label, int alias, Node... inputs) {
+        super(label, inputs);
+        assert alias > 1;
+        _alias = alias;
+    }
+
+    public MemPhiNode(MemPhiNode phi) {
+        super(phi,phi._label);
+        _alias = phi._alias;
+    }
+
+    @Override public Tag serialTag() { return Tag.MemPhi; }
+
+    @Override
+    public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types,
+                       IdentityHashMap<Node,Integer> anodes) {
+        super.packed(baos,strs,types,anodes);
+        baos.packed2(_alias);
+    }
+
+    static Node make(BAOS bais, String[] strs, Type[] types, GlobalBits fileAliases, GlobalBits aliases) {
+        Node[] ins = new Node[bais.packed1()];
+        String label = strs[bais.packed2()];
+        int alias = bais.packed2();
+        if( alias >= GlobalBits.RESERVED ) alias = aliases.map(fileAliases,alias);
+        return new MemPhiNode(label,alias,ins);
+    }
+
+    @Override
+    public Type compute() {
+        Type t = super.compute();
+        assert BulkMemPhiNode.checkMem(this,_alias);
+        if( !(t instanceof TypeMem tmem) ) return t;
+        assert tmem._alias==1 || tmem._alias==_alias;
+        // This Phi structurally knows its alias, but not whether the field is
+        // final.  Do not infer slice finality from evolving input types.
+        return TypeMem.make(_alias,tmem._t,tmem._one,tmem._clz,false,tmem._escFs,tmem._escAs);
+    }
+
+    @Override
+    public Node idealize() {
+        // A precise memory Phi can always bypass a MemMerge and select its
+        // matching slice.
+        for( int i=1; i<nIns(); i++ )
+            if( in(i) instanceof MemMergeNode mem ) {
+                setDef(i,mem.alias(_alias));
+                return this;
+            }
+        return super.idealize();
+    }
+
+    @Override public boolean eq(Node n) {
+        return _alias==((MemPhiNode)n)._alias && super.eq(n);
+    }
+
+    @Override int hash() { return _alias; }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/MinusFNode.java b/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
deleted file mode 100644
index 5bb0889f..00000000
--- a/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-import java.util.BitSet;
-
-public class MinusFNode extends Node {
-    public MinusFNode(Node in) { super(null, in); }
-
-    @Override public String label() { return "MinusF"; }
-
-    @Override public String glabel() { return "-"; }
-
-    @Override
-    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        in(1)._print0(sb.append("(-"), visited);
-        return sb.append(")");
-    }
-
-    @Override
-    public Type compute() {
-        if( in(1)._type.isHigh() ) return TypeFloat.TOP;
-        if( in(1)._type instanceof TypeFloat i0)
-            return i0.isConstant() ? TypeFloat.constant(-i0.value()) : i0;
-        return TypeFloat.F64;
-    }
-
-    @Override
-    public Node idealize() {
-        // -(-x) is x
-        if( in(1) instanceof MinusFNode minus )
-            return minus.in(1);
-
-        return null;
-    }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/src/main/java/com/seaofnodes/simple/node/MinusNode.java
index 3ab74625..6101fba2 100644
--- a/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MinusNode.java
@@ -1,16 +1,32 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
-public class MinusNode extends Node {
-    public MinusNode(Node in) { super(null, in); }
+public class MinusNode extends Node implements ModeNode {
+    // Mode is 0 for unknown, 1 for int, 2 for flt
+    byte _mode;
 
-    @Override public String label() { return "Minus"; }
+    public MinusNode(Node in) { super(null, in); }
+    public MinusNode(Node in, byte mode) { super(null, in); _mode = mode; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes) {
+        baos.packed1(_mode);
+    }
+    @Override public Tag serialTag() { return Tag.Minus; }
 
     @Override public String glabel() { return "-"; }
+    @Override public byte mode() { return _mode; }
+    @Override public Node setMode(byte mode) {
+        assert _mode==0 && (mode==1 || mode==2);
+        unlock();               // _mode participates in GVN hash and equality
+        _mode = mode;
+        return this;
+    }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
@@ -20,11 +36,22 @@ public class MinusNode extends Node {
 
     @Override
     public Type compute() {
-        if( in(1)._type.isHigh() ) return TypeInteger.TOP;
-        if( in(1)._type instanceof TypeInteger i0 &&
-            i0._min != Long.MIN_VALUE && i0._max != Long.MIN_VALUE )
-            return TypeInteger.make(-i0._max,-i0._min,i0._widen);
-        return TypeInteger.BOT;
+        Type t = in(1)._type;
+        if( t.isHigh() )
+            return _mode==0 ? Type.TOP :
+                _mode==1 ? TypeInteger.TOP :
+                t instanceof TypeFloat ? t : TypeFloat.F64.dual();
+        if( _mode==0 )
+            return Type.BOTTOM;
+        if( _mode==1 ) {
+            if( t instanceof TypeInteger i0 &&
+                i0._min != Long.MIN_VALUE && i0._max != Long.MIN_VALUE )
+                return TypeInteger.make(-i0._max,-i0._min,i0._widen);
+            return TypeInteger.BOT;
+        }
+        if( t instanceof TypeFloat f )
+            return f.isConstant() ? TypeFloat.constant(-f.value()) : f;
+        return TypeFloat.F64;
     }
 
     @Override
@@ -33,7 +60,19 @@ public class MinusNode extends Node {
         if( in(1) instanceof MinusNode minus )
             return minus.in(1);
 
+        // Can we decide int vs flt?
+        if( _mode==0 ) {
+            byte mode = (byte)(
+                in(1)._type instanceof TypeInteger ? 1 :
+                in(1)._type instanceof TypeFloat   ? 2 : 0);
+            if( mode!=0 ) return setMode(mode).init();
+        }
+
         return null;
     }
-    @Override Node copyF() { return new MinusFNode(null); }
+    @Override public Parser.ParseException err() {
+        return ArithNode.nodeErr(this,null,"-",_mode,true);
+    }
+    @Override public boolean eq( Node n ) { return _mode==((MinusNode)n)._mode; }
+    @Override public int hash() { return _mode; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/ModeNode.java b/src/main/java/com/seaofnodes/simple/node/ModeNode.java
new file mode 100644
index 00000000..dc635447
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/ModeNode.java
@@ -0,0 +1,12 @@
+package com.seaofnodes.simple.node;
+
+/**
+ * A node whose numeric input family is selected once: unknown, integer, or
+ * floating point.  Implementors remain ordinary Nodes; this interface only
+ * centralizes the structural mode contract shared by arithmetic, comparisons,
+ * and unary minus.
+ */
+public interface ModeNode {
+    byte mode();
+    Node setMode(byte mode);
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/MulFNode.java b/src/main/java/com/seaofnodes/simple/node/MulFNode.java
deleted file mode 100644
index 5c04af43..00000000
--- a/src/main/java/com/seaofnodes/simple/node/MulFNode.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-import java.util.BitSet;
-
-public class MulFNode extends ArithFNode {
-    public MulFNode(Node lhs, Node rhs) { super(lhs, rhs); }
-
-    @Override public String label() { return "MulF"; }
-
-    @Override public String glabel() { return "*"; }
-
-    @Override double doOp( double x, double y ) { return x*y; }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t1 = lhs._type;
-        Type t2 = rhs._type;
-
-        // Mul of 1.  We do not check for (1*x) because this will already
-        // canonicalize to (x*1)
-        if ( t2.isConstant() && t2 instanceof TypeFloat i && i.value()==1 )
-            return lhs;
-
-        // Move constants to RHS: con*arg becomes arg*con
-        if ( t1.isConstant() && !t2.isConstant() )
-            return swap12();
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new MulFNode(lhs,rhs); }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/MulNode.java b/src/main/java/com/seaofnodes/simple/node/MulNode.java
index debc2c56..e773ed57 100644
--- a/src/main/java/com/seaofnodes/simple/node/MulNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MulNode.java
@@ -1,17 +1,20 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 import java.util.BitSet;
 
 public class MulNode extends ArithNode {
+    @Override boolean allowFloat() { return true; }
     public MulNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
+    public MulNode(Node lhs, Node rhs, byte mode) { super(null, lhs, rhs, mode); }
+    @Override public Tag serialTag() { return Tag.Mul; }
 
-    @Override public String label() { return "Mul"; }
     @Override public String op() { return "*"; }
 
-    @Override long doOp( long x, long y ) { return x * y; }
+    @Override long   doOp( long  x,  long  y ) { return x * y; }
+    @Override double doOp(double x, double y ) { return x * y; }
     @Override TypeInteger doOp(TypeInteger x, TypeInteger y) {
         return TypeInteger.BOT;
     }
@@ -33,7 +36,7 @@ public class MulNode extends ArithNode {
             // canonicalize to (x*1)
             long c = i.value();
             if( c==1 )  return lhs;
-            if( c==0 )  return Parser.ZERO;
+            if( c==0 )  return CodeGen.CODE.ZERO;
             // Mul by a power of 2, +/-1.  Bit patterns more complex than this
             // are unlikely to win on an X86 vs the normal "imul", and so
             // become machine-specific.
@@ -58,6 +61,5 @@ public class MulNode extends ArithNode {
 
         return super.idealize();
     }
-    @Override Node copy(Node lhs, Node rhs) { return new MulNode(lhs,rhs); }
-    @Override Node copyF() { return new MulFNode(null,null); }
+    @Override Node copy(Node lhs, Node rhs) { return new MulNode(lhs,rhs,_mode); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/NeverNode.java b/src/main/java/com/seaofnodes/simple/node/NeverNode.java
index 516f218b..e2c279d2 100644
--- a/src/main/java/com/seaofnodes/simple/node/NeverNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NeverNode.java
@@ -10,7 +10,8 @@ import java.util.BitSet;
 // "Never true" for infinite loop exits
 public class NeverNode extends IfNode {
     public NeverNode(NeverNode ctrl) { super(ctrl); }
-    public NeverNode(Node ctrl) { super(ctrl,null); }
+    public NeverNode(float ignore, Node ctrl) { super(ctrl,null); }
+    @Override public Tag serialTag() { return Tag.Never; }
 
     @Override public String label() { return "Never"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/NewNode.java b/src/main/java/com/seaofnodes/simple/node/NewNode.java
index 9310aa38..26a9c0fd 100644
--- a/src/main/java/com/seaofnodes/simple/node/NewNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NewNode.java
@@ -2,107 +2,70 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
 
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
- *  Allocation!  Allocate a chunk of memory, and pre-zero it.
- *  The inputs include control and size, and ALL aliases being set.
- *  The output is large tuple, one for every alias plus the created pointer.
- *  New is expected to be followed by projections for every alias.
- */
+ * Allocation!  Allocate a chunk of memory, no init.
+ * Takes in ctrl and size, and TypeStruct.
+ * Produces a ptr and private memory.
+*/
 public class NewNode extends Node implements MultiNode {
+    public TypeStruct _ts;
+    public NewNode( TypeStruct ts, Node ctrl, Node size ) { super(ctrl,size); _ts = ts; }
 
-    public final TypeMemPtr _ptr;
-    public final int _len;
+    public Node ctrl() { return in(0); }
+    public Node size() { return in(1); }
 
-    public NewNode(TypeMemPtr ptr, Node... nodes) {
-        super(nodes);
-        assert !ptr.nullable();
-        _ptr = ptr;
-        _len = ptr._obj._fields.length;
-        // Control in slot 0
-        assert nodes[0]._type==Type.CONTROL || nodes[0]._type == Type.XCONTROL;
-        // Malloc-length in slot 1
-        assert nodes[1]._type instanceof TypeInteger || nodes[1]._type==Type.NIL;
-        for( int i=0; i<_len; i++ )
-          assert ptr._obj._fields[i]._one || nodes[2 + i]._type.isa( TypeMem.BOT );
+    // --- Serialization
+    public NewNode(NewNode nnn) { super(nnn); _ts = nnn._ts; }
+    @Override public Tag serialTag() { return Tag.New; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed2(types.get(_ts));
+    }
+    static Node make( BAOS bais, Type[] types)  {
+        TypeStruct ts = (TypeStruct)types[bais.packed2()];
+        return new NewNode(ts,null,null);
     }
 
-    public NewNode(NewNode nnn) { super(nnn); _ptr = nnn._ptr; _len = nnn._len; }
-
-    public Node mem (int idx) { return in(idx+2); }
-
-    @Override public String label() { return "new_"+glabel(); }
     @Override public String glabel() {
-        return _ptr._obj.isAry() ? "ary_"+_ptr._obj._fields[1]._t.str() : _ptr._obj.str();
+        return _ts.isAry() ? "ary_"+_ts._fields[1]._t.str() : _ts.str();
     }
+    @Override public String label() { return "new_"+glabel(); }
 
-    @Override
-    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("new ");
-        return sb.append(_ptr._obj.str());
+        return sb.append(_ts.str());
     }
 
-    int findAlias(int alias) {
-        int idx = _ptr._obj.findAlias(alias);
-        assert idx!= -1;        // Error, caller should be calling
-        return idx+2;           // Skip ctrl, size
+    @Override public TypeTuple compute() {
+        if( ctrl()._type.isHigh() )
+            return TypeTuple.DEAD_NEW;
+        TypeStruct ts = _ts.isAry() ? _ts : _ts.makeInit();
+        return TypeTuple.make(TypeMemPtr.make(_ts),
+                              // Arrays get pre-zeroed by constructor.
+                              // Objects start with default-zero memory for
+                              // fields that can be zero-initialized.  This is
+                              // still private memory, so no aliases escape yet.
+                              TypeMem.make(1,ts,true,false,false,null,null));
     }
 
-    // 0 - ctrl
-    // 1 - byte size
-    // 2-len+2 - aliases, one per field
-    // len+2 - 2*len+2 - initial values, one per field
-    public Node size() { return in(1); }
+    @Override public Node idealize() { return null; }
 
-    @Override
-    public TypeTuple compute() {
-        Field[] fs = _ptr._obj._fields;
-        Type[] ts = new Type[fs.length+2];
-        if( in(0)._type.isHigh() ) {
-            ts[0] = Type.XCONTROL;
-            ts[1] = _ptr.makeHigh();
-            for( int i=0; i<fs.length; i++ )
-                ts[i+2] = Type.TOP;
-        } else {
-            ts[0] = Type.CONTROL;
-            ts[1] = _ptr;
-            for( int i=0; i<fs.length; i++ ) {
-                if( _ptr._obj._fields[i]._one ) {
-                    // Once-only fields use the declared type
-                    ts[i+2] = _ptr._obj._fields[i]._t;
-                } else {
-                    // Others take from the inputs
-                    Type mt = in(i+2)._type;
-                    TypeMem mem = mt==Type.TOP ? TypeMem.TOP : (TypeMem)mt;
-                    //Type tfld = mem._t.meet(mem._t.makeZero());
-                    Type tfld = mem._t;
-                    Type tfld2 = tfld.join(fs[i]._t );
-                    ts[i+2] = TypeMem.make(fs[i]._alias,tfld2);
-                }
-            }
-        }
-        return TypeTuple.make(ts);
+    @Override boolean _upgradeType( HashMap<String,Type> TYPES) {
+        Type old = _ts; _ts = (TypeStruct)_ts.upgradeType(TYPES);  return old != _ts;
     }
 
-    @Override
-    public Node idealize() {
-        Node progress=null;
-        for( int i=1; i<nIns(); i++ ) {
-            if( in(i) instanceof CastNode cast )
-                progress = setDef(i,cast.in(1));
-        }
-        return progress == null ? null : this;
-    }
+    // Two NewNodes are never equal; NewNodes always make independent pointers
+    // so they are not functional - they internally bump-ptr allocate always a
+    // new pointer.
+    @Override public boolean eq(Node n) { return this==n; }
 
-    @Override
-    public boolean eq(Node n) { return this == n; }
-
-    @Override
-    int hash() { return _ptr.hashCode(); }
+    @Override int hash() { return _ts.hashCode(); }
 
     // ------------
     // MachNode specifics, shared across all CPUs
@@ -111,19 +74,19 @@ public class NewNode extends Node implements MultiNode {
     private RegMask _retMask;
     private RegMask _kills;
     public void cacheRegs(CodeGen code) {
-        _arg2Reg  = code._mach.callArgMask(TypeFunPtr.CALLOC,2,0).firstReg();
-        _arg3Mask = code._mach.callArgMask(TypeFunPtr.CALLOC,3,0);
+        _arg2Reg  = code._mach.callArgMask(TypeFunPtr.CALLOC,2,0,code._cCallingConv).firstReg();
+        _arg3Mask = code._mach.callArgMask(TypeFunPtr.CALLOC,3,0,code._cCallingConv);
         // Return mask depends on TFP (either GPR or FPR)
         _retMask = code._mach.retMask(TypeFunPtr.CALLOC);
         // Kill mask is all caller-saves, and any mirror stack slots for args
         // in registers.
-        RegMaskRW kills = code._callerSave.copy();
+        RegMaskRW kills = code._cCallerSave.copy();
         // Start of stack slots
         int maxReg = code._mach.regs().length;
         // Incoming function arg slots, all low numbered in the RA
         int fslot = cfg0().fun()._maxArgSlot;
         // Killed slots for this calls outgoing args
-        int xslot = code._mach.maxArgSlot(TypeFunPtr.CALLOC);
+        int xslot = code._mach.maxArgSlot(TypeFunPtr.CALLOC,code._cCallingConv);
         _xslot = (maxReg+fslot)+xslot;
         for( int i=0; i<xslot; i++ )
             kills.set((maxReg+fslot)+i);
@@ -132,9 +95,10 @@ public class NewNode extends Node implements MultiNode {
     public String op() { return "alloc"; }
     public RegMask regmap(int i) { return i==1 ? _arg3Mask : null; }
     public RegMask outregmap() { return null; }
-    public RegMask outregmap(int idx) { return idx==1  ? _retMask : null; }
+    public RegMask outregmap(int idx) { return idx==0  ? _retMask : null; }
     public RegMask killmap() { return _kills; }
     public void asm(CodeGen code, SB sb) {
-        sb.p("#calloc, ").p(code.reg(size()));
+        sb.p("#malloc, ").p(code.reg(size()));
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/Node.java b/src/main/java/com/seaofnodes/simple/node/Node.java
index 458a3407..1ce8382a 100644
--- a/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -2,14 +2,12 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.IterPeeps;
 import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.Utils;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.GlobalBits;
 import com.seaofnodes.simple.print.IRPrinter;
 import com.seaofnodes.simple.print.JSViewer;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.*;
 import java.util.*;
 import java.util.function.Function;
 import static com.seaofnodes.simple.codegen.CodeGen.CODE;
@@ -78,8 +76,83 @@ public abstract class Node implements Cloneable {
         _hash = 0;
     }
 
+    // Disk/serialized opcode tags
+    public enum Tag {
+        Add,And,EQ,NE,LT,LE,ULT,
+        CallEnd,Call,CheckCast,ConFldOff,Con,CProj,
+        Div,Escape,Extern,Fun,FunPtr,If,Load,Loop,
+        MemMerge,Minus,Mul,
+        New,Never,Not,Or,Parm,Phi,Proj,
+        ReadOnly,Return,Region,RoundF32,
+        Sar,Shl,Shr,Start,Stop,Store,Struct,Sub,ToFloat,
+        XCtrl,Xor,StartCU,StopCU,Guard,MemPhi,BulkMemPhi,PtrToInt;
+        public static final Tag[] VALS = values();
+        public Node make( BAOS bais, String[] strs, Type[] types, GlobalBits fileAliases, GlobalBits aliases ) {
+            return switch(this) {
+            case Add    -> new   AddNode(null,null,(byte)bais.packed1());
+            case And    -> { int mode=bais.packed1(); assert mode==1; yield new AndNode(null,null,null); }
+            case Div    -> new   DivNode(null,null,(byte)bais.packed1());
+            case If     -> new    IfNode(null,null);
+            case Loop   -> new  LoopNode(null,null,null);
+            case Minus  -> new MinusNode(null,(byte)bais.packed1());
+            case Mul    -> new   MulNode(null,null,(byte)bais.packed1());
+            case Never  -> new NeverNode(1.2f, null);
+            case Not    -> new   NotNode(null);
+            case Or     -> { int mode=bais.packed1(); assert mode==1; yield new OrNode(null,null,null); }
+            case ReadOnly-> new ReadOnlyNode((Node)null);
+            case Return ->new ReturnNode(null,null,null,null,null);
+            case RoundF32-> new RoundF32Node(null);
+            case PtrToInt-> new PtrToIntNode((Node)null);
+            case Sar    -> { int mode=bais.packed1(); assert mode==1; yield new SarNode(null,null,null); }
+            case Shl    -> { int mode=bais.packed1(); assert mode==1; yield new ShlNode(null,null,null); }
+            case Shr    -> { int mode=bais.packed1(); assert mode==1; yield new ShrNode(null,null,null); }
+            case Start  -> new StartNode(null,null,TypeInteger.BOT);
+            case Sub    -> new   SubNode(null,null,(byte)bais.packed1());
+            case ToFloat-> new ToFloatNode(null);
+            case XCtrl  -> new XCtrlNode();
+            case Xor    -> { int mode=bais.packed1(); assert mode==1; yield new XorNode(null,null,null); }
+            case Guard -> GuardNode.make(bais);
+
+            case EQ    -> new  BoolNode.EQ (null,null,(byte)bais.packed1());
+            case NE    -> new  BoolNode.NE (null,null,(byte)bais.packed1());
+            case LT    -> new  BoolNode.LT (null,null,(byte)bais.packed1());
+            case LE    -> new  BoolNode.LE (null,null,(byte)bais.packed1());
+            case ULT   -> new  BoolNode.ULT(null,null,(byte)bais.packed1());
+
+            case Call  ->      CallNode.make(bais);
+            case CallEnd->  CallEndNode.make(bais     ,types);
+            case CheckCast -> CheckCastNode.make(bais,types);
+            case CProj ->     CProjNode.make(bais,strs);
+            case Con   ->  ConstantNode.make(bais     ,types);
+            case Escape->    EscapeNode.make(bais     ,types);
+            case Extern->    ExternNode.make(bais,strs,types);
+            case FunPtr->   FunPtrNode.make(bais,     types);
+            case Fun   ->       FunNode.make(bais,strs,types);
+            case Load  ->       new LoadNode(bais,strs,types,fileAliases,aliases);
+            case MemMerge->MemMergeNode.make(bais);
+            case MemPhi->  MemPhiNode.make(bais,strs,types,fileAliases,aliases);
+            case BulkMemPhi-> BulkMemPhiNode.make(bais,strs,types,fileAliases,aliases);
+            case New   ->       NewNode.make(bais     ,types);
+            case Parm  ->      ParmNode.make(bais,strs,types);
+            case Phi   ->       PhiNode.make(bais,strs,types);
+            case Proj  ->      ProjNode.make(bais,strs);
+            case Store ->      new StoreNode(bais,strs,types,fileAliases,aliases);
+            case Stop ->       StopNode.make(bais);
+            case StartCU->  StartCUNode.make(bais,strs,types);
+            case StopCU ->   StopCUNode.make(bais);
+            case Struct->    StructNode.make(bais,     types);
+            case Region->    RegionNode.make(bais);
+
+            default -> throw Utils.TODO();
+            };
+        }
+    };
+    public Tag serialTag() { throw Utils.TODO(); }
+    // Serialize extra data, including input counts
+    public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {}
+
     // Easy reading label for debugger, e.g. "Add" or "Region" or "EQ"
-    public abstract String label();
+    public String label() { return serialTag().toString(); }
 
     // Unique label for graph visualization, e.g. "Add12" or "Region30" or "EQ99"
     public String uniqueName() {
@@ -115,7 +188,7 @@ public abstract class Node implements Cloneable {
     // This is the common print: check for repeats, check for DEAD and print
     // "DEAD" else call the per-Node print1.
     public final StringBuilder _print0(StringBuilder sb, BitSet visited) {
-        if (visited.get(_nid) && !(this instanceof ConstantNode) )
+        if( visited.get(_nid) && !(this instanceof ConstantNode) )
             return sb.append(label());
         visited.set(_nid);
         return isDead()
@@ -229,7 +302,8 @@ public abstract class Node implements Cloneable {
     }
 
     // Breaks the edge invariants, used temporarily
-    protected <N extends Node> void addUse(N n) { _outputs.add(n); }
+    @SuppressWarnings("unchecked")
+    protected <N extends Node> N addUse(Node n) { _outputs.add(n); return (N)this; }
 
     // Remove node 'use' from 'def's (i.e. our) output list, by compressing the list in-place.
     // Return true if the output list is empty afterward.
@@ -250,6 +324,12 @@ public abstract class Node implements Cloneable {
                 old_def.kill();        // Kill old def
         }
     }
+    public Node removeLast() {
+        Node old_def = _inputs.pop();
+        if( old_def != null )
+            old_def.delUse(this);
+        return old_def;
+    }
 
     /**
      * Kill a Node with no <em>uses</em>, by setting all of its <em>defs</em>
@@ -284,11 +364,13 @@ public abstract class Node implements Cloneable {
 
     // Shortcuts to stop DCE mid-parse
     // Add bogus null use to keep node alive
-    @SuppressWarnings("unchecked")
-    public <N extends Node> N keep() { addUse(null); return (N)this; }
+    public <N extends Node> N keep() { return addUse(null); }
     // Remove bogus null.
     @SuppressWarnings("unchecked")
-    public <N extends Node> N unkeep() { delUse(null); return (N)this; }
+    public <N extends Node> N unkeep() {
+        delUse(null);
+        return (N)this;
+    }
     // Test "keep" status
     public boolean iskeep() { return _outputs.find(null) != -1; }
     public void unkill() {
@@ -415,7 +497,15 @@ public abstract class Node implements Cloneable {
         // node.  If peeps are disabled, still allow high Phis to collapse;
         // they typically come from dead Regions, and we want the Region to
         // collapse, which requires the Phis to die first.
-        if( !isConst() && _type.isHighOrConst() )
+        if( !isConst() && !(this instanceof ParmNode parm && parm.inProgress()) &&
+            // A high Load through a bad pointer still owns the source error;
+            // do not replace it with an unlocated constant before typeCheck.
+            !(this instanceof LoadNode && err()!=null) &&
+            // A CallEnd can be temporarily high while optimistic call-graph
+            // linking is still discovering its target Returns.  Its result
+            // projections must remain attached so they can sharpen later.
+            !(this instanceof ProjNode proj && proj.in(0) instanceof CallEndNode && _type.isHigh()) &&
+            _type.isHighOrConst() )
             return ConstantNode.make(_type).peephole();
 
         // Global Value Numbering
@@ -483,7 +573,8 @@ public abstract class Node implements Cloneable {
     // If changing, add users to worklist.
     public Type setType(Type type) {
         Type old = _type;
-        assert old == null || type.isa(old) : "Monotonicity test failed";
+        assert old == null || type.isa(old) : "Monotonicity test failed: "+this+"#"+_nid+" old="+old+" new="+type;
+        //assert !type.hasClosedBuilder0(); // New types should not have closed builders
         if( old == type ) return old;
         _type = type;       // Set _type late for easier assert debugging
         CODE.addAll(_outputs);
@@ -549,19 +640,30 @@ public abstract class Node implements Cloneable {
     // revisit them if `this` changes.
     Ary<Node> _deps;
 
+    private boolean addDepImpl( Node dep ) {
+        // Running peepholes during the big assert cannot have side effects
+        // like adding dependencies.
+        if( CODE._midAssert ) return false;
+        if( dep._deps==null ) dep._deps = new Ary<>(Node.class);
+        if( dep._deps   .find(this) != -1 ) return false; // Already on list
+        if( dep._outputs.find(this) != -1 ) return false;
+        return true;
+    }
+
     /**
      * Add a node to the list of dependencies.  Only add it if it's not an input
      * or output of this node, that is, it is at least one step away.  The node
      * being added must benefit from this node being peepholed.
      */
-    <N extends Node> N addDep( N dep ) {
-        // Running peepholes during the big assert cannot have side effects
-        // like adding dependencies.
-        if( CODE._midAssert ) return dep;
-        if( dep._deps==null ) dep._deps = new Ary<>(Node.class);
-        if( dep._deps   .find(this) != -1 ) return dep; // Already on list
+    public <N extends Node> N addDep( N dep ) {
+        if( !addDepImpl(dep) ) return dep;
         if( dep._inputs .find(this) != -1 ) return dep; // No need for deps on immediate neighbors
-        if( dep._outputs.find(this) != -1 ) return dep;
+        dep._deps.add(this);
+        return dep;
+    }
+
+    public <N extends Node> N addDepForwards( N dep ) {
+        if( !addDepImpl(dep) ) return dep;
         dep._deps.add(this);
         return dep;
     }
@@ -574,6 +676,7 @@ public abstract class Node implements Cloneable {
         _deps.clear();
     }
 
+
     // Two nodes are equal if they have the same inputs and the same "opcode"
     // which means the same Java class, plus same internal parts.
     @Override public final boolean equals( Object o ) {
@@ -630,27 +733,6 @@ public abstract class Node implements Cloneable {
     /** Pinned in the schedule; these are data nodes whose input#0 is not allowed to change */
     public boolean isPinned() { return false; }
 
-    // Semantic change to the graph (so NOT a peephole), used by the Parser.
-    // If any input is a float, flip to a float-flavored opcode and widen any
-    // non-float input.
-    public final Node widen() {
-        if( !hasFloatInput() ) return this;
-        Node flt = copyF();
-        if( flt==null ) return this;
-        for( int i=1; i<nIns(); i++ )
-            flt.setDef(i, in(i)._type instanceof TypeFloat ? in(i) : new ToFloatNode(in(i)).peephole());
-        kill();
-        return flt;
-    }
-    private boolean hasFloatInput() {
-        for( int i=1; i<nIns(); i++ )
-            if( in(i)._type instanceof TypeFloat )
-                return true;
-        return false;
-    }
-    Node copyF() { return null; }
-
-
     // ------------------------------------------------------------------------
     // Peephole utilities
 
@@ -699,7 +781,7 @@ public abstract class Node implements Cloneable {
     public Parser.ParseException err() { return null; }
 
     // Common integer constants
-    public static ConstantNode con(long x) { return (ConstantNode)(new ConstantNode(TypeInteger.constant(x)).peephole()); }
+    public static ConstantNode con(long x) { return (ConstantNode)ConstantNode.make(TypeInteger.constant(x)).peephole(); }
 
     // Utility to walk the entire graph applying a function; return the first
     // not-null result.
@@ -720,6 +802,20 @@ public abstract class Node implements Cloneable {
         return null;
     }
 
+    public void gather(HashMap<String,Integer> strs ) { }
+
+    // If a Type upgrade happens, put on worklist
+    boolean _upgradeType( HashMap<String,Type> TYPES ) { return false; }
+    public final void upgradeType( HashMap<String,Type> TYPES ) {
+        Type old = _type;  _type = _type.upgradeType(TYPES);
+        boolean progress = _upgradeType(TYPES);
+        if( progress || old != _type ) {
+            CODE.add(this);
+            CODE.addAll(_outputs);
+            if( _deps!=null ) CODE.addAll(_deps);
+        }
+    }
+
     /**
      * Debugging utility to find a Node by index
      */
diff --git a/src/main/java/com/seaofnodes/simple/node/NotNode.java b/src/main/java/com/seaofnodes/simple/node/NotNode.java
index 4b80e61c..22b5bffe 100644
--- a/src/main/java/com/seaofnodes/simple/node/NotNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NotNode.java
@@ -6,8 +6,7 @@ import java.util.BitSet;
 
 public class NotNode extends Node {
     public NotNode(Node in) { super(null, in); }
-
-    @Override public String label() { return "Not"; }
+    @Override public Tag serialTag() { return Tag.Not; }
 
     @Override public String glabel() { return "!"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/OrNode.java b/src/main/java/com/seaofnodes/simple/node/OrNode.java
index ac0d8454..ba250c26 100644
--- a/src/main/java/com/seaofnodes/simple/node/OrNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/OrNode.java
@@ -5,7 +5,8 @@ import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
 public class OrNode extends ArithNode {
-    public OrNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs); }
+    public OrNode( Parser.Lexer loc, Node lhs, Node rhs) { super(loc,lhs, rhs, (byte)1); }
+    @Override public Tag serialTag() { return Tag.Or; }
 
     @Override public String label() { return "Or"; }
     @Override public String op() { return "|"; }
diff --git a/src/main/java/com/seaofnodes/simple/node/ParmNode.java b/src/main/java/com/seaofnodes/simple/node/ParmNode.java
index 880f936c..6488b827 100644
--- a/src/main/java/com/seaofnodes/simple/node/ParmNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ParmNode.java
@@ -1,30 +1,59 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMemPtr;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 public class ParmNode extends PhiNode {
 
     // Argument indices are mapped one-to-one on CallNode inputs
     public final int _idx;             // Argument index
+    public Type _declaredType;
 
     public ParmNode(String label, int idx, Type declaredType, Node... inputs) {
-        super(label,declaredType,inputs);
+        super(label, inputs);
         _idx = idx;
+        _declaredType = declaredType;
+        _type = declaredType;
+    }
+    public ParmNode(ParmNode parm) { super(parm, parm._label ); _idx = parm._idx; _declaredType = parm._declaredType; }
+    @Override public Tag serialTag() { return Tag.Parm; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed1(nIns());   // Number of linked calls
+        baos.packed2(_label==null ? 0 : strs.get(_label));
+        baos.packed2(types.get(_declaredType)); // NPE if fails lookup
+        baos.packed1(_idx);
+    }
+    static Node make( BAOS bais, String[] strs, Type[] types)  {
+        Node[] ins = new Node[bais.packed1()];
+        String label =   strs[bais.packed2()];
+        Type minType =  types[bais.packed2()];
+        return new ParmNode(label, bais.packed1(), minType, ins);
     }
-    public ParmNode(ParmNode parm) { super(parm, parm._label, parm._minType ); _idx = parm._idx; }
 
     @Override public String label() { return MemOpNode.mlabel(_label); }
 
     @Override public String glabel() { return _label; }
 
+    @Override protected Type declaredType() { return _declaredType; }
+    @Override protected Type constrain(Type t) { return t.join(_declaredType); }
+
+    @Override boolean _upgradeType( HashMap<String,Type> TYPES) {
+        Type t = _declaredType.upgradeType(TYPES);
+        if( t == _declaredType ) return false;
+        unlock();
+        _declaredType = t;
+        return true;
+    }
+
     public FunNode fun() { return (FunNode)in(0); }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        if( "main".equals(fun()._name) && _label.equals("arg") )
+        if( fun()._name!=null && fun()._name.endsWith("<clinit>") && _label.equals("arg") )
             return sb.append("arg");
         sb.append("Parm_").append(_label).append("(");
         for( Node in : _inputs ) {
@@ -48,14 +77,6 @@ public class ParmNode extends PhiNode {
         // If function is folding, do all possible peeps
         if( fun()._folding ) return super.idealize();
 
-        // Can upgrade minType even while in-progress
-        if( _minType instanceof TypeMemPtr tmp && _minType.isFRef() ) {
-            TypeMemPtr tmp2 = (TypeMemPtr) Parser.TYPES.get(tmp._obj._name);
-            if( tmp2!=null && tmp2 != _minType ) {
-                _minType = tmp2;
-                return this;
-            }
-        }
         // Skip most phi optimizations on parms
         return null;
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/src/main/java/com/seaofnodes/simple/node/PhiNode.java
index bdc0d0fa..2c57eb8b 100644
--- a/src/main/java/com/seaofnodes/simple/node/PhiNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/PhiNode.java
@@ -1,39 +1,51 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Serialize;
 import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.SB;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 public class PhiNode extends Node {
 
     public final String _label;
 
-    // The Phi type we compute must stay within the domain of the Phi.  Example
-    // Int stays Int, Ptr stays Ptr, Control stays Control, Mem stays Mem.
-    Type _minType;
-
-    int lattice_drop;
-
-    public PhiNode(String label, Type minType, Node... inputs) {
+    public PhiNode( String label, Node... inputs) {
         super(inputs);
         _label = label;
-        assert minType!=null;
-        _minType = minType;
+    }
+    public static PhiNode make(String label, Type minType, Node... inputs) {
+        return minType instanceof TypeMem mem
+            ? mem._alias==1
+                ? new BulkMemPhiNode(label,inputs)
+                : new MemPhiNode(label,mem._alias,inputs)
+            : new PhiNode(label, inputs);
     }
     // Used by ParmNode
-    public PhiNode(PhiNode phi, String label, Type minType) { super(phi); _label = label; _type = _minType = minType; }
+    public PhiNode(PhiNode phi, String label) { super(phi); _label = label; }
     // Used by instruction Selection
-    public PhiNode(PhiNode phi) { this(phi,phi._label,phi._minType );  }
+    public PhiNode(PhiNode phi) { this(phi,phi._label);  }
     // Used by the infinite-loop exit breaker
     public PhiNode(RegionNode r, Node sample) {
         super(new Node[]{r});
         _label = "";
-        _minType = sample._type;
+        _type = sample._type;
         while( nIns() < r.nIns() )
             addDef(sample);
     }
+    @Override public Tag serialTag() { return Tag.Phi; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed1(nIns());
+        baos.packed2(_label==null ? 0 : strs.get(_label));
+    }
+    static Node make( BAOS bais, String[] strs, Type[] types)  {
+        Node[] ins = new Node[bais.packed1()];
+        return new PhiNode(strs[bais.packed2()], ins);
+    }
 
     @Override public String label() { return "Phi_"+MemOpNode.mlabel(_label); }
 
@@ -55,7 +67,7 @@ public class PhiNode extends Node {
     }
 
     public CFGNode region() { return (CFGNode)in(0); }
-    @Override public boolean isMem() { return _minType instanceof TypeMem; }
+    @Override public boolean isMem() { return _type instanceof TypeMem; }
     @Override public boolean isPinned() { return true; }
     boolean isRPC() { return false; }
 
@@ -65,14 +77,10 @@ public class PhiNode extends Node {
             return region()._type==Type.XCONTROL || region()._type==Type.TOP ? (_type instanceof TypeMem ? TypeMem.TOP : Type.TOP) : _type;
         // During parsing Phis have to be computed type pessimistically.
         if( r.inProgress() )
-            // Loop-Phis must lift to the declared type, because that is how
-            // the Parser keeps precise types until the loop finishes parsing.
-            // Similar, ParmNodes use precise minType until all calls are
-            // linked (post opto).
-            return r instanceof LoopNode || (this instanceof ParmNode) ? _minType : Type.BOTTOM;
+            return declaredType();
         // Set type to local top of the starting type
         Type t = Type.TOP;
-        for (int i = 1; i < nIns(); i++) {
+        for( int i = 1; i < nIns(); i++ ) {
             // If the region's control input is live, add this as a dependency
             // to the control because we can be peeped should it become dead.
             Type ctrl = addDep(r.in(i))._type;
@@ -82,7 +90,8 @@ public class PhiNode extends Node {
                 t = t.meet(in(i)._type);
             }
         }
-        Type newt = t.join( _minType );
+        Type declared = declaredType();
+        Type newt = constrain(t);
 
         // phi loop widening part
         if( region() instanceof LoopNode && // Only around loops
@@ -90,60 +99,45 @@ public class PhiNode extends Node {
             // Types changed and are falling (the optimistic case, expected to fall forever)
             newi != _type ) {
             if( !newi.isConstant() && (!(_type instanceof TypeInteger oldi) || newi._widen <= oldi._widen) )
-                return newi.same_but_slightly_wider_than(_minType);
+                return newi.same_but_slightly_wider_than(
+                    declared instanceof TypeInteger ? declared : TypeInteger.BOT);
         }
 
         return newt;
     }
 
+    // Ordinary Phis have no parser-supplied type constraint.
+    protected Type declaredType() { return Type.BOTTOM; }
+    protected Type constrain(Type t) { return t; }
+
     @Override
     public Node idealize() {
         if( !(region() instanceof RegionNode r ) )
             return in(1);       // Input has collapse to e.g. starting control.
-        // Can upgrade minType even while in-progress
-        if( _minType instanceof TypeMemPtr tmp && _minType.isFRef() ) {
-            TypeMemPtr tmp2 = (TypeMemPtr) Parser.TYPES.get(tmp._obj._name);
-            if( tmp2!=null && tmp2 != _minType ) {
-                _minType = tmp2;
-                return this;
-            }
-        }
-        if( r.inProgress() || r.nIns()<=1 )
+        if( r.inProgress() || r.nIns()<=1 || nOuts()==0 )
             return null;        // Input is in-progress
 
         // If we have only a single unique input, become it.
         Node live = singleUniqueInput();
-        if( live != null ) {
-            if( live._type.isa(_type) )
-                return live;
-            // Keep the Phi upcast
-            return new CastNode(_type,null,live);
-        }
+        if( live != null )
+            return live;
 
         // No bother if region is going to fold dead paths soon
         for( int i=1; i<nIns(); i++ )
             if( r.in(i)._type == Type.XCONTROL )
                 return null;
 
-        // Simple Phi-after-MemMerge to a known alias can bypass.  Happens when inlining.
-        if( _type instanceof TypeMem tmem && tmem._alias!=1 ) {
-            for( int i=1; i<nIns(); i++ )
-                if( in(i) instanceof MemMergeNode mem ) {
-                    setDef(i,mem.alias(tmem._alias));
-                    return this;
-                }
-        }
-
         // Generic "pull down op"
         Node progress;
         if( same_op() && (progress = drop_same_op()) != null )
             return progress;
 
-        // If merging Phi(N, cast(N)) - we are losing the cast JOIN effects, so just remove.
+        // If merging Phi(ZERO, guardNZ(N)) - we are losing the cast JOIN effects, so just remove.
         if( nIns()==3 ) {
-            if( in(1) instanceof CastNode cast && addDep(cast.in(1))==in(2) ) return in(2);
-            if( in(2) instanceof CastNode cast && addDep(cast.in(1))==in(1) ) return in(1);
+            if( in(1) instanceof GuardNode cast && cast._nonZero && in(2)._type.makeZero()==in(2)._type && cast.in(1)!=this )  return cast.in(1);
+            if( in(2) instanceof GuardNode cast && cast._nonZero && in(1)._type.makeZero()==in(1)._type && cast.in(1)!=this )  return cast.in(1);
         }
+
         // If merging a null-checked null and the checked value, just use the value.
         // if( val ) ..; phi(Region,False=0/null,True=val);
         // then replace with plain val.
@@ -153,12 +147,12 @@ public class PhiNode extends Node {
             if( in(2)._type == in(2)._type.makeZero() ) nullx = 2;
             if( nullx != -1 ) {
                 Node val = in(3-nullx);
-                if( val instanceof CastNode cast )
+                if( val instanceof GuardNode cast && cast._nonZero )
                     val = cast.in(1);
                 Node ridom = r.idom(this);
                 if( ridom instanceof IfNode iff && addDep(iff.pred())==val ) {
                     // Must walk the idom on the null side to make sure we hit False.
-                    CFGNode idom = (CFGNode)r.in(nullx);
+                    CFGNode idom = r.cfg(nullx);
                     while( idom != null && idom.nIns() > 0 && idom.in(0) != iff ) idom = idom.idom();
                     if( idom instanceof CProjNode proj && proj._idx==1 )
                         return val;
@@ -172,17 +166,37 @@ public class PhiNode extends Node {
     // Same op on all Phi paths; all ops have only the Phi as a use.
     // None have a control input.
     private boolean same_op() {
+        Node busy=null;
         for( int i=1; i<nIns(); i++ ) {
             Node op = in(i);
+            if( op.nOuts()==0 )
+                { op.kill(); return false; }
             if( in(1).getClass() != op.getClass() || op.in(0)!=null || in(1).nIns() != op.nIns() )
                 return false;      // Wrong class or CFG bound or mismatched inputs
-            if( in(1) instanceof MemOpNode mem && mem._alias != ((MemOpNode)op)._alias )
-                return false;
-            if( op.nOuts() > 1 ) { // Too many users, but addDep in case lose users
-                for( Node out : op._outputs )
-                    if( out!=null && out!=this )
-                        addDep(out);
+            if( in(1) instanceof MemOpNode mem ) {
+                // Mismatched aliases
+                if( mem._alias != ((MemOpNode)op)._alias ) return false;
+                // Load is clobbered somewhere, and can not be pulled forward past the Phi?
+                if( mem instanceof LoadNode )
+                    for( Node use : op.outs() )
+                        if( use instanceof StoreNode )
+                            return false;
+            }
+            if( in(1) instanceof EscapeNode )
                 return false;
+            if( in(1) instanceof MemMergeNode )
+                return false;   // Have to keep aliases straight
+            if( op.nOuts() > 1 ) {
+                if( busy==null ) busy = op;
+                else {         // Too many users, but addDep in case lose users
+                    for( Node out : op._outputs )
+                        if( out!=null && out!=this )
+                            addDep(out);
+                    for( Node out : busy._outputs )
+                        if( out!=null && out!=this )
+                            addDep(out);
+                    return false;
+                }
             }
             for( int j=1; j<in(1).nIns(); j++ )
                 if( op.in(j) instanceof ScopeNode || (op.in(j)==null ^ in(1).in(j)==null) )
@@ -205,7 +219,7 @@ public class PhiNode extends Node {
                 if( in(i).in(j) != x )
                     { needsPhi=true; break; }
             if( needsPhi ) {
-                x = new PhiNode(_label,op.in(j)._type.glb(false));
+                x = make(_label,op.in(j)._type.glb(false));
                 x.addDef(region());
                 for( int i=1; i<nIns(); i++ )
                     x.addDef(in(i).in(j));
@@ -253,39 +267,28 @@ public class PhiNode extends Node {
     }
 
     // Never equal if inProgress.
-    // Also, joins
     @Override public boolean eq( Node n ) {
-        if( inProgress() ) return false;
-        Type min = ((PhiNode)n)._minType;
-        if( _minType==min ) return true;
-        Type mt = min.meet(_minType);
-        if( min!=mt && _minType!=mt ) return false;
-        //// Theory says these 2 Phis CAN be merged/GVNd, but I need to pick the
-        //// most general minType.
-        //_minType = ((PhiNode)n)._minType = mt;
-        //return true;
-        return false;
+        return !inProgress() && super.eq(n);
     }
 
     @Override
     public Parser.ParseException err() {
-        if( _type != Type.BOTTOM ) return null;
+        if( _type != Type.BOTTOM && _type != TypeScalar.BOT ) return null;
 
-        // BOTTOM means we mixed e.g. int and ptr
+        // Scalar BOT means we mixed scalar families, e.g. int and ptr.
+        // Global BOTTOM retains the same role for non-scalar families.
         for( int i=1; i<nIns(); i++ )
             // Already an error, but better error messages come from elsewhere
-            if( in(i)._type == Type.BOTTOM )
+            if( in(i)._type == Type.BOTTOM || in(i)._type == TypeScalar.BOT )
                 return null;
 
-        // Gather a minimal set of types that "cover" all the rest
-        boolean ti=false, tf=false, tp=false, tn=false;
-        for( int i=1; i<nIns(); i++ ) {
-            Type t = in(i)._type;
-            ti |= t instanceof TypeInteger x;
-            tf |= t instanceof TypeFloat   x;
-            tp |= t instanceof TypeMemPtr  x;
-            tn |= t==Type.NIL;
-        }
-        return ReturnNode.mixerr(ti,tf,tp,tn, ((RegionNode)region())._loc);
+        SB sb = new SB().p("No common type amongst ");
+        for( int i=1; i<nIns(); i++ )
+            sb.p(in(i)._type.toString()).p(" and ");
+        return Parser.error(sb.unchar(5).toString(),null);
+    }
+
+    @Override public void gather( HashMap<String,Integer> strs ) {
+        Serialize.gather(strs,_label);
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/Proj.java b/src/main/java/com/seaofnodes/simple/node/Proj.java
new file mode 100644
index 00000000..c8b9378f
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/Proj.java
@@ -0,0 +1,2 @@
+package com.seaofnodes.simple.node;
+public interface Proj { int idx(); }
diff --git a/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/src/main/java/com/seaofnodes/simple/node/ProjNode.java
index 586527c8..97b9ed45 100644
--- a/src/main/java/com/seaofnodes/simple/node/ProjNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ProjNode.java
@@ -1,12 +1,15 @@
 package com.seaofnodes.simple.node;
 
+import com.seaofnodes.simple.codegen.Serialize;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeMem;
 import com.seaofnodes.simple.type.TypeTuple;
-
+import com.seaofnodes.simple.util.BAOS;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
-public class ProjNode extends Node {
+public class ProjNode extends Node implements Proj {
 
     // Which slice of the incoming multipart value
     public final int _idx;
@@ -20,6 +23,14 @@ public class ProjNode extends Node {
         _label = label;
     }
     public ProjNode(ProjNode p) { super(p); _idx = p._idx; _label = p._label; }
+    @Override public Tag serialTag() { return Tag.Proj; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        baos.packed1(_idx);
+        baos.packed2(_label==null ? 0 : strs.get(_label));
+    }
+    static Node make( BAOS bais, String[] strs )  {
+        return new ProjNode(null, bais.packed1(), strs[bais.packed2()] );
+    }
 
     @Override public String label() { return _label; }
 
@@ -51,4 +62,10 @@ public class ProjNode extends Node {
 
     @Override
     int hash() { return _idx; }
+
+    @Override public int idx() { return _idx; }
+
+    @Override public void gather( HashMap<String,Integer> strs ) {
+        Serialize.gather(strs,_label);
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/PtrToIntMach.java b/src/main/java/com/seaofnodes/simple/node/PtrToIntMach.java
new file mode 100644
index 00000000..9a9b94fd
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/PtrToIntMach.java
@@ -0,0 +1,17 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.util.SB;
+
+/** Zero-code machine form of {@link PtrToIntNode}. */
+public class PtrToIntMach extends PtrToIntNode implements MachNode {
+    public PtrToIntMach(PtrToIntNode ptr) { super(ptr); }
+    @Override public String op() { return label(); }
+    @Override public RegMask regmap(int i) { assert i==1; return RegMask.FULL; }
+    @Override public RegMask outregmap() { return RegMask.FULL; }
+    @Override public int twoAddress() { return 1; }
+    @Override public void encoding(Encoding enc) { }
+    @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(in(1))); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/PtrToIntNode.java b/src/main/java/com/seaofnodes/simple/node/PtrToIntNode.java
new file mode 100644
index 00000000..d781620b
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/PtrToIntNode.java
@@ -0,0 +1,40 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeMemPtr;
+
+import java.util.BitSet;
+
+/**
+ * Reinterpret a non-null managed pointer as its raw integer address.
+ *
+ * This node changes representation families but emits no code.  In particular,
+ * it is not a {@link CheckCastNode}: no control-dependent proof can turn a
+ * pointer into an integer.  Array-to-C-pointer conversion adds the array body
+ * offset separately.
+ */
+public class PtrToIntNode extends Node {
+    public PtrToIntNode(Node ptr) { super(null,ptr); }
+    public PtrToIntNode(PtrToIntNode ptr) { super(ptr); }
+
+    @Override public Tag serialTag() { return Tag.PtrToInt; }
+    @Override public String glabel() { return "(i64*)"; }
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        return in(1)._print0(sb.append("(i64*)"),visited);
+    }
+
+    @Override public Type compute() {
+        return in(1)._type.isHigh() ? TypeInteger.TOP : TypeInteger.BOT;
+    }
+
+    @Override public Node idealize() { return null; }
+
+    @Override public Parser.ParseException err() {
+        Type t = in(1)._type;
+        if( t instanceof TypeMemPtr ptr )
+            return ptr.notNull() ? null : Parser.error("Cannot convert a nullable pointer to an integer",null);
+        return Parser.error("Cannot convert "+t.str()+" to an integer pointer",null);
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java b/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
index d8fe6286..c36be85a 100644
--- a/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
@@ -10,7 +10,7 @@ import java.util.BitSet;
 public class ReadOnlyNode extends Node {
     public ReadOnlyNode( Node n ) { super(null,n); }
     public ReadOnlyNode( ReadOnlyNode n ) { super(n); }
-    @Override public String label() { return "ReadOnly"; }
+    @Override public Tag serialTag() { return Tag.ReadOnly; }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
diff --git a/src/main/java/com/seaofnodes/simple/node/RegionNode.java b/src/main/java/com/seaofnodes/simple/node/RegionNode.java
index b115a260..dc48f6f2 100644
--- a/src/main/java/com/seaofnodes/simple/node/RegionNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/RegionNode.java
@@ -1,9 +1,9 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.*;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.util.BAOS;
 import java.util.*;
 
 public class RegionNode extends CFGNode {
@@ -13,9 +13,9 @@ public class RegionNode extends CFGNode {
     public RegionNode(Parser.Lexer loc, Node...   nodes) { super(nodes); _loc = loc; }
     public RegionNode(RegionNode r, Parser.Lexer loc) { super(r); _loc = loc; }
     public RegionNode(RegionNode r) { super(r); if( r!=null ) _loc = r._loc; }
-
-    @Override
-    public String label() { return "Region"; }
+    @Override public Tag serialTag() { return Tag.Region; }
+    public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { baos.packed1(nIns()); }
+    static Node make( BAOS bais ) { return new RegionNode(null,new Node[bais.packed1()]); }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
@@ -75,7 +75,7 @@ public class RegionNode extends CFGNode {
                     // Fold Region
                     for( int j=1; j<region.nIns(); j++ )
                         addDef(region.in(j));
-                    setDef(i,Parser.XCTRL);
+                    setDef(i,CodeGen.CODE.XCTRL);
                     return this;
                 }
         }
@@ -111,7 +111,7 @@ public class RegionNode extends CFGNode {
                     CodeGen.CODE.addAll(phi.delDef(path)._outputs);
                 }
         }
-        return isDead() ? Parser.XCTRL : delDef(path);
+        return isDead() ? CodeGen.CODE.XCTRL : delDef(path);
     }
 
     private int findDeadInput(int startIdx) {
diff --git a/src/main/java/com/seaofnodes/simple/node/ReturnNode.java b/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
index 0aa70214..b60d27d7 100644
--- a/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
@@ -27,6 +27,7 @@ public class ReturnNode extends CFGNode {
         _fun = fun;
     }
     public ReturnNode( ReturnNode ret, FunNode fun ) { super(ret);  _fun = fun;  }
+    @Override public Tag serialTag() { return Tag.Return; }
 
     public Node ctrl() { return in(0); }
     public Node mem () { return in(1); }
@@ -35,9 +36,6 @@ public class ReturnNode extends CFGNode {
     @Override public FunNode fun() { return _fun; }
 
     @Override
-    public String label() { return "Return"; }
-
-    @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("return ");
         if( expr()==null ) sb.append("----");
@@ -50,12 +48,10 @@ public class ReturnNode extends CFGNode {
 
     @Override
     public Type compute() {
-        if( inProgress () ) return TypeTuple.RET; // In progress
         return TypeTuple.make(ctrl()._type,mem()._type,expr()._type);
     }
 
     @Override public Node idealize() {
-        if( inProgress () ) return null;
         if( _fun.isDead() ) return null;
 
         // Upgrade signature based on return type
@@ -64,87 +60,44 @@ public class ReturnNode extends CFGNode {
         if( ret != fcn.ret() && ret.isa(fcn.ret()) )
             _fun.setSig(fcn.makeFrom(ret));
 
-        // If dead (cannot be reached; infinite loop), kill the exit values
-        if( ctrl()._type==Type.XCONTROL &&
-            !(mem() instanceof ConstantNode && expr() instanceof ConstantNode) ) {
-            Node top = new ConstantNode(Type.TOP).peephole();
-            setDef(1,top);
-            setDef(2,top);
-            return this;
-        }
-
         return null;
     }
 
-    public boolean inProgress() {
-        return ctrl().getClass() == RegionNode.class && ((RegionNode)ctrl()).inProgress();
-    }
-
-    // Gather parse-time return types for error reporting
-    private Type mt = Type.TOP;
-    private boolean ti=false, tf=false, tp=false, tn=false;
-
-    // Add a return exit to the current parsing function
-    void addReturn( Node ctrl, Node rmem, Node expr ) {
-        assert inProgress();
-
-        // Gather parse-time return types for error reporting
-        Type t = expr._type;
-        mt = mt.meet(t);
-        ti |= t instanceof TypeInteger x;
-        tf |= t instanceof TypeFloat   x;
-        tp |= t instanceof TypeMemPtr  x;
-        tn |= t==Type.NIL;
-
-        // Merge path into the One True Return
-        RegionNode r = (RegionNode)ctrl();
-        // Assert that the Phis are in particular outputs; not reordered or shuffled
-        PhiNode mem = (PhiNode)r.out(0); assert mem._minType == TypeMem.BOT;
-        PhiNode rez = (PhiNode)r.out(1); assert rez._minType == Type.BOTTOM;
-        // Pop "inProgress" null off
-        r  ._inputs.pop();
-        mem._inputs.pop();
-        rez._inputs.pop();
-        // Add new return point
-        r  .addDef(ctrl);
-        mem.addDef(rmem);
-        rez.addDef(expr);
-        // Back to being inProgress
-        r  .addDef(null);
-        mem.addDef(null);
-        rez.addDef(null);
-    }
-
     @Override public Parser.ParseException err() {
-        if( ctrl()._type != Type.CONTROL ) return null; // Exit path is dead
-        return expr()._type==Type.BOTTOM || expr()._type==Type.TOP ? mixerr(ti,tf,tp,tn,_fun._loc) : null;
+        if( ctrl()._type == Type.CONTROL &&
+            expr()._type == Type.TOP )
+            return Parser.error("No defined return type",null);
+        // With no user constructor, <init> doubles as the public no-arg
+        // constructor.  Required fields remain TOP in its private memory: a
+        // typed parser poison which deliberately emitted no Store or code.
+        if( ctrl()._type == Type.CONTROL && _fun.isInstance() ) {
+            TypeStruct self = ((TypeMemPtr)_fun.sig().arg(0))._obj;
+            if( !CodeGen.hasUserConstructor(self) && expr()._type instanceof TypeMem mem )
+                for( Field fld : self._fields ) {
+                    if( !(fld._t instanceof TypeNil tn && tn.notNull()) ) continue;
+                    Type actual = mem._alias==1 && mem._t instanceof TypeStruct ts
+                        ? ts.field(fld._fname)._t
+                        : mem._alias==fld._alias ? mem._t : Type.TOP;
+                    if( actual==Type.TOP || actual instanceof TypeNil atn && atn.nullable() )
+                        return Parser.error("'"+self._name+"' is not fully initialized, field '"+
+                                            fld._fname+"' is only partially set in the constructor",null);
+                }
+        }
+        return null;
     }
 
-    static Parser.ParseException mixerr( boolean ti, boolean tf, boolean tp, boolean tn, Parser.Lexer loc ) {
-        if( !ti && !tf && !tp && !tn )
-            // Hit when the function never returns.  e.g. `f = { -> return f() };`
-            return Parser.error("No defined return type", loc);
-        // Rather ugly way to print conflicting return types
-        int cnt = (ti?1:0) + (tf?1:0) + (tp||tn?1:0);
-        if( cnt==1 ) return null; // Uniform return type, something else errored and will report
-        SB sb = new SB().p("No common type amongst ");
-        if( ti ) sb.p("int and ");
-        if( tf ) sb.p("f64 and ");
-        if( tp || tn ) sb.p("reference and ");
-        return Parser.error(sb.unchar(5).toString(),loc);
+    @Override public boolean eq( Node n ) {
+        return !_fun.isDead() && !((ReturnNode)n)._fun.isDead();
     }
 
-
     // ------------
     // MachNode specifics, shared across all CPUs
     public String op() {
-        return _fun._frameAdjust > 0 ? "addi" : "ret";
+        return _fun._frameAdjust > 0 ? "epilog" : "ret  ";
     }
     // Correct Nodes outside the normal edges
     public void postSelect(CodeGen code) {
-        FunNode fun = (FunNode)rpc().in(0);
-        _fun = fun;
-        fun.setRet(this);
+        _fun.setRet(this);
     }
     public RegMask regmap(int i) {
         return i==2
@@ -156,13 +109,14 @@ public class ReturnNode extends CFGNode {
     public void asm(CodeGen code, SB sb) {
         int frameAdjust = fun()._frameAdjust;
         if( frameAdjust>0 )
-            sb.p("rsp += #").p(frameAdjust).p("\nret");
+            sb.p("\n").p("rsp += #").p(frameAdjust).p("\nret    ");
         // Post code-gen, just print the "ret"
-        if( code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() )
+        if( code._phase.ordinal() < CodeGen.Phase.RegAlloc.ordinal() ||
+            (code._phase.ordinal() == CodeGen.Phase.RegAlloc.ordinal() && !code._regAlloc.done()) )
             // Prints return reg (either RAX or XMM0), RPC and then the
             // callee-save registers.
             for( int i=2; i<nIns(); i++ )
-                sb.p(code.reg(in(i),fun())).p("  ");
+                sb.p(code.reg(in(i))).p("  ");
         // If we did not get the expected rpc, print which one we got
         else if( code._regAlloc.regnum(rpc()) != code._mach.rpc() )
             sb.p("[").p(code.reg(rpc())).p("]");
diff --git a/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java b/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
index 7936086d..322a6bc0 100644
--- a/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
+++ b/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
@@ -7,8 +7,7 @@ import java.util.BitSet;
 
 public class RoundF32Node extends Node {
     public RoundF32Node(Node lhs) { super(null, lhs); }
-
-    @Override public String label() { return "RoundF32"; }
+    @Override public Tag serialTag() { return Tag.RoundF32; }
 
     @Override public String glabel() { return "(f32)"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/SarNode.java b/src/main/java/com/seaofnodes/simple/node/SarNode.java
index ee15fa65..8ad5988d 100644
--- a/src/main/java/com/seaofnodes/simple/node/SarNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SarNode.java
@@ -5,9 +5,9 @@ import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
 public class SarNode extends ArithNode {
-    public SarNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs); }
+    public SarNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs, (byte)1); }
+    @Override public Tag serialTag() { return Tag.Sar; }
 
-    @Override public String label() { return "Sar"; }
     @Override public String op() { return ">>"; }
     @Override public String glabel() { return "&gt;&gt;"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/ScopeNode.java b/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
index 36746a81..58508a1c 100644
--- a/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
@@ -3,11 +3,11 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.Var;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.ParseAll;
+import com.seaofnodes.simple.codegen.CompUnit;
 import com.seaofnodes.simple.type.*;
 import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.AryInt;
 import com.seaofnodes.simple.util.Utils;
-
 import java.util.*;
 
 /**
@@ -31,21 +31,23 @@ public class ScopeNode extends MemMergeNode {
     // Lexical scope is typed:
     public static class Kind {
         // Basic block scoping
-        public static class Block  extends Kind { }
+        public static class Block extends Kind { }
+        // Constructor/initializer block for an allocated struct.
+        public static class Constructor extends Block {
+            public Constructor(TypeStruct self) { _self = self; }
+            public final TypeStruct _self;
+        }
         // Function scope
-        public static class Func   extends Kind { }
-        // Struct definition, mapping types  to fields
-        public static class Define extends Kind { public Define(TypeMemPtr tmp) { _tmp=tmp; } public final TypeMemPtr _tmp; }
-        // Struct allocation, mapping values to fields
-        public static class Alloc  extends Kind { public Alloc (TypeMemPtr tmp) { _tmp=tmp; } public final TypeMemPtr _tmp; }
+        public static class Func  extends Kind { public Func(String name) { _name=name;} public final String _name; }
 
         public int _lexSize;     // Number of Vars in this scope
     }
     public final Ary<Kind> _kinds;
     // Lexical scope nesting depth
     public int depth() { return _kinds._len; }
+    public Kind klast() { return _kinds.last(); }
 
-    // Extra guards; tested predicates and casted results
+    // Extra guards; tested predicates and cast results
     private final Ary<Node> _guards;
 
     // A new ScopeNode
@@ -64,8 +66,8 @@ public class ScopeNode extends MemMergeNode {
         int j=1;
         for( int i=0; i<nIns(); i++ ) {
             if( j < depth() && i == _kinds.at(j)._lexSize ) { sb.append("| "); j++; }
-            Var v = _vars.at(i);
-            sb.append(v.type());
+            Var v = var(i);
+            sb.append(v._type());
             sb.append(" ");
             if( v._final ) sb.append("!");
             sb.append(v._name);
@@ -85,7 +87,7 @@ public class ScopeNode extends MemMergeNode {
 
 
     public Node ctrl() { return in(0); }
-    public MemMergeNode mem() { return (MemMergeNode)in(1); }
+    public Node mem() { return in(1); }
     public Var var(int i) { return _vars.at(i); }
 
     /**
@@ -108,7 +110,11 @@ public class ScopeNode extends MemMergeNode {
 
     // Pop a lexical scope
     public void pop() {
-        promote();              // Promote forward references to the next outer scope
+        promote(null);    // Promote forward references to the next outer scope
+        _pop();
+    }
+    // Pop a scope, no promote FRefs
+    public void _pop() {
         int n = _kinds.pop()._lexSize;
         popUntil(n);            // Pop off inputs going out of scope
         _vars.setLen(n);        // Pop off variables going out of scope
@@ -117,59 +123,85 @@ public class ScopeNode extends MemMergeNode {
 
     // Look for forward references in the last lexical scope and promote to the
     // next outer lexical scope.  At the last scope declare them an error.
-    public void promote() {
-        Kind kind = _kinds.last();
+    public void promote(CodeGen code) {
+        Kind kind = klast();
         int n = kind._lexSize;
         for( int i=n; i<nIns(); i++ ) {
             Var v = var(i);
+            Node vn = in(i);
             if( !v.isFRef() ) continue;
-            if( depth()==1 )
-                throw Parser.error("Undefined name '" + v._name + "'",v._loc);
-            _vars  .swap(n,i);
-            _inputs.swap(n,i);
-            v._idx = n;
+            // Shuffle vars and inputs to move the forward reference to
+            // *before* the start of the using scope ("as if" it was not
+            // actually a forward reference).
+            for( int j=n; j<=i; j++ ) {
+                Var  vtmp = var(j);
+                Node ntmp = in (j);
+                v._idx = j;
+                _vars  .set(j,v );
+                _inputs.set(j,vn);
+                v  = vtmp;
+                vn = ntmp;
+            }
             kind._lexSize = ++n;
         }
     }
 
 
-    public boolean inConstructor() { return _kinds.last() instanceof Kind.Define; }
-    public boolean inAllocation () { return _kinds.last() instanceof Kind.Alloc ; }
-    public boolean inFunction   () { return _kinds.last() instanceof Kind.Func  ; }
-
-    public Kind kind( Var v ) {
+    public boolean inFunction   () { return klast() instanceof Kind.Func; }
+    // Is any enclosing scope a constructor?
+    public boolean inConstructor() { return constructorSelf() != null; }
+    // Nearest constructor self type, if any.
+    public TypeStruct constructorSelf() {
         for( int i=depth()-1; i>=0; i-- )
-            if( v._idx >= _kinds.at(i)._lexSize )
-                return _kinds.at(i);
-        throw Utils.TODO();
+            if( _kinds.at(i) instanceof Kind.Constructor ctor )
+                return ctor._self;
+            else if( _kinds.at(i) instanceof Kind.Func func && FunNode.isInstance(func._name) )
+                return ((TypeMemPtr)var(_kinds.at(i)._lexSize).type())._obj;
+        return null;
     }
 
-    // Return the kind for the defining scope, or a function scope if found
-    // first.  Block scopes means the variable can be r/w directly in the
-    // scope, Function scopes require final constants (no capture), and
-    // Constructor scopes mean an instance variable reference.
-
-    // Walk up-lexical scope looking for defining lexical Kind.
-    // - Skip any amount of nested block scopes
-    // - Walking out of a function requires v be a final constant (for now) -
-    // and we can stop walking.
+    // Find nearest enclosing function scope
+    public int enclosingFunction() {
+        for( int i=depth()-1; i>=0; i-- )
+            if( _kinds.at(i) instanceof Kind.Func func && !FunNode.isInstance(func._name) )
+                return i;
+        throw Utils.TODO("Should not reach here");
+    }
 
-    // - Walking out of a method and (skipping Blocks) into the matching struct
-    // is OK, and this is a instance var load.
+    // Find nearest enclosing function or declaration scope
+    public int enclosingFuncOrDecl() {
+        for( int i=depth()-1; i>=0; i-- )
+            if( _kinds.at(i) instanceof Kind.Func func )
+                return i;
+        throw Utils.TODO("Should not reach here");
+    }
 
-    // - Walking out of a method and into the wrong struct is an error;
-    // including nested structs containing (no nested classes yet)
+    // Which lexical scope contains this Var?
+    public int kindx( Var v ) {
+        for( int i=depth()-1; i>=0; i-- )
+            if( v._idx >= _kinds.at(i)._lexSize )
+                return i;
+        return -1;
+    }
 
-    // Returns error, forward-ref, ok containing struct, ok containing function/block.
+    // Which lexical scope contains this Var?
+    public Kind kind( Var v ) {
+        int kx = kindx(v);
+        return kx == -1 ? null : _kinds.at(kx);
+    }
 
-    public String outOfFunction( Var v ) {
-        //if( v==null ) return null; // Prolly forward reference
-        //int i; for( i=_lexSize._len-1; i>=0 && v._idx<_lexSize.at(i); i-- )
-        //    if( _kinds.at(i)=="{->}" ) return "{->}";
-        //return _kinds.at(i);
-        throw Utils.TODO();
+    public int kindFcnx( Var v ) {
+        for( int i=depth()-1; i>=0; i-- )
+            if( v._idx >= _kinds.at(i)._lexSize && _kinds.at(i) instanceof Kind.Func )
+                return i;
+        throw Utils.TODO("Should not reach here");
     }
 
+    // Which function scope contains this Var?
+    public Kind kindFcn( Var v ) {
+        int kx = kindFcnx(v);
+        return kx == -1 ? null : _kinds.at(kx);
+    }
 
     // Find name in reverse, return an index into _vars or -1.  Linear scan
     // instead of hashtable, but probably doesn't matter until the scan
@@ -185,9 +217,9 @@ public class ScopeNode extends MemMergeNode {
      * Create a new variable name in the current scope
      */
     public boolean define( String name, Type declaredType, boolean xfinal, Node init, Parser.Lexer loc ) {
-        assert _kinds.isEmpty() || name.charAt(0)!='$' ; // Later scopes do not define memory
+        assert _kinds.isEmpty() || name!=MEM0 ; // Later scopes do not define memory
         if( depth() > 0 )
-            for( int i=_vars.size()-1; i>=_kinds.last()._lexSize; i-- ) {
+            for( int i=_vars.size()-1; i>=klast()._lexSize; i-- ) {
                 Var n = var(i);
                 if( n._name.equals(name) ) {
                     if( !n.isFRef() ) return false;       // Double define
@@ -195,21 +227,47 @@ public class ScopeNode extends MemMergeNode {
                     if( !xfinal || !declaredType.isConstant() ) throw fref.err();  // Must be a final constant
                     n.defFRef(declaredType,xfinal,loc);   // Declare full correct type, final, source location
                     setDef(n._idx,fref.addDef(init));     // Set FRef to defined; tell parser also
+                    return true;
                 }
             }
-        Var v = new Var(nIns(),name,declaredType,xfinal,loc,init==Parser.XCTRL);
+        Var v = new Var(nIns(),name,declaredType,xfinal,loc,init==CodeGen.CODE.XCTRL);
         _vars.add(v);
         // Creating a forward reference
-        if( init==Parser.XCTRL )
-            init = new FRefNode(v).init();
+        if( init==CodeGen.CODE.XCTRL )
+            //init = new FRefNode(v).init();
+            throw Utils.TODO();
         addDef(init);
         return true;
     }
 
-    // Read from memory
-    public Node mem( int alias ) { return mem()._mem(alias,null); }
-    // Write to memory
-    public void mem( int alias, Node st ) { mem()._mem(alias,st); }
+    // Normal lookup was tried and failed.  Insert a forward ref outside any
+    // enclosing Kind.Func scope, skipping any nested Blocks or Allocs and
+    // return the Var.  May insert at the outermost scope, which means this
+    // must be defined externally, or it's an error.
+
+    public Var defineFRef( String id, Type t, boolean xfinal, Parser.Lexer loc ) {
+        // Kind/Lexical scope index
+        int kidx = enclosingFunction();
+        int idx = _kinds.at(kidx)._lexSize;
+        Var var = new Var(idx,id,t,xfinal,loc,true);
+        FRefNode fref = new FRefNode(id,loc).init();
+        fref._type = fref._con = t;
+        // Insert in the lex scope just prior to kidx
+        insert(var,fref,kidx);
+        return var;
+    }
+
+
+    // Parser state carries one complete, conservative memory value.  Precise
+    // alias partitions belong to the graph and are introduced by peepholes.
+    public Node mem( int alias ) {
+        assert alias == 1;
+        return in(update(var(1),null));
+    }
+    public void mem( int alias, Node st ) {
+        assert alias == 1;
+        update(var(1),st);
+    }
 
 
     /**
@@ -247,7 +305,7 @@ public class ScopeNode extends MemMergeNode {
                 // Set real Phi in the loop head
                 // The phi takes its one input (no backedge yet) from a recursive
                 // lookup, which might have insert a Phi in every loop nest.
-                : loop.setDef(v._idx,new PhiNode(v._name, v.type(), loop.ctrl(), loop.in(loop.update(v,null)._idx),null).peephole());
+                : loop.setDef(v._idx,PhiNode.make(v._name, v.type(), loop.ctrl(), loop.in(loop.update(v,null)._idx),null).init());
             setDef(v._idx,old);
         }
         //assert !v._final || st==null;
@@ -285,15 +343,9 @@ public class ScopeNode extends MemMergeNode {
                 n.keep();
         dup.addDef(ctrl());     // Control input is just copied
 
-        // Memory input is a shallow copy
-        MemMergeNode memdup = new MemMergeNode(true), mem = mem();
-        memdup.addDef(null);
-        memdup.addDef(loop ? this : mem.in(1));
-        for( int i=2; i<mem.nIns(); i++ )
-            // For lazy phis on loops we use a sentinel
-            // that will trigger phi creation on update
-            memdup.addDef(loop ? this : mem.in(i));
-        dup.addDef(memdup);
+        // Memory is one ordinary parser-state value.  At loop heads the
+        // Scope sentinel triggers the same lazy-Phi machinery as variables.
+        dup.addDef(loop ? this : mem());
 
         // Copy of other inputs
         for( int i=2; i<nIns(); i++ )
@@ -313,39 +365,49 @@ public class ScopeNode extends MemMergeNode {
      */
     public RegionNode mergeScopes(ScopeNode that, Parser.Lexer loc) {
         RegionNode r = ctrl(new RegionNode(loc,null,ctrl(), that.ctrl()).keep());
-        mem()._merge(that.mem(),r);
-        this ._merge(that      ,r);
+        this._merge(that,r);
         that.kill();            // Kill merged scope
         CodeGen.CODE.add(r);
         return r.unkeep();
     }
 
-    private void _merge(ScopeNode that, RegionNode r) {
-        for( int i = 2; i < nIns(); i++)
+    public void _merge(ScopeNode that, RegionNode r) {
+        _merge(that,r,nIns());
+    }
+    public void _merge(ScopeNode that, RegionNode r, int max ) {
+        for( int i = 1; i < max; i++)
             if( in(i) != that.in(i) ) { // No need for redundant Phis
                 // If we are in lazy phi mode we need to a lookup
                 // by name as it will trigger a phi creation
                 Var v = var(i);
                 Node lhs = this.in(this.update(v,null));
                 Node rhs = that.in(that.update(v,null));
-                setDef(i, new PhiNode(v._name, v.type(), r, lhs, rhs).peephole());
+                setDef(i, PhiNode.make(v._name, v.type(), r, lhs, rhs).peephole());
             }
     }
 
     // Balance arms of an IF.  Extra lonely defs are thrown: "if(pred) int x;".
     // Forward refs are copied to the other side, "as if" they were there all along.
+    // 'this' scope is the default, 'scope' might have frefs.
     public void balanceIf( ScopeNode scope ) {
-        for( int i = nIns(); i < scope.nIns(); i++ ) {
+        if( nIns()==scope.nIns() )
+            return;             // Fast-path cutout
+        int kidx = enclosingFunction();
+        assert _kinds.at(kidx) == scope._kinds.at(kidx);
+        if( kidx==0 ) kidx = 1;
+        for( int i = _kinds.at(kidx-1)._lexSize; i < scope.nIns(); i++ ) {
             Var n = scope.var(i);
+            if( i<nIns() && var(i)==n ) continue;
             if( n.isFRef() ) {  // RHS has forward refs
-                _vars.add(n);   // Copy to LHS
-                addDef(scope.in(i));
+                _vars.insert(n,i);
+                insertDef(i,scope.in(i));
             } else
                 throw Parser.error("Cannot define a '"+n._name+"' on one arm of an if",n._loc);
         }
     }
 
 
+    // ------------------------------------------------
     // peephole the backedge scope into this loop head scope
     // We set the second input to the phi from the back edge (i.e. loop body)
     public void endLoop(ScopeNode back, ScopeNode exit ) {
@@ -353,34 +415,30 @@ public class ScopeNode extends MemMergeNode {
         assert ctrl instanceof LoopNode loop && loop.inProgress();
         ctrl.setDef(2,back.ctrl());
 
-        mem()._endLoopMem( this, back.mem(), exit.mem() );
-        this ._endLoop   ( this, back      , exit       );
+        this._endLoop( this, back, exit);
         back.kill();            // Loop backedge is dead
         // Now one-time do a useless-phi removal
-        mem()._useless();
-        this ._useless();
-
-        // The exit mem's lazy default value had been the loop top,
-        // now it goes back to predating the loop.
-        exit.mem().setDef(1,mem().in(1));
+        this._useless();
     }
 
     // Fill in the backedge of any inserted Phis
     void _endLoop( ScopeNode scope, Node back, Node exit ) {
-        for( int i=2; i<nIns(); i++ ) {
+        for( int i=1; i<nIns(); i++ ) {
             if( var(i)._final ) continue; // Final vars did not get modified in the loop
-            if( var(i).type().isHighOrConst() ) continue; // Cannot lift higher than a constant, so no Phi
-            if( back.in(i) != scope ) {
-                PhiNode phi = (PhiNode)in(i);
+            Node n = in(i);
+            if( var(i).type().isHighOrConst() ) { // Cannot lift higher than a constant, so no Phi
+                n.subsume(n=ConstantNode.make(var(i).type()).init());
+            } else if( back.in(i) != scope ) {
+                PhiNode phi = (PhiNode)n;
                 assert phi.region()==scope.ctrl() && phi.in(2)==null;
                 phi.setDef(2,back.in(i)); // Fill backedge
             }
             if( exit.in(i) == scope ) // Replace a lazy-phi on the exit path also
-                exit.setDef(i,in(i));
+                exit.setDef(i,n);
         }
     }
 
-
+    // ------------------------------------------------
     // Up-casting: using the results of an If to improve a value.
     // E.g. "if( ptr ) ptr.field;" is legal because ptr is known not-null.
     public void addGuards( Node ctrl, Node pred, boolean invert ) {
@@ -392,33 +450,30 @@ public class ScopeNode extends MemMergeNode {
         // Invert the If conditional
         if( invert )
             pred = pred instanceof NotNode not ? not.in(1) : CodeGen.CODE.add(new NotNode(pred).peephole());
+        Node zeroPred = pred instanceof NotNode not ? not.in(1) : null;
         // This is a zero/null test.
         // Compute the positive test type.
-        Type tnz = pred._type.nonZero();
-        if( tnz!=null )
-            _addGuard(tnz,ctrl,pred);
+        _addGuard(true,ctrl,pred);
 
         // Compute the negative test type.
-        if( pred instanceof NotNode not ) {
-            Node npred = not.in(1);
-            Type tzero = npred._type.makeZero();
-            _addGuard(tzero,ctrl,npred);
-        }
+        if( zeroPred != null )
+            _addGuard(false,ctrl,zeroPred);
     }
 
-    private void _addGuard(Type guard, Node ctrl, Node pred) {
-        Type tcast = guard.join(pred._type);
-        if( tcast != pred._type && !tcast.isHigh() ) {
-            Node cast = new CastNode(tcast,ctrl,pred.keep()).peephole().keep();
+    private void _addGuard(boolean nonZero, Node ctrl, Node pred) {
+        Node guard = new GuardNode(nonZero,ctrl,pred).peephole();
+        if( guard != pred ) {
+            pred.keep();
+            guard.keep();
             _guards.add(pred);
-            _guards.add(cast);
-            replace(pred,cast);
+            _guards.add(guard);
+            replace(pred,guard);
         }
     }
 
 
     // Remove matching pred/cast pairs from this guarded region.
-    public ScopeNode removeGuards( Node ctrl ) {
+    public void removeGuards( Node ctrl ) {
         assert ctrl instanceof CFGNode;
         // 0,1 or 2 guards
         while( true ) {
@@ -428,7 +483,6 @@ public class ScopeNode extends MemMergeNode {
             g            .unkill(); // Pop/kill cast
             _guards.pop().unkill(); // Pop/kill pred
         }
-        return this;
     }
 
     // If we find a guarded instance of pred, replace with the upcasted version
@@ -465,4 +519,44 @@ public class ScopeNode extends MemMergeNode {
                 setDef(i,cast);
     }
 
+    // ------------------------------------------------------------------------
+    // Insert a top-level public external symbol, "as-if" some #include/import
+    // was executed at the top of tile.
+    public Var insertExtern( ExternNode ext ) {
+        // Size of top-level scope
+        int lexSize = _kinds.at(0)._lexSize;
+        Var var = new Var(lexSize,ext._extern,ext._con,true,null);
+        insert(var,ext,0);
+        return var;
+    }
+
+    // ------------------------------------------------------------------------
+    // Insert a Var with Node n in the lex scope just prior to kidx
+    private void insert( Var var, Node n, int kidx ) {
+        // Insert just prior to scope kidx
+        int nidx = _kinds.at(kidx)._lexSize;
+        _vars.insert(var,nidx);
+        insertDef(nidx,n);
+        // All outer Kinds lexical offsets bump by one
+        for( int i = kidx; i < depth(); i++ )
+            _kinds.at(i)._lexSize++;
+        // All Vars outside the innermost lexical scope bump out one
+        for( int i=nidx+1; i<_vars._len; i++ )
+            var(i)._idx++;
+    }
+
+    // Save the existing Node state to an array
+    public Node[] save() {
+        Node[] olds = new Node[nIns()];
+        for( int i=0; i<nIns(); i++ )
+            olds[i] = in(i)==null ? null : in(i).keep();
+        return olds;
+    }
+
+    // Restore saved Node state back into scope
+    public void restore( Node[] olds ) {
+        assert olds.length<=nIns();
+        for( int i=0; i<olds.length; i++ )
+            setDef(i,olds[i]==null ? null : olds[i].unkeep());
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/ShlNode.java b/src/main/java/com/seaofnodes/simple/node/ShlNode.java
index 2557bf6b..459b26eb 100644
--- a/src/main/java/com/seaofnodes/simple/node/ShlNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ShlNode.java
@@ -1,13 +1,14 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
 public class ShlNode extends ArithNode {
-    public ShlNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs); }
+    public ShlNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs, (byte)1); }
+    @Override public Tag serialTag() { return Tag.Shl; }
 
-    @Override public String label() { return "Shl"; }
     @Override public String op() { return "<<"; }
     @Override public String glabel() { return "&lt;&lt;"; }
 
@@ -38,7 +39,7 @@ public class ShlNode extends ArithNode {
             if( lhs instanceof AddNode add && addDep(add).in(2)._type instanceof TypeInteger c && c.isConstant() ) {
                 long sum = c.value() << shl.value();
                 if( Integer.MIN_VALUE <= sum  && sum <= Integer.MAX_VALUE )
-                    return new AddNode(new ShlNode(_loc,add.in(1),rhs).peephole(), Parser.con(sum) );
+                    return new AddNode(new ShlNode(_loc,add.in(1),rhs).peephole(), CodeGen.CODE.con(sum) );
             }
         }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/ShrNode.java b/src/main/java/com/seaofnodes/simple/node/ShrNode.java
index 269f6b7f..5e4870d1 100644
--- a/src/main/java/com/seaofnodes/simple/node/ShrNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ShrNode.java
@@ -5,9 +5,9 @@ import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
 public class ShrNode extends ArithNode {
-    public ShrNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs); }
+    public ShrNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs, (byte)1); }
+    @Override public Tag serialTag() { return Tag.Shr; }
 
-    @Override public String label() { return "Shr"; }
     @Override public String op() { return ">>>"; }
     @Override public String glabel() { return "&gt;&gt;&gt;"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/SplitNode.java b/src/main/java/com/seaofnodes/simple/node/SplitNode.java
index d061cdbd..4b58187f 100644
--- a/src/main/java/com/seaofnodes/simple/node/SplitNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SplitNode.java
@@ -1,14 +1,17 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.codegen.LRG;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.util.SB;
 import java.util.BitSet;
 
 public abstract class SplitNode extends MachConcreteNode {
+    public final LRG _lrg;      // Live range for split
     public final String _kind;  // Kind of split
-    public final byte _round;
-    public SplitNode(String kind, byte round, Node[] nodes) { super(nodes); _kind = kind; _round = round; }
+    public final byte _round;   // Debugging info for which RegAlloc round
+    public SplitNode(LRG lrg,String kind, byte round, Node[] nodes) { super(nodes); _lrg=lrg; _kind = kind; _round = round; }
     @Override public String op() { return "mov"; }
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("mov(");
@@ -16,6 +19,7 @@ public abstract class SplitNode extends MachConcreteNode {
         else in(1)._print0(sb,visited);
         return sb.append(")");
     }
+    public FunNode fun(Encoding enc) { return enc._code._regAlloc.lrg(this)._fun; }
     @Override public Type compute() { return in(0)._type; }
     @Override public Node idealize() { return null; }
     @Override public void asm(CodeGen code, SB sb) {
diff --git a/src/main/java/com/seaofnodes/simple/node/StartCUNode.java b/src/main/java/com/seaofnodes/simple/node/StartCUNode.java
new file mode 100644
index 00000000..d828c5f1
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/StartCUNode.java
@@ -0,0 +1,33 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Serialize;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.util.BAOS;
+
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+// Start of a single compilation unit, distinct from the outer whole-program Start.
+public class StartCUNode extends StartNode {
+    public final String _fname;
+    public StartCUNode(StartNode start, StopCUNode stop, Type arg, String fname) { super(start,stop,arg);  _fname = fname;  }
+    public StartCUNode(StartCUNode start) { super(start); _fname = start._fname; }
+    @Override public Tag serialTag() { return Tag.StartCU; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node,Integer> anodes ) {
+        baos.packed2(types.get(_arg));
+        baos.packed2(strs.get(_fname));
+    }
+    static Node make( BAOS bais, String[] strs, Type[] types )  {
+        return new StartCUNode(null,null,types[bais.packed2()],strs[bais.packed2()]);
+    }
+
+    @Override public CFGNode cfg0() { return (CFGNode)in(0); }
+
+    // IDom is cfg0() and depth is always Start+1 which is 0+1 or 1
+    @Override public int idepth() { return CodeGen.CODE.iDepthAt(1); }
+    @Override public CFGNode idom(Node dep) { return cfg0(); }
+    @Override public void gather( HashMap<String,Integer> strs ) {
+        Serialize.gather(strs,_fname);
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/StartNode.java b/src/main/java/com/seaofnodes/simple/node/StartNode.java
index e3806de7..7d2b2773 100644
--- a/src/main/java/com/seaofnodes/simple/node/StartNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StartNode.java
@@ -3,48 +3,78 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.Utils;
 import java.util.Arrays;
 import java.util.BitSet;
 import java.util.HashSet;
-import static com.seaofnodes.simple.util.Utils.TODO;
 
 /**
- * The Start node represents the start of the function.
+ * The Start node represents the external world calling, be it calling the
+ * entry <clinit> or just some linked caller calling.
  * <p>
  * Start initially has 1 input (arg) from outside and the initial control.
  * In ch10 we also add mem aliases as structs get defined; each field in struct
  * adds a distinct alias to Start's tuple.
+ * <p>
+ * By ch25, Start is the external world (or linker) calling with everything
+ * that has escaped.  Start is NOT the entry <clinit> itself, which can assume
+ * no memory nor fidxs exist nor escaped.  Start gets escaped things from Stop;
+ * together these close the Grand Cycle between the code we know and the code
+ * we don't.
  */
 public class StartNode extends LoopNode implements MultiNode {
 
     final Type _arg;
 
-    public StartNode(Type arg) { super(null,null); _arg = arg; _type = compute(); }
+    public StartNode(StartNode start, StopNode stop, Type arg) { super(null,start,stop); _arg = arg;  }
     public StartNode(StartNode start) { super(start); _arg = start==null ? null : start._arg; }
-
-    @Override public String label() { return "Start"; }
+    @Override public Tag serialTag() { return Tag.Start; }
+    public Type arg() { return _arg; }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
       return sb.append(label());
     }
 
-  @Override public CFGNode cfg0() { return null; }
+    @Override public CFGNode cfg0() { return null; }
 
     // Get the one control following; error to call with more than one e.g. an
-    // IfNode or other multi-way branch.  For Start, its "main"
+    // IfNode or other multi-way branch.  For Start, it's the class init for
+    // this compilation unit.
     @Override public CFGNode uctrl() {
-        // Find "main", it's the start.
+        // Find module.<clinit>, it's the start.
         CFGNode C = null;
         for( Node use : _outputs )
-            if( use instanceof FunNode fun && fun.sig().isa(CodeGen.CODE._main) )
+            if( use instanceof FunNode fun && fun.isModInit() )
                 { assert C==null; C = fun; }
+        if( C==null )
+            for( FunNode fun : CodeGen.CODE._linker )
+                if( fun!=null && !fun.isDead() && fun.isModInit() )
+                    { assert C==null; C = fun; }
         return C;
     }
 
+    boolean escapedFIDX(int fidx) {
+        // Public class fields are callable by the unknown external world
+        // regardless of the current SCCP approximation of Start memory.
+        if( CodeGen.CODE.publicFIDX(fidx) ) return true;
+        if( !(_type instanceof TypeTuple tt) )
+            return !_type.isHigh(); // TOP never escapes, BOTTOM always escapes
+        TypeMem tmem = (TypeMem)tt._types[1];
+        if( tmem == TypeMem.BOT ) return false;
+        if( tmem == TypeMem.TOP ) return false;
+        if( XInt.isHigh(tmem._escFs) )
+            return false;
+        return XInt.bit(tmem._escFs,fidx);
+    }
 
     @Override public TypeTuple compute() {
-        return TypeTuple.make(Type.CONTROL,TypeMem.TOP,_arg);
+        StopNode stop = (StopNode)in(1);
+        TypeMem tmem = stop._type instanceof TypeTuple tt
+            ? tt.mem()
+            : stop._type.isHigh() ? TypeMem.START : TypeMem.BOT;
+        assert tmem._alias==1 && !tmem._one;
+        return TypeTuple.make(Type.CONTROL,tmem,_arg);
     }
 
     @Override public Node idealize() { return null; }
@@ -53,4 +83,5 @@ public class StartNode extends LoopNode implements MultiNode {
     @Override public int idepth() { return CodeGen.CODE.iDepthAt(0); }
     @Override public CFGNode idom(Node dep) { return null; }
 
+    @Override public boolean eq( Node n ) { return true; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/StopCUNode.java b/src/main/java/com/seaofnodes/simple/node/StopCUNode.java
new file mode 100644
index 00000000..ab0f5da6
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/StopCUNode.java
@@ -0,0 +1,122 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+// Stop of a single compilation unit, distinct from the outer whole-program Stop.
+public class StopCUNode extends StopNode {
+    public StopCUNode() { super(); }
+    public StopCUNode(StopNode stop) { super(stop); }
+    @Override public Tag serialTag() { return Tag.StopCU; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { baos.packed1(nIns()); }
+    static Node make( BAOS bais ) {
+        StopCUNode stop = new StopCUNode();
+        stop.setDefX(bais.packed1()-1,null);
+        return stop;
+    }
+
+    public StartCUNode start() {
+        for( Node use : _outputs )
+            if( use instanceof StartCUNode start )
+                return start;
+        return null;
+    }
+
+    @Override
+    public TypeTuple compute() {
+        // During Parsing, new Stops and Returns are being added.  This Stop
+        // cannot know if more are coming, so must assume the worst.
+        if( CodeGen.CODE._phase ==null || CodeGen.CODE._phase == CodeGen.Phase.Parse )
+            return TypeTuple.STATE;
+
+        StartCUNode start = start();
+        // Memory start from all returns
+        TypeMem xmem = TypeMem.START;
+        // Escape summaries are monotone discovery facts.  In Opto, a Return
+        // can widen from a precise set to FULL; the public-only normalization
+        // below must not forget private bits already discovered precisely from
+        // that Return on an earlier SCCP step.
+        if( CodeGen.CODE._phase == CodeGen.Phase.Opto &&
+            _type instanceof TypeTuple old && old.mem() instanceof TypeMem omem )
+            xmem = xmem.makeFrom(XInt.meet(xmem._escFs,omem._escFs),
+                                 XInt.meet(xmem._escAs,omem._escAs));
+
+        for( Node def : _inputs ) {
+            ReturnNode ret = (ReturnNode)def;
+            if( ret._type == Type.TOP ) continue;
+            if( !(ret._type instanceof TypeTuple tret) )
+                return TypeTuple.STATE; // Must be Type.BOTTOM
+
+            FunNode fun = ret.fun();
+            boolean noUserCtor = fun.isInstance() &&
+                !CodeGen.hasUserConstructor(((TypeMemPtr)fun.sig().arg(0))._obj);
+            // Instance <init> is an allocation helper, never an externally
+            // callable constructor when a user constructor exists.  Otherwise
+            // the same no-arg <init> is the public constructor.
+            boolean pub = fun.isPublic() && (fun.isClz() || noUserCtor);
+            TypeFunPtr sig = fun.sig();
+            // If public init, the function escapes and the related class escapes
+            if( pub ) {
+                xmem = xmem.escapes(sig);
+                // Classes also escape their public clazz pointer, which then
+                // escapes all their public fields.  Private fields do not
+                // escape, and are only available from the local class code.
+                if( fun.isClz() )
+                    xmem = xmem.escapesAliases(sig._sig[0]);
+            }
+
+            // The instance <init> Start edge supplies conservative pre-Opto
+            // inputs, but its private-memory result is consumed only by the
+            // allocation sequence and is never an externally visible return.
+            if( fun.isInstance() && !noUserCtor ) continue;
+
+            // Does this function escape?  If not, then no need to MEET
+            // here as its effects are not visible to the outside world.
+            addDepForwards(start); // Check again if function escapes
+            if( pub || start.escapedFIDX(sig.fidx()) ) {
+                if( tret.ctl().isHigh() ) continue; // Return not reachable
+                // Capture (precisely?) all escaping pointer aliases and fidxs.
+                // Escaped fidxs means the linked world can call that function;
+                // escaped aliases means the linked world can R/W those aliases.
+                xmem = xmem.escapes(tret.ret());
+                xmem = publicBottom(xmem);
+                xmem = (TypeMem)xmem.meet(publicBottom(tret.mem(),xmem));
+            }
+        }
+        assert xmem._alias==1 && !xmem._one;
+        return TypeTuple.make(Type.CONTROL,xmem,Type.BOTTOM);
+    }
+
+    // FULL escape sets arise from global BOTTOM.  Across a compilation-unit
+    // boundary global BOTTOM exposes every public field, while retaining any
+    // private escapes already discovered precisely.
+    private TypeMem publicBottom(TypeMem mem) { return publicBottom(mem,mem); }
+    private TypeMem publicBottom(TypeMem mem, TypeMem prior) {
+        // The pessimistic Iter pass naturally lifts transient FULL inputs to
+        // precise finite sets.  Replacing FULL early there would let a later
+        // input refinement add bits, reversing Iter's monotonic direction.
+        // This normalization is needed only for Opto's optimistic grand cycle.
+        if( CodeGen.CODE._phase != CodeGen.Phase.Opto ) return mem;
+        int[] escFs = XInt.isHigh(mem._escFs)
+            ? XInt.meet(prior._escFs,CodeGen.CODE.publicFIDXs())
+            : mem._escFs;
+        int[] escAs = XInt.isHigh(mem._escAs)
+            ? XInt.meet(prior._escAs,CodeGen.CODE.publicAliases())
+            : mem._escAs;
+        return escFs==mem._escFs && escAs==mem._escAs ? mem : mem.makeFrom(escFs,escAs);
+    }
+
+    @Override
+    public Node idealize() {
+        int len = nIns();
+        for( int i=0; i<nIns(); i++ )
+            if( in(i) instanceof ReturnNode ret && addDep(ret.fun()).isDead() )
+                delDef(i--);
+        if( len != nIns() ) return this;
+        return null;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/StopNode.java b/src/main/java/com/seaofnodes/simple/node/StopNode.java
index 4b03bf4e..45f5519e 100644
--- a/src/main/java/com/seaofnodes/simple/node/StopNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StopNode.java
@@ -1,34 +1,45 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
+// A collection of function ReturnNodes for a compilation unit.
 public class StopNode extends CFGNode {
 
-    public final String _src;
-
-    public StopNode(String src) {
+    public StopNode() {
         super();
-        _src = src;
         _type = compute();
     }
-    public StopNode(StopNode stop) { super(stop);  _src = stop==null ? null : stop._src; }
-
-    @Override
-    public String label() {
-        return "Stop";
+    public StopNode(StopNode stop) { super(stop); }
+    @Override public Tag serialTag() { return Tag.Stop; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { baos.packed1(nIns()); }
+    static Node make( BAOS bais ) {
+        StopNode stop = new StopNode();
+        stop.setDefX(bais.packed1()-1,null);
+        return stop;
     }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         // For the sake of many old tests, and single value prints as "return val"
-        ReturnNode ret1 = ret();
+        ReturnNode ret1 = null;
+        for( Node n : _inputs ) {
+            if( n instanceof ReturnNode ret ) {
+                if( ret1 != null ) { ret1=null; break; }
+                ret1 = ret;
+            }
+        }
         if( ret1!=null ) return ret1._print0(sb,visited);
+
         sb.append("Stop[ ");
-        for( Node ret : _inputs )
-            if( ret!=null ) {
-                String name = ((ReturnNode)ret).fun()._name;
+        for( Node n : _inputs )
+            if( n instanceof ReturnNode ret ) {
+                String name = ret.fun()._name;
                 if( name== null || !name.startsWith("sys.") )
                     ret._print0(sb, visited).append(" ");
             }
@@ -41,25 +52,36 @@ public class StopNode extends CFGNode {
     // If a single Return, return it.
     // Otherwise, null because ambiguous.
     public ReturnNode ret() {
-        Node ret1 = this;
-        for( Node ret : _inputs ) {
-            String name = ((ReturnNode)ret).fun()._name;
-            if( name==null || !name.startsWith("sys.") )
-                ret1 = ret1==this ? ((ReturnNode)ret) : null;
+        ReturnNode ret1 = null;
+        for( Node n : _inputs ) {
+            // TODO: remove isPublic
+            if( n instanceof ReturnNode ret && ret.fun().isPublic() ) {
+                if( ret1 != null ) return null; // Ambiguous
+                ret1 = ret;
+            }
         }
-        return ret1==this ? null : (ReturnNode)ret1;
+        return ret1;
     }
 
     @Override
-    public Type compute() {
-        return Type.BOTTOM;
+    public TypeTuple compute() {
+        // During Parsing, new Stops and Returns are being added.  This Stop
+        // cannot know if more are coming, so must assume the worst.
+        if( CodeGen.CODE._phase ==null || CodeGen.CODE._phase == CodeGen.Phase.Parse )
+            return TypeTuple.STATE;
+
+        // Just meet-over-inputs.
+        TypeTuple tt = TypeTuple.STOP_HIGH;
+        for( Node def : _inputs )
+            tt = (TypeTuple)tt.meet(def._type);
+        assert tt.mem()._alias==1 && !tt.mem()._one;
+        return tt;
     }
 
-    @Override
-    public Node idealize() {
+    @Override public Node idealize() {
         int len = nIns();
         for( int i=0; i<nIns(); i++ )
-            if( addDep(((ReturnNode)in(i)).fun()).isDead() )
+            if( in(i).nIns()==0 )
                 delDef(i--);
         if( len != nIns() ) return this;
         return null;
@@ -69,7 +91,10 @@ public class StopNode extends CFGNode {
         if( _idepth!=0 ) return _idepth;
         int d=0;
         for( Node ret : _inputs )
-            d = Math.max(d,((ReturnNode)ret).idepth()+1);
+            // All public results are hooked on the Stop, including data
+            // values, so must check CFG
+            if( ret instanceof CFGNode cfg )
+                d = Math.max(d,cfg.idepth()+1);
         return _idepth=d;
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index 8e33512a..c0006511 100644
--- a/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -1,8 +1,14 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.GlobalBits;
 import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
  * Store represents setting a value to a memory based object, in chapter 10
@@ -10,7 +16,10 @@ import java.util.BitSet;
  */
 public class StoreNode extends MemOpNode {
 
-    private final boolean _init; // Initializing writes are allowed to write null
+    final boolean _init; // Initializing writes are allowed to write null
+    // Semantic store width in bytes.  Zero is the sole undecided state;
+    // otherwise hardware and ideal Stores are the 1/2/4/8-byte variants.
+    private byte _size;
 
     /**
      * @param name  The struct field we are assigning to
@@ -19,9 +28,25 @@ public class StoreNode extends MemOpNode {
      * @param off   The offset inside the struct base
      * @param value Value to be stored
      */
-    public StoreNode(Parser.Lexer loc, String name, int alias, Type glb, Node mem, Node ptr, Node off, Node value, boolean init) {
-        super(loc, name, alias, false, glb, mem, ptr, off, value);
+    public StoreNode(Parser.Lexer loc, String name, int alias, Type glb, Node ctrl, Node mem, Node ptr, Node off, Node value, boolean init) {
+        this(loc,name,alias,glb,ctrl,mem,ptr,off,value,init,(byte)0);
+    }
+    private StoreNode(Parser.Lexer loc, String name, int alias, Type glb, Node ctrl, Node mem, Node ptr, Node off, Node value, boolean init, byte size) {
+        super(loc, name, alias, false, glb, ctrl, mem, ptr, off, value);
         _init = init;
+        _size = size;
+    }
+    StoreNode( BAOS bais, String[] strs, Type[] types, GlobalBits fileAliases, GlobalBits aliases ) {
+        super(bais,strs,types,fileAliases,aliases,false);
+        addDef(null);
+        _init = bais.read() != 0;
+        _size = (byte)bais.read();
+    }
+    @Override public Tag serialTag() { return Tag.Store; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        super.packed(baos,strs,types, anodes );
+        baos.write(_init ? 1 : 0);
+        baos.write(_size);
     }
 
     // GraphVis DOT code and debugger labels
@@ -30,7 +55,10 @@ public class StoreNode extends MemOpNode {
     @Override public String glabel() { return "." +_name+"="; }
     @Override public boolean isMem() { return true; }
 
+    public Node nnptr() { return ptr() instanceof GuardNode cast && cast._nonZero ? cast.in(1) : ptr(); }
     public Node val() { return in(4); }
+    public int storeSize() { assert _size==1 || _size==2 || _size==4 || _size==8; return _size; }
+    @Override public int log_size() { return Integer.numberOfTrailingZeros(storeSize()); }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
@@ -39,28 +67,108 @@ public class StoreNode extends MemOpNode {
 
     @Override
     public Type compute() {
-        Type val = val()._type;
-        Type mem0 = mem()._type;
-        if( mem0 == Type.TOP ) return TypeMem.TOP;
-        TypeMem mem = (TypeMem)mem0; // Invariant
-        if( mem == TypeMem.TOP ) return TypeMem.TOP;
-        Type t = Type.BOTTOM;               // No idea on field contents
-        // Same alias, lift val to the declared type and then meet into other fields
-        if( mem._alias == _alias ) {
-            assert !_declaredType.isFRef();
-            // Sharpen memory value; required for narrowing stores where the parser inserts
-            // zero/sign masking and somebody reads the TypeMem type.
-            val = val.join(_declaredType);
-            t = val.meet(mem._t);
-        }
-        return TypeMem.make(_alias,t);
+        Type val  = val()._type;
+        Type mem0 = aliasMem()._type;
+        Type ptr0 = ptr()._type;
+        // Validate argument types
+        if( ptr0.isHigh() )
+            return TypeMem.TOP;
+        if( !(mem0 instanceof TypeMem    mem) ||
+            !(ptr0 instanceof TypeMemPtr ptr) )
+            return mem0.isHigh() || ptr0==Type.NIL ? TypeMem.TOP : TypeMem.BOT;
+
+        // Sharpen memory value; required for narrowing stores where the parser
+        // inserts zero/sign masking and somebody reads the TypeMem type.
+        Type decl = declaredType();
+        if( decl != Type.BOTTOM && decl != Type.TOP )
+            val = val.join(decl);
+        //if( err()!=null )
+        //    val = Type.BOTTOM;
+        // Allocation uses a private TypeMem and nothing else does.  This
+        // memory is truly private; a temporary singleton until it escapes -
+        // which is never does in a constructor.
+        if( !_name.equals("[]") && mem._one )
+            // Just track the stored value
+            return TypeMem.make(_alias,val,true,false,_init,null,null).escapesFrom(val);
+
+        // Normal aliasing Store.
+        assert mem._alias==1 || mem._alias==_alias; // Perfect aliasing
+
+        // Single alias store.  If memory is fat, attempt to get a narrow slice.
+        Type tfld = mem._alias==1 && mem._t instanceof TypeStruct ts
+            ? ts._fields[ts.findAlias(_alias)]._t
+            : mem._t;
+
+        // Same alias, meet into other fields.
+        Type t = val.meet(tfld);
+        // Bulk memory's final bit describes its conservative remainder, not
+        // this newly precise slice.  Slice finality comes from the field.
+        Field fld = ptr._obj.field(_name);
+        boolean xfinal = fld != null && fld._final;
+        return TypeMem.make(_alias,t,mem._one,mem._clz,xfinal,mem._escFs,mem._escAs).escapesFrom(val);
     }
 
     @Override
     public Node idealize() {
+        assert !(mem() instanceof CheckCastNode);
 
-        if( mem() instanceof CastNode cast ) {
-            setDef(1,cast.in(1));
+        // Freeze the semantic Store variant as soon as the pointer exposes a
+        // canonical field declaration.  Waiting until after structural memory
+        // peeps can lose the declaration to a flow-sensitive constant field
+        // state.  Imported Stores already carry a serialized non-zero width.
+        Type storage = storageType();
+        if( _size==0 && storage!=Type.BOTTOM && storage!=Type.TOP ) {
+            unlock();           // Width participates in GVN identity.
+            _size = storeSize(storage);
+            return init();
+        }
+
+        // A precise Store can confirm its alias from a precise memory input.
+        // Do not sharpen an alias-#1 (whole-memory) Store in place: users of
+        // that Store already treat it as the complete memory state.  The
+        // pointer/field path below replaces it with a precise Store wrapped in
+        // a MemMerge, preserving any other precise aliases in its input.
+        if( mem()._type instanceof TypeMem mem ) {
+            assert mem._alias > 0;
+            if( _alias != 1 && mem._alias != 1 )
+                assert _alias == mem._alias;
+        }
+
+        // Forward-ref loads eventually sharpen to a declared type
+        Field fld;
+        if( _alias==1 && ptr()._type instanceof TypeMemPtr tmp && (fld=tmp._obj.field(_name)) != null ) {
+            // Expand Store(bulkMem,alias#1) into MemMerge(bulkMem,#N:Store(bulkMem,alias#N)).
+
+            // Normally I'd like to just drop in this xform and move on, but
+            // users of the bulk Store memory might nontheless depend on the
+            // sharp memory type (e.g. I64) from the stores memory.  Using the
+            // MemMerge means using the bulk memory which e.g. might be BOT.
+            // Check for store users with the same alias, and use the new store
+            // directly, preserving the sharper graph.
+            Type decl = storageType();
+            byte size = _size==0 && decl!=Type.BOTTOM && decl!=Type.TOP ? storeSize(decl) : _size;
+            Node st = new StoreNode(_loc,_name,fld._alias,fld._t,in(0),mem(),ptr(),off(),val(),_init,size).peephole();
+            for( int i=0; i<nOuts(); i++ ) {
+                Node use = out(i);
+                if( useAlias(use)==fld._alias ) {
+                    int idx = use._inputs.find(this);
+                    assert idx != -1;
+                    use.setDef(idx,st);
+                    i--;        // setDef removed use from this Store's outputs
+                }
+            }
+            MemMergeNode mmm = mem() instanceof BulkMemPhiNode bulk
+                ? bulk.aggregate(mem(),fld._alias,st)
+                : new MemMergeNode(false,null,mem());
+            if( !(mem() instanceof BulkMemPhiNode) )
+                mmm.alias(fld._alias,st);
+            return mmm.init();
+        }
+        // Expose the same effective memory input already observed by compute.
+        Node aliasMem = aliasMem();
+        if( aliasMem != mem() ) {
+            setDef(1,aliasMem);
+            CodeGen.CODE.add(aliasMem);
             return this;
         }
 
@@ -73,20 +181,26 @@ public class StoreNode extends MemOpNode {
             // Must have exactly one use of "this" or you get weird
             // non-serializable memory effects in the worse case.
             checkOnlyUse(st) ) {
-            assert _name.equals(st._name); // Equiv class aliasing is perfect
+            assert _name==st._name; // Equiv class aliasing is perfect
             setDef(1,st.mem());
             return this;
         }
 
         // Simple store-after-MemMerge to a known alias can bypass.  Happens when inlining.
-        if( mem() instanceof MemMergeNode mem ) {
+        if( _alias != 1 && mem() instanceof MemMergeNode mem ) {
             setDef(1,mem.alias(_alias));
             return this;
         }
 
+        // Resolve the semantic Store variant exactly once, after structural
+        // memory/alias peeps.  This avoids publishing a half-sharpened Store
+        // while BulkMemPhi is constructing precise slices.
+        if( storage != Type.BOTTOM && storage != Type.TOP )
+            assert _size==storeSize(storage) : "Store width changed for '"+_name+"': "+_size+" from "+storage;
+
         // Value is automatically truncated by narrow store
-        if( val() instanceof AndNode and && and.in(2)._type.isConstant()  ) {
-            int log = _declaredType.log_size();
+        if( _size!=0 && val() instanceof AndNode and && and.in(2)._type.isConstant()  ) {
+            int log = log_size();
             if( log<3 ) {       // And-mask vs narrow store
                 long mask = ((TypeInteger)and.in(2)._type).value();
                 long bits = (1L<<(8<<log))-1;
@@ -98,7 +212,7 @@ public class StoreNode extends MemOpNode {
         }
 
         // Store will chop high order bits off; math to change those bits can be dropped.
-        if( val() instanceof SarNode shr &&
+        if( _size!=0 && val() instanceof SarNode shr &&
             shr.in(1) instanceof ShlNode shl &&
             shr.in(2)._type.isConstant() &&
             shl.in(2)._type.isConstant() ) {
@@ -114,9 +228,68 @@ public class StoreNode extends MemOpNode {
                 return this;
             }
         }
+
         return null;
     }
 
+    private static byte storeSize(Type decl) {
+        // `decl` is the target field declaration, not the stored value.  In
+        // particular a constant zero stored into u32 is still a 4-byte Store;
+        // taking the constant's GLB here would incorrectly select i64.
+        byte size = (byte)(1 << decl.log_size());
+        assert size==1 || size==2 || size==4 || size==8;
+        return size;
+    }
+
+    // Flow-sensitive pointer types can carry a current field value (e.g. the
+    // constant zero in a u32 field).  Storage width comes from the canonical
+    // struct declaration.  If the pointer/definition is not available yet,
+    // leave the Store undecided instead of consulting the value or `_con`.
+    private Type storageType() {
+        // Freshly parsed field stores retain the declaring structure on their
+        // symbolic offset even after the pointer's flow type sharpens.
+        if( off() instanceof ConFldOffNode coff ) {
+            Field fld = coff._ts.field(_name);
+            if( fld != null && fld._t != null ) return fld._t;
+        }
+        if( !(ptr()._type instanceof TypeMemPtr tmp) ) return Type.BOTTOM;
+        Type base = Parser.TYPES.get(tmp._obj._name);
+        TypeStruct obj = base instanceof TypeStruct ts ? ts : tmp._obj;
+        Field fld = obj.field(_name);
+        // Imported optimized structs can expose the current constant field
+        // value instead of its declaration.  A constant has no storage width;
+        // an imported Store already carries its serialized, frozen `_size`.
+        return fld == null || fld._t == null || fld._t.isConstant() ? Type.BOTTOM : fld._t;
+    }
+
+    // Alias required by a direct consumer of this Store's memory result.
+    // Keep in sync with BulkMemPhiNode.outputAlias.
+    private int useAlias(Node use) {
+        return switch( use ) {
+        case MemOpNode mem -> mem._alias;
+        case MemPhiNode phi -> phi._alias;
+        case EscapeNode esc -> esc.pub()==this ? esc.fld()._alias : 0;
+        default -> 0;
+        };
+    }
+
+    // Select a precise alias from a whole-memory partition.  Alias #1 is the
+    // bulk remainder itself.
+    private static Node memSlice( Node mem, int alias ) {
+        return alias != 1 && mem instanceof MemMergeNode merge
+            ? merge.alias(alias)
+            : mem;
+    }
+
+    // Semantic memory input for this Store.  Compute defines behavior from
+    // this view; ideal exposes the same edge in the graph.
+    private Node aliasMem() {
+        Node mem = mem();
+        if( _alias != 1 && mem instanceof MemMergeNode merge )
+            mem = merge.alias(_alias);
+        return mem;
+    }
+
     // Check that "mem" has no uses except "this"
     private boolean checkOnlyUse(Node mem) {
         if( mem.nOuts()==1 ) return true;
@@ -132,11 +305,17 @@ public class StoreNode extends MemOpNode {
     public Parser.ParseException err() {
         Parser.ParseException err = super.err();
         if( err != null ) return err;
+        if( _size==0 && CodeGen.CODE._phase.ordinal() > CodeGen.Phase.Opto.ordinal() )
+            throw Utils.TODO("Failed to decide Store size");
         if( ptr()._type == Type.TOP )
             return null; // This means we have an error input, report elsewhere
         TypeMemPtr tmp = (TypeMemPtr)ptr()._type;
-        if( tmp._obj.field(_name)._final && !_init )
+        Field f = tmp._obj.field(_name);
+        if( f!=null && f._final && !_init )
             return Parser.error("Cannot modify final field '"+_name+"'",_loc);
         return null;
     }
+
+    @Override public boolean eq(Node n) { return _size==((StoreNode)n)._size && super.eq(n); }
+    @Override int hash() { return super.hash() ^ _size; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/StructNode.java b/src/main/java/com/seaofnodes/simple/node/StructNode.java
index b5b59b81..4dcc695f 100644
--- a/src/main/java/com/seaofnodes/simple/node/StructNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StructNode.java
@@ -1,8 +1,11 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
 import java.util.BitSet;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
 
 /**
  * Build a compound object
@@ -11,13 +14,23 @@ public class StructNode extends Node {
 
     public final TypeStruct _ts;
     public StructNode(TypeStruct ts) { _ts=ts; assert !ts._open; }
-
-    @Override public String label() { return _ts==null ? "STRUCT?" : _ts.str(); }
+    @Override public Tag serialTag() { return Tag.Struct; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) {
+        //baos.packed1(nIns());
+        //baos.packed2(_label==null ? 0 : strs.get(_label));
+        //baos.packed2(types.get(_type)); // Write _type not _minType, which can be higher
+        throw Utils.TODO();
+    }
+    static Node make( BAOS bais, Type[] types)  {
+        //Node[] ins = new Node[bais.packed1()];
+        //return new StructNode(types[bais.packed2()], ins);
+        throw Utils.TODO();
+    }
 
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( _ts==null ) return sb.append("STRUCT?");
-        sb.append(_ts._name).append(" {");
+        sb.append(_ts._name).append(" {  ");
         for( int i=0; i<nIns(); i++ ) {
             sb.append(_ts._fields[i]._fname).append(":");
             sb.append(in(i)==null ? Type.BOTTOM : in(i)._type);
diff --git a/src/main/java/com/seaofnodes/simple/node/SubFNode.java b/src/main/java/com/seaofnodes/simple/node/SubFNode.java
deleted file mode 100644
index 3fc4f7ca..00000000
--- a/src/main/java/com/seaofnodes/simple/node/SubFNode.java
+++ /dev/null
@@ -1,27 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-import java.util.BitSet;
-
-public class SubFNode extends ArithFNode {
-    public SubFNode(Node lhs, Node rhs) { super(lhs, rhs); }
-
-    @Override public String label() { return "SubF"; }
-
-    @Override public String glabel() { return "-"; }
-
-    @Override double doOp( double x, double y ) { return x-y; }
-
-    @Override
-    public Node idealize() {
-        // Sub of 0.
-        Type t2 = in(2)._type;
-        if ( t2.isConstant() && t2 instanceof TypeFloat i && i.value()==0 )
-            return in(1);
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new SubFNode(lhs,rhs); }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/SubNode.java b/src/main/java/com/seaofnodes/simple/node/SubNode.java
index 8e4f6f79..aba1df90 100644
--- a/src/main/java/com/seaofnodes/simple/node/SubNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SubNode.java
@@ -6,12 +6,15 @@ import com.seaofnodes.simple.type.TypeInteger;
 import java.util.BitSet;
 
 public class SubNode extends ArithNode {
+    @Override boolean allowFloat() { return true; }
     public SubNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
+    public SubNode(Node lhs, Node rhs, byte mode) { super(null, lhs, rhs,mode); }
+    @Override public Tag serialTag() { return Tag.Sub; }
 
-    @Override public String label() { return "Sub"; }
     @Override public String op() { return "-"; }
 
-    @Override long doOp( long x, long y ) { return x - y; }
+    @Override long   doOp( long  x,  long  y ) { return x - y; }
+    @Override double doOp(double x, double y ) { return x - y; }
     @Override TypeInteger doOp(TypeInteger x, TypeInteger y) {
         // Sub of same is 0
         if( in(1)==in(2) )
@@ -38,6 +41,5 @@ public class SubNode extends ArithNode {
         return super.idealize();
     }
 
-    @Override Node copy(Node lhs, Node rhs) { return new SubNode(lhs,rhs); }
-    @Override Node copyF() { return new SubFNode(null,null); }
+    @Override Node copy(Node lhs, Node rhs) { return new SubNode(lhs,rhs,_mode); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java b/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
index e02183a0..2d8cc788 100644
--- a/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
@@ -8,8 +8,7 @@ import java.util.BitSet;
 
 public class ToFloatNode extends Node {
     public ToFloatNode(Node lhs) { super(null, lhs); }
-
-    @Override public String label() { return "ToFloat"; }
+    @Override public Tag serialTag() { return Tag.ToFloat; }
 
     @Override public String glabel() { return "(flt)"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/TypeNode.java b/src/main/java/com/seaofnodes/simple/node/TypeNode.java
new file mode 100644
index 00000000..3ab2d6f9
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/TypeNode.java
@@ -0,0 +1,33 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
+import java.util.BitSet;
+import java.util.HashMap;
+
+// Node carries an extra internal type
+public abstract class TypeNode extends Node {
+    public Type _con;
+    public TypeNode(Type t, Node... nodes) { super(nodes); assert t!=null; _con = t; }
+    public TypeNode(TypeNode tn) { super(tn); _con = tn._con; }
+    // Copy edges from ideal, but 'this' is a Type-Mach-Node (e.g. MemOpX86) and needs a _con
+    public TypeNode(Node ideal, Type con) { super(ideal); _con = con; }
+
+    // Upgrade the internal type
+    @Override boolean _upgradeType( HashMap<String,Type> TYPES) {
+        return liftType(_con.upgradeType(TYPES));
+    }
+
+    // Lift type
+    public boolean liftType( Type t ) {
+        if( t == _con ) return false;
+        unlock();               // Unlock before changing _con
+        _con = t;
+        return true;
+    }
+
+    @Override public boolean eq(Node n) { return _con==((TypeNode)n)._con; }
+    @Override int hash() { return _con.hashCode(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java b/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
index 8c620a04..a8c06b37 100644
--- a/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
@@ -7,7 +7,7 @@ import java.util.BitSet;
 
 public class XCtrlNode extends CFGNode {
     public XCtrlNode() { super(new Node[]{CodeGen.CODE._start}); }
-    @Override public String label() { return "Xctrl"; }
+    @Override public Tag serialTag() { return Tag.XCtrl; }
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append("Xctrl"); }
     @Override public boolean isConst() { return true; }
     @Override  public Type compute() { return Type.XCONTROL; }
diff --git a/src/main/java/com/seaofnodes/simple/node/XorNode.java b/src/main/java/com/seaofnodes/simple/node/XorNode.java
index fdb4863e..95d4461e 100644
--- a/src/main/java/com/seaofnodes/simple/node/XorNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/XorNode.java
@@ -5,9 +5,9 @@ import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
 public class XorNode extends ArithNode {
-    public XorNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs); }
+    public XorNode(Parser.Lexer loc, Node lhs, Node rhs) { super(loc, lhs, rhs, (byte)1); }
+    @Override public Tag serialTag() { return Tag.Xor; }
 
-    @Override public String label() { return "Xor"; }
     @Override public String op() { return "^"; }
     @Override public String glabel() { return "^"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java
index b9ede544..5cf8a89c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java
@@ -8,9 +8,11 @@ import com.seaofnodes.simple.util.Utils;
 // Jump on flags, uses flags
 public class BranchARM extends IfNode implements MachNode, RIPRelSize {
     String _bop;
-    BranchARM(IfNode iff, String bop ) {
+    final boolean _fp;
+    BranchARM(IfNode iff, String bop, boolean fp ) {
         super(iff);
         _bop = bop;
+        _fp = fp;
     }
     @Override public String op() { return "j"+_bop; }
     @Override public String label() { return op(); }
@@ -35,7 +37,7 @@ public class BranchARM extends IfNode implements MachNode, RIPRelSize {
         // by comparison (or sub).  No need for regs because it uses flags
         if( in(1)!=null ) {
             // B.cond
-            enc.add4( arm.b_cond(arm.OP_BRANCH, 0, arm.make_condition(_bop)) );
+            enc.add4( arm.b_cond(arm.OP_BRANCH, 0, arm.make_condition(_bop, _fp)) );
         } else {
             if( _bop=="!=" ) return; // Inverted, no code
             enc.add4(arm.b(arm.OP_UJMP, 0));
@@ -55,7 +57,7 @@ public class BranchARM extends IfNode implements MachNode, RIPRelSize {
     @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
         assert !( in(1)==null && _bop=="!=" ); // Inverted never-node, no code no patch
         if( opLen==4 ) {
-            enc.patch4(opStart,arm.b_cond(arm.OP_BRANCH, delta, arm.make_condition(_bop)));
+            enc.patch4(opStart,arm.b_cond(arm.OP_BRANCH, delta, arm.make_condition(_bop, _fp)));
         } else {
             throw Utils.TODO();
         }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java
index 427cf2e2..8f070525 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java
@@ -13,8 +13,7 @@ public class CallARM extends CallNode implements MachNode, RIPRelSize {
         _inputs.pop(); // Pop constant target
         assert tfp.isConstant();
         _tfp = tfp;
-        FunNode fun = CodeGen.CODE.link(tfp);
-        _name = fun==null ? ((ExternNode)call.fptr())._extern : fun._name; // Can be null for extern calls
+        _name = CodeGen.CODE.funcName(tfp.fidx());
     }
 
     @Override public String op() { return "call"; }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/FltARM.java
index b47b65ad..42553868 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/FltARM.java
@@ -3,21 +3,22 @@ package com.seaofnodes.simple.node.cpus.arm;
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 //FMOV (scalar, immediate)
 //Floating-point move immediate.
-public class FloatARM extends ConstantNode implements MachNode, RIPRelSize {
-    FloatARM(ConstantNode con) { super(con); }
+public class FltARM extends ConstantNode implements MachNode, RIPRelSize {
+    final String _ext;
+    FltARM( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return arm.DMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public FloatARM copy() { return new FloatARM(this); }
+    @Override public FltARM copy() { return new FltARM(this,_ext); }
 
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         enc.largeConstant(this,_con,0,-1/*TODO: ARM-style ELF patching*/);
         short dst = (short)(enc.reg(this) - arm.D_OFFSET);
         enc.add4(arm.load_pc(arm.OPF_ARM, 0, dst));
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java
index ee74b95e..dbed9487 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java
@@ -6,19 +6,22 @@ import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 // Integer constants
 public class IntARM extends ConstantNode implements MachNode {
-    IntARM( ConstantNode con ) { super(con); }
+    final String _ext;
+    IntARM( ConstantNode con, String ext ) { super(con); _ext = ext; }
 
     @Override public String op() { return "ldi"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return arm.WMASK; }
 
     @Override public boolean isClone() { return true; }
-    @Override public IntARM copy() { return new IntARM(this); }
+    @Override public IntARM copy() { return new IntARM(this,_ext); }
 
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         short self = enc.reg(this);
         long x = _con==Type.NIL ? 0 : ((TypeInteger)_con).value();
         int nb0 = 0;
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java
index 1e5d2094..f8c9bfef 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java
@@ -21,16 +21,16 @@ public class LoadARM extends MemOpARM {
 
     private static final int[] OP_LOADS  = new int[]{ arm.OP_LOAD_IMM_8,  arm.OP_LOAD_IMM_16,  arm.OP_LOAD_IMM_32,  arm.OP_LOAD_IMM_64, };
     private int imm_op() {
-        return _declaredType == TypeFloat.F32 ? arm.OPF_LOAD_IMM_32
-            :  _declaredType == TypeFloat.F64 ? arm.OPF_LOAD_IMM_64
-            :  OP_LOADS[_declaredType.log_size()];
+        return _con == TypeFloat.F32 ? arm.OPF_LOAD_IMM_32
+            :  _con == TypeFloat.F64 ? arm.OPF_LOAD_IMM_64
+            :  OP_LOADS[_con.log_size()];
     }
 
     private static final int[] OP_LOAD_RS  = new int[]{ arm.OP_LOAD_R_8 , arm.OP_LOAD_R_16 , arm.OP_LOAD_R_32 , arm.OP_LOAD_R_64,  };
 
     // ldr(immediate - unsigned offset) | ldr(register)
     @Override public void encoding( Encoding enc ) {
-        ldst_encode(enc, imm_op(), OP_LOAD_RS[_declaredType.log_size()], this, size());
+        ldst_encode(enc, imm_op(), OP_LOAD_RS[_con.log_size()], this, size());
     }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(",");
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java
index e877931d..08bdf974 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java
@@ -11,7 +11,8 @@ import java.util.BitSet;
 public abstract class MemOpARM extends MemOpNode implements MachNode {
     final int _off;             // Limit 9 bits sized, or (13 bits<<logsize) unsigned
     final int _imm;             // Limit ? bits
-    final char _sz = (char)('0'+(1<<_declaredType.log_size()));
+    final int _bytes;
+    final char _sz;
     MemOpARM(MemOpNode mop, Node ptr, Node idx, int off, int imm) {
         super(mop,mop);
         assert ptr._type instanceof TypeMemPtr && !(ptr instanceof AddNode);
@@ -20,6 +21,8 @@ public abstract class MemOpARM extends MemOpNode implements MachNode {
         _inputs.setX(3, idx);
         _off = off;
         _imm = imm;
+        _bytes = mop instanceof StoreNode st ? st.storeSize() : 1<<_con.log_size();
+        _sz = (char)('0'+_bytes);
     }
 
     // Store-based flavors have a value edge
@@ -36,7 +39,7 @@ public abstract class MemOpARM extends MemOpNode implements MachNode {
     @Override public Type compute() { throw Utils.TODO(); }
     @Override public Node idealize() { throw Utils.TODO(); }
 
-    int size() { return 1<<_declaredType.log_size(); }
+    int size() { return _bytes; }
 
     // Wider mask to store both GPRs and FPRs
     @Override public RegMask regmap(int i) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java
index c1aad15f..df2a6bc9 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java
@@ -31,7 +31,8 @@ public class NewARM extends NewNode implements MachNode, RIPRelSize {
     }
     // General form: "alloc #bytes  PC"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p("ldi   x0=#1\n");
+        sb.p("\n");             // Multi-op trigger
+        sb.p("ldi   ").p(code._mach.regs()[_arg2Reg]).p(" = #1\n");
         sb.p("call  #calloc");
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java
index e1b3b3b6..c597b9dd 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java
@@ -8,12 +8,14 @@ import com.seaofnodes.simple.util.SB;
 // e.g CSET, stores flag info into GPRS after compare
 public class SetARM extends MachConcreteNode implements MachNode {
     final String _bop;          // One of <,<=,==
-    SetARM(Node cmp, String bop) {
+    final boolean _fp;          // FP compare (unsigned encoding)
+    SetARM(Node cmp, String bop, boolean fp) {
         super(cmp);
         _inputs.setLen(1);   // Pop the cmp inputs
         // Replace with the matched cmp
         _inputs.push(cmp);
         _bop = bop;
+        _fp = fp;
     }
     @Override public String op() { return "set"+_bop; }
     @Override public RegMask regmap(int i) { assert i==1; return arm.FLAGS_MASK; }
@@ -21,7 +23,7 @@ public class SetARM extends MachConcreteNode implements MachNode {
 
     @Override public void encoding( Encoding enc ) {
         // Using RM==RN==31 implies a *zero* value, not R31.
-        int body = arm.cset(arm.OP_CSET,0b11111, arm.make_condition(_bop), 0b011111, enc.reg(this));
+        int body = arm.cset(arm.OP_CSET,0b11111, arm.make_condition(_bop, _fp), 0b011111, enc.reg(this));
         enc.add4(body);
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java
index 5af45892..be975fb6 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java
@@ -8,7 +8,7 @@ import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 public class SplitARM extends SplitNode {
-    SplitARM(String kind, byte round) { super(kind,round,new Node[2]);}
+    SplitARM(LRG lrg, String kind, byte round) { super(lrg,kind,round,new Node[2]);}
     @Override public RegMask regmap(int i) { return arm.SPLIT_MASK; }
     @Override public RegMask outregmap() { return arm.SPLIT_MASK; }
 
@@ -24,7 +24,7 @@ public class SplitARM extends SplitNode {
             if(src >= arm.MAX_REG) {
                 throw Utils.TODO();
             }
-            int off = enc._fun.computeStackOffset(enc._code,dst);
+            int off = fun(enc).computeStackOffset(enc._code,dst);
             if( srcX ) src -= arm.D_OFFSET;
             enc.add4(arm.load_str_imm(arm.OP_STORE_IMM_64, off, arm.RSP, src, 8));
             return;
@@ -32,7 +32,7 @@ public class SplitARM extends SplitNode {
 
         if(src >= arm.MAX_REG) {
             // Load from SP
-            int off = enc._fun.computeStackOffset(enc._code,src);
+            int off = fun(enc).computeStackOffset(enc._code,src);
             if( dstX ) dst -= arm.D_OFFSET;
             enc.add4(arm.load_str_imm(arm.OP_LOAD_IMM_64, off, arm.RSP, dst, 8));
             return;
@@ -56,10 +56,4 @@ public class SplitARM extends SplitNode {
             enc.add4(arm.f_mov_general(arm.OP_FMOV, 0b01, 0, 0b110, src - arm.D_OFFSET, dst));
         }
     }
-
-    // General form: "mov  dst = src"
-    @Override public void asm(CodeGen code, SB sb) {
-        FunNode fun = code._encoding==null ? null : code._encoding._fun;
-        sb.p(code.reg(this,fun)).p(" = ").p(code.reg(in(1),fun));
-    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java
index 91385ac9..b11a2c89 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java
@@ -25,15 +25,15 @@ public class StoreARM extends MemOpARM {
 
     private static final int[] OP_STORES = new int[]{ arm.OP_STORE_IMM_8, arm.OP_STORE_IMM_16, arm.OP_STORE_IMM_32, arm.OP_STORE_IMM_64, };
     private int imm_op() {
-        return _declaredType == TypeFloat.F32 ? arm.OPF_STORE_IMM_32
-            :  _declaredType == TypeFloat.F64 ? arm.OPF_STORE_IMM_64
-            :  OP_STORES[_declaredType.log_size()];
+        return val()!=null && val()._type instanceof TypeFloat
+            ? (_bytes==4 ? arm.OPF_STORE_IMM_32 : arm.OPF_STORE_IMM_64)
+            : OP_STORES[Integer.numberOfTrailingZeros(_bytes)];
     }
 
     private static final int[] OP_STORE_RS = new int[]{ arm.OP_STORE_R_8, arm.OP_STORE_R_16, arm.OP_STORE_R_32, arm.OP_STORE_R_64, };
 
     @Override public void encoding( Encoding enc ) {
-        ldst_encode(enc, imm_op(), OP_STORE_RS[_declaredType.log_size()], val(), size());
+        ldst_encode(enc, imm_op(), OP_STORE_RS[Integer.numberOfTrailingZeros(_bytes)], val(), size());
     }
     @Override public void asm(CodeGen code, SB sb) {
         asm_address(code,sb).p(",");
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java
index 29d490ef..9d490c8b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java
@@ -1,28 +1,30 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.codegen.*;
-import com.seaofnodes.simple.node.ConstantNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeFunPtr;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
-public class TFPARM extends ConstantNode implements MachNode, RIPRelSize {
-    TFPARM( ConstantNode con ) { super(con); }
+public class TFPARM extends FunPtrNode implements MachNode, RIPRelSize {
+    final String _ext;
+    // Pointer to a Simple function
+    TFPARM( FunPtrNode fptr ) { super(fptr); _ext = null; }
+    // Pointer to an Extern "C" function
+    TFPARM( TypeFunPtr fptr, String ext ) { super(fptr,CodeGen.CODE._start,null); _type = fptr; _ext = ext; }
     @Override public String op() { return "ldx"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return arm.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public TFPARM copy() { return new TFPARM(this); }
+    @Override public TFPARM copy() { return new TFPARM((TypeFunPtr)_con,_ext); }
     @Override public void encoding( Encoding enc ) {
-        enc.relo(this);
-        short self = enc.reg(this);
+        if( _ext==null ) enc.relo(this);          // Internal patch
+        else             enc.external(this,_ext); // ELF-file external patch
+        short dst = enc.reg(this);
         // adrp    x0, 0
-        int adrp = arm.adrp(1,0, arm.OP_ADRP, 0,self);
+        enc.add4(arm.adrp(1,0, arm.OP_ADRP, 0,dst));
         // add     x0, x0, 0
-        enc.add4(adrp);
-        arm.imm_inst(enc,arm.OPI_ADD,0, 0);
+        arm.imm_inst(enc,arm.OPI_ADD,0, dst);
     }
 
     @Override public byte encSize(int delta) {
@@ -33,15 +35,7 @@ public class TFPARM extends ConstantNode implements MachNode, RIPRelSize {
     @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
         short rpc = enc.reg(this);
         if(opLen == 8 ) {
-            // ARM encoding delta is from PC & 0xFFF
-            int target = opStart+delta;
-            int base = opStart & ~0xFFF;
-            delta = target-base;
-            int adrp_delta = delta >> 12;
-            // patch upper 20 bits via adrp
-            enc.patch4(opStart, arm.adrp(1, adrp_delta & 0b11, 0b10000, adrp_delta >> 2, rpc));
-            // low 12 bits via add
-            enc.patch4(opStart+4, arm.imm_inst_l(arm.OPI_ADD, delta & 0xfff, rpc));
+            arm.patch_adrp_add(enc, opStart, delta, rpc);
         } else {
             // should not happen as one instruction is 4 byte, and TFP arm encodes 2.
             throw Utils.TODO();
@@ -50,7 +44,7 @@ public class TFPARM extends ConstantNode implements MachNode, RIPRelSize {
 
     @Override public void asm(CodeGen code, SB sb) {
         String reg = code.reg(this);
-        _con.print(sb.p(reg).p(" #"));
+        _type.print(sb.p(reg).p(" #"));
     }
     @Override public boolean eq(Node n) { return this==n; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/TMPARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/TMPARM.java
index cdcaa433..f86d85dc 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/TMPARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/TMPARM.java
@@ -9,13 +9,15 @@ import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 public class TMPARM extends ConstantNode implements MachNode, RIPRelSize {
-    TMPARM( ConstantNode con ) { super(con); }
+    final String _ext;
+    TMPARM( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ldp"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return arm.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public TMPARM copy() { return new TMPARM(this); }
+    @Override public TMPARM copy() { return new TMPARM(this,_ext); }
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         enc.largeConstant(this,((TypeMemPtr)_con)._obj,0,-1);
         short dst = enc.reg(this);
         // adrp    x0, 0
@@ -32,15 +34,7 @@ public class TMPARM extends ConstantNode implements MachNode, RIPRelSize {
     @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
         short dst = enc.reg(this);
         if(opLen == 8 ) {
-            // ARM encoding delta is from PC & 0xFFF
-            int target = opStart+delta;
-            int base = opStart & ~0xFFF;
-            delta = target-base;
-            int adrp_delta = delta >> 12;
-            // patch upper 20 bits via adrp
-            enc.patch4(opStart, arm.adrp(1, adrp_delta & 0b11, 0b10000, adrp_delta >> 2, dst));
-            // low 12 bits via add
-            enc.patch4(opStart+4, arm.imm_inst_l(arm.OPI_ADD, delta & 0xfff, dst));
+            arm.patch_adrp_add(enc, opStart, delta, dst);
         } else {
             throw Utils.TODO();
         }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
index a5dac751..852fbdb1 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
@@ -466,9 +466,19 @@ public class arm extends Machine {
     // int l
     public static int adrp(int op, int imlo,int opcode, int imhi, int rd) {
         assert 0 <= rd && rd < 32;
+        assert 0 <= imlo && imlo <= 0x3;     //  2 bits
+        assert 0 <= imhi && imhi <= 0x7FFFF; // 19 bits
         return (op << 31) | (imlo << 29) |(opcode << 24) | (imhi << 5) | rd;
     }
 
+    public static void patch_adrp_add(Encoding enc, int opStart, int delta, int rd) {
+        int target = opStart + delta;
+        int pageDelta = ((target & ~0xFFF) - (opStart & ~0xFFF)) >> 12;
+        int imm21 = pageDelta & 0x1FFFFF;
+        enc.patch4(opStart  , adrp(1, imm21 & 3, OP_ADRP, imm21 >>> 2, rd));
+        enc.patch4(opStart+4, imm_inst_l(OPI_ADD, target & 0xFFF, rd));
+    }
+
     // [Rptr+Roff]
     public static int indr_adr(int opcode, int off, STORE_LOAD_OPTION option, int s, int ptr, int rt) {
         assert 0 <= ptr && ptr < 32;
@@ -514,19 +524,31 @@ public class arm extends Machine {
     public static void f_cmp(Encoding enc, Node n) {
         short reg1 = (short)(enc.reg(n.in(1))-D_OFFSET);
         short reg2 = (short)(enc.reg(n.in(2))-D_OFFSET);
-        int body = f_cmp(0b00011110, 3, reg1,  reg2);
+        int body = f_cmp(0b00011110, 3, reg2,  reg1);
         enc.add4(body);
     }
 
-    public static COND make_condition(String bop) {
-        return switch (bop) {
-        case "==" -> COND.EQ;
-        case "!=" -> COND.NE;
-        case "<"  -> COND.LT;
-        case "<=" -> COND.LE;
-        case ">=" -> COND.GE;
-        case ">"  -> COND.GT;
-        default   -> throw Utils.TODO();
+    public static COND make_condition(String bop, boolean fp) {
+        // One of {N,Z,C} and !V
+        // OR { !N, !Z, C, V }
+        return fp
+            ? switch (bop) {    // FP uses unsigned encodings
+            case "==" -> COND.EQ;  //  Z
+            case "!=" -> COND.NE;  // !Z
+            case "<"  -> COND.MI;  //        N
+            case "<=" -> COND.LS;  //  Z || !C
+            case ">=" -> COND.PL;  //       !N
+            case ">"  -> COND.HI;  // !Z &&  C
+            default   -> throw Utils.TODO();
+        }
+            : switch (bop) {
+            case "==" -> COND.EQ;  //  Z
+            case "!=" -> COND.NE;  // !Z
+            case "<"  -> COND.LT;  //       N != V
+            case "<=" -> COND.LE;  //  Z || N != V
+            case ">=" -> COND.GE;  //       N == V
+            case ">"  -> COND.GT;  // !Z && N == V
+            default   -> throw Utils.TODO();
         };
     }
 
@@ -594,10 +616,16 @@ public class arm extends Machine {
         if( idx==1 ) return null;
         // Count floats in signature up to index
         if( idx-2 >= tfp.nargs() ) return null; // Anti-dependence
+        boolean hidden = hiddenSelf(tfp);
+        int sigidx = idx-2;
+        if( hidden ) {
+            if( sigidx==0 ) return null;
+            sigidx--;
+        }
         // Count floats in signature up to index
         int fcnt=0;
-        for( int i=2; i<idx; i++ )
-            if( tfp.arg(i-2) instanceof TypeFloat)
+        for( int i=hidden ? 1 : 0; i<idx-2; i++ )
+            if( tfp.arg(i) instanceof TypeFloat)
                 fcnt++;
         // Floats up to XMMS in XMM registers
         if( tfp.arg(idx-2) instanceof TypeFloat ) {
@@ -605,24 +633,27 @@ public class arm extends Machine {
                 return XMMS[fcnt];
         } else {
             RegMask[] cargs = CALLINMASK;
-            if( idx-2-fcnt < cargs.length )
-                return cargs[idx-2-fcnt];
+            if( sigidx-fcnt < cargs.length )
+                return cargs[sigidx-fcnt];
         }
         // Pass on stack slot (8 and higher)
         if( maxArgSlot>0 ) throw Utils.TODO();
-        return new RegMask(MAX_REG + 1 + (idx - 2));
+        return new RegMask(MAX_REG + 1 + sigidx);
     }
 
     // Return the max stack slot used by this signature, or 0
     @Override public short maxArgSlot( TypeFunPtr tfp ) {
         int icnt=0, fcnt=0;     // Count of ints, floats
-        for( int i=0; i<tfp.nargs(); i++ ) {
+        for( int i=hiddenSelf(tfp) ? 1 : 0; i<tfp.nargs(); i++ ) {
             if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
             else icnt++;
         }
         int nstk = Math.max(icnt-8,0)+Math.max(fcnt-8,0);
         return (short)nstk;
     }
+    private static boolean hiddenSelf(TypeFunPtr tfp) {
+        return tfp.nargs() > 0 && tfp.arg(0) == TypePtr.PTR;
+    }
 
     private static final long CALLEE_SAVE =
         1L<<X19 |
@@ -640,7 +671,7 @@ public class arm extends Machine {
     @Override public int rpc() { return X30; }
 
     // Create a split op; any register to any register, including stack slots
-    @Override public SplitNode split(String kind, byte round, LRG lrg) {  return new SplitARM(kind,round);  }
+    @Override public SplitNode split(LRG lrg, String kind, byte round) {  return new SplitARM(lrg,kind,round);  }
 
     // Return a MachNode unconditional branch
     @Override public CFGNode jump() {
@@ -650,40 +681,47 @@ public class arm extends Machine {
     // Instruction selection
     @Override public Node instSelect(Node n ) {
         return switch( n ) {
-        case AddFNode addf   -> new AddFARM(addf);
         case AddNode add     -> add(add);
         case AndNode and     -> and(and);
         case BoolNode bool   -> cmp(bool);
         case CallNode call   -> call(call);
-        case CastNode cast   -> new CastMach(cast);
+        case CheckCastNode cast -> new CheckCastMach(cast);
+        case PtrToIntNode ptr -> new PtrToIntMach(ptr);
+        case GuardNode guard -> new GuardMach(guard);
         case CallEndNode cend-> new CallEndMach(cend);
         case CProjNode c     -> new CProjNode(c);
         case ConstantNode con-> con(con);
-        case DivFNode divf   -> new DivFARM(divf);
-        case DivNode div     -> new DivARM(div);
+        case DivNode div     -> div.mode()==2 ? new DivFARM(div) : new DivARM(div);
+        case EscapeNode esc  -> new EscapeNode(esc);
         case FunNode fun     -> new FunARM(fun);
+        case FunPtrNode  fptr -> fptr(fptr);
         case IfNode iff      -> jmp(iff);
         case LoadNode ld     -> ld(ld);
         case MemMergeNode mem-> new MemMergeNode(mem);
-        case MinusNode neg   -> new NegARM(neg);
-        case MulFNode mulf   -> new MulFARM(mulf);
-        case MulNode mul     -> new MulARM(mul);
+        case MinusNode neg   -> {
+            if( neg.mode()==2 ) throw Utils.TODO();
+            yield new NegARM(neg);
+        }
+        case MulNode mul     -> mul.mode()==2 ? new MulFARM(mul) : new MulARM(mul);
         case NewNode nnn     -> new NewARM(nnn);
         case NotNode not     -> new NotARM(not);
         case OrNode or       -> or(or);
         case ParmNode parm   -> new ParmARM(parm);
+        case BulkMemPhiNode phi -> new BulkMemPhiNode(phi);
+        case MemPhiNode phi  -> new MemPhiNode(phi);
         case PhiNode phi     -> new PhiNode(phi);
-        case ProjNode prj    -> new ProjARM(prj);
+        case ProjNode prj    -> prj(prj);
         case ReadOnlyNode read -> new ReadOnlyMach(read);
         case ReturnNode ret  -> new RetARM(ret,ret.fun());
         case SarNode sar     -> asr(sar);
         case ShlNode shl     -> lsl(shl);
         case ShrNode shr     -> lsr(shr);
+        case StartCUNode start -> new StartCUNode(start);
+        case StopCUNode stop   -> new StopCUNode(stop);
         case StartNode start -> new StartNode(start);
         case StopNode stop   -> new StopNode(stop);
         case StoreNode st    -> st(st);
-        case SubFNode subf   -> new SubFARM(subf);
-        case SubNode sub     -> sub(sub);
+        case SubNode sub     -> sub.mode()==2 ? new SubFARM(sub) : sub(sub);
         case ToFloatNode tfn -> new I2F8ARM(tfn);
         case XorNode xor     -> xor(xor);
 
@@ -695,7 +733,7 @@ public class arm extends Machine {
 
     private Node cmp(BoolNode bool){
         Node cmp = _cmp(bool);
-        return new SetARM(cmp, bool.op());
+        return new SetARM(cmp, bool.op(), cmp instanceof CmpFARM);
     }
     private Node _cmp(BoolNode bool) {
         if( bool.isFloat() )
@@ -714,13 +752,18 @@ public class arm extends Machine {
         // Most general arith ops will also set flags, which the Jmp needs directly.
         // Loads do not set the flags, and will need an explicit TEST
         String op = "!=";
-        if( iff.in(1) instanceof BoolNode bool ) op = bool.op();
+        boolean fp = false;
+        if( iff.in(1) instanceof BoolNode bool ) { op = bool.op(); fp = bool.isFloat(); }
         else if( iff.in(1)==null ) op = "=="; // Never-node cutout
-        else iff.setDef(1, new BoolNode.NE(iff.in(1), new ConstantNode(TypeInteger.ZERO)));
-        return new BranchARM(iff, op);
+        else iff.setDef(1, new BoolNode.NE(iff.in(1),
+                                           ConstantNode.raw(TypeInteger.ZERO),
+                                           (byte)(iff.in(1)._type instanceof TypeFloat ? 2 : 1)));
+        return new BranchARM(iff, op, fp);
     }
 
     private Node add(AddNode add) {
+        if( add.mode()==2 )
+            return new AddFARM(add);
         return add.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && imm12(ti)
                 ? new AddIARM(add, (int)ti.value())
                 : new AddARM(add);
@@ -733,22 +776,30 @@ public class arm extends Machine {
     }
 
     private Node con( ConstantNode con ) {
-        if( !con._con.isConstant() ) return new ConstantNode( con ); // Default unknown caller inputs
+        if( !con._con.isConstant() )
+            return ConstantNode.raw(con); // Default unknown caller inputs
+        String ext = con instanceof ExternNode ext0 ? ext0._extern : null;
         return switch( con._con ) {
-        case TypeInteger ti -> new IntARM(con);
-        case TypeFloat   tf -> new FloatARM(con);
-        case TypeFunPtr tfp -> new TFPARM(con);
-        case TypeMemPtr tmp -> new TMPARM(con);
+        case TypeInteger ti -> new IntARM(con,ext);
+        case TypeFloat   tf -> new FltARM(con,ext);
+        case TypeMemPtr tmp -> new TMPARM(con,ext);
+        case TypeFunPtr tfp -> new TFPARM(tfp,ext);
         case TypeNil tn  -> throw Utils.TODO();
         // TOP, BOTTOM, XCtrl, Ctrl, etc.  Never any executable code.
-        case Type t -> t==Type.NIL ? new IntARM(con) : new ConstantNode(con);
+        case Type t -> t==Type.NIL ? new IntARM(con,ext) : ConstantNode.raw(con);
         };
     }
 
+    private Node fptr( FunPtrNode con ) {
+        return new TFPARM(con);
+    }
+
     private Node call(CallNode call){
-        return call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp
-                ? new CallARM(call, tfp)
-                : new CallRRARM(call);
+        return call.fptr() instanceof FunPtrNode fptr
+            ? new CallARM(call, (TypeFunPtr)fptr._type)
+            : call.fptr() instanceof ConstantNode con
+            ? new CallARM(call, (TypeFunPtr)con._type)
+            : new CallRRARM(call);
     }
 
     private Node or(OrNode or) {
@@ -790,6 +841,10 @@ public class arm extends Machine {
                 : new LsrARM(lsr);
     }
 
+    private Node prj(ProjNode prj) {
+        return prj.in(0) instanceof StartNode ? new ProjNode(prj) : new ProjARM(prj);
+    }
+
 
     private static int off;
     private static Node idx;
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java
index 2cd00845..1c157bc1 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java
@@ -1,19 +1,19 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.codegen.*;
-import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.node.FunPtrNode;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 // Add upper 20bits to PC.  Immediate comes from the relocation info.
-public class AUIPC extends ConstantNode implements MachNode, RIPRelSize {
-    AUIPC( Type tfp ) { super(tfp); }
+public class AUIPC extends FunPtrNode implements MachNode, RIPRelSize {
+    AUIPC( FunPtrNode fptr ) { super(fptr); }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public AUIPC copy() { return new AUIPC(_con); }
+    @Override public AUIPC copy() { return new AUIPC(this); }
     @Override public String op() { return "auipc"; }
     @Override public void encoding( Encoding enc ) {
         enc.relo(this);
@@ -36,7 +36,6 @@ public class AUIPC extends ConstantNode implements MachNode, RIPRelSize {
     @Override public void asm(CodeGen code, SB sb) {
         String reg = code.reg(this);
         sb.p(reg).p(" = PC+#");
-        if( _con == null ) sb.p("---");
-        else _con.print(sb);
+        _type.print(sb);
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java
index bd5dabe5..8e1b4a48 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java
@@ -14,8 +14,7 @@ public class CallRISC extends CallNode implements MachNode, RIPRelSize {
         assert tfp.isConstant();
         _inputs.pop(); // Pop constant target
         _tfp = tfp;
-        FunNode fun = CodeGen.CODE.link(tfp);
-        _name = fun==null ? ((ExternNode)call.fptr())._extern : fun._name; // Can be null for extern calls
+        _name = CodeGen.CODE.funcName(tfp.fidx());
     }
 
     @Override public String op() { return "call"; }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java
index 298789e8..7369f9f5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java
@@ -13,7 +13,7 @@ public class CallRRISC extends CallNode implements MachNode {
             ? riscv.RMASK                // Function call target
             : riscv.callInMask(tfp(),i,fun()._maxArgSlot); // Normal argument
     }
-    @Override public RegMask outregmap() { return null; }
+    @Override public RegMask outregmap() { return riscv.RPC_MASK; }
 
     @Override public void encoding( Encoding enc ) {
         short rpc = enc.reg(this);
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
index 81726200..c1a9b018 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
@@ -8,12 +8,13 @@ import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 public class FltRISC extends ConstantNode implements MachNode, RIPRelSize {
-    FltRISC(ConstantNode con) { super(con); }
+    final String _ext;
+    FltRISC( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return riscv.FMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public FltRISC copy() { return new FltRISC(this); }
+    @Override public FltRISC copy() { return new FltRISC(this,_ext); }
 
     @Override public void encoding( Encoding enc ) {
         enc.largeConstant(this,_con, 0, -1);
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/Int8RISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/Int8RISC.java
index edd1850f..e6b4c4ed 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/Int8RISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/Int8RISC.java
@@ -4,21 +4,23 @@ import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 // Special instruction for loading 8 byte constants from the constant pool.
 
 public class Int8RISC extends ConstantNode implements MachNode, RIPRelSize {
-    public Int8RISC(ConstantNode con) { super(con); }
-
+    final String _ext;
+    Int8RISC( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public Int8RISC copy() { return new Int8RISC(this); }
+    @Override public Int8RISC copy() { return new Int8RISC(this,_ext); }
 
     @Override public byte encSize(int delta) { return 8;  }
 
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         short dst  = enc.reg(this);
         short tmp = (short)riscv.T6;
         enc.largeConstant(this,_con, 0, -1);
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java
index f8af913a..b795ba96 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java
@@ -10,7 +10,7 @@ import com.seaofnodes.simple.util.SB;
 // 12-bit integer constant.  Larger constants are made up in the instruction
 // selection by adding with a LUI.
 public class IntRISC extends ConstantNode implements MachNode {
-    public IntRISC(ConstantNode con) { super(con); }
+    IntRISC(ConstantNode con) { super(con); }
     @Override public String op() { return "ldi"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java
index 7e08a01d..592cdb84 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java
@@ -2,7 +2,9 @@ package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.*;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 // Load memory addressing on RISC
 // Support imm, reg(direct), or reg+off(indirect) addressing
@@ -21,6 +23,39 @@ public class LoadRISC extends MemOpRISC {
         if( dst >= riscv.F_OFFSET  ) dst -= riscv.F_OFFSET;
         enc.add4(riscv.i_type(op, dst, func3(), ptr, _off));
     }
+    @Override int func3() {
+        int func3 = -1;
+        // no unsigned flavour for store, so both signed and unsigned trigger the same
+        Type declType = _con;
+        if( declType == TypeInteger. I8 ) func3=0; // LB
+        if( declType == TypeInteger.I16 ) func3=1; // LH
+        if( declType == TypeInteger.I32 ) func3=2; // LW
+        if( declType == TypeInteger.BOT ) func3=3; // LD
+        if( declType == TypeInteger. U8 ) func3=4; // LBU
+        if( declType == TypeInteger.BOOL) func3=4; // LBU
+        if( declType == TypeInteger.U16 ) func3=5; // LHU
+        if( declType == TypeInteger.U32 ) func3=6; // LWU
+        if( declType instanceof TypeInteger ti ) {
+            if( -128 <= ti._min && ti._max < 128 ) func3 = 0; // LB
+        }
+
+        // float
+        if( declType == TypeFloat.F32) func3 = 2; // fLW   fSW
+        if( declType == TypeFloat.F64) func3 = 3; // fLD   fSD
+
+        if( declType instanceof TypeMemPtr) func3 = 3; // 8 byte pointers (pick ld)
+        if( declType instanceof TypeFunPtr) func3 = 3; // 8 byte function pointers
+        if( declType instanceof TypeConAry ary )
+            func3 = switch( ary.log_size() ) {
+            case 0 -> 4;         // LBU
+            case 1 -> 5;         // LHU
+            case 2 -> 2;         // LW
+            case 3 -> 3;         // LD
+            default -> throw Utils.TODO("RISC-V constant-array load for "+declType);
+            };
+        if( func3 == -1 ) throw Utils.TODO("RISC-V load for "+declType);
+        return func3;
+    }
 
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(",");
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java
index b9e6e5ba..79f22fb8 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java
@@ -10,6 +10,7 @@ import java.util.BitSet;
 public abstract class MemOpRISC extends MemOpNode implements MachNode {
     final int _off;             // Limit 12 bits
     final char _sz;
+    final int _bytes;
     MemOpRISC(MemOpNode mop, Node base, int off, Node val) {
         super(mop,mop);
         assert base._type instanceof TypeMemPtr;
@@ -17,7 +18,8 @@ public abstract class MemOpRISC extends MemOpNode implements MachNode {
         _inputs.setX(3, null);  // Never an index
         _inputs.setX(4, val );
         _off = off;
-        _sz = (char)('0'+(1<<_declaredType.log_size()));
+        _bytes = mop instanceof StoreNode st ? st.storeSize() : 1<<_con.log_size();
+        _sz = (char)('0'+_bytes);
     }
 
     @Override public String label() { return op(); }
@@ -29,38 +31,7 @@ public abstract class MemOpRISC extends MemOpNode implements MachNode {
     @Override public Node idealize() { throw Utils.TODO(); }
 
     // func3 is based on load/store size and extend
-    int func3() {
-        int func3 = -1;
-        // no unsigned flavour for store, so both signed and unsigned trigger the same
-        if(this instanceof StoreRISC) {
-            if( _declaredType == TypeInteger. I8 || _declaredType == TypeInteger.U8  || _declaredType == TypeInteger.BOOL) func3=0; //   SB
-            if( _declaredType == TypeInteger.I16 || _declaredType == TypeInteger.U16 ) func3=1; // SH
-            if( _declaredType == TypeInteger.I32 || _declaredType == TypeInteger.U32 ) func3=2; //  SW
-            if( _declaredType instanceof TypeMemPtr) func3=3; //  SD
-            if( _declaredType == TypeInteger.BOT   ) func3=3; //   SD
-            if( func3 == -1 ) throw Utils.TODO();
-            return func3;
-        }
-        if( _declaredType == TypeInteger. I8 ) func3=0; // LB
-        if( _declaredType == TypeInteger.I16 ) func3=1; // LH
-        if( _declaredType == TypeInteger.I32 ) func3=2; // LW
-        if( _declaredType == TypeInteger.BOT ) func3=3; // LD
-        if( _declaredType == TypeInteger. U8 ) func3=4; // LBU
-        if( _declaredType == TypeInteger.BOOL) func3=4; // LBU
-        if( _declaredType == TypeInteger.U16 ) func3=5; // LHU
-        if( _declaredType == TypeInteger.U32 ) func3=6; // LWU
-        if( _declaredType instanceof TypeInteger ti ) {
-            if( -128 <= ti._min && ti._max < 128 ) func3 = 0; // LB
-        }
-
-        // float
-        if( _declaredType == TypeFloat.F32) func3 = 2; // fLW   fSW
-        if( _declaredType == TypeFloat.F64) func3 = 3; // fLD   fSD
-
-        if( _declaredType instanceof TypeMemPtr) func3 = 3; // 8 byte pointers (pick ld)
-        if( func3 == -1 ) throw Utils.TODO();
-        return func3;
-    }
+    abstract int func3();
 
     // Register mask allowed on input i.
     @Override public RegMask regmap(int i) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java
index 6c03bda6..4a6583ce 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java
@@ -40,8 +40,9 @@ public class NewRISC extends NewNode implements MachNode, RIPRelSize {
 
     // General form: "alloc #bytes  PC"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p("ldi   a1=#1\n");
+        sb.p("\n");             // Multi-op trigger
+        sb.p("ldi   ").p(code._mach.regs()[_arg2Reg]).p(" = #1\n");
         sb.p("auipc a2=#calloc\n");
-        sb.p("call  a2+#calloc, a0");
+        sb.p("call  a2+#calloc");
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java
index 6082cbbf..58fa8a4b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java
@@ -8,7 +8,7 @@ import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 public class SplitRISC extends SplitNode {
-    SplitRISC( String kind, byte round ) { super(kind,round, new Node[2]); }
+    SplitRISC( LRG lrg, String kind, byte round ) { super(lrg, kind,round, new Node[2]); }
     @Override public RegMask regmap(int i) { return riscv.SPLIT_MASK; }
     @Override public RegMask outregmap() { return riscv.SPLIT_MASK; }
     @Override public void encoding( Encoding enc ) {
@@ -24,7 +24,7 @@ public class SplitRISC extends SplitNode {
             if( src >= riscv.MAX_REG ) {
                 throw Utils.TODO(); // Very rare stack-stack move
             }
-            int off = enc._fun.computeStackOffset(enc._code,dst);
+            int off = fun(enc).computeStackOffset(enc._code,dst);
             int op = srcX ? riscv.OP_STOREFP : riscv.OP_STORE;
             if( srcX ) src -= riscv.F_OFFSET;
             enc.add4(riscv.s_type(op, 0b011, riscv.RSP, src, off));
@@ -32,7 +32,7 @@ public class SplitRISC extends SplitNode {
         }
         if( src >= riscv.MAX_REG ) {
             // Load from SP
-            int off = enc._fun.computeStackOffset(enc._code,src);
+            int off = fun(enc).computeStackOffset(enc._code,src);
             int op = dstX ? riscv.OP_LOADFP : riscv.OP_LOAD;
             if( dstX ) dst -= riscv.F_OFFSET;
             enc.add4(riscv.i_type(op, dst, 0b011, riscv.RSP, off));
@@ -57,10 +57,4 @@ public class SplitRISC extends SplitNode {
             enc.add4(riscv.r_type(riscv.OP_FP, dst, 0, src - riscv.F_OFFSET, 0, 0b1110001));
         }
     }
-
-    // General form: "mov  dst = src"
-    @Override public void asm(CodeGen code, SB sb) {
-        FunNode fun = code._encoding==null ? null : code._encoding._fun;
-        sb.p(code.reg(this,fun)).p(" = ").p(code.reg(in(1),fun));
-    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java
index d06c0c35..ebd6a5ae 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java
@@ -3,6 +3,7 @@ package com.seaofnodes.simple.node.cpus.riscv;
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.*;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
@@ -39,6 +40,11 @@ public class StoreRISC extends MemOpRISC {
         enc.add4(riscv.s_type(op, func3()&7, ptr, val == -1 ? riscv.ZERO : val, _off));
     }
 
+    // func3 is based on load/store size and extend
+    @Override int func3() {
+        return Integer.numberOfTrailingZeros(_bytes);
+    }
+
     @Override public void asm(CodeGen code, SB sb) {
         asm_address(code,sb).p(",");
         if( val()==null ) sb.p("#").p("0");
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java
index 7e057507..1f269152 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java
@@ -1,46 +1,46 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.codegen.*;
-import com.seaofnodes.simple.node.ConstantNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeFunPtr;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
-public class TFPRISC extends ConstantNode implements MachNode, RIPRelSize {
-    TFPRISC(ConstantNode con) { super(con); }
+public class TFPRISC extends FunPtrNode implements MachNode, RIPRelSize {
+    final String _ext;
+    // Pointer to a Simple function
+    TFPRISC( FunPtrNode fptr ) { super(fptr); _ext = null; }
+    // Pointer to an Extern "C" function
+    TFPRISC( TypeFunPtr fptr, String ext ) { super(fptr,CodeGen.CODE._start,null); _type = fptr; _ext = ext; }
     @Override public String op() { return "ldx"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public TFPRISC copy() { return new TFPRISC(this); }
+    @Override public TFPRISC copy() { return new TFPRISC((TypeFunPtr)_con,_ext); }
     @Override public void encoding( Encoding enc ) {
-        enc.relo(this);
+        if( _ext==null ) enc.relo(this);          // Internal patch
+        else             enc.external(this,_ext); // ELF-file external patch
         // TODO: 1 op encoding, plus a TODO if it does not fit
         short dst = enc.reg(this);
-        TypeFunPtr tfp = (TypeFunPtr)_con;
         // auipc  t0,0
         enc.add4(riscv.u_type(riscv.OP_AUIPC, dst, 0));
         // addi   t1,t0 + #0
         enc.add4(riscv.i_type(riscv.OP_IMM, dst, 0, dst, 0));
     }
 
-    @Override public byte encSize(int delta) {
-        if( -(1L<<11) <= delta && delta < (1L<<11) ) return 4;
-        throw Utils.TODO();
-    }
+    @Override public byte encSize(int delta) { return 8; }
 
     // Delta is from opcode start
     @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
         short rpc = enc.reg(this);
         if( opLen==8 ) {
+            int hi20 = (delta + 0x800) >> 12;
+            int lo12 = delta - (hi20 << 12);
             // AUIPC (upper 20 bits)
             // opstart of add
-            int next = opStart + opLen;
-            enc.patch4(opStart,riscv.u_type(riscv.OP_AUIPC, rpc, delta>>12));
+            enc.patch4(opStart  ,riscv.u_type(riscv.OP_AUIPC, rpc, hi20));
             // addi(low 12 bits)
-            enc.patch4(next,riscv.i_type(riscv.OP_IMM, rpc, 0, rpc, delta & 0xFFF));
+            enc.patch4(opStart+4,riscv.i_type(riscv.OP_IMM, rpc, 0, rpc, lo12 & 0xFFF));
             // addi
         } else {
              // should not happen as one instruction is 4 byte, and TFP arm encodes 2.
@@ -49,7 +49,7 @@ public class TFPRISC extends ConstantNode implements MachNode, RIPRelSize {
     }
 
     @Override public void asm(CodeGen code, SB sb) {
-        _con.print(sb.p(code.reg(this)).p(" #"));
+        _type.print(sb.p(code.reg(this)).p(" #"));
     }
     @Override public boolean eq(Node n) { return this==n; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TMPRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TMPRISC.java
index 44e73d1d..aa001e1e 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TMPRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TMPRISC.java
@@ -6,15 +6,18 @@ import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.Node;
 import com.seaofnodes.simple.type.TypeMemPtr;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 public class TMPRISC extends ConstantNode implements MachNode, RIPRelSize {
-    TMPRISC(ConstantNode con) { super(con); }
+    final String _ext;
+    TMPRISC( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ldp"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public TMPRISC copy() { return new TMPRISC(this); }
+    @Override public TMPRISC copy() { return new TMPRISC(this,_ext); }
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         enc.largeConstant(this,((TypeMemPtr)_con)._obj,0,-1);
         short dst = enc.reg(this);
         // AUIPC dst,#hi20_constant_pool
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
index 7a6361bc..078a7693 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
@@ -13,7 +13,6 @@ public class riscv extends Machine {
     }
 
     @Override public String name() {return "riscv";}
-    //@Override public int maxReg() { return MAX_REG; }
 
     // Using ABI names instead of register names
     public static int ZERO =  0,  RPC=  1,  RSP=  2,  S12=  3,  S13=  4,  T0 =  5,  T1 =  6,  T2 =  7;
@@ -32,24 +31,24 @@ public class riscv extends Machine {
     public static final int F_OFFSET = 32;
 
     static final String[] REGS = new String[] {
-        "zero","rpc"  , "rsp" , "s12" , "s13" , "t0"  , "t1"  , "t2"  ,
-        "s0"  , "s1"  , "a0"  , "a1"  , "a2"  , "a3"  , "a4"  , "a5"  ,
-        "a6"  , "a7"  , "s2"  , "s3"  , "s4"  , "s5"  , "s6"  , "s7"  ,
-        "s8"  , "s9"  , "s10" , "s11" , "t3"  , "t4"  , "t5"  , "t6"  ,
-        "f0"  , "f1"  , "f2"  , "f3"  , "f4"  , "f5"  , "f6"  , "f7"  ,
-        "fs0" , "fs1" , "fa0" , "fa1" , "fa2" , "fa3" , "fa4" , "fa5" ,
-        "fa6" , "fa7" , "fs2" , "fs3" , "fs4" , "fs5" , "fs6" , "fs7" ,
-        "fs8" , "fs9" , "fs10", "fs11", "ft8" , "ft9" , "ft10", "ft11"
-        // Register-based naming hella easier to debug than "official" register
-        // names when single-stepping in debugger.
-        //"zero", "r1"  , "rsp" , "r3" , "r4" , "r5" , "r6" , "r7" ,
-        //"r8"  , "r9"  , "r10" , "r11", "r12", "r13", "r14", "r15",
-        //"r16" , "r17" , "r18" , "r19", "r20", "r21", "r22", "r23",
-        //"r24" , "r25" , "r26" , "r27", "r28", "r29", "r30", "r31",
+        //"zero","rpc"  , "rsp" , "s12" , "s13" , "t0"  , "t1"  , "t2"  ,
+        //"s0"  , "s1"  , "a0"  , "a1"  , "a2"  , "a3"  , "a4"  , "a5"  ,
+        //"a6"  , "a7"  , "s2"  , "s3"  , "s4"  , "s5"  , "s6"  , "s7"  ,
+        //"s8"  , "s9"  , "s10" , "s11" , "t3"  , "t4"  , "t5"  , "t6"  ,
         //"f0"  , "f1"  , "f2"  , "f3"  , "f4"  , "f5"  , "f6"  , "f7"  ,
         //"fs0" , "fs1" , "fa0" , "fa1" , "fa2" , "fa3" , "fa4" , "fa5" ,
         //"fa6" , "fa7" , "fs2" , "fs3" , "fs4" , "fs5" , "fs6" , "fs7" ,
         //"fs8" , "fs9" , "fs10", "fs11", "ft8" , "ft9" , "ft10", "ft11"
+        // Register-based naming hella easier to debug than "official" register
+        // names when single-stepping in debugger.
+        "zero", "r1"  , "rsp" , "r3" , "r4" , "r5" , "r6" , "r7" ,
+        "r8"  , "r9"  , "r10" , "r11", "r12", "r13", "r14", "r15",
+        "r16" , "r17" , "r18" , "r19", "r20", "r21", "r22", "r23",
+        "r24" , "r25" , "r26" , "r27", "r28", "r29", "r30", "r31",
+        "f0"  , "f1"  , "f2"  , "f3"  , "f4"  , "f5"  , "f6"  , "f7"  ,
+        "fs0" , "fs1" , "fa0" , "fa1" , "fa2" , "fa3" , "fa4" , "fa5" ,
+        "fa6" , "fa7" , "fs2" , "fs3" , "fs4" , "fs5" , "fs6" , "fs7" ,
+        "fs8" , "fs9" , "fs10", "fs11", "ft8" , "ft9" , "ft10", "ft11"
     };
     @Override public String[] regs() { return REGS; }
 
@@ -91,7 +90,7 @@ public class riscv extends Machine {
     public static RegMask FA6_MASK = new RegMask(FA6);
     public static RegMask FA7_MASK = new RegMask(FA7);
 
-    // Int arguments calling conv
+    // Int/ptr arguments calling convention
     static RegMask[] CALLINMASK = new RegMask[] {
         A0_MASK,
         A1_MASK,
@@ -257,10 +256,16 @@ public class riscv extends Machine {
         if( idx==0 ) return RPC_MASK;
         if( idx==1 ) return null;
         if( idx-2 >= tfp.nargs() ) return null; // Anti-dependence
+        boolean hidden = hiddenSelf(tfp);
+        int sigidx = idx-2;
+        if( hidden ) {
+            if( sigidx==0 ) return null;
+            sigidx--;
+        }
         // Count floats in signature up to index
         int fcnt=0;
-        for( int i=2; i<idx; i++ )
-            if( tfp.arg(i-2) instanceof TypeFloat )
+        for( int i=hidden ? 1 : 0; i<idx-2; i++ )
+            if( tfp.arg(i) instanceof TypeFloat )
                 fcnt++;
         // Floats up to XMMS in XMM registers
         if( tfp.arg(idx-2) instanceof TypeFloat ) {
@@ -268,23 +273,26 @@ public class riscv extends Machine {
                 return XMMS[fcnt];
         } else {
             RegMask[] cargs = CALLINMASK;
-            if( idx-2-fcnt < cargs.length )
-                return cargs[idx-2-fcnt];
+            if( sigidx-fcnt < cargs.length )
+                return cargs[sigidx-fcnt];
         }
         // Pass on stack slot(8 and higher)
         if( maxArgSlot>0 ) throw Utils.TODO();
-        return new RegMask(MAX_REG + 1 + (idx - 2));
+        return new RegMask(MAX_REG + 1 + sigidx);
     }
 
     @Override public short maxArgSlot( TypeFunPtr tfp ) {
         int icnt=0, fcnt=0;     // Count of ints, floats
-        for( int i=0; i<tfp.nargs(); i++ ) {
+        for( int i=hiddenSelf(tfp) ? 1 : 0; i<tfp.nargs(); i++ ) {
             if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
             else icnt++;
         }
         int nstk = Math.max(icnt-8,0)+Math.max(fcnt-8,0);
         return (short)nstk;
     }
+    private static boolean hiddenSelf(TypeFunPtr tfp) {
+        return tfp.nargs() > 0 && tfp.arg(0) == TypePtr.PTR;
+    }
 
     static final long CALLER_SAVE =
         (1L<<RPC) |
@@ -306,7 +314,7 @@ public class riscv extends Machine {
     @Override public CFGNode jump() { return new UJmpRISC(); }
 
     // Create a split op; any register to any register, including stack slots
-    @Override  public SplitNode split(String kind, byte round, LRG lrg) { return new SplitRISC(kind,round);  }
+    @Override public SplitNode split(LRG lrg, String kind, byte round ) { return new SplitRISC(lrg, kind,round);  }
 
     // True if signed 12-bit immediate
     public static boolean imm12(TypeInteger ti) {
@@ -323,28 +331,34 @@ public class riscv extends Machine {
 
     @Override public Node instSelect( Node n ) {
         return switch (n) {
-        case AddFNode    addf -> addf(addf);
         case AddNode      add -> add(add);
         case AndNode      and -> and(and);
         case BoolNode    bool -> cmp(bool);
         case CallNode    call -> call(call);
-        case CastNode   cast  -> new CastMach(cast);
+        case CheckCastNode cast -> new CheckCastMach(cast);
+        case PtrToIntNode  ptr -> new PtrToIntMach(ptr);
+        case GuardNode guard  -> new GuardMach(guard);
         case CallEndNode cend -> new CallEndMach(cend);
         case CProjNode      c -> new CProjNode(c);
         case ConstantNode con -> con(con);
-        case DivFNode    divf -> new DivFRISC(divf);
-        case DivNode      div -> new DivRISC(div);
+        case DivNode      div -> div.mode()==2 ? new DivFRISC(div) : new DivRISC(div);
+        case EscapeNode   esc -> new EscapeNode(esc);
         case FunNode      fun -> new FunRISC(fun);
+        case FunPtrNode  fptr -> fptr(fptr);
         case IfNode       iff -> jmp(iff);
         case LoadNode      ld -> ld(ld);
         case MemMergeNode mem -> new MemMergeNode(mem);
-        case MinusNode    neg -> new NegRISC(neg);
-        case MulFNode    mulf -> new MulFRISC(mulf);
-        case MulNode      mul -> new MulRISC(mul);
+        case MinusNode    neg -> {
+            if( neg.mode()==2 ) throw Utils.TODO();
+            yield new NegRISC(neg);
+        }
+        case MulNode      mul -> mul.mode()==2 ? new MulFRISC(mul) : new MulRISC(mul);
         case NewNode      nnn -> nnn(nnn);
         case NotNode      not -> new NotRISC(not);
         case OrNode        or -> or(or);
         case ParmNode    parm -> new ParmRISC(parm);
+        case BulkMemPhiNode phi-> new BulkMemPhiNode(phi);
+        case MemPhiNode  phi  -> new MemPhiNode(phi);
         case PhiNode      phi -> new PhiNode(phi);
         case ProjNode     prj -> prj(prj);
         case ReadOnlyNode read-> new ReadOnlyMach(read);
@@ -352,11 +366,12 @@ public class riscv extends Machine {
         case SarNode      sar -> sra(sar);
         case ShlNode      shl -> sll(shl);
         case ShrNode      shr -> srl(shr);
+        case StartCUNode start -> new StartCUNode(start);
+        case StopCUNode  stop -> new StopCUNode(stop);
         case StartNode  start -> new StartNode(start);
         case StopNode    stop -> new StopNode(stop);
         case StoreNode     st -> st(st);
-        case SubFNode    subf -> new SubFRISC(subf);
-        case SubNode      sub -> sub(sub);
+        case SubNode      sub -> sub.mode()==2 ? new SubFRISC(sub) : sub(sub);
         case ToFloatNode  tfn -> i2f8(tfn);
         case XorNode      xor -> xor(xor);
 
@@ -366,11 +381,9 @@ public class riscv extends Machine {
         };
     }
 
-    private Node addf(AddFNode addf) {
-        return new AddFRISC(addf);
-    }
-
     private Node add(AddNode add) {
+        if( add.mode()==2 )
+            return new AddFRISC(add);
         if( add.in(2) instanceof ConstantNode off2 && off2._con instanceof TypeInteger ti && imm12(ti) )
             return new AddIRISC(add, (int)ti.value(),true);
         return new AddRISC(add);
@@ -388,8 +401,10 @@ public class riscv extends Machine {
     }
 
     private Node call(CallNode call) {
-        return call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp
-            ? new CallRISC(call, tfp)
+        return call.fptr() instanceof FunPtrNode fptr
+            ? new CallRISC(call, (TypeFunPtr)fptr._type)
+            : call.fptr() instanceof ConstantNode con
+            ? new CallRISC(call, (TypeFunPtr)con._type)
             : new CallRRISC(call);
     }
     private Node nnn(NewNode nnn) {
@@ -428,9 +443,13 @@ public class riscv extends Machine {
     }
 
     private Node con( ConstantNode con ) {
-        if( !con._con.isConstant() ) return new ConstantNode( con ); // Default unknown caller inputs
+        if( !con._con.isConstant() )
+            return ConstantNode.raw(con); // Default unknown caller inputs
+        String ext = con instanceof ExternNode ext0 ? ext0._extern : null;
         return switch( con._con ) {
         case TypeInteger ti -> {
+            // External; without knowing the size assume we have to load something
+            if( ext!=null ) yield new Int8RISC(con,ext);
             if( imm12(ti) ) yield new IntRISC(con);
             long x = ti.value();
             if( imm20Exact(ti) ) yield new LUI((int)x);
@@ -443,18 +462,22 @@ public class riscv extends Machine {
             }
             // Need more complex sequence for larger constants... or a load
             // from a constant pool, which does not need an extra register
-            yield new Int8RISC(con);
+            yield new Int8RISC(con,null);
         }
         // Load from constant pool
-        case TypeFloat   tf  -> new FltRISC(con);
-        case TypeFunPtr  tfp -> new TFPRISC(con);
-        case TypeMemPtr  tmp -> new TMPRISC(con);
+        case TypeFloat   tf  -> new FltRISC(con,ext);
+        case TypeMemPtr  tmp -> new TMPRISC(con,ext);
+        case TypeFunPtr  tfp -> new TFPRISC(tfp,ext);
         case TypeNil     tn  -> throw Utils.TODO();
         // TOP, BOTTOM, XCtrl, Ctrl, etc.  Never any executable code.
-        case Type t -> t==Type.NIL ? new IntRISC(con) : new ConstantNode(con);
+        case Type t -> t==Type.NIL ? new IntRISC(con) : ConstantNode.raw(con);
         };
     }
 
+    private Node fptr( FunPtrNode con ) {
+        return new TFPRISC(con);
+    }
+
     private Node jmp( IfNode iff ) {
         if( iff.in(1) instanceof BoolNode bool && !bool.isFloat() ) {
             // if less than or equal switch inputs
@@ -509,7 +532,7 @@ public class riscv extends Machine {
     }
 
     private Node prj(ProjNode prj) {
-        return new ProjRISC(prj);
+        return prj.in(0) instanceof StartNode ? new ProjNode(prj) : new ProjRISC(prj);
     }
 
     private Node ld(LoadNode ld) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java
index 2513de37..093e2bd2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java
@@ -6,7 +6,7 @@ import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 public class AddFMemX86 extends MemOpX86 {
-    AddFMemX86( AddFNode add, LoadNode ld , Node base, Node idx, int off, int scale, Node val ) {
+    AddFMemX86( AddNode add, LoadNode ld , Node base, Node idx, int off, int scale, Node val ) {
         super(add,ld, base, idx, off, scale, 0, val );
     }
     @Override public String op() { return "addf"+_sz; }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java
index 460f568b..14b8e4da 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java
@@ -20,7 +20,7 @@ public class CallRX86 extends CallNode implements MachNode {
         // calls the function in the register
         short src = enc.reg(fptr());
         enc.add1(0xFF);
-        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT,2,src));
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT,2,src));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java
index d74e3833..989895b2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java
@@ -8,21 +8,27 @@ import com.seaofnodes.simple.util.SB;
 public class CallX86 extends CallNode implements MachNode, RIPRelSize {
     final TypeFunPtr _tfp;
     final String _name;
+    final boolean _extern;
     CallX86( CallNode call, TypeFunPtr tfp ) {
         super(call);
         _inputs.pop(); // Pop constant target
         assert tfp.isConstant();
         _tfp = tfp;
-        FunNode fun = CodeGen.CODE.link(tfp);
-        _name = fun==null ? ((ExternNode)call.fptr())._extern : fun._name; // Can be null for extern calls
+        _name = CodeGen.CODE.funcName(tfp.fidx());
+        _extern = CodeGen.CODE.externFunc(tfp.fidx()) != null;
     }
     @Override public String op() { return "call"; }
     @Override public String label() { return op(); }
     @Override public String name() { return _name; }
     @Override public TypeFunPtr tfp() { return _tfp; }
-    @Override public RegMask regmap(int i) { return x86_64_v2.callInMask(_tfp,i,fun()._maxArgSlot);  }
+    @Override public RegMask regmap(int i) {
+        return _extern
+            ? x86_64_v2.callInMask(_tfp,i,fun()._maxArgSlot,CodeGen.CODE._cCallingConv)
+            : x86_64_v2.callInMask(_tfp,i,fun()._maxArgSlot);
+    }
     @Override public RegMask outregmap() { return null; }
     @Override public int nargs() { return nIns()-2; } // Minus control, memory, fptr
+    @Override public boolean external() { return _extern; }
 
     @Override public void encoding( Encoding enc ) {
         FunNode fun = CodeGen.CODE.link(_tfp);
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
index 11f900ed..24812fea 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
@@ -25,7 +25,7 @@ public class CmpMemX86 extends MemOpX86 {
 
         if(src == -1) {
             assert !_swap;
-            int log = _declaredType.log_size();
+            int log = _con.log_size();
             x86_64_v2.rexF(-1, ptr, idx, log==3, enc);
             switch(log) {
             case 0: enc.add1(0x80); break;
@@ -41,7 +41,7 @@ public class CmpMemX86 extends MemOpX86 {
             case 3: enc.add8(_imm); break;
             }
         } else {
-            encVal(enc, _declaredType, ptr, idx, src, _off, _scale, _swap);
+            encVal(enc, _con, ptr, idx, src, _off, _scale, _swap);
         }
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
index 9bcbac8f..15e95374 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
@@ -3,17 +3,20 @@ package com.seaofnodes.simple.node.cpus.x86_64_v2;
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 public class FltX86 extends ConstantNode implements MachNode, RIPRelSize{
     private byte _encSize;
-    FltX86(ConstantNode con ) { super(con); }
+    final String _ext;
+    FltX86( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public Node copy() { return new FltX86(this); }
+    @Override public Node copy() { return new FltX86(this,_ext); }
 
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         // Load the constant into a FPR
         // movsd xmm, [rip + 0]
         // F2 0F 10 /r MOVSD xmm1, m64
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java
index cbd5fdbf..1724109a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java
@@ -10,6 +10,7 @@ public class FunX86 extends FunNode implements MachNode {
     FunX86( FunNode fun ) { super(fun); }
     @Override public void postSelect(CodeGen code) {
         super.postSelect(code);
+        _maxArgSlot = code._mach.maxArgSlot(sig(),code._callingConv);
         // One more for RPC pre-pushed; X86 special
         _maxArgSlot++;
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java
index 3f2f696c..1973ea4e 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java
@@ -5,15 +5,17 @@ import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 // Integer constants
 public class IntX86 extends ConstantNode implements MachNode {
-    IntX86( ConstantNode con ) { super(con); }
+    final String _ext;
+    IntX86( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() {
         return _con == Type.NIL || _con == TypeInteger.ZERO ? "xor" : "ldi";
     }
     @Override public boolean isClone() { return true; }
-    @Override public Node copy() { return new IntX86(this); }
+    @Override public Node copy() { return new IntX86(this,_ext); }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
     // Zero-set uses XOR kills flags
@@ -33,6 +35,7 @@ public class IntX86 extends ConstantNode implements MachNode {
             return;
         }
 
+        if( _ext!=null ) throw Utils.TODO();
         // Simply move the constant into a GPR
         // Conditional encoding based on 64 or 32 bits
         //REX.W + C7 /0 id	MOV r/m64, imm32
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java
index 441cf693..c55002c1 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java
@@ -12,7 +12,7 @@ public class LoadX86 extends MemOpX86 {
         super(ld,ld, base, idx, off, scale, 0);
     }
     @Override public String op() { return "ld"+_sz; }
-    @Override public RegMask outregmap() { return x86_64_v2.MEM_MASK; }
+    @Override public RegMask outregmap() { return _con instanceof TypeFloat ? x86_64_v2.XMASK : x86_64_v2.WMASK; }
     @Override public void encoding( Encoding enc ) {
         // REX.W + 8B /r	MOV r64, r/m64
         // Zero extension for u8, u16 and u32 but sign extension i8, i16, i32
@@ -20,7 +20,7 @@ public class LoadX86 extends MemOpX86 {
         short dst = enc.reg(this );
         short ptr = enc.reg(ptr());
         short idx = enc.reg(idx());
-        enc(enc, _declaredType, dst, ptr, idx, _off, _scale);
+        enc(enc, _con, dst, ptr, idx, _off, _scale);
     }
 
     static void enc( Encoding enc, Type decl, short dst, short ptr, short idx, int off, int scale ) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java
index 5f090717..6069c07b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java
@@ -41,7 +41,8 @@ public abstract class MemOpX86 extends MemOpNode implements MachNode {
         _off = off;
         _scale = scale;
         _imm = imm;
-        _sz = (char)('0'+(1<<_declaredType.log_size()));
+        int size = mop instanceof StoreNode st ? st.storeSize() : 1<<_con.log_size();
+        _sz = (char)('0'+size);
     }
 
     // Store-based flavors have a value edge
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java
index 280b8185..1e9e708f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java
@@ -19,7 +19,7 @@ public class MulIX86 extends MachConcreteNode implements MachNode {
     @Override public final void encoding( Encoding enc ) {
         short dst = enc.reg(this ); // Also src1
         short src = enc.reg(in(1));
-        enc.add1(x86_64_v2.rex(src, dst, 0));
+        enc.add1(x86_64_v2.rex(dst, src, 0));
         // opcode; 0x69 or 0x6B
         enc.add1( 0x69 + (x86_64_v2.imm8(_imm) ? 2 : 0) );
         enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src) );
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java
index fc896dce..40a38809 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java
@@ -18,7 +18,8 @@ public class NewX86 extends NewNode implements MachNode {
     }
     // General form: "alloc #bytes  PC"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p("ldi   rcx = #1\n");
+        sb.p("\n");             // Multi-op trigger
+        sb.p("ldi   ").p(code._mach.regs()[_arg2Reg]).p(" = #1\n");
         sb.p("call  #calloc");
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java
index 4a14240a..bc3d421d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java
@@ -11,8 +11,7 @@ import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
 
 public class SplitX86 extends SplitNode {
-    SplitX86( String kind, byte round ) { super(kind,round, new Node[2]); }
-    @Override public String op() { return "mov"; }
+    SplitX86( LRG lrg, String kind, byte round ) { super(lrg,kind,round, new Node[2]); }
     @Override public RegMask regmap(int i) { return x86_64_v2.SPLIT_MASK; }
     @Override public RegMask outregmap() { return x86_64_v2.SPLIT_MASK; }
 
@@ -49,10 +48,10 @@ public class SplitX86 extends SplitNode {
 
         // Stack spills
         if( dst >= x86_64_v2.MAX_REG ) {
-            int off = enc._fun.computeStackOffset(enc._code,dst);
+            int off = fun(enc).computeStackOffset(enc._code,dst);
             if( src >= x86_64_v2.MAX_REG ) {
                 // Rare stack-stack move.  push [RSP+soff]; pop [RSP+doff]
-                int soff = enc._fun.computeStackOffset(enc._code,src);
+                int soff = fun(enc).computeStackOffset(enc._code,src);
                 enc.add1(0xFF);
                 x86_64_v2.indirectAdr(0, (short)-1/*index*/, (short)x86_64_v2.RSP, soff, 6, enc);
                 enc.add1(0x8F);
@@ -63,7 +62,7 @@ public class SplitX86 extends SplitNode {
             return;
         }
         if( src >= x86_64_v2.MAX_REG ) {
-            int off = enc._fun.computeStackOffset(enc._code,src);
+            int off = fun(enc).computeStackOffset(enc._code,src);
             LoadX86.enc(enc, dstX ? TypeFloat.F64 : TypeInteger.BOT, dst, (short)x86_64_v2.RSP, (short)-1, off, 0);
             return;
         }
@@ -98,10 +97,4 @@ public class SplitX86 extends SplitNode {
 
         enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
     }
-
-    // General form: "mov  dst = src"
-    @Override public void asm(CodeGen code, SB sb) {
-        FunNode fun = code._encoding==null ? null : code._encoding._fun;
-        sb.p(code.reg(this,fun)).p(" = ").p(code.reg(in(1),fun));
-    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java
index 4403b02b..faedeb8b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java
@@ -31,7 +31,7 @@ public class StoreX86 extends MemOpX86 {
         short src = enc.reg(val());
 
         if( src == -1 ) {
-            int log = _declaredType.log_size();
+            int log = Integer.numberOfTrailingZeros(_sz-'0');
             x86_64_v2.rexF(-1, ptr, idx, log==3, enc);
             switch( log ) {
             case 0: enc           .add1(0xC6); break;
@@ -47,7 +47,7 @@ public class StoreX86 extends MemOpX86 {
             case 3: enc.add4(_imm); break; // Limit of a 4 byte immediate
             }
         } else {
-            encVal(enc,_declaredType,ptr,idx,src,_off,_scale);
+            encVal(enc,_con,ptr,idx,src,_off,_scale);
         }
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java
index 359b6d83..8d8d3950 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java
@@ -2,54 +2,51 @@ package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.node.cpus.riscv.riscv;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFunPtr;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 // Function constants
-public class TFPX86 extends ConstantNode implements MachNode, RIPRelSize {
-    TFPX86( ConstantNode con ) {  super(con); }
-    @Override public String op() {
-        return _con == Type.NIL ? "xor" : "ldx";
-    }
+public class TFPX86 extends FunPtrNode implements MachNode, RIPRelSize {
+    private byte _opLen;
+    final String _ext;          // External name
+    // Pointer to a Simple function
+    TFPX86( FunPtrNode fptr ) { this((TypeFunPtr)fptr._type,null); }
+    // Spill clone: copy inputs without registering their reverse edges;
+    // insertBefore will place and register the clone in its use block.
+    private TFPX86( TFPX86 fptr ) { super(fptr); _ext = fptr._ext; }
+    // Pointer to an Extern "C" function
+    TFPX86( TypeFunPtr fptr, String ext ) { super(fptr,CodeGen.CODE._start,null); _type = fptr; _ext = ext; }
+    @Override public String op() { return "ldx"; }
+    @Override public String label() { return op(); }
+    // The ideal FunPtrNode is pinned because its Return input is a lifetime
+    // hook.  After selection this is an ordinary cloneable load-address
+    // instruction and must be scheduled down near its actual use.
+    @Override public boolean isPinned() { return false; }
     @Override public boolean isClone() { return true; }
-    @Override public Node copy() { return new TFPX86(this); }
+    @Override public TFPX86 copy() { return new TFPX86(this); }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    // Zero-set uses XOR kills flags
-    @Override public RegMask killmap() {
-        return _con == Type.NIL ? x86_64_v2.FLAGS_MASK : null;
-    }
-
     @Override public void encoding( Encoding enc ) {
-        short dst = enc.reg(this);
-        // Short form for zero
-        if( _con==Type.NIL ) {
-            // XOR dst,dst.  Can skip REX is dst is low 8, makes this a 32b
-            // xor, which will also zero the high bits.
-            if( dst >= 8 ) enc.add1(x86_64_v2.rex(dst, dst, 0));
-            enc.add1(0x33); // opcode
-            enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, dst));
-            return;
-        }
-
+        if( _ext==null ) enc.relo(this);          // Internal patch
+        else             enc.external(this,_ext); // ELF-file external patch
         // lea to load function pointer address
         // lea rax, [rip+disp32]
-        enc.relo(this);
-        enc.add1(x86_64_v2.rex(dst, 0, 0));
+        short dst = enc.reg(this);
+        // 0 or 1 for REX depending on the dst.
+        // Zero/sign extend should be fine, so not wide.
+        _opLen = (byte)(6+ x86_64_v2.rexF(dst, 0, 0, true, enc));
         enc.add1(0x8D); // opcode
         enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT, dst, 0b101));
         enc.add4(0);
     }
 
-    @Override public byte encSize(int delta) {
-        return 7;
-    }
+    @Override public byte encSize(int delta) { return _opLen; }
 
-    // Delta is from opcode start
+    // Delta is from opcode start, X86 expects it from opcode end
     @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
-        enc.patch4(opStart + 3, delta - 7);
+        enc.patch4(opStart + opLen - 4, delta - opLen);
     }
 
     // Human-readable form appended to the SB.  Things like the encoding,
@@ -57,11 +54,9 @@ public class TFPX86 extends ConstantNode implements MachNode, RIPRelSize {
     // Just something like "ld4\tR17=[R18+12] // Load array base".
     // General form: "op\tdst=src+src"
     @Override public void asm(CodeGen code, SB sb) {
-        String reg = code.reg(this);
-        if( _con == Type.NIL )
-            sb.p(reg).p(",").p(reg);
-        else
-            _con.print(sb.p(reg).p(" = #"));
+        sb.p(code.reg(this));
+        if( _ext == null ) _type.print(sb.p(" #"));
+        else sb.p(_ext);
     }
     @Override public boolean eq(Node n) { return this==n; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TMPX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TMPX86.java
index c23f6c5f..cc8741b3 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TMPX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TMPX86.java
@@ -4,32 +4,33 @@ import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeMemPtr;
 import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
 
 public class TMPX86 extends ConstantNode implements MachNode, RIPRelSize{
-    TMPX86(ConstantNode con ) { super(con); }
+    private byte _opLen;
+    final String _ext;
+    TMPX86( ConstantNode con, String ext ) { super(con); _ext = ext; }
     @Override public String op() { return "ldp"; }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public Node copy() { return new TMPX86(this); }
+    @Override public Node copy() { return new TMPX86(this,_ext); }
 
     @Override public void encoding( Encoding enc ) {
+        if( _ext!=null ) throw Utils.TODO();
         short dst = enc.reg(this);
-        x86_64_v2.rexF(dst, 0, 0, true, enc);
+        // 0 or 1 for REX depending on the dst.
+        _opLen = (byte)(6+ x86_64_v2.rexF(dst, 0, 0, true, enc));
         enc.add1(0x8D).add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT, dst, 0b101)).add4(0);
-        int opLen = 1/*rexF*/+1/*opcode 0x8D*/+1/*modrm*/+4/*pc rel offset*/;
-        // Base of constant array
-        TypeMemPtr tmp = (TypeMemPtr)_con;
-        int baseOff = tmp._obj.aryBase();
-        enc.largeConstant(this,tmp._obj,opLen-baseOff,2/*ELF encoding PC32*/);
+        enc.largeConstant(this,((TypeMemPtr)_con)._obj, _opLen-4, 2/*ELF encoding PC32*/);
     }
 
     // Delta is from opcode start
-    @Override public byte encSize(int delta) { return (byte)7; }
+    @Override public byte encSize(int delta) { return _opLen; }
 
     // Delta is from opcode start
     @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
-        enc.patch4(opStart+opLen-4,delta-opLen);
+        enc.patch4(opStart + opLen - 4, delta - opLen);
     }
 
     @Override public void asm(CodeGen code, SB sb) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
index 026e12aa..a1ad17dc 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
@@ -70,7 +70,7 @@ public class x86_64_v2 extends Machine {
     public static int REX_WB = 0x49;
 
     public enum MOD {
-        INDIRECT,               //  [mem]
+        INDIRECT,               // [mem]
         INDIRECT_disp8,         // [mem + 0x12]
         INDIRECT_disp32,        // [mem + 0x12345678]
         DIRECT,                 // mem
@@ -188,22 +188,29 @@ public class x86_64_v2 extends Machine {
     // Map from function signature and argument index to register.
     // Used to set input registers to CallNodes, and ParmNode outputs.
     @Override public RegMask callArgMask( TypeFunPtr tfp, int idx, int maxArgSlot ) { return callInMask(tfp,idx,maxArgSlot); }
+    @Override public RegMask callArgMask( TypeFunPtr tfp, int idx, int maxArgSlot, String conv ) { return callInMask(tfp,idx,maxArgSlot,conv); }
     static RegMask callInMask( TypeFunPtr tfp, int idx, int maxArgSlot ) {
+        return callInMask(tfp,idx,maxArgSlot,CodeGen.CODE._callingConv);
+    }
+    static RegMask callInMask( TypeFunPtr tfp, int idx, int maxArgSlot, String conv ) {
         if( idx==0 ) return RPC_MASK;
         if( idx==1 ) return null;
         if( idx-2 >= tfp.nargs() ) return null; // Anti-dependence
-        return switch( CodeGen.CODE._callingConv ) {
+        return switch( conv ) {
         case "SystemV" -> callSys5 (tfp,idx,maxArgSlot);
-        case "Win64"   -> callWin64(tfp,idx,maxArgSlot);
+        case "win64"   -> callWin64(tfp,idx,maxArgSlot);
         default -> throw Utils.TODO();
         };
     }
 
     // Maximum stack args used by this signature
     @Override public short maxArgSlot( TypeFunPtr tfp ) {
-        return switch( CodeGen.CODE._callingConv ) {
+        return maxArgSlot(tfp,CodeGen.CODE._callingConv);
+    }
+    @Override public short maxArgSlot( TypeFunPtr tfp, String conv ) {
+        return switch( conv ) {
         case "SystemV" -> maxArgSlotSys5 (tfp);
-        case "Win64"   -> maxArgSlotWin64(tfp);
+        case "win64"   -> maxArgSlotWin64(tfp);
         default -> throw Utils.TODO();
         };
     }
@@ -236,14 +243,22 @@ public class x86_64_v2 extends Machine {
     static RegMask callWin64(TypeFunPtr tfp, int idx, int maxArgSlot ) {
         // idx 2,3,4,5 passed in registers, with stack slot mirrors.
         // idx >= 6 passed on stack, starting at slot#1 (#0 reserved for RPC).
-        if( idx >= 6 )
-            return new RegMask(MAX_REG+maxArgSlot+(idx-2));
+        int sigidx = idx-2;
+        if( hiddenSelf(tfp) ) {
+            if( sigidx==0 ) return null;
+            sigidx--;
+        }
+        if( sigidx >= 4 )
+            return new RegMask(MAX_REG+maxArgSlot+sigidx);
         return tfp.arg(idx-2) instanceof TypeFloat
-            ? XMMS8     [idx-2]
-            : WIN64_CALL[idx-2];
+            ? XMMS8     [sigidx]
+            : WIN64_CALL[sigidx];
     }
     static short maxArgSlotWin64(TypeFunPtr tfp) {
-        return (short)tfp.nargs();
+        return (short)Math.max(4,tfp.nargs() - (hiddenSelf(tfp) ? 1 : 0));
+    }
+    static short maxIncomingArgSlotWin64(TypeFunPtr tfp) {
+        return (short)Math.max(0,tfp.nargs() - (hiddenSelf(tfp) ? 1 : 0) - 4);
     }
 
     // Sys5: max 6 GPRs and 8 FPRS filled first.  Extra args land in increasing
@@ -277,9 +292,14 @@ public class x86_64_v2 extends Machine {
     static RegMask callSys5(TypeFunPtr tfp, int idx, int maxArgSlot ) {
         // First 6 integers passed in registers: rdi,rsi,rdx,rcx,r08,r09
         // First 8 floats passed in registers: xmm0-xmm7
+        int sigidx = idx-2;
+        if( hiddenSelf(tfp) ) {
+            if( sigidx==0 ) return null;
+            sigidx--;
+        }
         int icnt=0, fcnt=0;     // Count of ints, floats
-        for( int i=2; i<idx; i++ ) {
-            if( tfp.arg(i-2) instanceof TypeFloat ) fcnt++;
+        for( int i=hiddenSelf(tfp) ? 1 : 0; i<idx-2; i++ ) {
+            if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
             else icnt++;
         }
         int nstk = Math.max(icnt-6,0)+Math.max(fcnt-8,0);
@@ -289,13 +309,16 @@ public class x86_64_v2 extends Machine {
     }
     static short maxArgSlotSys5(TypeFunPtr tfp) {
         int icnt=0, fcnt=0;     // Count of ints, floats
-        for( int i=0; i<tfp.nargs(); i++ ) {
+        for( int i=hiddenSelf(tfp) ? 1 : 0; i<tfp.nargs(); i++ ) {
             if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
             else icnt++;
         }
         int nstk = Math.max(icnt-6,0)+Math.max(fcnt-8,0);
         return (short)nstk;
     }
+    private static boolean hiddenSelf(TypeFunPtr tfp) {
+        return tfp.nargs() > 0 && tfp.arg(0) == TypePtr.PTR;
+    }
 
     static final long SYSTEM5_CALLER_SAVE =
         (1L << RAX) | (1L << RCX) | (1L << RDX) |
@@ -314,12 +337,18 @@ public class x86_64_v2 extends Machine {
         (1L<<XMM4) | (1L<<XMM5) ;
 
     @Override public long callerSave() {
-        return switch (CodeGen.CODE._callingConv) {
+        return callerSave(CodeGen.CODE._callingConv);
+    }
+    @Override public long callerSave(String conv) {
+        return switch (conv) {
         case "SystemV" -> SYSTEM5_CALLER_SAVE;
-        case "Win64"   ->   WIN64_CALLER_SAVE;
-        default -> throw new IllegalArgumentException("Unknown calling convention: " + CodeGen.CODE._callingConv);
+        case "win64"   ->   WIN64_CALLER_SAVE;
+        default -> throw new IllegalArgumentException("Unknown calling convention: " + conv);
         };
     }
+    @Override public String cCallingConv(String callingConv) {
+        return callingConv;
+    }
     @Override public long neverSave() { return 1L<<RSP; }
     @Override public RegMask retMask( TypeFunPtr tfp ) {
         return tfp.ret() instanceof TypeFloat ? XMM0_MASK : RAX_MASK;
@@ -328,8 +357,8 @@ public class x86_64_v2 extends Machine {
 
 
     // Create a split op; any register to any register, including stack slots
-    @Override public SplitNode split(String kind, byte round, LRG lrg) {
-        return new SplitX86(kind, round);
+    @Override public SplitNode split(LRG lrg, String kind, byte round ) {
+        return new SplitX86(lrg,kind, round);
     }
 
     // Return a MachNode unconditional branch
@@ -341,28 +370,34 @@ public class x86_64_v2 extends Machine {
     @Override
     public Node instSelect(Node n) {
         return switch (n) {
-        case AddFNode    addf -> addf(addf);
         case AddNode      add -> add(add);
         case AndNode      and -> and(and);
         case BoolNode    bool -> cmp(bool);
         case CProjNode      c -> new CProjNode(c);
         case CallEndNode cend -> new CallEndMach(cend);
         case CallNode    call -> call(call);
-        case CastNode    cast -> new CastMach(cast);
+        case CheckCastNode cast -> new CheckCastMach(cast);
+        case PtrToIntNode  ptr -> new PtrToIntMach(ptr);
+        case GuardNode  guard -> new GuardMach(guard);
         case ConstantNode con -> con(con);
-        case DivFNode    divf -> new DivFX86(divf);
-        case DivNode      div -> new DivX86(div);
+        case DivNode      div -> div.mode()==2 ? new DivFX86(div) : new DivX86(div);
+        case EscapeNode   esc -> new EscapeNode(esc);
         case FunNode      fun -> new FunX86(fun);
+        case FunPtrNode  fptr -> fptr(fptr);
         case IfNode       iff -> jmp(iff);
         case LoadNode      ld -> ld(ld);
         case MemMergeNode mem -> new MemMergeNode(mem);
-        case MinusNode    neg -> new NegX86(neg);
-        case MulFNode    mulf -> new MulFX86(mulf);
-        case MulNode      mul -> mul(mul);
+        case MinusNode    neg -> {
+            if( neg.mode()==2 ) throw Utils.TODO();
+            yield new NegX86(neg);
+        }
+        case MulNode      mul -> mul.mode()==2 ? new MulFX86(mul) : mul(mul);
         case NewNode      nnn -> new NewX86(nnn);
         case NotNode      not -> new NotX86(not);
         case OrNode        or -> or(or);
         case ParmNode    parm -> new ParmX86(parm);
+        case BulkMemPhiNode phi-> new BulkMemPhiNode(phi);
+        case MemPhiNode  phi  -> new MemPhiNode(phi);
         case PhiNode      phi -> new PhiNode(phi);
         case ProjNode     prj -> prj(prj);
         case ReadOnlyNode read-> new ReadOnlyMach(read);
@@ -370,13 +405,14 @@ public class x86_64_v2 extends Machine {
         case SarNode      sar -> sar(sar);
         case ShlNode      shl -> shl(shl);
         case ShrNode      shr -> shr(shr);
+        case StartCUNode start -> new StartCUNode(start);
+        case StopCUNode  stop -> new StopCUNode(stop);
         case StartNode  start -> new StartNode(start);
         case StopNode    stop -> new StopNode(stop);
         case StoreNode     st -> st(st);
-        case SubFNode    subf -> new SubFX86(subf);
-        case SubNode      sub -> sub(sub);
+        case SubNode      sub -> sub.mode()==2 ? new SubFX86(sub) : sub(sub);
         case ToFloatNode  tfn -> i2f8(tfn);
-        case XCtrlNode      x -> new ConstantNode(Type.XCONTROL);
+        case XCtrlNode      x -> ConstantNode.raw(Type.XCONTROL);
         case XorNode      xor -> xor(xor);
 
         case LoopNode loop -> new LoopNode(loop);
@@ -391,15 +427,12 @@ public class x86_64_v2 extends Machine {
 
     // Attempt a full LEA-style break down.
     private Node add(AddNode add) {
+        if( add.mode()==2 )
+            return new AddFX86(add);
         Node lhs = add.in(1);
         Node rhs = add.in(2);
-        if( lhs instanceof LoadNode ld && ld.nOuts() == 1 && ld._declaredType.log_size() >= 3)
+        if( lhs instanceof LoadNode ld && ld.nOuts() == 1 && ld.declaredType().log_size() >= 3)
             return new AddMemX86(add, address(ld), ld.ptr(), idx, off, scale, 0, rhs);
-
-//        if(rhs instanceof LoadNode ld && ld.nOuts() == 1 && ld._declaredType.log_size() >= 3) {
-//            throw Utils.TODO(); // Swap load sides
-//        }
-
         // Attempt a full LEA-style break down.
         // Returns one of AddX86, AddIX86, LeaX86, or LHS
         if( rhs instanceof ConstantNode off2 && off2._con instanceof TypeInteger toff ) {
@@ -422,17 +455,6 @@ public class x86_64_v2 extends Machine {
     }
 
 
-    private Node addf(AddFNode addf) {
-        if(addf.in(1) instanceof LoadNode ld && ld.nOuts() == 1)
-            return new AddFMemX86(addf, address(ld), ld.ptr(), idx, off, scale, addf.in(2));
-
-//        if(addf.in(2) instanceof LoadNode ld && ld.nOuts() == 1)
-//            throw Utils.TODO(); // Swap load sides
-
-        return new AddFX86(addf);
-    }
-
-
     private Node _lea(Node add, Node base, Node idx, int off) {
         int scale = 0;
         if( base instanceof ShlNode && !(idx instanceof ShlNode) )
@@ -456,8 +478,10 @@ public class x86_64_v2 extends Machine {
     }
 
     private Node call(CallNode call) {
-        return call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp
-            ? new CallX86(call, tfp)
+        return call.fptr() instanceof FunPtrNode con
+            ? new CallX86(call, (TypeFunPtr)con._type)
+            : call.fptr() instanceof ConstantNode con && con._type instanceof TypeFunPtr
+            ? new CallX86(call, (TypeFunPtr)con._type)
             : new CallRX86(call);
     }
 
@@ -482,11 +506,11 @@ public class x86_64_v2 extends Machine {
         // Since cmp does not record a BOP, SetX/Jmp need to know if the CMP is swapped.
 
         // Vs memory
-        if( lhs instanceof LoadNode ld && ld.nOuts() == 1 && rhs._type.isa(ld._declaredType) )
+        if( lhs instanceof LoadNode ld && ld.nOuts() == 1 && rhs._type.isa(ld.declaredType()) )
             return new CmpMemX86(bool, address(ld), ld.ptr(), idx, off, scale, imm(rhs), val, false);
 
         // Operands swap in the encoding directly, no need for Set/Jmp to swap `bop`
-        if( rhs instanceof LoadNode ld && ld.nOuts() == 1 && lhs._type.isa(ld._declaredType) &&
+        if( rhs instanceof LoadNode ld && ld.nOuts() == 1 && lhs._type.isa(ld.declaredType()) &&
             (val!=null || bool.op()=="==" || bool.op()=="!=") )
             return new CmpMemX86(bool, address(ld), ld.ptr(), idx, off, scale, imm(lhs), val, true );
 
@@ -504,18 +528,23 @@ public class x86_64_v2 extends Machine {
 
     private Node con( ConstantNode con ) {
         if( !con._con.isConstant() )
-            return new ConstantNode(con); // Default unknown caller inputs
+            return ConstantNode.raw(con); // Default unknown caller inputs
+        String ext = con instanceof ExternNode ext0 ? ext0._extern : null;
         return switch (con._con) {
-        case TypeInteger ti -> new IntX86(con);
-        case TypeFloat   tf -> new FltX86(con);
-        case TypeFunPtr tfp -> new TFPX86(con);
-        case TypeMemPtr tmp -> new TMPX86(con);
+        case TypeInteger ti -> new IntX86(con,ext);
+        case TypeFloat   tf -> new FltX86(con,ext);
+        case TypeMemPtr tmp -> new TMPX86(con,ext);
+        case TypeFunPtr tfp -> new TFPX86(tfp,ext);
         case TypeNil tn -> throw Utils.TODO();
         // TOP, BOTTOM, XCtrl, Ctrl, etc.  Never any executable code.
-        case Type t -> t == Type.NIL ? new IntX86(con) : new ConstantNode(con);
+        case Type t -> t == Type.NIL ? new IntX86(con,null) : ConstantNode.raw(con);
         };
     }
 
+    private Node fptr( FunPtrNode con ) {
+        return new TFPX86(con);
+    }
+
     private Node i2f8(ToFloatNode tfn) {
         assert tfn.in(1)._type instanceof TypeInteger ti;
         return new I2f8X86(tfn);
@@ -528,7 +557,9 @@ public class x86_64_v2 extends Machine {
         String op = "!=";
         if( iff.in(1) instanceof BoolNode bool ) op = swap ? IfNode.swap(bool.op()) : bool.op();
         else if( iff.in(1)==null ) op = "=="; // Never-node cutout
-        else iff.setDef(1, new BoolNode.NE(iff.in(1), new ConstantNode(TypeInteger.ZERO)));
+        else iff.setDef(1, new BoolNode.NE(iff.in(1),
+                                           ConstantNode.raw(TypeInteger.ZERO),
+                                           (byte)(iff.in(1)._type instanceof TypeFloat ? 2 : 1)));
         return new JmpX86(iff, op);
     }
 
@@ -549,7 +580,7 @@ public class x86_64_v2 extends Machine {
     }
 
     private Node prj( ProjNode prj ) {
-        return new ProjX86(prj);
+        return prj.in(0) instanceof StartNode ? new ProjNode(prj) : new ProjX86(prj);
     }
 
     private Node sar(SarNode sar) {
diff --git a/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java b/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
index a9f86ce8..206983a0 100644
--- a/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
+++ b/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
@@ -1,130 +1,126 @@
 package com.seaofnodes.simple.print;
 
+import com.seaofnodes.simple.codegen.CompUnit;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.codegen.Encoding.Relo;
 import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.*;
+import java.util.HashMap;
 import java.util.HashSet;
 
 public abstract class ASMPrinter {
 
-    public static SB print(SB sb, CodeGen code) {
-        if( code._cfg==null )
-            return sb.p("Need _cfg set, run after GCM");
+    public static SB print(SB sb, CodeGen code ) {
+        Encoding enc = code._encoding;
+        if( enc == null ) return sb.p("No encoding for ").p(code._srcName);
 
         // instruction address
         int iadr = 0;
-        for( int i=0; i<code._cfg._len; i++ )
-            if( code._cfg.at(i) instanceof FunNode fun )
-                iadr = print(iadr,sb,code,fun,i);
+        // Print all functions in order
+        for( int i=0; i<enc._cfg._len; i++ )
+            if( enc._cfg.at(i) instanceof FunNode fun )
+                iadr = print(iadr,sb,code,enc,fun,i);
 
-        // constant pool
+        // constant pools
         iadr = (iadr+15)&-16; // pad to 16
-        Encoding enc = code._encoding;
-        if(  enc!=null && !enc._bigCons.isEmpty() && iadr < enc._bits.size() ) {
-            // radix sort the big constants by alignment
-            Ary<Relo>[] raligns = new Ary[5];
-            for( Node op : enc._bigCons.keySet() ) {
-                Relo relo = enc._bigCons.get(op);
-                int align = relo._t.alignment();
-                Ary<Relo> relos = raligns[align]==null ? (raligns[align]=new Ary<>( Relo.class)) : raligns[align];
-                relos.add(relo);
-            }
+        if( enc._cpool.size()>0 )
+            iadr = printConstantPool(iadr, sb, enc._cpool,enc._bigCons,true ,"Constant Pool");
 
-            HashSet<Type> targets = new HashSet<>();
-            sb.p("--- Constant Pool ------").nl();
-
-            // By alignment
-            for( int align = 4; align >= 0; align-- ) {
-                Ary<Relo> relos = raligns[align];
-                if( relos == null ) continue;
-                for( Relo relo : relos ) {
-                    if( targets.contains(relo._t) ) continue;
-                    targets.add(relo._t);
-                    sb.hex2(iadr).p("  ");
-                    switch( relo._t ) {
-                    case TypeTuple  tt -> {
-                        for( Type tx : tt._types ) {
-                            pN(enc,sb,iadr,align).p(" ");
-                            iadr += (1<<align);
-                        }
-                    }
-
-                    case TypeStruct ts -> {
-                        int sz = ts.size();
-                        int log = 1<<align;
-                        sz = (sz + (log -1)) & -log; // Round up final padding
-                        for( int i=0; i<sz; i++ )
-                            sb.hex1(enc.read1(iadr++));
-                    }
+        iadr = (iadr+15)&-16; // pad to 16
+        if( enc._sdata.size()>0 )
+            iadr = printConstantPool(iadr, sb,enc._sdata,enc._bigCons,false, "Static Data"  );
 
+        return sb;
+    }
+
+
+    static int printConstantPool( int iadr, SB sb, BAOS bits, HashMap<Node,Relo> bigCons, boolean ro, String msg ) {
+        sb.p("--- ").p(msg).p(" ------").nl();
+        // radix sort the big constants by alignment
+        Ary<Relo>[] raligns = new Ary[5];
+        for( Node op : bigCons.keySet() ) {
+            Relo relo = bigCons.get(op);
+            // non-constant structs in the r/w data, everything else in r/o data
+            if( (relo._t instanceof TypeStruct ts && !ts.isConstant()) == ro )
+                continue;
+            int align = relo._t.alignment();
+            Ary<Relo> relos = raligns[align]==null ? (raligns[align]=new Ary<>( Relo.class)) : raligns[align];
+            relos.add(relo);
+        }
+
+        HashSet<Type> targets = new HashSet<>();
+
+        // By alignment
+        int dadr=0;
+        for( int align = 4; align >= 0; align-- ) {
+            Ary<Relo> relos = raligns[align];
+            if( relos == null ) continue;
+            for( Relo relo : relos ) {
+                if( targets.contains(relo._t) ) continue;
+                targets.add(relo._t);
+                sb.hex2(iadr+dadr).p("  ");
+                if( relo._t instanceof TypeStruct ts ) {
+                    int sz = ts.size();
+                    int log = 1<<align;
+                    sz = (sz + (log -1)) & -log; // Round up final padding
+                    for( int i=0; i<sz; i++ )
+                        sb.hex1(bits.read1(dadr++));
+                } else {
                     // Simple primitive (e.g. larger int, float)
-                    default -> {
-                        pN(enc,sb,iadr,align).fix(9-(1<<align),"");
-                        iadr += (1<<align);
-                    }
-                    }
-                    relo._t.print(sb).nl();
+                    pN(bits,sb,dadr,align).fix(9-(1<<align),"");
+                    dadr += (1<<align);
                 }
+                relo._t.print(sb.p('\t')).nl();
             }
         }
-
-        return sb;
+        return iadr+dadr;
     }
 
-    private static SB pN( Encoding enc, SB sb, int iadr, int log ) {
+
+    private static SB pN( BAOS bits, SB sb, int dadr, int log ) {
         switch( log ) {
-        case 0: sb.hex1(enc.read1(iadr)); break;
-        case 1: sb.hex2(enc.read2(iadr)); break;
-        case 2: sb.hex4(enc.read4(iadr)); break;
-        case 3: sb.hex8(enc.read8(iadr)); break;
+        case 0: sb.hex1(bits.read1(dadr)); break;
+        case 1: sb.hex2(bits.read2(dadr)); break;
+        case 2: sb.hex4(bits.read4(dadr)); break;
+        case 3: sb.hex8(bits.read8(dadr)); break;
         }
         return sb;
     }
 
 
-    private static int print(int iadr, SB sb, CodeGen code, FunNode fun, int cfgidx) {
-        FunNode old=null;
-        if( code._encoding!=null ) {
-            old = code._encoding._fun;
-            code._encoding._fun = fun; // Useful printing after RA
-        }
+    private static int print(int iadr, SB sb, CodeGen code, Encoding enc, FunNode fun, int cfgidx) {
         // Function header
         sb.nl().p("---");
         if( fun._name != null ) sb.p(fun._name).p(" ");
         fun.sig().print(sb);
         sb.p("---------------------------").nl();
-        if( code._encoding!=null && code._encoding._padFunHeads )
-            iadr = (iadr + 15)&-16; // All function entries padded to 16 align
+        iadr = (iadr + 15)&-16; // All function entries padded to 16 align
 
         if( fun._frameAdjust != 0 )
-            iadr = doInst(iadr,sb,code,fun,cfgidx,fun,true,true);
-        while( !(code._cfg.at(cfgidx) instanceof ReturnNode) )
-            iadr = doBlock(iadr,sb,code,fun,cfgidx++);
+            iadr = doInst(iadr,sb,code,enc, cfgidx,fun,true,enc!=null);
+        while( !(enc._cfg.at(cfgidx) instanceof ReturnNode) )
+            iadr = doBlock(iadr,sb,code,enc,fun,cfgidx++);
 
         // Function separator
         sb.p("---");
         fun.sig().print(sb);
         sb.p("---------------------------").nl();
-        if( code._encoding != null )
-            code._encoding._fun = old;
         return iadr;
     }
 
     static private final int opWidth = 5;
     static private final int argWidth = 30;
-    static int doBlock(int iadr, SB sb, CodeGen code, FunNode fun, int cfgidx) {
+    static int doBlock(int iadr, SB sb, CodeGen code, Encoding enc, FunNode fun, int cfgidx) {
         final int encWidth = code._mach==null ? 2 : code._mach.defaultOpSize()*2;
-        CFGNode bb = code._cfg.at(cfgidx);
+        CFGNode bb = enc._cfg.at(cfgidx);
         if( bb != fun && !(bb instanceof IfNode) && !(bb instanceof CallEndNode) && !(bb instanceof CallNode)  && !(bb instanceof CProjNode && bb.in(0) instanceof CallEndNode ))
             sb.p(label(bb)).p(":").nl();
         if( bb instanceof CallNode ) return iadr;
-        final boolean postAlloc = code._phase.ordinal() > CodeGen.Phase.RegAlloc.ordinal();
         final boolean postEncode= code._phase.ordinal() >=CodeGen.Phase.Encoding.ordinal();
+        final boolean postAlloc = code._phase.ordinal() > CodeGen.Phase.RegAlloc.ordinal() ||
+            (code._phase.ordinal() == CodeGen.Phase.RegAlloc.ordinal() && code._regAlloc.done());
 
         boolean once=false;
         for( Node n : bb.outs() ) {
@@ -133,10 +129,10 @@ public abstract class ASMPrinter {
             // Post-RegAlloc phi prints all on one line
             if( postAlloc ) {
                 if( !once ) { once=true; sb.fix(4," ").p(" ").fix(encWidth,"").p("  "); }
-                sb.p(phi._label).p(':').p(code.reg(phi,fun)).p(',');
+                sb.p(phi._label).p(':').p(code.reg(phi)).p(',');
             } else {
                 // Pre-RegAlloc phi prints one line per
-                sb.fix(4," ").p(" ").fix(encWidth,"").p("  ").fix(opWidth,phi._label).p(" ").p(code.reg(phi,fun));
+                sb.fix(4," ").p(" ").fix(encWidth,"").p("  ").fix(opWidth,phi._label).p(" ").p(code.reg(phi));
                 if( phi.getClass() == PhiNode.class ) {
                     sb.p(" = phi( ");
                     for( int i=1; i<phi.nIns(); i++ )
@@ -151,16 +147,17 @@ public abstract class ASMPrinter {
         // All the non-phis
         for( int i=0; i<bb.nOuts(); i++ )
             if( !(bb.out(i) instanceof PhiNode) )
-                iadr = doInst(iadr, sb,code, fun, cfgidx, bb.out(i),postAlloc, postEncode );
+                iadr = doInst(iadr, sb,code, enc, cfgidx, bb.out(i),postAlloc, postEncode );
 
         return iadr;
     }
 
-    static int doInst( int iadr, SB sb, CodeGen code, FunNode fun, int cfgidx, Node n, boolean postAlloc, boolean postEncode ) {
+    static int doInst( int iadr, SB sb, CodeGen code, Encoding enc, int cfgidx, Node n, boolean postAlloc, boolean postEncode ) {
         if( n==null || n instanceof CProjNode ) return iadr;
         if( postAlloc && n instanceof CalleeSaveNode ) return iadr;
         if( postEncode && n instanceof ProjNode ) return iadr;
         if( n instanceof MemMergeNode ) return iadr;
+        if( n instanceof EscapeNode ) return iadr;
         if( n.getClass() == ConstantNode.class ) return iadr; // Default placeholders
         final int dopz = code._mach==null ? 2 : code._mach.defaultOpSize();
         final int encWidth = dopz*2;
@@ -170,8 +167,8 @@ public abstract class ASMPrinter {
         // need to assume a jump.  There's no real hardware op here, yet.
         if( n instanceof RegionNode cfg && !(n instanceof FunNode) ) {
             if( postEncode ) return iadr; // All jumps inserted already
-            while( cfgidx < code._cfg._len-1 ) {
-                CFGNode next = code._cfg.at(++cfgidx);
+            while( cfgidx < enc._cfg._len-1 ) {
+                CFGNode next = enc._cfg.at(++cfgidx);
                 if( next == n ) return iadr; // Fall-through, no branch
                 if( next.nOuts()>1 )
                     break;      // Has code in the block, need to jump around
@@ -185,7 +182,9 @@ public abstract class ASMPrinter {
         // get indent slightly and just print their index & node#
         if( n instanceof ProjNode proj ) {
             if( proj._type instanceof TypeMem ) return iadr; // Nothing for the hidden ones
-            sb.fix(4," ").p(" ").fix(encWidth,"").p("    ").fix(opWidth,proj._label==null ? "---" : proj._label).p(" ").p(code.reg(n,fun)).nl();
+            sb.fix(4," ").p(" ").fix(encWidth,"").p("    ").fix(opWidth,code.reg(n)).p(" // ");
+            if( proj._label != null ) sb.p(proj._label);
+            sb.nl();
             return iadr;
         }
 
@@ -195,15 +194,15 @@ public abstract class ASMPrinter {
 
         // Encoding
         int fatEncoding = 0;
-        if( code._encoding != null && code._encoding._opLen!=null ) {
-            int size = code._encoding._opLen[n._nid];
+        if( enc != null ) {
+            int size = enc.opLen(n);
             if( code._asmLittle )
                 for( int i=0; i<Math.min(size,dopz); i++ )
-                    sb.hex1(code._encoding._bits.buf()[iadr++]);
+                    sb.hex1(enc._bits.buf()[iadr++]);
             else {
                 iadr += Math.min(size,dopz);
                 for( int i=0; i<Math.min(size,dopz); i++ )
-                    sb.hex1(code._encoding._bits.buf()[iadr-i-1]);
+                    sb.hex1(enc._bits.buf()[iadr-i-1]);
             }
             for( int i=size*2; i<encWidth; i++ )
                 sb.p(" ");
@@ -244,16 +243,16 @@ public abstract class ASMPrinter {
         sb.nl();
 
         // Printing more op bits than fit
-        if( isMultiOp != null && code._encoding != null && code._encoding._opLen!=null ) {
+        if( isMultiOp != null ) {
             // Multiple ops, template style, no RA, no scheduling.  Print out
             // one-line-per-newline, with encoding bits up front.
-            int size = code._encoding._opLen[n._nid];
+            int size = enc != null ? enc.opLen(n) : 0;
             int off = Math.min(size,dopz);
             while( isMultiOp!=null ) {
                 sb.hex2(iadr).p(" ");
                 int len = Math.min(size-off,dopz);
                 for( int i=0; i<len; i++ )
-                    sb.hex1(code._encoding._bits.buf()[iadr++]);
+                    sb.hex1(enc._bits.buf()[iadr++]);
                 off += len;
                 for( int i=len; i<dopz; i++ ) sb.p("  ");
                 sb.p("  ");
@@ -273,7 +272,7 @@ public abstract class ASMPrinter {
             // themselves.  X86 special for super long encodings
             sb.hex2(iadr).p(" ");
             for( int i=0; i<fatEncoding; i++ )
-                sb.hex1(code._encoding._bits.buf()[iadr++]);
+                sb.hex1(enc._bits.buf()[iadr++]);
             sb.nl();
         }
 
@@ -282,7 +281,7 @@ public abstract class ASMPrinter {
         if( !(n instanceof CFGNode) && n instanceof MultiNode ) {
             for( Node proj : n._outputs ) {
                 if( proj instanceof ProjNode ) // it could also be an ante-dep
-                    doInst(iadr,sb,code,fun, cfgidx, proj,postAlloc,postEncode);
+                    doInst(iadr,sb,code,enc, cfgidx, proj,postAlloc,postEncode);
             }
         }
 
@@ -294,13 +293,10 @@ public abstract class ASMPrinter {
     }
 
     private static String isMultiOp(SB sb, int old, int len) {
-        for( int i=old; i<len; i++ )
-            if( sb.at(i)=='\n' ) {
-                String s = sb.subString(i+1,len);
-                sb.setLen(i);
-                return s;
-            }
-        return null;
+        if( old==len || sb.at(old)!='\n' ) return null;
+        String rest = sb.subString(old+1,len);
+        sb.setLen(old);
+        return rest;
     }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/print/GraphVisualizer.java b/src/main/java/com/seaofnodes/simple/print/GraphVisualizer.java
index 20c8439a..ad2df8b6 100644
--- a/src/main/java/com/seaofnodes/simple/print/GraphVisualizer.java
+++ b/src/main/java/com/seaofnodes/simple/print/GraphVisualizer.java
@@ -1,6 +1,7 @@
 package com.seaofnodes.simple.print;
 
 import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CompUnit;
 import com.seaofnodes.simple.node.*;
 import java.util.*;
 import static com.seaofnodes.simple.util.Utils.TODO;
@@ -21,16 +22,16 @@ public class GraphVisualizer {
     public GraphVisualizer(boolean separateControlCluster) { this._separateControlCluster = separateControlCluster; }
     public GraphVisualizer() { this(false); }
 
-    public String generateDotOutput(Parser parse) { return generateDotOutput(parse._code._stop,parse._scope,parse._xScopes); }
-    public String generateDotOutput(StopNode stop, Node scope, Stack<ScopeNode> xScopes) {
+    public String generateDotOutput(Parser parse) { return generateDotOutput(parse._ref,parse._scope,parse._xScopes); }
+    public String generateDotOutput(CompUnit cu, Node scope, Stack<ScopeNode> xScopes) {
 
         // Since the graph has cycles, we need to create a flat list of all the
         // nodes in the graph.
-        Collection<Node> all = findAll(xScopes, stop, scope);
+        Collection<Node> all = findAll(xScopes, cu._stop, scope);
         StringBuilder sb = new StringBuilder();
         sb.append("digraph chapter18 {\n");
         sb.append("/*\n");
-        sb.append(stop._src);
+        sb.append(cu._src);
         sb.append("\n*/\n");
 
         // To keep the Scopes below the graph and pointing up into the graph we
@@ -80,7 +81,7 @@ public class GraphVisualizer {
         // Just the Nodes first, in a cluster no edges
         sb.append(doCtrl ? "\tsubgraph cluster_Controls {\n" : "\tsubgraph cluster_Nodes {\n"); // Magic "cluster_" in the subgraph name
         for (Node n : all) {
-            if (n instanceof ProjNode || n instanceof CProjNode || n instanceof MemMergeNode || n==Parser.XCTRL)
+            if( n instanceof ProjNode || n instanceof CProjNode || n instanceof MemMergeNode || n instanceof XCtrlNode )
                 continue; // Do not emit, rolled into MultiNode or Scope cluster already
             if( _separateControlCluster &&  doCtrl && !(n instanceof CFGNode) ) continue;
             if( _separateControlCluster && !doCtrl &&  (n instanceof CFGNode) ) continue;
@@ -162,7 +163,7 @@ public class GraphVisualizer {
             sb.append("\tsubgraph cluster_").append(scopeName).append(" {\n"); // Magic "cluster_" in the subgraph name
             // Special for memory ScopeMinNode
             if( level==0 ) {
-                MemMergeNode n = scope.mem();
+                Node n = scope.mem();
                 sb.append("\t\t").append(n.uniqueName()).append(" [label=\"").append(n.glabel()).append("\"];\n");
             }
             sb.append("\t\t").append(scopeName).append(" [label=<\n");
@@ -195,7 +196,7 @@ public class GraphVisualizer {
             // Do not display the Constant->Start edge;
             // ProjNodes handled by Multi;
             // ScopeNodes are done separately
-            if( n instanceof ConstantNode || n instanceof ProjNode || n instanceof CProjNode || n instanceof ScopeNode || n==Parser.XCTRL )
+            if( n instanceof ConstantNode || n instanceof ProjNode || n instanceof CProjNode || n instanceof ScopeNode || n instanceof XCtrlNode )
                 continue;
             for( int i=0; i<n.nIns(); i++ ) {
                 Node def = n.in(i);
diff --git a/src/main/java/com/seaofnodes/simple/print/IRPrinter.java b/src/main/java/com/seaofnodes/simple/print/IRPrinter.java
index d1265bef..7c0f84f3 100644
--- a/src/main/java/com/seaofnodes/simple/print/IRPrinter.java
+++ b/src/main/java/com/seaofnodes/simple/print/IRPrinter.java
@@ -1,14 +1,12 @@
 package com.seaofnodes.simple.print;
 
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Serialize;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeFunPtr;
 import com.seaofnodes.simple.util.Ary;
 import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
-import java.util.ArrayList;
-import java.util.BitSet;
-import java.util.HashMap;
+
+import java.util.*;
 
 public abstract class IRPrinter {
 
@@ -37,295 +35,138 @@ public abstract class IRPrinter {
         return sb.p("\n");
     }
 
-
-    public static String prettyPrint(Node node, int depth) {
-        return CodeGen.CODE._phase.ordinal() > CodeGen.Phase.Schedule.ordinal()
-            ? _prettyPrintScheduled( node, depth )
-            : _prettyPrint( node, depth );
-    }
-
-    // Another bulk pretty-printer.  Makes more effort at basic-block grouping.
-    private static String _prettyPrint( Node node, int depth ) {
-        // First, a Breadth First Search at a fixed depth.
-        BFS bfs = new BFS(node,depth);
-        // Convert just that set to a post-order
-        ArrayList<Node> rpos = new ArrayList<>();
-        BitSet visit = new BitSet();
-        for( int i=bfs._lim; i< bfs._bfs.size(); i++ )
-            postOrd( bfs._bfs.get(i), null, rpos, visit, bfs._bs);
-        // Reverse the post-order walk
+    // Bulk whole program pretty print
+    public static String prettyPrint( CodeGen code ) {
+        // Loop-tree for nodeOrder
+        CFGNode.LoopTree old = code._start._ltree;
+        if( old==null )
+            code._start.buildLoopTree( code._linker, code._stop);
+        Ary<Node> nodes = Serialize.nodeOrder(code);
+        if( old == null )
+            code._start._ltree = null;
         SB sb = new SB();
-        boolean gap=false;
-        for( int i=rpos.size()-1; i>=0; i-- ) {
-            Node n = rpos.get(i);
-            if( n instanceof CFGNode || n instanceof MultiNode ) {
-                if( !gap ) sb.p("\n"); // Blank before multihead
-                if( n instanceof FunNode fun )
-                    fun.sig().print(sb.p("--- ").p(fun._name==null ? "" : fun._name).p(" ")).p("----------------------\n");
-                printLine( n, sb );         // Print head
-                while( --i >= 0 ) {
-                    Node t = rpos.get(i);
-                    if( !(t.in(0) instanceof MultiNode) ) { i++; break; }
-                    printLine( t, sb );
-                }
-                if( n instanceof ReturnNode ret ) {
-                    FunNode fun = ret.fun();
-                    sb.p("--- ");
-                    if( fun != null )
-                        fun.sig().print(sb.p(fun._name==null ? "" : fun._name).p(" "));
-                    sb.p("----------------------\n");
-                }
-                if( !(n instanceof CallNode) ) {
-                    sb.p("\n"); // Blank after multitail
-                    gap = true;
-                }
-            } else {
-                printLine( n, sb );
-                gap = false;
+        Node prior=null;
+        for( Node n : nodes ) {
+            if( n instanceof FunNode fun ) {
+                sb.nl().p("--- ");
+                fun.sig().print(sb.p(fun._name==null ? "" : fun._name).p(" "));
+                sb.p("----------------------\n");
             }
+            if( n instanceof MultiNode || n instanceof RegionNode || n instanceof CallNode ||
+                (isMultiChild(prior) && !isMultiChild(n)) )
+                sb.nl();
+            printLine(n,sb);
+            if( n instanceof ReturnNode ret )
+                sb.p("--- ").p(ret._fun._name==null ? "" : ret._fun._name).p(" ----------------------\n");
+            prior = n;
         }
         return sb.toString();
     }
 
-    private static void postOrd(Node n, Node prior, ArrayList<Node> rpos, BitSet visit, BitSet bfs) {
-        if( !bfs.get(n._nid) )
-            return;  // Not in the BFS visit
-        if( n instanceof FunNode && !(prior instanceof StartNode) )
-            return;                     // Only visit Fun from Start
-        if( visit.get(n._nid) ) return; // Already post-order walked
-        visit.set(n._nid);
-        // First walk the CFG, then everything
-        if( n instanceof CFGNode ) {
-            for( Node use : n._outputs )
-                // Follow CFG, not across call/function borders, and not around backedges
-                if( use instanceof CFGNode && !(n instanceof CallNode && use instanceof FunNode) &&
-                    use.nOuts() >= 1 &&  !(use._outputs.get(0) instanceof LoopNode) )
-                    postOrd(use, n, rpos,visit,bfs);
-            for( Node use : n._outputs )
-                // Follow CFG, not across call/function borders
-                if( use instanceof CFGNode && !(n instanceof CallNode && use instanceof FunNode) )
-                    postOrd(use,n,rpos,visit,bfs);
-        }
-        // Follow all outputs
-        for( Node use : n._outputs )
-            if( use != null &&
-                !(n instanceof CallNode && use instanceof FunNode) &&
-                (n instanceof FunNode || !(use instanceof ParmNode)) )
-                postOrd(use, n, rpos,visit,bfs);
-        // Post-order
-        rpos.add(n);
+    private static boolean isMultiHead(Node n) {
+        return n instanceof RegionNode || n instanceof MultiNode;
     }
 
-    // Breadth-first search, broken out in a class to keep in more independent.
-    // Maintains a root-set of Nodes at the limit (or past by 1 if MultiHead).
-    public static class BFS {
-        // A breadth first search, plus MultiHeads for any MultiTails
-        public final ArrayList<Node> _bfs;
-        public final BitSet _bs; // Visited members by node id
-        public final int _depth; // Depth limit
-        public final int _lim; // From here to _bfs._len can be roots for a reverse search
-        public BFS( Node base, int d ) {
-            _depth = d;
-            _bfs = new ArrayList<>();
-            _bs = new BitSet();
-
-            add(base);                 // Prime the pump
-            int idx=0, lim=1;          // Limit is where depth counter changes
-            while( idx < _bfs.size() ) { // Ran out of nodes below depth
-                Node n = _bfs.get(idx++);
-                for( Node def : n._inputs )
-                    if( def!=null && !_bs.get(def._nid) )
-                        add(def);
-                if( idx==lim ) {    // Depth counter changes at limit
-                    if( --d < 0 )
-                        break;      // Ran out of depth
-                    lim = _bfs.size();  // New depth limit
-                }
-            }
-            // Toss things past the limit except multi-heads
-            while( idx < _bfs.size() ) {
-                Node n = _bfs.get(idx);
-                if( n instanceof MultiNode ) idx++;
-                else del(idx);
-            }
-            // Root set is any node with no inputs in the visited set
-            lim = _bfs.size();
-            for( int i=_bfs.size()-1; i>=0; i-- )
-                if( !any_visited(_bfs.get(i)) )
-                    swap( i,--lim);
-            _lim = lim;
-        }
-        void swap( int x, int y ) {
-            if( x==y ) return;
-            Node tx = _bfs.get(x);
-            Node ty = _bfs.get(y);
-            _bfs.set(x,ty);
-            _bfs.set(y,tx);
-        }
-        void add(Node n) {
-            _bfs.add(n);
-            _bs.set(n._nid);
-        }
-        void del(int idx) {
-            _bs.clear(_bfs.get(idx)._nid);
-            Utils.del(_bfs, idx);
-        }
-        boolean any_visited( Node n ) {
-            for( Node def : n._inputs )
-                if( def!=null && _bs.get(def._nid) )
-                    return true;
-            return false;
-        }
+    private static boolean isMultiChild(Node n) {
+        return n!=null && n.nIns() > 0 && n.in(0) != null && isMultiHead(n.in(0));
     }
 
-    public static String _prettyPrint( CodeGen code ) {
-        SB sb = new SB();
-        // Print the Start "block"
-        printLine(code._start,sb);
-        for( Node n : code._start._outputs )
-            printLine(n,sb);
-        sb.nl();
 
-        // Skip start, stop
-        for( int i=1; i<code._cfg._len-1; i++ ) {
-            CFGNode blk = code._cfg.at(i);
-            if( blk.blockHead() && (!(blk instanceof CProjNode) || (blk.cfg0() instanceof IfNode )) ) {
-                if( blk instanceof FunNode fun )
-                    sb.p("--- ").p(fun.label()).p(" ---------------------------").nl();
-                // Print block header
-                sb.p("%-13.13s".formatted(label(blk)+":"));
-                sb.p( "     ".repeat(4) ).p(" [[  ");
-                if( blk instanceof RegionNode )
-                    for( int j=1; j<blk.nIns(); j++ )
-                        label(sb,blk.cfg(j));
-                else
-                    label(sb,blk.cfg(0));
-                sb.p(" ]]  \n");
-            }
-            printLine(blk,sb);
-            if( blk instanceof ReturnNode ret )
-                sb.p("--- ").p(ret.fun().label()).p(" ---------------------------").nl();
+    // ----------------------------------------
+    // Another bulk pretty-printer.  Makes more effort at basic-block grouping.
+    public static String prettyPrint(Node node, int depth) {
+        // Convert just that set to a post-order
+        Ary<Node> post = new Ary<>(Node.class);
+        Ary<Node> rets = new Ary<>(Node.class);
+        var visit = new IdentityHashMap<Node,Integer>();
+        assert depth < 5000;
+        postOrd( node, 0, depth, visit, post, rets);
+        // Function calls all print independent
+        while( rets.size()>0 )
+            postOrd( rets.pop(), 0, depth, visit, post, rets );
 
-            // Block contents
-            for( Node n : blk._outputs ) {
-                if( n instanceof CFGNode cfg ) continue;
-                printLine(n,sb);
-                if( !(n instanceof CFGNode) && n instanceof MultiNode )
-                    for( Node use : n._outputs )
-                        if( use instanceof ProjNode )
-                            printLine(use,sb);
+
+        // Reverse the post-order walk
+        SB sb = new SB();
+        for( int i=0; i<post._len; i++ ) {
+            Node n = post.at(i);
+            // Split ahead of a Region/MultiNode
+            if( n instanceof RegionNode || n instanceof MultiNode ||
+                (i>0 && isMultiChild(post.at(i-1)) && !isMultiChild(n)) )
+                sb.nl();
+            if( n instanceof FunNode fun )
+                fun.sig().print(sb.p("--- ").p(fun._name==null ? "" : fun._name).p(" ")).p("----------------------\n");
+            printLine( n, sb );         // Print head
+            if( n instanceof ReturnNode ret ) {
+                FunNode fun = ret.fun();
+                sb.p("--- ").p(fun==null ? "" : fun._name).p("----------------------\n");
             }
         }
-
-        printLine(code._stop,sb);
         return sb.toString();
     }
 
-    // Bulk pretty printer, knowing scheduling information is available
-    private static String _prettyPrintScheduled( Node node, int depth ) {
-        // Backwards DFS walk to depth.
-        HashMap<Integer,Integer> ds = new HashMap<>();
-        Ary<Node> ns = new Ary<>(Node.class);
-        _walk(ds,ns,node,depth);
-        // Remove data projections, these are force-printed behind their multinode head
-        for( int i=0; i<ns.size(); i++ ) {
-            if( ns.get(i) instanceof ProjNode proj && !(proj.in(0) instanceof CFGNode) ) {
-                ns.del(i--);
-                ds.remove(proj._nid);
-            }
-        }
-        // Print by block with least idepth
-        SB sb = new SB();
-        Ary<Node> bns = new Ary<>(Node.class);
-        while( !ds.isEmpty() ) {
-            CFGNode blk = null;
-            for( Node n : ns ) {
-                CFGNode cfg = n instanceof CFGNode cfg0 && cfg0.blockHead() ? cfg0 : n.cfg0();
-                if( blk==null || cfg.idepth() < blk.idepth() )
-                    blk = cfg;
-            }
-            Integer d = ds.remove(blk._nid);
-            ns.del(ns.find(blk));
 
-            // Print block header
-            sb.p("%-13.13s".formatted(label(blk)+":"));
-            sb.p( "     ".repeat(4) ).p(" [[  ");
-            if( blk instanceof StartNode ) ;
-            else if( blk instanceof RegionNode || blk instanceof StopNode )
-                for( int i=(blk instanceof StopNode ? 3 : 1); i<blk.nIns(); i++ )
-                    label(sb,blk.cfg(i));
-            else
-                label(sb,blk.cfg(0));
-            sb.p(" ]]  \n");
-            printLine(blk,sb);
+    // keep the largest PO depth?; probably want *shortest*
+    private static void postOrd( Node n, int d, int cutoff, IdentityHashMap<Node,Integer> visit, Ary<Node> post, Ary<Node> rets ) {
+        if( n==null ) return;
+        if( d >= cutoff ) return; // Too deep
+        Integer depth = visit.get(n);
+        if( depth!=null ) return; // Been there, done that
+
+        // Not a multi-child (Phi of a Region or Proj of a MultiNode)
+        if( !isMultiHead(n) && !isMultiChild(n) ) {
+            visit.put(n,d);             // Visit node N and depth D
+            for( Node def : n._inputs ) // Children before visit
+                postOrd(def, d+1, cutoff, visit, post, rets);
+            post.add(n);        // Post-order add
+            return;
+        }
 
-            // Collect block contents that are in the depth limit
-            bns.clear();
-            int xd = Integer.MAX_VALUE;
-            for( Node use : blk._outputs ) {
-                Integer i = ds.get(use._nid);
-                if( i!=null && !(use instanceof CFGNode cfg && cfg.blockHead()) ) {
-                    if( bns.find(use)==-1 )
-                        bns.add(use);
-                    xd = Math.min(xd,i);
+        // Multi-child; print the parent and all children together
+        Node multi = isMultiHead(n) ? n : n.in(0);
+        // Multi + children are visited all at once
+        visit.put(multi,d+1);
+        for( Node out : multi.outs() )
+            visit.put(out,d);
+
+        // Order to visit all the children
+        Node[] outs = multi.outs().asAry();
+        Arrays.sort(outs, Comparator.comparingInt( IRPrinter::sortOrder ) );
+
+        // Do not walk out of Functions, this makes functions stand-alone
+        // but otherwise unordered
+        if( !(multi instanceof FunNode fun && fun._folding) ) {
+            // Visit all children inputs all at once
+            for( Node out : outs ) {
+                // A FunNode is both a multi-head AND a multi-child from Start
+                if( !isMultiHead(out) && out != null ) {
+                    for( Node def : out._inputs ) {
+                        postOrd(def, d+1, cutoff, visit, post, rets);
+                    }
                 }
             }
-            // Print Phis up front, if any
-            for( int i=0; i<bns.size(); i++ )
-                if( bns.get(i) instanceof PhiNode phi )
-                    printLine( phi, sb,bns,i--,ds,ns);
-
-            // Print block contents in depth order, bumping depth until whole block printed
-            for( ; !bns.isEmpty(); xd++ )
-                for( int i=0; i<bns.size(); i++ ) {
-                    Node n = bns.get(i);
-                    if( ds.get(n._nid)==xd ) {
-                        printLine( n, sb, bns, i--, ds,ns );
-                        if( n instanceof MultiNode && !(n instanceof CFGNode) ) {
-                            for( Node use : n._outputs ) {
-                                if( use instanceof ProjNode )
-                                    printLine(use,sb,bns,bns.indexOf(use),ds,ns);
-                            }
-                        }
-                    }
+            // Visit multi inputs
+            for( Node def : multi._inputs ) {
+                if( multi instanceof CallEndNode && def instanceof ReturnNode ret && !ret._fun._folding ) {
+                    rets.add(ret);  // But save the Return for a separate function print
+                } else {
+                    postOrd(def, d+2, cutoff, visit, post, rets);
                 }
-            sb.p("\n");
+            }
         }
-        return sb.toString();
-    }
 
-    private static void _walk( HashMap<Integer,Integer> ds, Ary<Node> ns, Node node, int d ) {
-        Integer nd = ds.get(node._nid);
-        if( nd!=null && d <= nd ) return; // Been there, done that
-        Integer old = ds.put(node._nid,d) ;
-        if( old == null )
-          ns.add(node);
-        if( d == 0 ) return;    // Depth cutoff
-        for( Node def : node._inputs )
-            if( def != null &&
-                !(node instanceof LoopNode loop && loop.back()==def) &&
-                // Don't walk into or out of functions
-                !(node instanceof CallEndNode && def instanceof ReturnNode) &&
-                !(node instanceof FunNode && def instanceof CallNode) &&
-                !(node instanceof ParmNode && !(def instanceof FunNode))
-            )
-                _walk(ds,ns,def,d-1);
+        // Post visit the multi and all children
+        post.add(multi);
+        for( Node out : outs )
+            if( !isMultiHead(out) )
+                post.add(out);
     }
 
-    static String label( CFGNode blk ) {
-        if( blk instanceof StartNode ) return "START";
-        return (blk instanceof LoopNode ? "LOOP" : "L")+blk._nid;
-    }
-    static void label( SB sb, CFGNode blk ) {
-        if( !blk.blockHead() ) blk = blk.cfg(0);
-        sb.p( "%-9.9s ".formatted( label( blk ) ) );
-    }
-    static void printLine( Node n, SB sb, Ary<Node> bns, int i, HashMap<Integer,Integer> ds, Ary<Node> ns ) {
-        printLine( n, sb );
-        if( i != -1 ) bns.del(i);
-        ds.remove(n._nid);
-        int idx = ns.find(n);
-        if( idx!=-1 ) ns.del(idx);
+    static int sortOrder( Node n ) {
+        if( n instanceof ProjNode proj ) return proj._idx;
+        if( n instanceof PhiNode phi ) return phi._nid;
+        if( n == null ) return 0;
+        return n._nid+1000000;
     }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/print/JSViewer.java b/src/main/java/com/seaofnodes/simple/print/JSViewer.java
index 62ff0001..0f34af2e 100644
--- a/src/main/java/com/seaofnodes/simple/print/JSViewer.java
+++ b/src/main/java/com/seaofnodes/simple/print/JSViewer.java
@@ -202,11 +202,11 @@ public class JSViewer implements AutoCloseable {
             int lexStart = level==0 ? 0 : scope._kinds.at(level-1)._lexSize;
 
             // Special for memory ScopeMinNode
-            MemMergeNode n = scope.nIns()>1 ? scope.mem() : null;
-            if( level==0 && n!=null && n.nIns()>2 ) {
+            Node n = scope.nIns()>1 ? scope.mem() : null;
+            if( level==0 && n instanceof MemMergeNode merge && n.nIns()>2 ) {
                 sb.i().p("<TR>");
                 for( int m=2; m<n.nIns(); m++ )
-                    cell(sb,"#"+m,n.alias(m),"m"+m);
+                    cell(sb,"#"+m,merge.alias(m),"m"+m);
                 sb.p("</TR>\n"); // End scope level
             }
 
@@ -346,7 +346,7 @@ public class JSViewer implements AutoCloseable {
                 sb.i().p(scopeName).p(" -> ").p(n.uniqueName()).p(" [ style=dashed color=grey];\n");
             }
             // Force functions above return
-            if( n instanceof ReturnNode ret && ret.inProgress() && !ret.fun().isDead() )
+            if( n instanceof ReturnNode ret && !ret.fun().isDead() )
                 sb.i().p(ret.ctrl().uniqueName()).p(" -> ").p(ret.fun().uniqueName()).p("[style=invis]\n");
         }
     }
@@ -376,8 +376,7 @@ public class JSViewer implements AutoCloseable {
         }
 
         // Memory
-        if( scope.nIns()>1 ) {
-            MemMergeNode n = scope.mem();
+        if( scope.nIns()>1 && scope.mem() instanceof MemMergeNode n ) {
             for( int i=2; i<n.nIns(); i++ ) {
                 Node def = n.in(i);
                 while( def instanceof ScopeNode lazy )
diff --git a/src/main/java/com/seaofnodes/simple/type/Field.java b/src/main/java/com/seaofnodes/simple/type/Field.java
index b2b2deca..b6ea5843 100644
--- a/src/main/java/com/seaofnodes/simple/type/Field.java
+++ b/src/main/java/com/seaofnodes/simple/type/Field.java
@@ -1,6 +1,8 @@
 package com.seaofnodes.simple.type;
 
 import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.AryInt;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.SB;
 import java.util.*;
 
@@ -8,6 +10,7 @@ import java.util.*;
  * Represents a field in a struct. This is not a Type in the type system.
  */
 public class Field extends Type {
+    static final Field[] EMPTY = new Field[0];
 
     // The pair {fieldName,type} uniquely identifies a field.
 
@@ -17,29 +20,25 @@ public class Field extends Type {
     public Type _t;
     // Unique memory alias, not sensibly part of a "type" but very convenient here.
     public int _alias;
-    // Field must be written to exactly once, no more, no less
+    // Field is only written in the constructor
     public boolean _final;
-    // Field is final in the declaration; value is the same for all instances
-    // and will be moved to the class object
-    public boolean _one;
 
     private static final Ary<Field> FREE = new Ary<>(Field.class);
-    private Field(String fname, Type type, int alias, boolean xfinal, boolean one ) { super(TFLD); init(fname,type,alias,xfinal,one); }
-    private Field init(String fname, Type type, int alias, boolean xfinal, boolean one ) {
+    private Field(String fname, Type type, int alias, boolean xfinal ) { super(TFLD); init(fname,type,alias,xfinal); }
+    private Field init(String fname, Type type, int alias, boolean xfinal ) {
         _fname = fname;
         _t     = type;
         _alias = alias;
         _final = xfinal;
-        _one   = one;
         return this;
     }
 
     // Return a filled-in Field; either from free list or alloc new.
-    private static Field malloc(String fname, Type type, int alias, boolean xfinal, boolean one ) {
-        return FREE.isEmpty() ? new Field(fname,type,alias,xfinal,one) : FREE.pop().init(fname,type,alias,xfinal,one);
+    private static Field malloc(String fname, Type type, int alias, boolean xfinal ) {
+        return FREE.isEmpty() ? new Field(fname,type,alias,xfinal) : FREE.pop().init(fname,type,alias,xfinal);
     }
     // Malloc-from
-    public Field malloc( ) { return malloc(_fname,null,_alias,_final,_one); }
+    public Field malloc( ) { return malloc(_fname,null,_alias,_final); }
     @Override Field free(Type t) {
         Field f = (Field)t;
         assert !f.isFree() && !f._terned;
@@ -52,26 +51,26 @@ public class Field extends Type {
     @Override boolean isFree() { return _t ==null; }
 
     // Make and intern with listed fields
-    public static Field make( String fname, Type type, int alias, boolean xfinal, boolean one ) {
-        Field f = malloc(fname,type,alias,xfinal,one);
+    public static Field make( String fname, Type type, int alias, boolean xfinal ) {
+        Field f = malloc(fname,type,alias,xfinal);
         Field f2 = f.intern();
         if( f2==f ) return f;
         return VISIT.isEmpty() ? f2.free(f) : f2.delayFree(f);
     }
     public Field makeFrom( Type type ) {
-        return type == _t ? this : make(_fname,type,_alias,_final,_one);
+        return type == _t ? this : make(_fname,type,_alias,_final);
     }
     public Field makeFrom( boolean xfinal ) {
-        return xfinal == _final ? this : make(_fname,_t,_alias,xfinal,_one);
+        return xfinal == _final ? this : make(_fname,_t,_alias,xfinal);
     }
 
     // Cycle-making-breaking
     void setType(Type t) { assert _t ==null; _t = t; }
 
-    public static final Field BOT   = make(" ",Type.BOTTOM,-999,true,false);
-    public static final Field TEST  = make("test",Type.NIL,-2,false,false);
-    public static final Field TEST2 = make("test",Type.NIL,-2,true, false);
-    public static final Field FLT   = make("flt ",TypeFloat.F32,-2,false,false);
+    public static final Field BOT   = make(" ",Type.BOTTOM,-999,false);
+    public static final Field TEST  = make("test",Type.NIL,-2,false);
+    public static final Field TEST2 = make("test",Type.NIL,-2,true);
+    public static final Field FLT   = make("flt ",TypeFloat.F32,-2,false);
     public static void gather(ArrayList<Type> ts) { ts.add(TEST); ts.add(TEST2); ts.add(FLT); }
 
     @Override Field xmeet( Type that ) {
@@ -81,17 +80,16 @@ public class Field extends Type {
         if( fld ==BOT.dual() ) return this;
         if( _fname!=fld._fname ) { assert !_fname.equals(fld._fname); return BOT; }
         assert _alias==fld._alias;
-        assert _one  ==fld._one  ;
-        return make(_fname, _t.meet(fld._t ),_alias,_final | fld._final, _one);
+        return make(_fname, _t.meet(fld._t ), _alias, _final | fld._final);
     }
 
     @Override
-    Field xdual() { return malloc(_fname, _t.dual(),_alias,!_final,_one); }
+    Field xdual() { return malloc(_fname, _t.dual(),_alias,!_final); }
 
     @Override Field rdual() {
         if( _dual!=null ) return dual();
         assert !_terned;
-        Field d = malloc(_fname,null,_alias,!_final,_one);
+        Field d = malloc(_fname,null,_alias,!_final);
         (_dual = d)._dual = this; // Cross link duals
         d._t = _t._terned ? _t.dual() : _t.rdual();
         return d;
@@ -99,38 +97,52 @@ public class Field extends Type {
 
     @Override boolean _isConstant() { return _t._isConstant(); }
     @Override boolean _isFinal() { return _final && _t._isFinal(); }
-    @Override Field _makeRO() { return _final ? this : make(_fname, _t._makeRO(),_alias,true,_one);  }
-    boolean isGLB2() { return _final && _t._isGLB(true); }
-    Field glb2() {
-        Type glb = _t._glb(true);
-        return (glb== _t && _final ) ? this : make(_fname,glb,_alias,true,_one);
+    @Override Field _makeRO() { return _final ? this : make(_fname, _t._makeRO(),_alias,true);  }
+    @Override boolean _isGLB(boolean mem) { return _t._isGLB(true); }
+    @Override public Type _glb(boolean mem) { return make(_fname,_t._glb(true),_alias,true); }
+    @Override Field _close( String name, HashMap<String, Type> TYPES ) { return makeFrom( _t._close(name, TYPES )); }
+
+    @Override Type _upgradeType(HashMap<String,Type> TYPES) {
+        return makeFrom(_t._upgradeType(TYPES));
     }
-    @Override Field _close() { return makeFrom( _t._close()); }
 
     // Override in subclasses
-    int hash() { return _fname.hashCode() ^ _t.hashCode() ^ _alias ^ (_final ? 1024 : 0) ^ (_one ? 2048 : 0); }
+    int hash() { return _fname.hashCode() ^ _t.hashCode() ^ _alias ^ (_final ? 1024 : 0); }
 
     private boolean static_eq( Field f ) {
-        return _fname.equals(f._fname) && _alias==f._alias && _final==f._final && _one==f._one && _t !=null && f._t !=null;
+        return _fname.equals(f._fname) && _alias==f._alias && _final==f._final && _t !=null && f._t !=null;
     }
     @Override boolean eq( Type t ) {
         Field f = (Field)t;
         return static_eq(f) && _t ==f._t;
     }
     @Override boolean cycle_eq(Type t) {
+        if( this==t ) return true;
         Field f = (Field)t;
         return static_eq(f) && _t.cycle_eq(f._t );
     }
 
-    @Override int nkids() { return 1; }
-    @Override Type at( int idx ) { return _t; }
-    @Override void set( int idx, Type t ) { _t = t; }
+    @Override public int nkids() { return 1; }
+    @Override public Type at( int idx ) { return _t; }
+    @Override public void set( int idx, Type t ) { _t = t; }
+    // Tags: final/!final; +alias+name
+    @Override int TAGOFF() { return 2; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        baos.write(TAGOFFS[_type] + (_final ? 1 : 0));
+        baos.packed2(_alias);
+        baos.packed2(strs.get(_fname));
+    }
+    static Field packed( int tag, BAOS bais, String[] strs ) {
+        int alias = bais.packed2();
+        String fname = strs[bais.packed2()];
+        return malloc(fname,null,alias,(tag&1)==1);
+    }
 
     @Override
     public SB _print( SB sb, BitSet visit, boolean html ) {
-        sb.p(_final?"":"!").p(_one?"$":"").p(_fname).p(":").p(_alias).p(" : ");
+        sb.p(_final?"":"!").p(_fname).p(":").p(_alias).p(" : ");
         return _t ==null ? sb.p("---") : _t.print(sb,visit,html);
     }
 
-    @Override public String str() { return (_final?"":"!")+(_one?"$":"")+_fname; }
+    @Override public String str() { return (_final?"":"!")+_fname; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/Type.java b/src/main/java/com/seaofnodes/simple/type/Type.java
index 2d5a6d04..fd3a7c59 100644
--- a/src/main/java/com/seaofnodes/simple/type/Type.java
+++ b/src/main/java/com/seaofnodes/simple/type/Type.java
@@ -1,5 +1,6 @@
 package com.seaofnodes.simple.type;
 
+import com.seaofnodes.simple.codegen.GlobalBits;
 import com.seaofnodes.simple.util.*;
 import java.util.*;
 
@@ -56,34 +57,38 @@ public class Type /*implements Cloneable*/ {
     static final byte TXCTRL  = 3; // Ctrl flow top (mini-lattice: any-xctrl-ctrl-all)
     static final byte TNIL    = 4; // low null of all flavors
     static final byte TXNIL   = 5; // high or choice null
-    static final byte TSIMPLE = 6; // End of the Simple Types
+    static final byte TSIMPLE = 5; // End of the Simple Types
 
-    static final byte TPTR    = 7; // All nil-able scalar values
+    static final byte TSCALAR = 6; // Integer, float, memory pointer or function pointer
+    static final byte TPTR    = 7; // All nil-able pointer values
     static final byte TINT    = 8; // All Integers; see TypeInteger
     static final byte TFLT    = 9; // All Floats  ; see TypeFloat
     static final byte TCONARY =10; // Constant array
     static final byte TRPC    =11; // Return Program Control (Return PC or RPC)
-    static final byte TTUPLE  =12; // Tuples; finite collections of unrelated Types, kept in parallel
 
-    static final byte TCYCLIC =13; // Has internal pointers, needs recursive treatment
-    static final byte TMEMPTR =13; // Memory pointer to a struct type
-    static final byte TFUNPTR =14; // Function pointer; unique signature and code address (just a bit)
-    static final byte TMEM    =15; // All memory (alias 0) or A slice of memory - with specific alias
+    static final byte TCYCLIC =12; // Has internal pointers, needs recursive treatment
+    static final byte TMEMPTR =12; // Memory pointer to a struct type
+    static final byte TFUNPTR =13; // Function pointer; unique signature and code address (just a bit)
+    static final byte TMEM    =14; // All memory (alias 0) or A slice of memory - with specific alias
+    static final byte TFLD    =15; // Named fields in structs
     static final byte TSTRUCT =16; // Structs; tuples with named fields
-    static final byte TFLD    =17; // Named fields in structs
+    static final byte TTUPLE  =17; // Tuples; finite collections of unrelated Types, kept in parallel
+
+    static final byte TMAX    =18;
 
     // Basic RTTI, useful for a lot of fast tests.
     public final byte _type;
     public boolean _terned;
 
-    public boolean is_simple() { return _type < TSIMPLE; }
+    public boolean is_simple() { return _type <= TSIMPLE; }
+    public boolean is_nokids() { return _type < TCYCLIC; }
     private static final String[] STRS = new String[]{"Bot","Top","Ctrl","~Ctrl","null","~nil"};
-    static final int[] CNTS = new int[TFLD+1];
     protected Type(byte type) {
         _type = type;           // RTTI
         _uid = (char)UID++;     // A unique ID for every type
+        if( UID > 32000 )
+            type = type;
         assert _uid!=0;         // Overflow
-        CNTS[type]++;
     }
 
     public static final Type BOTTOM   = new Type( TBOT   ).intern(); // ALL
@@ -97,6 +102,7 @@ public class Type /*implements Cloneable*/ {
         ts.add(BOTTOM);
         ts.add(CONTROL);
         ts.add(NIL);
+        TypeScalar.gather(ts);
         TypeNil.gather(ts);
         TypePtr.gather(ts);
         TypeInteger.gather(ts);
@@ -135,7 +141,7 @@ public class Type /*implements Cloneable*/ {
 
     // Factory method which interns "this"
     @SuppressWarnings("unchecked")
-    <T extends Type> T intern() {
+    public <T extends Type> T intern() {
         //assert check();
         assert !_terned;        // Do not ask for already-interned
         T t2 = (T)INTERN.get(this);
@@ -216,16 +222,16 @@ public class Type /*implements Cloneable*/ {
     }
     // Overridden in subclasses; subclass can assume "this!=t" and java classes are same
     boolean       eq(Type t) { return this==t; }
-    boolean cycle_eq(Type t) { assert _type < TCYCLIC; return eq(t); }
+    boolean cycle_eq(Type t) { assert is_nokids(); return _type==t._type && eq(t); }
     // A pair of uids
     int pid( Type that ) {
         return _uid < that._uid ? (_uid<<16 | that._uid) : (that._uid<<16 | _uid);
     }
 
     // At/Set child at 'idx' to t
-    Type at ( int idx ) { throw Utils.TODO(); }
-    void set( int idx, Type t ) { throw Utils.TODO(); }
-    int nkids() { assert _type < TTUPLE; return 0; }   // Number of kids
+    public Type at( int idx ) { throw Utils.TODO(); }
+    public void set( int idx, Type t ) { throw Utils.TODO(); }
+    public int nkids() { return 0; }   // Number of kids
 
 
     // Clear and re-insert the basic Type INTERN table
@@ -254,6 +260,7 @@ public class Type /*implements Cloneable*/ {
 
     // ----------------------------------------------------------
     public final Type meet(Type t) {
+        assert _terned && t._terned;
         // Shortcut for the self case
         if( t == this ) return this;
         // Same-type is always safe in the subclasses
@@ -264,7 +271,14 @@ public class Type /*implements Cloneable*/ {
         // Reverse; xmeet 2nd arg is never "is_simple" and never equal to "this".
         if(   is_simple() ) return this.xmeet(t   );
         if( t.is_simple() ) return t   .xmeet(this);
-        return Type.BOTTOM;     // Mixing 2 unrelated types
+        // TypeConAry meet its element type is OK
+        if( this instanceof TypeConAry tcon && tcon.elemT() == t._type ) return tcon.ymeet(t);
+        if( t    instanceof TypeConAry tcon && tcon.elemT() ==   _type ) return tcon.ymeet(this);
+        // Two distinct scalar families meet at the scalar envelope.
+        if( this instanceof TypeScalar scalar0 && t instanceof TypeScalar scalar1 )
+            return scalar0.smeet(scalar1);
+        // Mixing 2 unrelated types
+        return Type.BOTTOM;
     }
 
     // Compute meet right now.  Overridden in subclasses.
@@ -277,8 +291,14 @@ public class Type /*implements Cloneable*/ {
         if( _type==TTOP || t._type==TBOT ) return    t;
 
         // RHS TypeNil vs NIL/XNIL
-        if( _type==  TNIL ) return t instanceof TypeNil ptr ? ptr.meet0() : (t._type==TXNIL ? TypePtr.PTR : BOTTOM);
-        if( _type== TXNIL ) return t instanceof TypeNil ptr ? ptr.meetX() : (t._type== TNIL ? TypePtr.PTR : BOTTOM);
+        if( _type==TNIL || _type==TXNIL ) {
+            if( t instanceof TypeNil ptr ) return _type==TNIL ? ptr.meet0() : ptr.meetX();
+            if( t instanceof TypeScalar scalar ) {
+                if( t._type==TSCALAR ) return t.isHigh() ? this : t;
+                return TypeScalar.BOT;
+            }
+            return t._type==(_type==TNIL ? TXNIL : TNIL) ? TypePtr.PTR : BOTTOM;
+        }
 
         // 'this' is only {TCTRL,TXCTRL}
         // Other non-simple RHS things bottom out
@@ -316,19 +336,15 @@ public class Type /*implements Cloneable*/ {
     }
 
     // True if this "isa" t; e.g. 17 isa TypeInteger.BOT
-    // Applies for pessimistic case
-    public boolean isa( Type t )     { return meet(t)==t; }
+    public boolean isa( Type t ) { return meet(t)==t; }
 
-    // True if this "isa" t up to named structures
-    public boolean shallowISA( Type t ) { return isa(t); }
-
-    public Type nonZero() { return TypePtr.NPTR; }
+    public Type nonZero() { return this==NIL ? TypePtr.XNPTR : TypePtr.NPTR; }
 
     // Make a zero version of this type, 0 for integers and null for pointers.
     public Type makeZero() { return Type.NIL; }
 
-    // Is forward-reference
-    public boolean isFRef() { return false; }
+    //// Is forward-reference
+    //public boolean isFRef() { return false; }
 
     // Cap at limits
     public Type oob() { return isHigh() ? TOP : BOTTOM; }
@@ -337,7 +353,7 @@ public class Type /*implements Cloneable*/ {
 
     // Cyclic types!  Flag the start of a cyclic type by putting a sentinel in
     // VISIT (and eventually clearing VISIT when done).  Then do a normal
-    // recursive descent visit of all types; this will accumilate types without
+    // recursive descent visit of all types; this will accumulate types without
     // interning them.  When done we have to visit the possibly cyclic type and
     // intern the whole cycle, possibly hitting the entire cycle on a prior
     // interned cycle.  Any sub-part might also be interned, including whole
@@ -350,7 +366,8 @@ public class Type /*implements Cloneable*/ {
     // "C0<->D0" cycle.
 
     Type recurOpen() { assert VISIT.isEmpty(); VISIT.put(0L,BOTTOM); return this; }
-    Type recurClose() {
+    Type recurClose() { return recurClose(null); }
+    Type recurClose(Type[] types) {
         VISIT.remove(0L);       // Just ignore the sentinel
         Ary<Type> ts = new Ary<>(Type.class);
         ts.addAll(VISIT.values());
@@ -374,6 +391,9 @@ public class Type /*implements Cloneable*/ {
         // Upgrade the result
         Type rez = INTERN.get(this);
         assert rez!=null;
+        if( types!=null )
+            for( int i=0; i<types.length; i++ )
+                types[i] = INTERN.get(types[i]);
 
         // Pass#4?: Free up any created-but-already interned
         for( Type t : FREES )
@@ -415,10 +435,12 @@ public class Type /*implements Cloneable*/ {
         free(this);
     }
 
-    Type free(Type free) { return this; }
+    Type free(Type free) {
+        return this;
+    }
     boolean isFree() { return false; }
 
-    <T extends Type> T delayFree(Type free) {
+    final <T extends Type> T delayFree(Type free) {
         assert !free._terned;
         FREES.push(free);
         return (T)this;
@@ -427,7 +449,7 @@ public class Type /*implements Cloneable*/ {
     final Type install() {
         if( this instanceof TypeStruct ) {
             Type x = _intern();     // Stop the recursion
-            assert x==this;
+            if( x!=this ) return x.delayFree(this);
         }
         int nkids = nkids();
         for( int i=0; i<nkids; i++ ) {
@@ -440,7 +462,7 @@ public class Type /*implements Cloneable*/ {
                 }
             }
         }
-        return this instanceof TypeStruct ? this : _intern();
+        return this instanceof TypeStruct || _terned ? this : _intern();
     }
 
     // Strict constant values, things on the lattice centerline.
@@ -450,7 +472,7 @@ public class Type /*implements Cloneable*/ {
 
     // Are all reachable struct Fields are final?
     public final boolean isFinal() { return recurClose(recurOpen()._isFinal()); }
-    boolean _isFinal() { assert _type < TCYCLIC; return true; }
+    boolean _isFinal() { assert is_nokids(); return true; }
 
     public final Type makeRO() {
         if( isFinal() ) return this;
@@ -464,6 +486,7 @@ public class Type /*implements Cloneable*/ {
     boolean _isGLB(boolean mem) {
         return switch(_type) {
         case TBOT -> false;
+        case TSCALAR -> this==TypeScalar.BOT;
         case TNIL -> false;
         case TCTRL -> true;
         case TXCTRL -> false;
@@ -480,9 +503,149 @@ public class Type /*implements Cloneable*/ {
     }
     Type _glb(boolean mem) { assert is_simple(); return Type.BOTTOM; }
 
-    Type _close() { return this; }
+    // Bulk close-over all recursive types
+    public static TypeStruct[] closeOver(TypeStruct[] ts, HashMap<String,Type> TYPES) {
+        BOTTOM.recurOpen();
+        for( TypeStruct t : ts )
+            t._close(null, TYPES);
+        for( int i=0; i<ts.length; i++ ) {
+            // Parser only tracks the mutable name of arrays, so the closeOver
+            // returns that one.  However, internal types might have immutable
+            // versions.
+            String name = ts[i].isAry() ? (ts[i]._name+"!").intern() : ts[i]._name;
+            ts[i] = (TypeStruct)VISIT.get(name);
+        }
+        BOTTOM.recurClose(ts);
+        return ts;
+    }
+
+    Type _close( String name, HashMap<String, Type> TYPES ) { return this; }
     public Type widen() { return this; }
 
+    // Replace recursively all TypeBuilders with cyclic TypeStructs
+    public Type upgradeType(HashMap<String,Type> TYPES) {
+        return recurOpen()._upgradeType(TYPES).recurClose();
+    }
+    Type _upgradeType(HashMap<String,Type> TYPES) { assert is_nokids(); return this;  }
+
+
+    // Recursively gather all types
+    public void gather(HashMap<Type,Integer> types ) {
+        if( types.containsKey(this) ) return; // TEST
+        types.put(this,types.size());      // SET
+        int nkids = nkids();
+        for( int i=0; i<nkids; i++ )
+            at(i).gather(types);
+    }
+
+    // Compute serialization byte tag compression space
+    final static int[] TAGOFFS = new int[TMAX+1];
+    public static int[] TAGOFFS() {
+        if( TAGOFFS[TMAX-1]==0 )
+            // One entry per unique tag-space, using the BOT value from that
+            // tag-space except for the first tag-space which uses 1 tag for
+            // multiple Types instead of 1 Type having multiple tags.  Has to
+            // be ordered to match _type enum.
+            for( Type t : new Type[]{Type.XNIL,TypeScalar.BOT,TypePtr.PTR,TypeInteger.BOT,TypeFloat.F64,TypeConAryB.ABC,TypeRPC.BOT,TypeMemPtr.BOT,TypeFunPtr.BOT,TypeMem.BOT,Field.BOT,TypeStruct.BOT,TypeTuple.BOT} )
+                TAGOFFS[t._type+1] = TAGOFFS[t._type] + t.TAGOFF();
+        assert TAGOFFS[TMAX] <= 255;
+        return TAGOFFS;
+    }
+    // Reserve 6 tags, 0-5, for plain Types
+    int TAGOFF() { assert is_simple(); return 6; }
+
+    public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        assert is_simple();
+        baos.write(_type);
+    }
+    static Type packed( int tag ) {
+        return switch( tag ) {
+        case TBOT  -> BOTTOM;
+        case TTOP  -> TOP;
+        case TCTRL -> CONTROL;
+        case TXCTRL->XCONTROL;
+        case TNIL  -> NIL;
+        default -> throw Utils.TODO();
+        };
+    }
+
+    // Produce a type with null child types
+    static Type packed( BAOS bais, String[] strs ) {
+        int x = bais.read();
+        int type = Arrays.binarySearch( TAGOFFS, x );
+        if( type < 0 ) type = -(type+1)-1;
+        int off = x - TAGOFFS[type];
+        return switch( type ) {
+        case 0, 1, 2, 3, 4, 5 -> Type.packed( off );
+        case TSCALAR ->   TypeScalar .packed( off );
+        case TPTR    ->   TypePtr    .packed( off );
+        case TINT    ->   TypeInteger.packed( off, bais );
+        case TFLT    ->   TypeFloat  .packed( off, bais );
+        case TCONARY ->   TypeConAry .packed( off, bais );
+        case TRPC    ->   TypeRPC    .packed( off, bais );
+        case TMEMPTR ->   TypeMemPtr .packed( off, bais );
+        case TFUNPTR ->   TypeFunPtr .packed( off, bais );
+        case TMEM    ->   TypeMem    .packed( off, bais );
+        case TFLD    ->   Field      .packed( off, bais, strs );
+        case TSTRUCT ->   TypeStruct .packed( off, bais, strs );
+        case TTUPLE  ->   TypeTuple  .packed( off, bais );
+        default -> throw Utils.TODO();
+        };
+    }
+
+    // Read a packed Type array
+    public static Type[] packed( BAOS bais, String[] strs, int ntypes, HashMap<String,Type> existingTypes,
+                                 GlobalBits fileAliases, GlobalBits aliases,
+                                 GlobalBits fileFidxs  , GlobalBits fidxs  ,
+                                 GlobalBits fileRpcs   , GlobalBits rpcs   ) {
+        Type[] types = new Type[ntypes];
+        // Read Types in ID# order, no children
+        for( int i=0; i<ntypes; i++ )
+            types[i] = Type.packed(bais,strs);
+        // Start possibly recursive type collection
+        BOTTOM.recurOpen();
+        // Read Types in ID# order, only children
+        for( int i=0; i<ntypes; i++ ) {
+            VISIT.put(types[i]._uid,types[i]);
+            int nkids = types[i].nkids();
+            for( int j=0; j<nkids; j++ )
+                types[i].set(j,types[bais.packed4()]);
+        }
+        // Remap file-local aliases/fidxs/rpcs into this compilation unit's
+        // local dense indexes via their global identities.
+        for( int i=0; i<ntypes; i++ ) {
+            if( types[i] instanceof Field fld ) {
+                if( fld._alias >= GlobalBits.RESERVED )
+                    fld._alias = aliases.map(fileAliases,fld._alias);
+            }
+            if( types[i] instanceof TypeFunPtr tfp )
+                tfp._fidxs = remapBits(fileFidxs,fidxs,tfp._fidxs,GlobalBits.RESERVED);
+            if( types[i] instanceof TypeRPC rpc )
+                rpc._rpcs = remapBits(fileRpcs,rpcs,rpc._rpcs,GlobalBits.RESERVED);
+            if( types[i] instanceof TypeMem mem ) {
+                if( mem._alias >= GlobalBits.RESERVED )
+                    mem._alias = aliases.map(fileAliases,mem._alias);
+                mem._escFs = remapBits(fileFidxs  ,fidxs  ,mem._escFs,GlobalBits.RESERVED);
+                mem._escAs = remapBits(fileAliases,aliases,mem._escAs,GlobalBits.RESERVED);
+            }
+        }
+
+        // Intern them all at once
+        BOTTOM.recurClose(types);
+        return types;
+    }
+
+    private static int[] remapBits(GlobalBits fileBits, GlobalBits bits, int[] fileLocals, int firstMapped ) {
+        if( fileLocals == XInt.EMPTY || fileLocals == XInt.FULL )
+            return fileLocals;
+        assert !XInt.isHigh(fileLocals);
+        int[] locals = XInt.EMPTY;
+        for( int fileLocal = XInt.next(fileLocals,-1); fileLocal >=0; fileLocal = XInt.next(fileLocals,fileLocal) )
+            locals = XInt.make(locals,fileLocal < firstMapped ? fileLocal : bits.map(fileBits,fileLocal));
+        return locals;
+    }
+
+
     // ----------------------------------------------------------
 
     // Size in bits to hold an instance of this type.
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeConAry.java b/src/main/java/com/seaofnodes/simple/type/TypeConAry.java
index c5543030..26fa4a67 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeConAry.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeConAry.java
@@ -1,54 +1,51 @@
 package com.seaofnodes.simple.type;
 
-import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.AryInt;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
-import java.io.ByteArrayOutputStream;
 import java.util.ArrayList;
+import java.util.HashMap;
 
 /**
  * Represents a constant array of primitives
  */
-public class TypeConAry<A> extends Type {
+public abstract class TypeConAry<A> extends TypeScalar {
     boolean _any;
     // One of byte,short,int,long,float,double array
     public final A _ary;
 
-    TypeConAry( boolean any, byte type, A ary ) { super(type); _any = any; _ary = ary; }
-    public static final TypeConAry BOT = new TypeConAry(false, TINT, null).intern();
+    TypeConAry( boolean any, A ary ) { super(TCONARY); _any = any; _ary = ary; }
     public static void gather(ArrayList<Type> ts) {
-        ts.add(BOT);
         TypeConAryB.gather(ts);
         TypeConAryI.gather(ts);
     }
 
     @Override public String str() { return (_any?"~":"") + "[]"; }
-    @Override TypeConAry xdual() {
-        if( _ary==null )
-            return new TypeConAry(!_any,_type,null);
-        return this;
-    }
+    @Override TypeConAry xdual() { return this; }
 
     @Override Type xmeet(Type t) {
-        if( t instanceof TypeInteger ti ) return imeet(ti);
         TypeConAry ary = (TypeConAry)t; // Invariant
-        if( this==BOT ) return BOT;
-        if( ary ==BOT ) return BOT;
-        if( this==BOT.dual() ) return ary ;
-        if( ary ==BOT.dual() ) return this;
         assert _ary!=ary._ary;  // Already interned and this!=t
+        // Unrelated constant arrays
         return elem().meet(ary.elem());
     }
-    Type imeet( TypeInteger ti ) {
-        if( this==BOT.dual() ) return ti;
-        if( this==BOT        ) return BOT;
-        Type elem = elem();
-        if( !(elem instanceof TypeInteger) ) return BOTTOM;
-        if( ti.isHigh() && elem.isa(ti.dual()) )
+
+    Type ymeet( Type t ) {
+        if( t instanceof TypeInteger ti ) {
+            // if i can isa *each* element, then maybe can keep.
+            // no good to i.isa(elem()) because fails the dual
+            boolean fail = false;
+            for( int j=0; j<len(); j++ )
+                if( !ti.isa(TypeInteger.constant(at8(j))) )
+                    { fail=true; break; }
+            Type e = elem();
+            if( fail )
+                return ti.meet(e);
             return this;
-        return elem.meet(ti);
+        }
+        throw Utils.TODO();
     }
 
-
     @Override public boolean isHigh() { return this==TOP; }
     @Override boolean _isConstant() { return true; }
     @Override Type _glb(boolean mem) { return this; }
@@ -67,10 +64,24 @@ public class TypeConAry<A> extends Type {
         }
         return TypeInteger.make(min,max);
     }
+    // Generic element _type
+    public int elemT() { return TBOT; }
     public long at8(int idx) { throw Utils.TODO(); }
     public int len() { throw Utils.TODO(); }
     @Override public int log_size() { throw Utils.TODO(); }
-    public void write( ByteArrayOutputStream baos ) { throw Utils.TODO(); }
+    public void write( BAOS baos ) { throw Utils.TODO(); }
+
+    // Reserve tags for u8 array
+    @Override int TAGOFF() { return 1; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        assert log_size()==0 && !_any;
+        baos.write(TAGOFFS[TCONARY]+0);
+        baos.packed4(len());
+        baos.write((byte[])_ary);
+    }
+    static TypeConAry packed( int tag, BAOS bais ) {
+        return TypeConAryB.make(bais.read(new byte[bais.packed4()]));
+    }
 
     @Override boolean eq(Type t) {
         return t instanceof TypeConAry ary && _any==ary._any && ary._ary==null;
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeConAryB.java b/src/main/java/com/seaofnodes/simple/type/TypeConAryB.java
index 9e5f0a2d..bd2827ed 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeConAryB.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeConAryB.java
@@ -1,21 +1,22 @@
 package com.seaofnodes.simple.type;
 
+import com.seaofnodes.simple.util.BAOS;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.io.ByteArrayOutputStream;
 
 public class TypeConAryB extends TypeConAry<byte[]> {
-    private TypeConAryB(byte[] bs) { super(false,TINT,bs); }
+    private TypeConAryB(byte[] bs) { super(false,bs); }
     public static TypeConAryB make( byte[] bs ) { return new TypeConAryB(bs).intern(); }
     public static TypeConAryB make( String s ) { return make(s.getBytes()); }
     static final TypeConAryB ABC  = make("abc");
     static final TypeConAryB ABCD = make("abcd");
     public static void gather(ArrayList<Type> ts) { ts.add(ABC); ts.add(ABCD); }
+    @Override public int elemT() { return TINT; }
     @Override public long at8(int idx) { return _ary[idx]; }
     @Override public int len() { return _ary.length; }
     @Override public int log_size() { return 0; }
     @Override public String str() { return "[\""+new String(_ary)+"\"]"; }
     @Override boolean eq(Type t) { return t instanceof TypeConAryB ary && Arrays.equals(_ary,ary._ary); }
     @Override int hash() { return Arrays.hashCode(_ary); }
-    @Override public void write( ByteArrayOutputStream baos ) { baos.write(_ary,0,_ary.length); }
+    @Override public void write( BAOS baos ) { baos.write(_ary); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeConAryI.java b/src/main/java/com/seaofnodes/simple/type/TypeConAryI.java
index 8228887e..bb2ab83c 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeConAryI.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeConAryI.java
@@ -4,10 +4,11 @@ import java.util.ArrayList;
 import java.util.Arrays;
 
 public class TypeConAryI extends TypeConAry<int[]> {
-    private TypeConAryI(int[] bs) { super(false,TINT,bs); }
+    private TypeConAryI(int[] bs) { super(false,bs); }
     public static TypeConAryI make( int[] bs ) { return new TypeConAryI(bs).intern(); }
     private static final TypeConAryI I123  = make(new int[]{1,2,3});
     public static void gather(ArrayList<Type> ts) { ts.add(I123); }
+    @Override public int elemT() { return TINT; }
     @Override public long at8(int idx) { return _ary[idx]; }
     @Override public int len() { return _ary.length; }
     @Override public int log_size() { return 2; }
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeFloat.java b/src/main/java/com/seaofnodes/simple/type/TypeFloat.java
index f3de581c..f4968f28 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeFloat.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeFloat.java
@@ -1,14 +1,16 @@
 package com.seaofnodes.simple.type;
 
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
 import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.AryInt;
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.Utils;
 import java.util.ArrayList;
+import java.util.HashMap;
 
 /**
  * Float Type
  */
-public class TypeFloat extends Type {
+public class TypeFloat extends TypeScalar {
 
     // - high -64, high -32, con 0, low +32, low +64
     public byte _sz;
@@ -98,6 +100,28 @@ public class TypeFloat extends Type {
     @Override boolean _isConstant() { return _sz==0; }
 
     @Override public Type makeZero() { return FZERO; }
+
+    // Reserve tags for F64,F32,constant
+    @Override int TAGOFF() { return 3; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        if(      this==F64 ) baos.write(TAGOFFS[_type] + 0);
+        else if( this==F32 ) baos.write(TAGOFFS[_type] + 1);
+        else {
+            assert isConstant();
+            baos.write(TAGOFFS[_type] + 2);
+            baos.packed8(Double.doubleToLongBits(_con));
+        }
+    }
+
+    static Type packed( int tag, BAOS bais ) {
+        return switch( tag ) {
+        case 0 -> F64;
+        case 1 -> F32;
+        case 2 -> constant(Double.longBitsToDouble(bais.packed8()));
+        default -> throw Utils.TODO();
+        };
+    }
+
     @Override
     int hash() { return (int)(Double.hashCode(_con) ^ _sz ^ (1<<17)); }
     @Override
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java b/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java
index ddef9651..e2ec6263 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java
@@ -1,8 +1,6 @@
 package com.seaofnodes.simple.type;
 
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
-import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.*;
 import java.util.*;
 
 /**
@@ -21,27 +19,25 @@ public class TypeFunPtr extends TypeNil {
     // A TypeFunPtr is Signature and a set of functions.
     public Type[] _sig;
     public Type _ret;
-    // TODO:
-    boolean _open;              // Extra args are true:BOTTOM, false:TOP
-    // Cheesy easy implementation for a small set; 1 bit per unique function
-    // within the same Type[].  Can be upgraded to a BitSet for larger classes
-    // of functions.  Negative means "these 63 concrete bits plus infinite
-    // unknown more"
-    public long _fidxs; // 63 unique functions per signature
+    boolean _open;              // Extra args are true:scalar BOT, false:scalar TOP
+    // Set of functions.  Bit zero is used for mutable/immutable safety.  Sign
+    // bit repeats infinitely.
+    public int[] _fidxs;
 
     private static final Ary<TypeFunPtr> FREE = new Ary<>(TypeFunPtr.class);
-    private TypeFunPtr(byte nil, boolean open, Type[] sig, Type ret, long fidxs) { super(TFUNPTR,nil); init(nil,open,sig,ret,fidxs); }
-    private TypeFunPtr init(byte nil, boolean open, Type[] sig, Type ret, long fidxs ) {
+    private TypeFunPtr(byte nil) { super(TFUNPTR,nil); }
+    private TypeFunPtr init(byte nil, boolean open, Type[] sig, Type ret, int[] fidxs ) {
         assert sig != null;
         _nil  = nil;
         _open = open;
         _sig  = sig;
         _ret  = ret;
-        _fidxs= fidxs;
+        assert _fidxs == null;
+        _fidxs= XInt.intern(fidxs);
         return this;
     }
-    static TypeFunPtr malloc( byte nil, boolean open, Type[] sig, Type ret, long fidxs ) {
-        return FREE.isEmpty() ? new TypeFunPtr(nil,open,sig,ret,fidxs) : FREE.pop().init(nil,open,sig,ret,fidxs);
+    static TypeFunPtr malloc( byte nil, boolean open, Type[] sig, Type ret, int[] fidxs ) {
+        return (FREE.isEmpty() ? new TypeFunPtr(nil) : FREE.pop()).init(nil,open,sig,ret,fidxs);
     }
     @Override TypeFunPtr free(Type t) {
         TypeFunPtr fun = (TypeFunPtr)t;
@@ -50,55 +46,75 @@ public class TypeFunPtr extends TypeNil {
         fun._ret = null;
         fun._dual = null;
         fun._hash = 0;
+        fun._fidxs = null;
         FREE.push(fun);
         return this;
     }
     @Override boolean isFree() { return _sig==null; }
 
     // All fields directly listed
-    public static TypeFunPtr make( byte nil, boolean open, Type[] sig, Type ret, long fidxs ) {
+    public static TypeFunPtr make( byte nil, boolean open, Type[] sig, Type ret, int[] fidxs ) {
         TypeFunPtr fun = malloc(nil,open,sig,ret,fidxs);
         TypeFunPtr f2  = fun.intern();
         if( f2==fun ) return fun;
         return VISIT.isEmpty() ? f2.free(fun) : f2.delayFree(fun);
     }
-    public static TypeFunPtr make( boolean nil, boolean open, Type[] sig, Type ret ) { return make((byte)(nil ? 3 : 2),open,sig,ret,-1); }
+    public static TypeFunPtr make( boolean nil, Type[] sig, Type ret ) { return make((byte)(nil ? 3 : 2),true,sig,ret, XInt.FULL); }
+    public static TypeFunPtr make1( byte nil, boolean open, Type[] sig, Type ret, int fidx ) {
+        return make(nil,open,sig,ret,XInt.make(fidx));
+    }
+
 
 
     @Override TypeFunPtr makeFrom( byte nil ) { return  nil ==_nil ? this : make(  nil,_open,_sig,_ret, _fidxs); }
     public    TypeFunPtr makeFrom( Type ret ) { return  ret ==_ret ? this : make( _nil,_open,_sig, ret, _fidxs); }
-    public    TypeFunPtr makeFrom( int fidx ) { return make((byte)2, _open, _sig,_ret,1L<<fidx ); }
-
+    public    TypeFunPtr makeFrom( int fidx ) { return make1((byte)2,_open,_sig,_ret,fidx); }
+    public    TypeFunPtr makeFrom( Type arg, int idx ) {
+        // Alter named arg
+        Type[] sig = _sig.clone();
+        sig[idx] = arg;
+        return make(_nil,_open,sig,_ret,_fidxs);
+    }
+    @Override public Type nonZero() { return makeFrom((byte)(_nil <= 1 ? 1 : 2)); }
 
     public static final Type[] TEMPTY = new Type[0];
     static final Type[] TINT    = new Type[]{TypeInteger.BOT};
     static final Type[] TINTMEM = new Type[]{TypeInteger.BOT,TypeFloat.F32};
     static final Type[] TINTINT = new Type[]{TypeInteger.BOT,TypeInteger.BOT};
-    public static TypeFunPtr BOT   = make((byte)3,true ,TEMPTY,Type.BOTTOM,-1);
-    public static TypeFunPtr TEST  = make((byte)2,false,TINTMEM,TypeInteger.BOT, 1);
-    public static TypeFunPtr TEST0 = make((byte)3,false,TINTMEM,TypeInteger.BOT, 3);
-    public static TypeFunPtr MAIN  = make((byte)3,false,TINT   ,Type.BOTTOM,-1); // Main can return anything
-    public static TypeFunPtr CALLOC= make((byte)3,false,TINTINT,TypeMemPtr .BOT,-1);
+    public static TypeFunPtr BOT   = make((byte)3,true,TEMPTY,Type.BOTTOM, XInt.FULL);
+    public static TypeFunPtr TEST  = make((byte)2,true,TINTMEM,TypeInteger.BOT, XInt.SET1);
+    public static TypeFunPtr TEST0 = make((byte)3,true,TINTMEM,TypeInteger.BOT, XInt.SET3);
+    public static TypeFunPtr MAIN  = make((byte)3,true,TINT   ,Type.BOTTOM, XInt.FULL); // Main can return anything
+    public static TypeFunPtr CALLOC= make((byte)3,true,TINTINT,TypeMemPtr .BOT, XInt.FULL);
     public static void gather(ArrayList<Type> ts) { ts.add(TEST); ts.add(TEST0); ts.add(BOT);  ts.add(MAIN);ts.add(CALLOC); }
 
+    private static final Type[] ARG_EMPTY = new Type[0];
     @Override
     Type xmeet(Type t) {
         TypeFunPtr that = (TypeFunPtr) t;
-        // if equal, no matters.
-        // if short is BOT, chop     ; recurPre on short.
-        // if short is TOP, copy long; recurPre on long.
-        TypeFunPtr min = _sig.length < that._sig.length ? this : that;
-        if( _sig.length != that._sig.length && (min._open ^ min==this) )
-            return that.xmeet(this);
-        // Recurse all common fields
-        Type[] args = new Type[_sig.length];
-        for( int i=0; i<min._sig.length; i++ )
-            args[i] = _sig[i].meet(that._sig[i]);
-        // Handle extra args
-        for( int i=min._sig.length; i<_sig.length; i++ )
-            args[i] = _sig[i];
-        return make(xmeet0(that),_open | that._open, args, _ret.meet(that._ret), _fidxs | that._fidxs);
+        boolean open = _open | that._open;
+        Type def0 = this._open ? TypeScalar.BOT : TypeScalar.TOP;
+        Type def1 = that._open ? TypeScalar.BOT : TypeScalar.TOP;
+        Type def  =       open ? TypeScalar.BOT : TypeScalar.TOP;
+
+        int nargs = Math.max(_sig.length,that._sig.length);
+        Type[] args = new Type[nargs];
+
+        for( int i=0; i<nargs; i++ ) {
+            Type t0 = i < this._sig.length ? this._sig[i] : def0;
+            Type t1 = i < that._sig.length ? that._sig[i] : def1;
+            args[i] = t0.meet(t1);
+        }
+
+        while( nargs>0 && args[nargs-1] == def )
+            nargs--;
+
+        if( nargs != args.length )
+            args = nargs == 0 ? ARG_EMPTY : Arrays.copyOf(args,nargs);
+
+        return make(xmeet0(that), open, args, _ret.meet(that._ret), XInt.meet(_fidxs,that._fidxs));
     }
+
     static Type[] xmeet( Type[] ts0, Type[] ts1) {
         if( ts0==ts1 ) return ts0;
         assert ts0.length==ts1.length;
@@ -108,7 +124,7 @@ public class TypeFunPtr extends TypeNil {
         return ts;
     }
 
-    @Override TypeFunPtr xdual() { return malloc(dual0(), !_open, xdual(_sig), _ret.dual(), ~_fidxs); }
+    @Override TypeFunPtr xdual() { return malloc(dual0(), !_open, xdual(_sig), _ret.dual(), XInt.dual(_fidxs)); }
     static Type[] xdual(Type[] ts) {
         Type[] dual = new Type[ts.length];
         for( int i=0; i<ts.length; i++ )
@@ -120,7 +136,7 @@ public class TypeFunPtr extends TypeNil {
         if( _dual!=null ) return dual();
         assert !_terned;
         Type[] sigs = new Type[_sig.length];
-        TypeFunPtr d = malloc(dual0(),!_open,sigs,null,~_fidxs);
+        TypeFunPtr d = malloc(dual0(),!_open,sigs,null, XInt.dual(_fidxs));
         (_dual = d)._dual = this; // Cross link duals
         // Return rdual
         d._ret = _ret._terned ? _ret.dual() : _ret.rdual();
@@ -130,53 +146,97 @@ public class TypeFunPtr extends TypeNil {
         return d;
     }
 
-    // RHS is NIL; do not deep-dual when crossing the centerline
-    @Override public Type meet0() { return _nil==3 ? this : make((byte)3,_open,_sig,_ret,_fidxs); }
+    // RHS is NIL; deep-dual when crossing the centerline
+    @Override public Type meet0() {
+        if( _nil==3 ) return this;
+        if( _nil==2 ) return make((byte)3,_open,_sig,_ret,_fidxs);
+
+        return make((byte)3,_open,_sig,_ret,_fidxs);
+    }
 
-    @Override public boolean isHigh() { return _nil <= 1 || (_nil==2 && _fidxs==0); }
+    @Override public boolean isHigh() { return _nil <= 1 || (_nil==2 && _fidxs== XInt.EMPTY); }
 
-    @Override boolean _isConstant() { return (_nil==2 && Long.bitCount(_fidxs)==1) || (_nil==3 && _fidxs==0); }
+    @Override boolean _isConstant() { return (_nil==2 && XInt.isConstant(_fidxs)) || (_nil==3 && _fidxs== XInt.EMPTY); }
 
     @Override boolean _isFinal() { return true; }
     @Override boolean _isGLB(boolean mem) { return true; }
     @Override TypeFunPtr _glb(boolean mem) { return this; }
-    @Override TypeFunPtr _close() {
+
+    @Override TypeFunPtr _close( String name, HashMap<String, Type> TYPES ) {
         Type[] sig = new Type[_sig.length];
-        TypeFunPtr fun = malloc(_nil,false,sig,null,_fidxs);
+        TypeFunPtr fun = malloc(_nil,true,sig,null,_fidxs);
         // Now start the recursion
-        fun._ret = _ret._close();
+        fun._ret = _ret._close(name, TYPES );
         for( int i=0; i<sig.length; i++ )
-            sig[i] = _sig[i]._close();
+            sig[i] = _sig[i]._close(name, TYPES );
+        return fun;
+    }
 
+    // Replace recursively all TypeBuilders with cyclic TypeStructs
+    @Override Type _upgradeType(HashMap<String,Type> TYPES) {
+        Type[] sig = new Type[_sig.length];
+        TypeFunPtr fun = malloc(_nil,_open,sig,null,_fidxs);
+        // Now start the recursion
+        fun._ret = _ret._upgradeType(TYPES);
+        for( int i=0; i<sig.length; i++ )
+            sig[i] = _sig[i]._upgradeType(TYPES);
         return fun;
     }
 
     @Override public int log_size() { return 2; } // (1<<2)==4-byte pointers
 
     public Type arg(int i) { return _sig[i]; }
-    public long fidxs() { return _fidxs; }
+    public int[] fidxs() { return _fidxs; }
     public Type ret() { return _ret; }
     public int nargs() { return _sig.length; }
-    public int fidx() { assert Long.bitCount(_fidxs)==1; return Long.numberOfTrailingZeros(_fidxs); }
+    public int fidx() { return XInt.onlyBit(_fidxs); }
     public int nfcns() {
-        if( _fidxs < 0 ) return Integer.MAX_VALUE; // Infinite choices
-        return Long.bitCount(_fidxs);
+        if( XInt.isHigh(_fidxs) ) return Integer.MAX_VALUE; // Infinite choices
+        return XInt.bitCount(_fidxs);
     }
 
 
     // Used to walk over type structures
-    @Override int nkids() { return _sig.length+1; }
-    @Override Type at( int idx ) {
+    @Override public int nkids() { return _sig.length+1; }
+    @Override public Type at( int idx ) {
         return idx == _sig.length ? _ret : _sig[idx];
     }
-    @Override void set( int idx, Type t ) {
+    @Override public void set( int idx, Type t ) {
         if( idx == _sig.length ) _ret = t;
         else _sig[idx] = t;
     }
 
+    // Reserve tags for null/not and open/close, one fidx/bitset, 0-6 args
+    // Tags 0-5 - not,close,1 fidx, 0-5 args (+fidx)
+    // Tag 6 - not ,close+fidxs+nargs
+    // Tag 7 - null,close+fidxs+nargs
+    @Override int TAGOFF() { return 8; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        assert _open;           // Open: Passing extra args is fine, and extras ignored.
+        if( _nil==2 && nargs()<6 && nfcns() == 1 ) {
+            baos.write(TAGOFFS[_type] + nargs());
+            baos.packed2(fidx());
+        } else {
+            baos.write(TAGOFFS[_type] + 6 + (_nil==2 ? 0 : 1));
+            baos.packed1(nargs());
+            XInt.packed(baos,_fidxs);
+        }
+    }
+    static TypeFunPtr packed( int tag, BAOS bais ) {
+        if( tag < 6 ) {
+            int fidx = bais.read();
+            assert fidx < 64; // Need a larger fidx space
+            return malloc((byte)2,true,new Type[tag],null, XInt.make(fidx));
+        }
+        byte nil = (byte)(tag==6 ? 2 : 3);
+        int nargs = bais.packed1();
+        int[] fidxs = XInt.packed(bais);
+        return malloc(nil,true,new Type[nargs],null,fidxs);
+    }
+
     @Override
     int hash() {
-        long hash = _ret.hashCode() ^ _fidxs ^ super.hash();
+        long hash = _ret.hashCode() ^ XInt.hash(_fidxs) ^ super.hash();
         for( Type arg : _sig )
             hash = hash*19 ^ arg.hashCode();
         return Utils.fold(hash);
@@ -221,26 +281,24 @@ public class TypeFunPtr extends TypeNil {
 
     @Override public String str() { return "{"+printFIDX()+"}"; }
 
+    @Override
     SB _print(SB sb, BitSet visit, boolean html ) {
         sb.p(x()).p("{ ");
         if( _sig!=null )
             for( Type t : _sig )
-                sb.p(t.str()).p(" "); // Short form in signature
+                sb.p(t==null ? "---" : t.str()).p(" "); // Short form in signature
+        if( !_open ) sb.p("^ ");
         _ret.print(sb.p(html ? "&rarr; " : "-> "),visit,html).p(" #");
         // Print fidxs
         return sb.p(printFIDX()).p("}").p(q());
     }
     String printFIDX() {
         String tilde = isHigh() ? "~" : "";
-        long fidxs = isHigh() ? ~_fidxs : _fidxs;
-        String fidx = fidxs==0 ? ""
-            : Long.bitCount(fidxs) == 1 ? ""+Long.numberOfTrailingZeros(fidxs)
-            : fidxs == -1 ? "ALL"
-            : "b"+Long.toBinaryString(fidxs); // Just some function bits
+        String fidx = XInt.str(_fidxs);
         return tilde+fidx;
     }
 
     // Usage: for( long fidxs=fidxs(); fidxs!=0; fidxs=nextFIDX(fidxs) ) { int fidx = Long.numberOfTrailingZeros(fidxs); ... }
-    public static long nextFIDX(long fidxs) { return fidxs & (fidxs-1); }
+    //public static long nextFIDX(long fidxs) { return fidxs & (fidxs-1); }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeInteger.java b/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
index 97c17a34..25c3fa6f 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
@@ -1,14 +1,16 @@
 package com.seaofnodes.simple.type;
 
 import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.AryInt;
+import com.seaofnodes.simple.util.BAOS;
 import com.seaofnodes.simple.util.Utils;
 import java.util.ArrayList;
+import java.util.HashMap;
 
 /**
  * Integer Type
  */
-public class TypeInteger extends Type {
+public class TypeInteger extends TypeScalar {
     /**
      * Describes an integer *range* - everything from min to max; both min and
      * max are inclusive.  If min==max, this is a constant.
@@ -116,14 +118,17 @@ public class TypeInteger extends Type {
         if( this==I16 || this==U16              ) return 1; // 1<<1 == 2 bytes
         if( this==I32 || this==U32              ) return 2; // 1<<2 == 4 bytes
         if( this==BOT                           ) return 3; // 1<<3 == 8 bytes
-        if( isConstant() ) {                                // just const here
-            if (-0xFF <= _min && _min <= 0xFF)                    return 0;
-            else if (-0xFFFF <= _min && _min <= 0xFFFF)           return 1;
-            else if (-0xFFFFFFFFL <= _min && _min <= 0xFFFFFFFFL) return 2;
-            else return 3;
-        }
-        if( -128 <= _min && _max < 128 ) return 0; // 1 byte
-        throw Utils.TODO();
+        if( isConstant() ) return log(_min);                // just const here
+        int lo = log(_min);
+        int hi = log(_max);
+        return Math.max(lo,hi);
+    }
+
+    private static int log(long x) {
+        if(      -0xFFL <= x && x <=       0xFFL) return 0;
+        if(    -0xFFFFL <= x && x <=     0xFFFFL) return 1;
+        if(-0xFFFFFFFFL <= x && x <= 0xFFFFFFFFL) return 2;
+        return 3;
     }
 
     public long value() { assert isConstant(); return _min; }
@@ -147,7 +152,6 @@ public class TypeInteger extends Type {
 
     @Override
     public Type xmeet(Type other) {
-        if( other instanceof TypeConAry ary ) return ary.imeet(this);
         // Invariant from caller: 'this' != 'other' and same class (TypeInteger)
         TypeInteger i = (TypeInteger)other; // Contract
         return make(Math.min(_min,i._min), Math.max(_max,i._max), (byte)Math.max(_widen,i._widen));
@@ -160,8 +164,8 @@ public class TypeInteger extends Type {
     @Override public TypeInteger nonZero() {
         if( isHigh() ) return this;
         if( this==ZERO ) return null;                  // No sane answer
-        if( _min==0 ) return make(1,Math.max(_max,1)); // specifically good on BOOL
-        if( _max==0 ) return make(_min,-1);
+        if( _min==0 ) return make(1,Math.max(_max,1),_widen); // specifically good on BOOL
+        if( _max==0 ) return make(_min,-1,_widen);
         return this;
     }
     @Override public Type makeZero() { return ZERO; }
@@ -174,6 +178,39 @@ public class TypeInteger extends Type {
         return isHigh() ? dual() : this;
     }
 
+    // Reserve tags for I64,I32,U32,0,constant,generic
+    @Override int TAGOFF() { return 7; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        if(      this==BOT ) baos.write(TAGOFFS[_type] + 0);
+        else if( this==I32 ) baos.write(TAGOFFS[_type] + 1);
+        else if( this==U32 ) baos.write(TAGOFFS[_type] + 2);
+        else if( this==BOOL) baos.write(TAGOFFS[_type] + 3);
+        else if( this==ZERO) baos.write(TAGOFFS[_type] + 4);
+        else if( isConstant() ) {
+            baos.write(TAGOFFS[_type] + 5);
+            baos.packed8(_min);
+        } else {
+            baos.write(TAGOFFS[_type] + 6);
+            baos.packed8(_min);
+            baos.packed8(_max);
+            assert -3 <= _widen && _widen <= 3;
+            baos.packed1(_widen + 3);
+        }
+    }
+
+    static Type packed( int tag, BAOS bais ) {
+        return switch( tag ) {
+        case 0 -> BOT;
+        case 1 -> I32;
+        case 2 -> U32;
+        case 3 -> BOOL;
+        case 4 -> ZERO;
+        case 5 -> constant(bais.packed8());
+        case 6 -> make(bais.packed8(),bais.packed8(),(byte)(bais.packed1()-3));
+        default -> throw Utils.TODO();
+        };
+    }
+
     @Override int hash() { return Utils.fold(_min) * Utils.fold(_max) + _widen; }
     @Override public boolean eq( Type t ) {
         return t instanceof TypeInteger i && _min==i._min && _max==i._max && _widen==i._widen;
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeMem.java b/src/main/java/com/seaofnodes/simple/type/TypeMem.java
index 99b19c75..3bbdf1df 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeMem.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeMem.java
@@ -1,10 +1,9 @@
 package com.seaofnodes.simple.type;
 
-import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.*;
 import java.util.ArrayList;
 import java.util.BitSet;
+import java.util.HashMap;
 
 
 /**
@@ -18,13 +17,35 @@ public class TypeMem extends Type {
     //  N means alias slice#N.
     public int _alias;
     public Type _t;       // Memory contents, some scalar type
+    public boolean _one;  // Singleton memory, corresponding to TypeMemPtr._one.
+    public boolean _clz;  // Class-object singleton memory; true singletons stay constant after construction.
+    public boolean _final;// Memory is only set in the constructor
+
+    // Escaped aliases and functions - escaped into this memory.  These are
+    // reachable from some chain of indirections from `_t`.  Bit zero is
+    // used for mutable/immutable safety.  Sign bit repeats infinitely.
+    public int[] _escFs;
+    public int[] _escAs;
+
+    static public int CNT;
 
     private static final Ary<TypeMem> FREE = new Ary<>(TypeMem.class);
-    private TypeMem(int alias, Type t) { super(TMEM); init(alias,t); }
-    private TypeMem init(int alias, Type t) {
-        assert alias>1 || (t==Type.TOP || t==Type.BOTTOM);
+
+    private TypeMem() { super(TMEM); CNT++; }
+    private TypeMem init(int alias, Type t, boolean one, boolean clz, boolean xfinal, int[] fidxs, int[] aliases) {
         _alias = alias;
         _t = t;
+        _one = one;
+        _clz = clz;
+        // Public bulk memory is an aggregate of otherwise-unsplit aliases;
+        // a single final bit cannot describe it.  Keep the lattice-dual high
+        // form distinct, and retain finality for private singleton memory and
+        // precise alias slices.
+        _final = t!=null && alias==1 && !one && !t.isHigh() ? false : xfinal;
+
+        assert _escFs == null && _escAs == null;
+        _escFs = XInt.intern(fidxs);
+        _escAs = XInt.intern(aliases);
         return this;
     }
     @Override TypeMem free(Type t) {
@@ -32,25 +53,59 @@ public class TypeMem extends Type {
         mem._alias= -99;
         mem._dual = null;
         mem._hash = 0;
+        mem._t = null;
+        mem._one = false;
+        mem._clz = false;
+        mem._final = false;
+        mem._escFs = null;
+        mem._escAs = null;
         FREE.push(mem);
         return this;
     }
     @Override boolean isFree() { return _alias == -99; }
 
-    public static TypeMem malloc(int alias, Type t) {
-        return FREE.isEmpty() ? new TypeMem(alias,t) : FREE.pop().init(alias,t);
+    public static TypeMem malloc(int alias, Type t, boolean one, boolean clz, boolean xfinal, int[] fidxs, int[] aliases) {
+        return (FREE.isEmpty() ? new TypeMem() : FREE.pop()).init(alias,t,one,clz,xfinal,fidxs,aliases);
     }
-    public static TypeMem make(int alias, Type t) {
-        TypeMem f = malloc(alias,t);
+    public static TypeMem make(int alias, Type t, boolean one, boolean clz, boolean xfinal, int[] fidxs, int[] aliases) {
+        if( fidxs  ==null ) fidxs  = XInt.EMPTY;
+        if( aliases==null ) aliases= XInt.EMPTY;
+        TypeMem f = malloc(alias,t,one,clz,xfinal, fidxs, aliases);
         TypeMem f2 = f.intern();
         if( f2==f ) return f;
         return VISIT.isEmpty() ? f2.free(f) : f2.delayFree(f);
     }
+    public static TypeMem make(int alias, Type t) { return make(alias,t,false,false,false,null,null); }
+    // Make a private memory
+    public static TypeMem makePrivate(Type t) { return make(1,t,true,false,false,escapeFIDX(XInt.EMPTY,t), escapeAlias(XInt.EMPTY,t)); }
+
+    public TypeMem makeFrom(Type t) { return make(_alias,t,_one,_clz,_final,_escFs,_escAs); }
+    public TypeMem makeFrom(int alias) { return make(alias,_t,_one,_clz,_final,_escFs,_escAs); }
+    public TypeMem makeFrom(int[] fidxes, int[] aliases) {
+        return make(_alias,_t,_one,_clz,_final,fidxes,aliases);
+    }
+    // Existing escapes plus `t` escapes
+    public TypeMem escapes(Type t) {
+        return make(_alias,_t,_one,_clz,_final, escapeFIDX(_escFs,t), escapeAlias(_escAs,t));
+    }
+    // Existing escapes plus `t` escapes
+    public TypeMem escapesFrom(Type t) {
+        return make(_alias,_t,_one,_clz,_final, escapeFIDX(_escFs,t), escapeAlias(_escAs,t));
+    }
+    // Existing escapes plus `t` escapes
+    public TypeMem escapesFrom(int alias, Type t) {
+        return make(alias,t,_one,_clz,_final, escapeFIDX(_escFs,t), escapeAlias(_escAs,t));
+    }
+    public TypeMem escapesAliases(Type t) {
+        return make(_alias,_t,_one,_clz,_final, _escFs, escapeAlias(_escAs,t));
+    }
 
-    public static final TypeMem TOP = make(1, Type.TOP   );
-    public static final TypeMem BOT = make(1, Type.BOTTOM);
+    public static final TypeMem TOP = make(1, Type.TOP   ,true ,true, true , XInt.EMPTY, XInt.EMPTY);
+    public static final TypeMem BOT = make(1, Type.BOTTOM,false,false,true , XInt.FULL , XInt.FULL );
+    public static final TypeMem START= make(1,Type.BOTTOM,false,false,false, XInt.EMPTY, XInt.EMPTY);
+    public static final TypeMem SELF_MEM = make(1, TypeStruct.BOT);
 
-    public static void gather(ArrayList<Type> ts) { ts.add(make(2,Type.NIL)); ts.add(make(2,TypeInteger.ZERO)); ts.add(BOT); }
+    public static void gather(ArrayList<Type> ts) { ts.add(make(2,Type.NIL)); ts.add(make(2,TypeInteger.ZERO)); ts.add(BOT); ts.add(SELF_MEM); ts.add(START); }
 
     @Override
     TypeMem xmeet(Type t) {
@@ -59,50 +114,139 @@ public class TypeMem extends Type {
         if( that==TOP ) return this;
         if( this==BOT ) return BOT;
         if( that==BOT ) return BOT;
-        int alias = _alias==that._alias ? _alias : 1;
+        // Treat a alias-1 has either very-high or very-low, according to "_t"
+        int alias = _alias==that._alias ? _alias // Same-same
+            : this._alias==1 && this._t.isHigh() ? that._alias // this is high-1 alias, so take that
+            : that._alias==1 && that._t.isHigh() ? this._alias // that is high-1 alias, so take this
+            : 1;
         Type mt = _t.meet(that._t);
-        return make(alias,mt);
+        int[] fidxs  = XInt.meet( _escFs, that._escFs );
+        int[] aliases= XInt.meet( _escAs, that._escAs );
+        // Singleton & class facts are kept only when both sides agree.
+        
+        // Final is kept if either side is final, merging a final & non-final
+        // memory can be argued either way here:
+        
+        // - Keep it: merging a final & non-final memory means a later Store
+        //   update will be flagged as an error.
+        // - Lose it: merging a final & non-final memory means a later Load
+        //   cannot be promised the memory is unchanging.
+        return make(alias, mt, _one & that._one, _clz & that._clz, _final | that._final, fidxs, aliases);
     }
 
     @Override
-    Type xdual() { return _t._dual==_t ? this : malloc(_alias,_t.dual()); }
+    Type xdual() { return malloc(_alias,_t.dual(),!_one,!_clz,!_final, XInt.dual(_escFs), XInt.dual(_escAs)); }
 
     @Override TypeMem rdual() {
         if( _dual!=null ) return dual();
         assert !_terned;
-        TypeMem d = malloc(_alias,null);
+        TypeMem d = malloc(_alias,null,!_one,!_clz,!_final, XInt.dual(_escFs), XInt.dual(_escAs));
         (_dual = d)._dual = this; // Cross link duals
         d._t = _t._terned ? _t.dual() : _t.rdual();
+        if( d._alias==1 && !d._one && !d._t.isHigh() ) d._final = false;
         return d;
     }
 
+    @Override public TypeMem makeZero() { return TOP; }
     @Override public boolean isHigh() { return _t.isHigh(); }
+    @Override boolean _isConstant() { return _one && _clz && _alias!= 1 && _t._isConstant(); }
     @Override public int log_size() { throw Utils.TODO(); }
     @Override boolean _isFinal() { return _t._isFinal(); }
     @Override boolean _isGLB(boolean mem) { return _t._isGLB(true); }
-    @Override public Type _glb(boolean mem) { return make(_alias,_t._glb(true)); }
+    @Override public Type _glb(boolean mem) { return make(_alias,_t._glb(true),_one,_clz,_final,_escFs,_escAs); }
+
+    @Override TypeMem _close( String name, HashMap<String, Type> TYPES ) { return malloc(_alias,_t._close(name, TYPES ),_one,_clz,_final,_escFs,_escAs); }
+
+    @Override Type _upgradeType(HashMap<String,Type> TYPES) {
+        return make(_alias,_t._upgradeType(TYPES),_one,_clz,_final,_escFs,_escAs);
+    }
 
-    @Override int hash() { return 9876543 + _alias + _t.hashCode(); }
+    @Override int hash() { return 9876543 + _alias + _t.hashCode() + (_one ? 8196 : 0) + (_clz ? 4098 : 0) + (_final ? 16392 : 0) + XInt.hash(_escFs) + XInt.hash(_escAs); }
 
     @Override boolean eq(Type t) {
         TypeMem that = (TypeMem) t; // Invariant
-        return _alias == that._alias && _t == that._t;
+        return _alias == that._alias && _t == that._t && _one == that._one && _clz == that._clz && _final == that._final && _escFs == that._escFs && _escAs == that._escAs;
     }
 
     @Override boolean cycle_eq(Type t) {
         TypeMem that = (TypeMem) t; // Invariant
-        return _alias == that._alias && _t.cycle_eq(that._t);
+        return _alias == that._alias && _one == that._one && _clz == that._clz && _final == that._final && _escFs == that._escFs && _escAs == that._escAs && _t.cycle_eq(that._t);
     }
 
-    @Override int nkids() { return 1; }
-    @Override Type at( int idx ) { return _t; }
-    @Override void set( int idx, Type t ) { _t = t; }
+    @Override public int nkids() { return 1; }
+    @Override public Type at( int idx ) { return _t; }
+    @Override public void set( int idx, Type t ) { _t = t; }
+    // one tag for alias#1, one tag for generic alias.
+    // tag bit for _one, another bit for _final.
+    @Override int TAGOFF() { return 12; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        baos.write(TAGOFFS[_type]
+                   + (_alias==1 ? 0 : 1)
+                   + (!_final   ? 0 : 2)
+                   + (!_one     ? 0 : (_clz ? 4 : 8)));
+        if( _alias!=1 ) {
+            // generic alias
+            assert _alias <= 255;
+            baos.packed1( _alias );
+        }
+        XInt.packed(baos,_escFs);
+        XInt.packed(baos,_escAs);
+    }
+    static TypeMem packed( int tag, BAOS bais ) {
+        int alias = (tag&1)==0 ? 1 : bais.packed1();
+        boolean xfinal= (tag&2)==2;
+        boolean one   = (tag&12)!=0;
+        boolean clz   = (tag&4)==4;
+        int[] escFs = XInt.packed(bais);
+        int[] escAs = XInt.packed(bais);
+        return malloc(alias,null,one,clz,xfinal,escFs,escAs);
+    }
 
     @Override public SB _print(SB sb, BitSet visit, boolean html) {
-        sb.p("#");
+        sb.p('#');
+        if( !_final ) sb.p('!'); // Mutable memory
+        if( _one ) sb.p(_clz ? 'z' : '-');
         if( _alias==0 ) return sb.p(_t._type==TTOP ? "TOP" : "BOT");
-        return _t.print(sb.p(_alias).p(":"),visit,html);
+        sb.p(_alias).p(":[");
+        _t.print(sb,visit,html).p(",");
+        XInt.str(sb,_escFs).p(",");
+        return XInt.str(sb,_escAs).p("]");
+    }
+
+    @Override public String str() {
+        SB sb = new SB().p('#');
+        if( !_final ) sb.p('!'); // Mutable memory
+        if( _one ) sb.p(_clz ? 'z' : '-');
+        if( _alias==0 ) return sb.p(_t._type==TTOP ? "TOP" : "BOT").toString();
+        sb.p(_alias).p(":[").p(_t.str()).p(",");
+        XInt.str(sb,_escFs).p(",");
+        return XInt.str(sb,_escAs).p("]").toString();
     }
 
-    @Override public String str() { return toString(); }
+
+    // Tracking bulk escaped aliases and fidxs
+
+    // Escape all FIDXs from t
+    private static int[] escapeFIDX( int[] xs, Type t ) {
+        return switch(t) {
+        case TypeMemPtr tmp -> escapeFIDX(xs,tmp._obj);
+        case TypeStruct ts  -> ts._open
+                ? XInt.FULL         // Open structs can have any fields
+                : XInt.meet(xs,ts.fidxs());
+        case TypeFunPtr tfp -> XInt.meet(xs,tfp.fidxs());
+        case TypeMem    mem -> XInt.meet(xs,mem._escFs);
+        case Type tt -> tt == BOTTOM ? XInt.FULL : xs;
+        };
+    }
+
+    private static int[] escapeAlias( int[] xs, Type t ) {
+        return switch(t) {
+        case TypeMemPtr tmp -> escapeAlias(xs,tmp._obj);
+        case TypeStruct ts  -> ts._open
+            ? XInt.FULL         // Open structs can have any fields
+            : XInt.meet(xs,ts.aliases());
+        case TypeMem    mem -> XInt.meet(xs,mem._escAs);
+        case Type tt -> tt == BOTTOM ? XInt.FULL : xs;
+        };
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java b/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
index 689b73ce..67d80591 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
@@ -1,8 +1,9 @@
 package com.seaofnodes.simple.type;
 
 import com.seaofnodes.simple.util.Ary;
+import com.seaofnodes.simple.util.AryInt;
 import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.BAOS;
 import java.util.*;
 
 /**
@@ -26,19 +27,23 @@ public class TypeMemPtr extends TypeNil {
     // (TOP   ,true ) - a nil
 
     public TypeStruct _obj;
-    public boolean _one;  // Singleton instance
+    public boolean _one;      // Singleton pointer value; the pointer itself is constant.
+    public boolean _pub;      // Escaped/public pointer.  False means constructor-private.
 
     private static final Ary<TypeMemPtr> FREE = new Ary<>(TypeMemPtr.class);
-    private TypeMemPtr(byte nil, TypeStruct obj, boolean one) { super(TMEMPTR,nil); init(nil,obj,one); }
-    private TypeMemPtr init(byte nil, TypeStruct obj, boolean one) { _nil=nil; _obj=obj; _one=one; return this; }
+    private TypeMemPtr(byte nil, TypeStruct obj, boolean one, boolean pub) { super(TMEMPTR,nil); init(nil,obj,one,pub); }
+    private TypeMemPtr init(byte nil, TypeStruct obj, boolean one, boolean pub) { _nil=nil; _obj=obj; _one=one; _pub=pub; return this; }
     // Return a filled-in TypeMemPtr; either from free list or alloc new.
-    private static TypeMemPtr malloc(byte nil, TypeStruct obj, boolean one) {
-        return FREE.isEmpty() ? new TypeMemPtr(nil,obj,one) : FREE.pop().init(nil,obj,one);
+    static TypeMemPtr malloc(byte nil, TypeStruct obj, boolean one, boolean pub) {
+        return FREE.isEmpty() ? new TypeMemPtr(nil,obj,one,pub) : FREE.pop().init(nil,obj,one,pub);
     }
 
     // All fields directly listed
     public static TypeMemPtr make(byte nil, TypeStruct obj, boolean one) {
-        TypeMemPtr tmp = malloc(nil, obj, one);
+        return make(nil,obj,one,true);
+    }
+    public static TypeMemPtr make(byte nil, TypeStruct obj, boolean one, boolean pub) {
+        TypeMemPtr tmp = malloc(nil, obj, one, pub);
         TypeMemPtr t2 = tmp.intern();
         if( t2==tmp ) return tmp;
         return VISIT.isEmpty() ? t2.free(tmp) : t2.delayFree(tmp);
@@ -47,6 +52,8 @@ public class TypeMemPtr extends TypeNil {
         TypeMemPtr tmp = (TypeMemPtr)t;
         tmp._nil  = -99;
         tmp._obj  = null;
+        tmp._one  = false;
+        tmp._pub = true;
         tmp._dual = null;
         tmp._hash = 0;
         FREE.push(tmp);
@@ -57,11 +64,13 @@ public class TypeMemPtr extends TypeNil {
     static TypeMemPtr make(byte nil, TypeStruct obj) { return make(nil, obj, false); }
     public static TypeMemPtr make        (TypeStruct obj) { return make((byte)2, obj); }
     public static TypeMemPtr makeNullable(TypeStruct obj) { return make((byte)3, obj); }
+    public static TypeMemPtr makePrivate (TypeStruct obj) { return make((byte)2, obj, false, false); }
 
-    public TypeMemPtr makeFrom(TypeStruct obj) { return obj==_obj ? this : make(_nil, obj, _one); }
+    public TypeMemPtr makeFrom(TypeStruct obj) { return obj==_obj ? this : make(_nil, obj, _one, _pub); }
     public TypeMemPtr makeNullable() { return makeFrom((byte)3); }
-    @Override TypeMemPtr makeFrom(byte nil) { return nil==_nil ? this : make(nil, _obj, _one); }
-    public TypeMemPtr makeHigh() { return make((byte)0,_obj.makeHigh(),false); }
+    @Override TypeMemPtr makeFrom(byte nil) { return nil==_nil ? this : make(nil, _obj, _one, _pub); }
+    public TypeMemPtr makeHigh(byte nil) { return make(nil,_obj.makeHigh(),false); }
+    @Override public Type nonZero() { return makeFrom((byte)(_nil <= 1 ? 1 : 2)); }
 
     // An abstract pointer, pointing to either a Struct or an Array.
     // Can also be null or not, so 4 choices {TOP,BOT} x {nil,not}
@@ -76,16 +85,19 @@ public class TypeMemPtr extends TypeNil {
     public TypeNil xmeet(Type t) {
         TypeMemPtr that = (TypeMemPtr) t;
         assert !isFree() && !that.isFree();
-        return make(xmeet0(that), (TypeStruct)_obj.meet(that._obj), _one & that._one);
+        // Can't keep _one if mixing two unequal singletons; the result is not
+        // either singleton.  Once either side is public, the meet is public.
+        boolean one = _one && that._one && (_obj==that._obj || !(_obj.isConAry() || that._obj.isConAry()));
+        return make(xmeet0(that), (TypeStruct)_obj.meet(that._obj), one, _pub | that._pub);
     }
 
     @Override
-    TypeMemPtr xdual() { return malloc( dual0(), _obj.dual(), _one); }
+    TypeMemPtr xdual() { return malloc( dual0(), _obj.dual(), !_one, !_pub); }
 
     @Override TypeMemPtr rdual() {
         if( _dual!=null ) return dual();
         assert !_terned;
-        TypeMemPtr d = malloc(dual0(), null, _one);
+        TypeMemPtr d = malloc(dual0(), null, !_one, !_pub);
         (_dual = d)._dual = this; // Cross link duals
         d._obj = _obj._terned ? _obj.dual() : _obj.rdual();
         return d;
@@ -94,50 +106,52 @@ public class TypeMemPtr extends TypeNil {
     // RHS is NIL; do not deep-dual when crossing the center line
     @Override Type meet0() { return _nil==3 ? this : make((byte)3,_obj); }
 
-    @Override boolean _isConstant() { return _one && _obj._isConstant(); }
+    @Override boolean _isConstant() { return _one; }
     @Override boolean _isFinal() { return _obj._isFinal(); }
     @Override TypeMemPtr _makeRO() { return makeFrom(_obj._makeRO()); }
-    @Override boolean _isGLB(boolean mem) { return _obj.isGLB2(); }
+    @Override boolean _isGLB(boolean mem) { return _obj._isGLB(true); }
     @Override TypeMemPtr _glb(boolean mem) { return make((byte)3,_obj.glb2()); }
-    @Override TypeMemPtr _close() { return makeFrom(_obj._close()); }
-
-
-    // True if this "isa" t up to named structures
-    @Override public boolean shallowISA( Type t ) {
-        if( !(t instanceof TypeMemPtr that) ) return false;
-        if( this==that ) return true;
-        if( xmeet0(that)!=that._nil ) return false;
-        if( _obj==that._obj ) return true;
-        if( _obj._name.equals(that._obj._name) )
-            return true;        // Shallow, do not follow matching names, just assume ok
-        throw Utils.TODO(); // return _obj.shallowISA(that._obj);
-    }
+    @Override TypeMemPtr _close( String name, HashMap<String, Type> TYPES ) { return malloc(_nil,_obj._close(name, TYPES ),_one,_pub); }
 
-    // Is forward-reference
-    @Override public boolean isFRef() { return _obj.isFRef(); }
+    @Override Type _upgradeType(HashMap<String,Type> TYPES) {
+        return makeFrom((TypeStruct)_obj._upgradeType(TYPES));
+    }
 
     @Override public int log_size() { return 3; } // (1<<3)==8-byte pointers
 
-    @Override int hash() { return _obj.hashCode() ^ super.hash() ^ (_one ? 2048 : 0); }
+    @Override int hash() { return _obj.hashCode() ^ super.hash() ^ (_one ? 2048 : 0) ^ (_pub ? 4096 : 0); }
 
     @Override boolean eq(Type t) {
         TypeMemPtr ptr = (TypeMemPtr)t; // Invariant
-        return super.eq(ptr) && _one == ptr._one && _obj == ptr._obj;
+        return super.eq(ptr) && _one == ptr._one && _pub == ptr._pub && _obj == ptr._obj;
     }
     @Override boolean cycle_eq(Type t) {
         if( t._type != TMEMPTR ) return false;
         TypeMemPtr ptr = (TypeMemPtr)t; // Invariant
-        return super.eq(ptr) && _one == ptr._one && _obj.cycle_eq(ptr._obj);
+        return super.eq(ptr) && _one == ptr._one && _pub == ptr._pub && _obj.cycle_eq(ptr._obj);
     }
 
-    @Override int nkids() { return 1; }
-    @Override Type at( int idx ) { return _obj; }
-    @Override void set( int idx, Type t ) { _obj = (TypeStruct)t; }
+    @Override public int nkids() { return 1; }
+    @Override public Type at( int idx ) { return _obj; }
+    @Override public void set( int idx, Type t ) { _obj = (TypeStruct)t; }
+
+    // Reserve tags for null/not, one/general and public/private
+    @Override int TAGOFF() { return 8; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        assert _nil>=2;
+        baos.write(TAGOFFS[_type]
+                   + (_nil==2 ? 0 : 1)
+                   + (!_one   ? 0 : 2)
+                   + (!_pub    ? 0 : 4) );
+    }
+    static TypeMemPtr packed( int tag, BAOS bais ) {
+        return malloc((byte)((tag&1)+2),null,(tag&2)==2,(tag&4)==4);
+    }
 
     @Override public String str() {
         if( this== NOTBOT) return "*void";
         if( this==    BOT) return "*void?";
-        return x()+"*"+_obj.str()+q();
+        return x()+"*"+(_obj==null?"---":_obj.str())+q();
     }
 
     @Override SB _print(SB sb, BitSet visit, boolean html ) {
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeNil.java b/src/main/java/com/seaofnodes/simple/type/TypeNil.java
index 56d73b00..32505aa2 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeNil.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeNil.java
@@ -7,7 +7,7 @@ import java.util.ArrayList;
 /**
  * Nil-able Scalar types
  */
-public abstract class TypeNil extends Type {
+public abstract class TypeNil extends TypeScalar {
     // 0 = high-subclass choice nil
     // 1 = high-subclass no nil
     // 2 = low -subclass no nil
diff --git a/src/main/java/com/seaofnodes/simple/type/TypePtr.java b/src/main/java/com/seaofnodes/simple/type/TypePtr.java
index 75478119..3ff9765b 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypePtr.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypePtr.java
@@ -1,9 +1,12 @@
 package com.seaofnodes.simple.type;
 
+import com.seaofnodes.simple.util.AryInt;
 import com.seaofnodes.simple.util.SB;
 import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.BAOS;
 import java.util.ArrayList;
 import java.util.BitSet;
+import java.util.HashMap;
 
 /**
  * Represents a Scalar; a single register-sized value.
@@ -50,6 +53,14 @@ public class TypePtr extends TypeNil {
     boolean _isGLB(boolean mem) { return this==PTR; }
     @Override TypePtr _glb(boolean mem) { return PTR; }
 
+    // Reserve 2 tags, PTR and NPTR
+    @Override int TAGOFF() { return 2; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        assert _nil>=2;
+        baos.write(TAGOFFS[_type] + (_nil==2 ? 0 : 1));
+    }
+    static TypePtr packed( int tag ) { return tag==0 ? NPTR : PTR; }
+
     @Override public String str() { return STRS[_nil]; }
     @Override public SB _print(SB sb, BitSet visit, boolean html) { return sb.p(str()); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeRPC.java b/src/main/java/com/seaofnodes/simple/type/TypeRPC.java
index a1389540..a39ebc04 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeRPC.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeRPC.java
@@ -1,32 +1,26 @@
 package com.seaofnodes.simple.type;
 
 import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
-import java.util.ArrayList;
-import java.util.BitSet;
-import java.util.HashSet;
+import com.seaofnodes.simple.util.BAOS;
+import java.util.*;
 
 /**
  *  Return Program Control or Return PC or RPC
  */
 public class TypeRPC extends Type {
 
-    // A set of CallEndNode IDs (or StopNode); commonly just one.
-    // Basically a sparse bit set
-    HashSet<Integer> _rpcs;
-
-    // If true, invert the meaning of the bits
-    boolean _any;
+    // A set of CallEndNode IDs (or StopNode); commonly just one.  High-bit
+    // XInt sets represent complements/infinite sets.
+    public int[] _rpcs;
 
     private static final Ary<TypeRPC> FREE = new Ary<>(TypeRPC.class);
-    private TypeRPC init(boolean any, HashSet<Integer> rpcs) { _any=any; _rpcs=rpcs; return this; }
+    private TypeRPC init(int[] rpcs) { _rpcs = XInt.intern(rpcs); return this; }
     private TypeRPC() { super(TRPC); }
-    private static TypeRPC malloc(boolean any, HashSet<Integer> rpcs) {
-        return (FREE.isEmpty() ? new TypeRPC() : FREE.pop()).init(any,rpcs);
+    private static TypeRPC malloc(int[] rpcs) {
+        return (FREE.isEmpty() ? new TypeRPC() : FREE.pop()).init(rpcs);
     }
-    private static TypeRPC make(boolean any, HashSet<Integer> rpcs) {
-        TypeRPC rpc = (FREE.isEmpty() ? new TypeRPC() : FREE.pop()).init(any,rpcs);
+    private static TypeRPC make(int[] rpcs) {
+        TypeRPC rpc = malloc(rpcs);
         TypeRPC t2 = rpc.intern();
         return t2==rpc ? rpc : t2.free(rpc);
     }
@@ -41,71 +35,72 @@ public class TypeRPC extends Type {
     @Override boolean isFree() { return _rpcs==null; }
 
     public static TypeRPC constant(int cend) {
-        HashSet<Integer> rpcs = new HashSet<>();
-        rpcs.add(cend);
-        return make(false,rpcs);
+        return make(XInt.make(cend));
+    }
+
+    public int rpc() {
+        return XInt.onlyBit(_rpcs);
     }
 
-    public  static final TypeRPC BOT = make(true,new HashSet<>());
+
+    public  static final TypeRPC BOT = make(XInt.FULL);
     private static final TypeRPC TEST2 = constant(2);
     private static final TypeRPC TEST3 = constant(2);
+    public  static final TypeRPC EMPTY = make(XInt.EMPTY);
 
     public static void gather(ArrayList<Type> ts) { ts.add(BOT); ts.add(TEST2); ts.add(TEST3); }
 
+    @Override public TypeRPC makeZero() { return EMPTY; }
+
+
     @Override public String str() {
-        if( _rpcs.isEmpty() )
-            return _any ? "$[ALL]" : "$[]";
-        if( _rpcs.size()==1 )
-            for( Integer rpc : _rpcs )
-                return _any ? "$[-"+rpc+"]" : "$["+rpc+"]";
-        return "$["+(_any ? "-" : "")+_rpcs+"]";
+        if( _rpcs == XInt.FULL  ) return "$[ALL]";
+        if( _rpcs == XInt.EMPTY ) return "$[]";
+        return "$"+XInt.str(_rpcs);
     }
 
     @Override
     public TypeRPC xmeet(Type other) {
         TypeRPC rpc = (TypeRPC)other;
-        // If the two sets are equal, the _any must be unequal (invariant),
-        // so they cancel and all bits are set.
-        if( _rpcs.equals(rpc._rpcs) )
-            return BOT;
-        // Classic union of bit sets (which might be infinite).
-        HashSet<Integer> lhs = _rpcs, rhs = rpc._rpcs;
-        // Smaller on left
-        if( lhs.size() > rhs.size() ) { lhs = rpc._rpcs; rhs = _rpcs; }
-
-        HashSet<Integer> rpcs = new HashSet<>();
-        boolean any = true;
-        // If both sets are infinite, intersect.
-        if( _any && rpc._any ) {
-            for( Integer i : lhs )  if( rhs.contains(i) )  rpcs.add(i);
-
-        } else if( !_any && !rpc._any ) {
-            // if neither set is infinite, union.
-            rpcs.addAll( lhs );
-            rpcs.addAll( rhs );
-            any = false;
-        } else {
-            // If one is infinite, subtract the other from it.
-            HashSet<Integer> sub = _any ? rpc._rpcs : _rpcs;
-            HashSet<Integer> inf = _any ? _rpcs : rpc._rpcs;
-            for( Integer i : inf )
-                if( inf.contains(i) && !sub.contains(i) )
-                    rpcs.add(i);
-        }
-        return make(any,rpcs);
+        return make(XInt.meet(_rpcs,rpc._rpcs));
     }
 
-    @Override Type xdual() { return malloc(!_any,_rpcs); }
+    @Override TypeRPC xdual() { return malloc(XInt.dual(_rpcs)); }
+    @Override Type rdual() {
+        TypeRPC d = xdual();
+        (_dual = d)._dual = this;
+        return d;
+    }
 
-    @Override boolean _isConstant() { return !_any && _rpcs.size()==1; }
+    @Override boolean _isConstant() { return XInt.isConstant(_rpcs); }
     @Override boolean _isGLB(boolean mem) { return true; }
 
+    // Reserve tags for ALL, singleton, generic
+    @Override int TAGOFF() { return 3; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        if( this==BOT ) {
+            baos.write( TAGOFFS[_type] + 0 );
+        } else if( XInt.isConstant(_rpcs) ) { // Singleton
+            baos.write(TAGOFFS[_type] + 1);
+            baos.packed2(rpc());
+        } else {                // Generic
+            assert !XInt.isHigh(_rpcs); // Not serializing above-center RPC
+            baos.write(TAGOFFS[_type] + 2);
+            XInt.packed(baos,_rpcs);
+        }
+    }
+    static TypeRPC packed( int tag, BAOS bais ) {
+        if( tag==0 ) return BOT;
+        if( tag==1 ) return malloc(XInt.make(bais.packed2()));
+        return malloc(XInt.packed(bais));
+    }
+
     @Override
-    int hash() { return _rpcs.hashCode() ^ (_any ? -1 : 0) ; }
+    int hash() { return XInt.hash(_rpcs); }
     @Override
     public boolean eq( Type t ) {
         TypeRPC rpc = (TypeRPC)t; // Contract
-        return _any==rpc._any && _rpcs.equals(rpc._rpcs);
+        return _rpcs==rpc._rpcs;
     }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeScalar.java b/src/main/java/com/seaofnodes/simple/type/TypeScalar.java
new file mode 100644
index 00000000..7b5d6317
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/type/TypeScalar.java
@@ -0,0 +1,58 @@
+package com.seaofnodes.simple.type;
+
+import com.seaofnodes.simple.util.BAOS;
+import com.seaofnodes.simple.util.SB;
+
+import java.util.ArrayList;
+import java.util.BitSet;
+import java.util.HashMap;
+
+/**
+ * The envelope for values which can live in an ordinary register or memory
+ * field: integers, floats, memory pointers, and function pointers.
+ *
+ * `BOT` means any scalar value and `TOP` means no scalar value.  They sit
+ * strictly inside the global {@link Type#BOTTOM}/{@link Type#TOP} pair, which
+ * also includes non-values such as control and memory.
+ */
+public class TypeScalar extends Type {
+    protected TypeScalar(byte type) { super(type); }
+    private TypeScalar() { this(TSCALAR); }
+
+    public static final TypeScalar BOT = new TypeScalar().intern();
+    public static final TypeScalar TOP = BOT.dual();
+
+    public static void gather(ArrayList<Type> ts) { ts.add(BOT); }
+
+    /** Meet two different scalar families. */
+    final Type smeet(TypeScalar scalar) {
+        if( _type == TSCALAR ) return isHigh() ? scalar : this;
+        if( scalar._type == TSCALAR ) return scalar.isHigh() ? this : scalar;
+        return BOT;
+    }
+
+    @Override Type xmeet(Type t) {
+        TypeScalar scalar = (TypeScalar)t;
+        return isHigh() ? scalar : this;
+    }
+
+    @Override TypeScalar xdual() { return new TypeScalar(); }
+    @Override public boolean isHigh() { return this == TOP; }
+    @Override boolean _isGLB(boolean mem) { return this == BOT; }
+    @Override Type _glb(boolean mem) { return BOT; }
+
+    // Reserve tags for both lattice endpoints.  Unlike most concrete scalar
+    // families, generic scalar TOP can survive into a serialized graph.
+    @Override int TAGOFF() { return 2; }
+    @Override public void packed(BAOS baos, HashMap<String,Integer> strs) {
+        assert this == BOT || this == TOP;
+        baos.write(TAGOFFS[_type] + (this == BOT ? 0 : 1));
+    }
+    static TypeScalar packed(int tag) {
+        assert tag == 0 || tag == 1;
+        return tag == 0 ? BOT : TOP;
+    }
+
+    @Override public String str() { return isHigh() ? "~scalar" : "scalar"; }
+    @Override SB _print(SB sb, BitSet visit, boolean html) { return sb.p(str()); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeStruct.java b/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
index 1cabbe32..f51ab859 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
@@ -10,42 +10,65 @@ import java.util.*;
 public class TypeStruct extends Type {
 
     // A Struct has a name and a set of fields; the fields themselves have
-    // names, types and aliases.  The name has no semantic meaning, but is
-    // useful for debugging.
-
-    // During parsing a mid-declaration struct is flagged as a "open".  It is
-    // treated as having infinite fields with correct name and type BOTTOM.
+    // names, types and aliases.  The name is essentially another field,
+    // immutable and type ignored (BOT).
+
+    /**
+     * `_open` and `_fref` are independent lattice coordinates.
+     *
+     * `_open` says the structural tail is not known yet.  On the low side an
+     * open struct has infinitely many implicit BOT fields; its dual has an
+     * implicit TOP tail.  A real declaration is therefore open while its body
+     * is being parsed:
+     *
+     * ```text
+     * struct S { int x; /* more declared fields may follow *\/ }
+     * ```
+     *
+     * `_fref` says no actual declaration has contributed to the type.  The
+     * parser may still invent fields demanded by uses, leaving a useful open
+     * structural constraint:
+     *
+     * ```text
+     * S? p; p.x;       // fref S { BOT x; ... }
+     * ```
+     *
+     * Meeting that constraint with a real definition ANDs `_fref` off while
+     * retaining and checking the invented field.  Closing recursive types must
+     * not by itself clear `_fref`; closure discovers shape, not a declaration.
+     */
 
     public String _name;  // Struct name
-    public boolean _open; // infinite fields are all true:BOTTOM, false:TOP
+    public boolean _open;
+    public boolean _fref;
     public Field[] _fields;
 
-    private TypeStruct(String name, boolean open, Field[] fields) {
-        super(TSTRUCT);
+    private TypeStruct() { super(TSTRUCT); }
+    private static final Ary<TypeStruct> FREE = new Ary<>(TypeStruct.class);
+    private TypeStruct init(String name, boolean open, boolean fref, Field[] fields) {
+        // Check for const array element name with mutable field
+        //assert !name.startsWith("[~]") || fields.length!=2 || fields[1]._t==null || (fields[1]._final != fields[1]._t.isHigh());
         _name = name;
         _open = open;
+        _fref = fref;
         _fields = fields;
+        return this;
     }
-
-    private static final Ary<TypeStruct> FREE = new Ary<>(TypeStruct.class);
     // Return a filled-in TypeStruct; either from free list or alloc new.
-    private static TypeStruct malloc(String name, boolean open, Field[] fields) {
-        if( FREE.isEmpty() ) return new TypeStruct(name,open,fields);
-        TypeStruct ts = FREE.pop();
-        assert ts.isFree();
-        ts._name = name;
-        ts._open = open;
-        ts._fields = fields;
-        return ts;
+    private static TypeStruct malloc(String name, boolean open, boolean fref, Field[] fields) {
+        return (FREE.isEmpty() ? new TypeStruct() : FREE.pop()).init(name,open,fref,fields);
     }
     // Free ts; return this.
     @Override TypeStruct free(Type t) {
         TypeStruct ts = (TypeStruct)t;
         assert !ts.isFree() && !ts._terned;
+        ts._name = null;
         ts._fields = null;
         ts._offs = null;
         ts._dual = null;
         ts._hash = 0;
+        ts._aliases = null;
+        ts._fidxs   = null;
         FREE.push(ts);
         return this;
     }
@@ -54,73 +77,202 @@ public class TypeStruct extends Type {
 
     // All fields directly listed
     public static TypeStruct make(String name, boolean open, Field... fields) {
-        TypeStruct ts = malloc(name, open, fields);
+        return make(name,open,false,fields);
+    }
+    public static TypeStruct make(String name, boolean open, boolean fref, Field... fields) {
+        TypeStruct ts = malloc(name, open, fref, fields);
         TypeStruct t2 = ts.intern();
         if( t2==ts ) return ts;
         return VISIT.isEmpty() ? t2.free(ts) : ts.delayFree(ts);
     }
+
+    // Summary aliases, after interning.  Skips private
+    // fields which need to be explicitly loaded.
+    private int[] _aliases;
+    public int[] aliases() {
+        if( _aliases != null ) return _aliases;
+        if( _fields.length==0 ) return (_aliases=XInt.EMPTY);
+        assert _terned;
+        int maxAlias = 0;
+        for( Field f : _fields )
+            maxAlias = Math.max(maxAlias,f._alias);
+        int len = XInt.idx(maxAlias)+1;
+        if( (maxAlias&31)==31 ) len++;
+        int[] xs = XInt.free(len);
+        for( Field f : _fields )
+            if( f._fname.charAt(0) != '_' &&  // Skip private fields.
+                !hiddenInit(f) &&             // Skip private allocation helper.
+                f._t != Type.TOP )            // Skip uninit fields
+                xs[XInt.idx(f._alias)] |= XInt.mask(f._alias);
+        return (_aliases=XInt.intern(xs));
+    }
+
+    // Summary fidxs, after interning.  Skips private
+    // fields which need to be explicitly loaded.
+    private int[] _fidxs;
+    public int[] fidxs() {
+        if( _fidxs != null ) return _fidxs;
+        assert _terned;
+        int[] xs = XInt.EMPTY;
+        for( Field f : _fields )
+            if( f._fname.charAt(0) != '_' &&     // Skip private fields.
+                !hiddenInit(f) &&                // Skip private allocation helper.
+                f._t instanceof TypeFunPtr tfp ) // Looking for TFP
+                xs = XInt.meet(xs,tfp._fidxs);
+        return (_fidxs = xs);
+    }
+
+    // With a user constructor, the same-named function field is the hidden
+    // default <init> allocation helper, not part of the public class surface.
+    public boolean hiddenInit(Field fld) {
+        if( field("<ctor>") == null || !_name.startsWith("class:") ) return false;
+        int idx = _name.lastIndexOf('.');
+        String name = _name.substring(idx<0 ? "class:".length() : idx+1);
+        return fld._fname.equals(name);
+    }
+
     // New open struct with no fields
     public static TypeStruct open( String name ) { return make(name,true); }
+    public static TypeStruct forward( String name ) { return make(name,true,true); }
+    public TypeStruct defined() { return _fref ? make(_name,_open,false,_fields) : this; }
 
-    // Array
+    // Array, variant body
     public static TypeStruct makeAry(String name, TypeInteger len, int lenAlias, Type body, int bodyAlias, boolean efinal) {
         return make(name,false,
-                    Field.make("#" ,len , lenAlias,true  ,false),
-                    Field.make("[]",body,bodyAlias,efinal,false));
+                    Field.make("#" , len, lenAlias, true ),
+                    Field.make("[]",body,bodyAlias,efinal));
+    }
+    // Array, known constant body
+    public static TypeStruct makeAry(String name, int lenAlias, int bodyAlias, TypeConAry con) {
+        Type len = TypeInteger.constant(con.len());
+        return make(name,false,
+                    Field.make("#"    ,len       , lenAlias,true),
+                    Field.make("[]"   ,con.elem(),bodyAlias,true),
+                    Field.make("[con]",con       ,bodyAlias,true));
     }
+
     public TypeStruct makeHigh() {
         Field[] fs = new Field[_fields.length];
         for( int i=0; i<_fields.length; i++ )
             fs[i] = _fields[i].makeFrom(Type.TOP);
-        return make(_name,false,fs);
+        return make(_name,_open,_fref,fs);
+    }
+
+    public TypeStruct makeInit() {
+        Field[] fs = new Field[_fields.length];
+        for( int i=0; i<_fields.length; i++ ) {
+            Type zero = _fields[i]._t.makeZero();
+            fs[i] = _fields[i].makeFrom(_fields[i]._t != Type.BOTTOM && _fields[i]._t != Type.TOP && zero.isa(_fields[i]._t) ? zero : Type.TOP);
+        }
+        return make(_name,_open,_fref,fs);
     }
 
     public TypeStruct add( Field f ) {
-        assert _open && find(f._fname)==-1; // No double field names
+        assert find(f._fname)==-1; // No double field names
         Field[] flds = Arrays.copyOf(_fields,_fields.length+1);
         flds[_fields.length] = f;
-        return make(_name,true,flds);
+        return make(_name,_open,_fref,flds);
     }
     public TypeStruct replace( Field f ) {
-        assert !_open;
         Field[] flds = Arrays.copyOf(_fields,_fields.length);
         flds[find(f._fname)] = f;
-        return make(_name,false,flds);
+        return make(_name,_open,_fref,flds);
+    }
+    public TypeStruct remove( int i ) {
+        Field[] flds = new Field[_fields.length-1];
+        System.arraycopy(_fields,  0,flds,0,i);
+        System.arraycopy(_fields,i+1,flds,i,flds.length-i);
+        return make(_name,_open,_fref,flds);
     }
 
+    public TypeStruct addOrUpdate(Field fld) {
+        int idx = find(fld._fname);
+        int len = idx == -1 ? (idx=_fields.length)+1 : _fields.length;
+        Field[] flds = Arrays.copyOf(_fields,len);
+        flds[idx] = fld;
+        return make(_name,_open,_fref,flds);
+    }
 
     public final TypeStruct close() {
-        return (TypeStruct)recurOpen()._close().recurClose();
+        return (TypeStruct)recurOpen()._close(_name, null).recurClose();
     }
-    @Override TypeStruct _close() {
-        TypeStruct ts = (TypeStruct)VISIT.get(_name);
+    @Override TypeStruct _close( String name, HashMap<String, Type> TYPES ) {
+        assert (name==null) != (TYPES==null); // One or the other
+        String namePlusFinal = isAry() ? (_name+(_fields[1]._final ? "~" : "!")).intern() : _name;
+        TypeStruct ts = (TypeStruct)VISIT.get(namePlusFinal);
         if( ts!=null ) return ts;
-        ts = recurPre(_name,false);
+        TypeStruct base = name==null ? (TypeStruct)TYPES.get(_name) : this;
+        if( base == null ) base = this;
+        boolean open = base._fref ? base._open : name != _name && name != null && _open;
+        ts = base.recurPre(namePlusFinal, _name, open, base._fref );
         Field[] flds = ts._fields;
-
         // Now start the recursion
         for( int i=0; i<flds.length; i++ )
-            flds[i].setType(_fields[i]._t._close());
+            flds[i].setType(base._fields[i]._t._close(name, TYPES));
 
+        // Note: this whole complex shenanigans here is because there are
+        // actually two flavors of any array (non-/final contents) but I
+        // allow the parser to represent both with the same name string.
+        if( isAry() && _fields[1]._final && !flds[1]._final ) // This is a final array variant
+            flds[1] = flds[1].makeFrom(true); // Add final to the base TYPES non-final array
+
+        return ts;
+    }
+
+    // Needs full recursive treatment; e.g.
+    //     struct LL { LL? next; int !q; }  // Q is mutable field.
+    // Stored into a not-mutable, so need that version also:
+    //     struct LL { LL? next; int  q; }  // Q is NOT mutable field.
+    // Now upgrade:
+    //     it is not the default version from TYPES.
+    //     it is fully cyclic
+    //
+    // Evil question: has no *open* internal fields, so can I assume it is fully correct and never needs upgrade?
+    //
+    // upgrades are for well-formed types with internal ptrs to early open
+    // versions of other types, as happens in all the CoRecur tests.
+    // During the co-recur tests, can I make non-default cycles with
+    // weaker versions of other early types?
+    // Seems plausible...
+    @Override Type _upgradeType(HashMap<String,Type> TYPES) {
+        TypeStruct base = (TypeStruct)TYPES.get(_name);
+        if( this == base ) return this; // Already the good form
+        TypeStruct ts = (TypeStruct)VISIT.get(_uid);
+        if( ts!=null ) return ts;
+        // Main work: replace open with closed
+        if( _open )
+            return base;
+        // Build recursive version
+        ts = recurPre(_uid,_name,false,_fref);
+        Field[] flds = ts._fields;
+        // Now start the recursion
+        for( int i=0; i<flds.length; i++ )
+            flds[i].setType(_fields[i]._t._upgradeType(TYPES));
         return ts;
     }
 
     static final AryInt CEQUALS = new AryInt();
 
-    public  static final TypeStruct BOT = open("$STRUCT");
-    public  static final TypeStruct TOP = BOT.dual();
+    public  static final String TOPNAME = "$TOP", BOTNAME = "$BOT";
+    public  static final TypeStruct TOP = make("$TOP",false);
+    public  static final TypeStruct BOT = TOP.dual();
     public  static final TypeStruct TEST= make("test",false,Field.TEST);
     private static final TypeStruct ARY = makeAry("[]i64",TypeInteger.U32,-1,TypeInteger.BOT,-2,false);
     private static final TypeStruct STR = makeAry("[]u8" ,TypeInteger.U32,-1,TypeInteger.U8 ,-4,false);
-    private static final TypeStruct ABC = makeAry("[]u8",TypeInteger.constant(3),-1,TypeConAryB.ABC,-4,true);
+    private static final TypeStruct ABC = makeAry("[]u8",-1,-4,TypeConAryB.ABC);
+    // Representative unresolved forms for the exhaustive lattice tests:
+    // bare forward ref, forward ref constrained by a field use, and definition.
+    private static final TypeStruct FREF0 = forward("%FREF");
+    private static final TypeStruct FREF1 = FREF0.add(Field.make("x",Type.BOTTOM,-20,false));
+    private static final TypeStruct FDEF1 = make("%FREF",false,Field.make("x",TypeInteger.BOT,-20,false));
 
     // A pair of self-cyclic types
-    private static final TypeStruct SINT0  = open("%SINT");
-    private static final TypeStruct SFLT0  = open("%SFLT");
-    private static final TypeStruct SINT1  = SINT0.add(Field.make("a", TypeInteger.U32, -1, false, false)).add(Field.make("s2",TypeMemPtr.make((byte)2,SFLT0),-2, false, false));
-    private static final TypeStruct SFLT1  = SFLT0.add(Field.make("b", TypeFloat  .F32, -3, false, false)).add(Field.make("s1",TypeMemPtr.make((byte)2,SINT1),-4, false, false));
-    public  static final TypeStruct SFLT2  = SFLT1.close();
+    private static final TypeStruct SINT0  = make("%SINT",false);
+    private static final TypeStruct SFLT0  = make("%SFLT",false);
+    public  static final TypeStruct SINT1  = SINT0.add(Field.make("a", TypeInteger.U32, -1, false)).add(Field.make("s2",TypeMemPtr.make((byte)2,SFLT0),-2, false));
+    public  static final TypeStruct SFLT1  = SFLT0.add(Field.make("b", TypeFloat  .F32, -3, false)).add(Field.make("s1",TypeMemPtr.make((byte)2,SINT1),-4, false));
 
+    @Override public boolean isHigh() { return _name==TOPNAME; }
 
     public static void gather(ArrayList<Type> ts) {
         ts.add(BOT);
@@ -128,14 +280,15 @@ public class TypeStruct extends Type {
         ts.add(ARY);
         ts.add(STR);
         ts.add(ABC);
+        ts.add(FREF0);
+        ts.add(FREF1);
+        ts.add(FDEF1);
         ts.add(SINT0);
         ts.add(SFLT0);
         ts.add(SINT1);
         ts.add(SFLT1);
-        ts.add(SFLT2);
-        ts.add(((TypeMemPtr)(SFLT2.field("s1")._t))._obj);
         // Break cyclic init: built a struct
-        Field fcalloc = Field.make("calloc",TypeFunPtr.CALLOC,-2,true,true);
+        Field fcalloc = Field.make("calloc",TypeFunPtr.CALLOC,-2,true);
         TypeStruct scalloc = make("calloc",false,fcalloc);
         ts.add(scalloc);
 
@@ -144,7 +297,7 @@ public class TypeStruct extends Type {
     // Find field index by name
     public int find(String fname) {
         for( int i=0; i<_fields.length; i++ )
-            if( _fields[i]._fname.equals(fname) )
+            if( _fields[i]._fname==fname )
                 return i;
         return -1;
     }
@@ -170,28 +323,27 @@ public class TypeStruct extends Type {
         if( this==BOT ) return BOT;
         if( that==BOT ) return BOT;
 
-        // Within the same compilation unit, struct names are unique.  If the
-        // names differ, its different structs.  Across many compilation units,
-        // structs with the same name but different field layouts can be
-        // interned... which begs the question:
-        // "What is the meet of structs from two different compilation units?"
-        // And the answer is: "don't ask".
-        if( !_name.equals(that._name) )
-            return BOT;         // It's a struct; that's about all we know
-
         // if equal, no matters.
         // if short is BOT, chop     ; recurPre on short.
         // if short is TOP, copy long; recurPre on long.
         TypeStruct min = _fields.length < that._fields.length ? this : that;
-        if( _fields.length != that._fields.length && (min._open ^ min==this) )
+        if( _fields.length != that._fields.length && (!min._open ^ min!=this) )
             return that.xmeet(this);
 
+        assert (_name==that._name) == (_name.equals(that._name)); // Strings are interned
+        String name =
+            that._name==TOPNAME ?      _name :
+                 _name==TOPNAME ? that._name :
+            that._name==_name ? _name :
+            BOTNAME;
+        if( name==BOTNAME ) return BOT;
+
         // Check all other fields are sanely similar; same struct type but
         // different field contents (e.g. field "age" is either 'int' or '18').
         int len = Math.min(_fields.length,that._fields.length);
         for( int i=0; i<len; i++ ) {
             Field f0 = _fields[i], f1 = that._fields[i];
-            if( !f0._fname.equals(f1._fname) || f0._alias != f1._alias || f0._one != f1._one )
+            if( !f0._fname.equals(f1._fname) || f0._alias != f1._alias )
                 return BOT;
         }
 
@@ -205,7 +357,7 @@ public class TypeStruct extends Type {
 
         // Setup and install the type, prior to recursing, so we can find our
         // recursive self again.
-        ts = recurPre(pid,_open | that._open);
+        ts = recurPre(pid,name,_open | that._open,_fref & that._fref);
 
         // Recurse all common fields
         Field[] flds = ts._fields;
@@ -226,12 +378,10 @@ public class TypeStruct extends Type {
 
     @Override
     TypeStruct xdual() {
-        if( _name=="$STRUCT" )
-            return malloc("$STRUCT",false,new Field[0]);
         Field[] flds = new Field[_fields.length];
         for( int i=0; i<_fields.length; i++ )
             flds[i] = _fields[i].dual();
-        return malloc(_name,!_open,flds);
+        return malloc(sdual(),!_open,!_fref,flds);
     }
 
     // Recursive dual
@@ -239,19 +389,26 @@ public class TypeStruct extends Type {
         if( _dual!=null ) return dual();
         assert !_terned;
         Field[] flds = new Field[_fields.length];
-        TypeStruct d = malloc(_name,!_open,flds);
+        TypeStruct d = malloc(sdual(),!_open,!_fref,flds);
         (_dual = d)._dual = this; // Cross link duals
         for( int i=0; i<_fields.length; i++ )
             flds[i] = _fields[i]._terned ? _fields[i].dual() : _fields[i].rdual();
         return d;
     }
 
-    // Is forward-reference
-    @Override public boolean isFRef() { return _open; }
+    private String sdual() {
+        return
+            _name==TOPNAME ? BOTNAME :
+            _name==BOTNAME ? TOPNAME :
+            _name;
+    }
 
     @Override boolean _isConstant() {
         if( VISIT.containsKey(_uid) ) return true; // Cycles assume constant
         VISIT.put(_uid,this);
+        if( _open ) return false; // Infinite BOT fields
+        // Special case for constant arrays
+
         // Check all fields for being constant
         for( Field field : _fields )
             if( !field._isConstant() )
@@ -261,69 +418,63 @@ public class TypeStruct extends Type {
 
     // All fields are final
     @Override boolean _isFinal() {
-        if( _open ) return false;     // May have more more non-final fields
+        if( _open ) return false;     // May have more non-final fields
         if( VISIT.containsKey(_uid) ) // Test: been here before?
             return true;              // Cycles assume final
-        VISIT.put(_uid,this);         // Set: dont do this again
+        VISIT.put(_uid,this);         // Set: don't do this again
         for( Field fld : _fields )
             if( !fld._isFinal() )
                 return false;
         return true;
     }
 
-    private TypeStruct recurPre(Object key, boolean open) {
+    private TypeStruct recurPre(Object key, String name, boolean open, boolean fref) {
         // Make a clone of original; suitable for hashing so can build
         // e.g. TMPs to clone as part of cycles - but will fail the 'eq' check
         // until the entire cycle is built.
         Field[] flds  = new Field[_fields.length];
         for( int i=0; i<flds.length; i++ )
             flds[i] = _fields[i].malloc(); // Blank copy, but can be hashed
-        TypeStruct ts = malloc(_name, open, flds );
+        TypeStruct ts = malloc(name, open, fref, flds );
+        ts._aliases = aliases();
         VISIT.put(key,ts);
         return ts;
     }
 
-    // Make a read-only version
-    @Override TypeStruct _makeRO() {
-        // Check for already visited
-        TypeStruct ts = (TypeStruct)VISIT.get(_name);
+    private interface FieldTransform { Type apply(Type t); }
+
+    private TypeStruct recurTransform(Object key, String name, boolean open, boolean fref, boolean xfinal, FieldTransform transform) {
+        TypeStruct ts = (TypeStruct)VISIT.get(key);
         if( ts!=null ) return ts;   // Already visited
-        ts = recurPre(_name,_open); // Make a new type with blank fields
+        ts = recurPre(key,name,open,fref);
         Field[] flds = ts._fields;
-        for( Field fld : flds ) fld._final = true;
+        for( Field fld : flds )
+            fld._final |= xfinal;
 
         // Now start the recursion
         for( int i=0; i<flds.length; i++ )
-            flds[i].setType(_fields[i]._t._makeRO());
+            flds[i].setType(transform.apply(_fields[i]._t));
 
         return ts;
     }
 
-
-    // All fields are at GLB already
-    boolean isGLB2() {
-        if( VISIT.containsKey(_uid) ) return true; // Cycles assume GLB
-        VISIT.put(_uid,this);
-        for( Field fld : _fields )
-            if( !fld.isGLB2() )
-                return false;
-        return true;
+    // Make a read-only version
+    @Override TypeStruct _makeRO() {
+        return recurTransform(_name,_name,_open,_fref,true,Type::_makeRO);
     }
 
     // Keeps the same struct, but lower-bounds all fields.
     public TypeStruct glb2() {
-        TypeStruct ts = (TypeStruct)VISIT.get(_name);
-        if( ts!=null ) return ts;
-        ts = recurPre(_name,_open);
-        Field[] flds = ts._fields;
-        for( int i=0; i<flds.length; i++ )
-            flds[i]._final = true ;
-
-        // Now start the recursion
-        for( int i=0; i<flds.length; i++ )
-            flds[i].setType(_fields[i]._t._glb(true));
+        return recurTransform(_uid,_name,_open,false,false,t -> t._glb(true));
+    }
 
-        return ts;
+    @Override boolean _isGLB(boolean mem) {
+        if( VISIT.containsKey(_uid) ) return true; // Cycles assume GLB
+        VISIT.put(_uid,this);
+        for( Field f : _fields )
+            if( !f._t._isGLB(mem) )
+                return false;
+        return true;
     }
 
     // log_size for a struct is not defined, unless its exactly some power of
@@ -340,10 +491,13 @@ public class TypeStruct extends Type {
     // If false, always false.
     // If true , maybe true, need to check recursive fields.
     private boolean static_eq( TypeStruct ts ) {
-        return _name.equals(ts._name) && _open==ts._open && _fields.length==ts._fields.length;
+        assert (_name==ts._name) == (_name.equals(ts._name)); // Strings are interned
+        return _name==ts._name && _open==ts._open && _fref==ts._fref && _fields.length==ts._fields.length;
     }
 
     @Override boolean eq(Type t) {
+        TypeStruct ts = (TypeStruct)t; // Invariant
+
         // Recursive; so use cyclic equals
         if( !VISIT.isEmpty() ) {
             assert CEQUALS.isEmpty();
@@ -352,7 +506,6 @@ public class TypeStruct extends Type {
             return rez;
         }
         // Normal equals
-        TypeStruct ts = (TypeStruct)t; // Invariant
         if( !static_eq(ts) ) return false;
         if( _fields==ts._fields ) return true;
         for( int i = 0; i < _fields.length; i++ )
@@ -380,15 +533,35 @@ public class TypeStruct extends Type {
 
     @Override
     int hash() {
-        long hash = _name.hashCode() ^ (_open ? 4 : 0);
+        long hash = _name.hashCode() ^ (_open ? 4 : 0) ^ (_fref ? 8 : 0);
         for( Field f : _fields )
             hash = Utils.rot(hash,13) ^ ((long)f._fname.hashCode() * f._alias);
         return Utils.fold(hash);
     }
 
-    @Override int nkids() { return _fields.length; }
-    @Override Type at( int idx ) { return _fields[idx]; }
-    @Override void set( int idx, Type t ) { _fields[idx] = (Field)t; }
+    @Override public int nkids() { return _fields.length; }
+    @Override public Field at( int idx ) { return _fields[idx]; }
+    @Override public void set( int idx, Type t ) { _fields[idx] = (Field)t; }
+    // Tags 0-4 - closed +#nflds (+name)
+    // Tags 5   - closed(+ nflds  +name)
+    // Tags 6-10- open   +#nflds (+name)
+    // Tags 11  - open  (+ nflds  +name)
+    @Override int TAGOFF() { return 24; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        baos.write(TAGOFFS[_type]+ (_fref ? 12 : 0) + (_open ? 6 : 0) + Math.min(5,_fields.length));
+        if( _fields.length >= 5 )
+            baos.packed2(_fields.length);
+        baos.packed2(strs.get(_name));
+        // TODO: Write aliases summary
+    }
+    static TypeStruct packed( int tag, BAOS bais, String[] strs ) {
+        boolean fref = tag >= 12;
+        if( fref ) tag -= 12;
+        int ntag = tag >= 6 ? tag-6 : tag;
+        int nflds = ntag < 5 ? ntag : bais.packed2();
+        String name = strs[bais.packed2()];
+        return malloc(name,ntag!=tag,fref,new Field[nflds]);
+    }
 
     @Override
     SB _print(SB sb, BitSet visit, boolean html ) {
@@ -401,14 +574,17 @@ public class TypeStruct extends Type {
         sb.p(" {");
         for( Field f : _fields )
             (f._t ==null ? sb.p("---") : f._t.print(sb,visit,html)).p(f._final ? " " : " !").p(f._fname).p("; ");
-        if( _open ) sb.p("... ");
+        if( _open && !_fref ) sb.p("... ");
         return sb.p("}");
     }
 
     @Override public String str() { return (isFree() ? "FREE:":"")+_name; }
 
 
-    public boolean isAry() { return _fields.length>=2 && _fields[_fields.length-1]._fname=="[]"; }
+    public boolean isAry() { return find("[]")!=-1; }
+    public boolean isConAry() {
+        return isAry() && _fields[1]._t instanceof TypeConAry;
+    }
 
     public int aryBase() {
         assert isAry();
@@ -446,8 +622,7 @@ public class TypeStruct extends Type {
             int[] cnts = new int[5]; // Count of fields at log field size
             int flen = _fields.length;
             for( int i=0; i<flen; i++ )
-                if( !_fields[i]._one )
-                    cnts[_fields[i]._t.log_size()]++; // Log size is 0(byte), 1(i16/u16), 2(i32/f32), 3(i64/dbl)
+                cnts[_fields[i]._t.log_size()]++; // Log size is 0(byte), 1(i16/u16), 2(i32/f32), 3(i64/dbl)
             int off = 0, idx = 0; // Base common struct fields go here, e.g. Mark/Klass
             // Compute offsets to the start of each power-of-2 aligned fields.
             int[] offs = new int[4];
@@ -458,7 +633,6 @@ public class TypeStruct extends Type {
             // Assign offsets to all fields.
             // Really a hidden radix sort.
             for( int i=0; i<flen; i++ ) {
-                if( _fields[i]._one ) continue;
                 int log = _fields[i]._t.log_size();
                 _offs[idx++] = offs[log]; // Field offset
                 offs[log] += 1<<log;      // Next field offset at same alignment
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeTuple.java b/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
index df9aba31..86f8aef1 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
@@ -1,8 +1,6 @@
 package com.seaofnodes.simple.type;
 
-import com.seaofnodes.simple.util.Ary;
-import com.seaofnodes.simple.util.SB;
-import com.seaofnodes.simple.util.Utils;
+import com.seaofnodes.simple.util.*;
 import java.util.*;
 
 public class TypeTuple extends Type {
@@ -31,20 +29,32 @@ public class TypeTuple extends Type {
     }
     @Override boolean isFree() { return _types==null; }
 
+    public TypeTuple makeFrom(int idx, Type tx ) {
+        if( _types[idx]==tx ) return this;
+        Type[] types = _types.clone();
+        types[idx] = tx;
+        return make(types);
+    }
+    public TypeTuple meetFrom(int idx, Type t ) { return makeFrom(idx,_types[idx].meet(t)); }
 
     public static final TypeTuple BOT = malloc(new Type[0]).intern();
     public static final TypeTuple TOP = BOT.dual();
+    // The default state, a triple of CONTROL, Memory, and Value, with bottoms
+    // for all.  This is the default StopNode type, when new functions are
+    // being created and we cannot tell what the future holds.  This is the
+    // default ReturnNode type, returning what the worst a function can do.
+    public static final TypeTuple STATE = make(Type.CONTROL,TypeMem.BOT,Type.BOTTOM);
+    public static final TypeTuple STOP_HIGH = make(Type.CONTROL,TypeMem.START,Type.TOP);
 
     public static final TypeTuple TEST = make(TypeInteger.BOT,TypeMemPtr.TEST);
-    public static final TypeTuple START= make(Type.CONTROL,TypeMem.TOP,TypeInteger.BOT);
-    public static final TypeTuple RET  = make(Type.CONTROL,TypeMem.BOT,Type.BOTTOM);
+    public static final TypeTuple DEAD_NEW = make(TypeMemPtr.TOP,TypeMem.TOP);
 
     public static final TypeTuple IF_BOTH    = make(Type. CONTROL,Type. CONTROL);
     public static final TypeTuple IF_NEITHER = make(Type.XCONTROL,Type.XCONTROL);
     public static final TypeTuple IF_TRUE    = make(Type. CONTROL,Type.XCONTROL);
     public static final TypeTuple IF_FALSE   = make(Type.XCONTROL,Type. CONTROL);
 
-    public static void gather(ArrayList<Type> ts) { ts.add(BOT); ts.add(TEST); ts.add(START); ts.add(IF_TRUE); }
+    public static void gather(ArrayList<Type> ts) { ts.add(BOT); ts.add(TEST); ts.add(STATE); ts.add(IF_TRUE); }
 
     @Override
     Type xmeet(Type other) {
@@ -58,7 +68,24 @@ public class TypeTuple extends Type {
 
     @Override TypeTuple xdual() {
         if( _types.length==0 ) return malloc(null);
-        return malloc(TypeFunPtr.xdual(_types));
+        boolean isCon=true;
+        for( Type t : _types )
+            if( t._dual!=t )
+                // Not a constant
+                return malloc(TypeFunPtr.xdual(_types));
+        return this;
+    }
+    @Override TypeTuple rdual() {
+        if( _dual!=null ) return dual();
+        assert !_terned;
+        assert _types.length>0;
+        Type[] ts = new Type[_types.length];
+        TypeTuple d = malloc(ts);
+        (_dual = d)._dual = this; // Cross link duals
+        // Collection rdual
+        for( int i=0; i<_types.length; i++ )
+            ts[i] = _types[i]._terned ? _types[i].dual() : _types[i].rdual();
+        return d;
     }
 
     @Override boolean _isConstant() {
@@ -71,6 +98,13 @@ public class TypeTuple extends Type {
 
     @Override TypeMemPtr _makeRO() { throw Utils.TODO(); }
 
+    @Override Type _upgradeType(HashMap<String,Type> TYPES) {
+        Type[] ts = new Type[_types.length];
+        for( int i=0; i<ts.length; i++ )
+            ts[i] = _types[i]._upgradeType(TYPES);
+        return make(ts);
+    }
+
     @Override public int log_size() { throw Utils.TODO(); }
     @Override public int alignment() {
         assert isConstant();
@@ -80,7 +114,30 @@ public class TypeTuple extends Type {
         return align;
     }
 
-    public Type ret() { assert _types.length==3; return _types[2]; }
+    public Type    ctl() { assert _types.length>=3; return _types[0]; }
+    public Type    ret() { assert _types.length>=3; return _types[2]; }
+    public TypeMem mem() { assert _types.length>=3;
+        return _types[1] instanceof TypeMem tmem ? tmem : (_types[1].isHigh() ? TypeMem.START : TypeMem.BOT);
+    }
+
+    @Override public int nkids() { return _types.length; }
+    @Override public Type at( int idx ) { return _types[idx]; }
+    @Override public void set( int idx, Type t ) { _types[idx] = t; }
+
+    // Reserve tags for tuples with 2,3,generic
+    @Override int TAGOFF() { return 4; }
+    @Override public void packed( BAOS baos, HashMap<String,Integer> strs ) {
+        if( _types.length==2 ) baos.write(TAGOFFS[_type] + 0);
+        else if( _types.length==3 ) baos.write(TAGOFFS[_type] + 1);
+        else if( _types.length==4 ) baos.write(TAGOFFS[_type] + 2);
+        else baos.write(TAGOFFS[_type] + 3).packed2(_types.length);
+    }
+    static TypeTuple packed( int tag, BAOS bais ) {
+        if( tag==0 ) return malloc(new Type[2]);
+        if( tag==1 ) return malloc(new Type[3]);
+        if( tag==2 ) return malloc(new Type[4]);
+        return malloc(new Type[bais.packed2()]);
+    }
 
     @Override SB _print(SB sb, BitSet visit, boolean html ) {
         if( this==TOP ) return sb.p("[TOP]");
@@ -112,8 +169,4 @@ public class TypeTuple extends Type {
         return true;
     }
 
-    @Override int nkids() { return _types.length; }
-    @Override Type at( int idx ) { return _types[idx]; }
-    @Override void set( int idx, Type t ) { _types[idx] = t; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/type/XInt.java b/src/main/java/com/seaofnodes/simple/type/XInt.java
new file mode 100644
index 00000000..e3054a73
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/type/XInt.java
@@ -0,0 +1,266 @@
+package com.seaofnodes.simple.type;
+
+import com.seaofnodes.simple.util.*;
+import java.lang.Integer;
+import java.util.Arrays;
+
+// Stupidly overkill interned immutable int[]'s
+public abstract class XInt {
+    private static final Ary<Ary<int[]>> FREES = new Ary(Ary.class);
+    private static final Ary<Ary<int[]>> INTERNS = new Ary(Ary.class);
+    private static int PROBES, HITS, NEWS;
+
+    public static final int[] EMPTY = intern(new int[]{0, 0});
+    public static final int[] FULL  = intern(new int[]{0,-1});
+    public static final int[] SET1  = make(1);
+    public static final int[] SET3  = make(SET1, 2);
+
+    static int idx(int x) { return (x>>5)+1; }
+    static int mask(int x) { return 1<<(x&31); }
+
+    // No hash set, still mutable
+    public static boolean isMutable(int[] xs) { return xs[0]==0; }
+    // Return hash code; must be set hence frozen
+    public static int hash(int[] xs) { return xs[0]; }
+
+    // High bit set (infinite 1's extension)
+    public static boolean isHigh(int[] xs) { return xs[xs.length-1] < 0; }
+
+    // Check for a bit
+    public static boolean bit(int[] xs, int x) {
+        int idx = idx(x);
+        if( idx >= xs.length )
+            return isHigh(xs);
+        return (xs[idx] & mask(x))!=0;
+    }
+
+    // Number of bits set
+    public static int bitCount(int[] xs) {
+        assert !isHigh(xs);       // Dont ask if infinite
+        int cnt=0;
+        for( int i=1; i<xs.length; i++ )
+            cnt += Integer.bitCount(xs[i]);
+        return cnt;
+    }
+
+    // Largest bit
+    public static int max(int[] xs) {
+        assert !isHigh(xs);
+        return Integer.numberOfTrailingZeros(xs[xs.length-1])+((xs.length-1-1)<<5);
+    }
+
+    // Has 1 bit set
+    public static boolean isConstant(int[] xs) { return !isHigh(xs) && bitCount(xs)==1; }
+    // Return the 1 set bit or assert
+    public static int onlyBit(int[] xs) {
+        assert isConstant(xs);
+        for( int i=1; i<xs.length; i++ )
+            if( xs[i] != 0 )
+                return Integer.numberOfTrailingZeros(xs[i]) + ((i-1)<<5);
+        throw Utils.TODO("Should not reach here");
+    }
+
+    // Subset check: ys is a subset of xs
+    public static boolean subset(int[] xs, int[] ys) {
+        assert !isMutable(ys);
+        if( xs==ys ) return true;
+        if( xs==FULL ) return true;
+        if( ys==EMPTY ) return true;
+        int min = Math.min(xs.length,ys.length);
+        for( int i=1; i<min; i++ )
+            if( (xs[i] | ys[i])!=xs[i] )
+                return false;
+        if( xs.length == ys.length )
+            return true;
+        if( ys.length < xs.length )
+            return !isHigh(ys); // If ys is infinite, it'll hit one of the xs extra zeros
+        return isHigh(xs);
+    }
+
+
+    // Construct a set with 1 bit set
+    public static int[] make(int x ) { return make(EMPTY,x); }
+
+    // Add a bit
+    public static int[] make(int[] xs, int x ) {
+        assert !isMutable(xs);
+        int idx = idx(x);
+        if( idx >= xs.length && isHigh(xs) )
+            return xs;          // Set in the default infinite
+        if( idx < xs.length && (mask(x) & xs[idx])!=0 )
+            return xs;          // Already set
+        int len = Math.max(xs.length,idx+1);
+        if( (x&31)==31 && idx+1==len )
+            len++;
+        int[] ys = free(len);
+        System.arraycopy(xs,1,ys,1,xs.length-1);
+        ys[idx] |= mask(x);
+        return intern(ys);
+    }
+
+    // Interning, and life-cycle management
+    // Intern the array
+    public static int[] intern(int[] xs) {
+        if( !isMutable(xs) ) return xs; // Already interned
+        PROBES++;
+
+        // Trim trailing 0s or -1s, use the infinite extend bit
+        int len = xs.length;
+        while( len > 2 &&
+               ((xs[len-1]==  0 && xs[len-2]>=0) ||
+                (xs[len-1]== -1 && xs[len-2]< 0) ) )
+            len--;
+        // Replace with trimmed
+        if( len < xs.length ) {
+            var ys = free(len);
+            System.arraycopy(xs,1,ys,1,len-1);
+            xs = _free(xs,ys);
+        }
+
+        // Compute lame hash code
+        int hash = 0;
+        for( int i=1; i<len; i++ )
+            hash += xs[i];
+        if( hash == 0 ) hash = 0xCAFEBABE;
+        xs[0] = hash;           // Set lame hashcode, and mark immutable
+
+        // Get length-specific INTERN table
+        var xss = INTERNS.atX(len);
+        if( xss==null )
+            INTERNS.setX( xs.length, xss = new Ary<>(int[].class));
+
+        // Probe for a hit
+        for( int[] ys : xss )
+            if( Arrays.equals(xs,ys) ) // Hit!
+                // Free new array and return old array
+                { HITS++;  return _free(xs,ys);  }
+
+        // Intern new array and return
+        return xss.push(xs);
+    }
+
+    // Return Ary of free int[]s of fixed size
+    private static Ary<int[]> _xss(int len) {
+        Ary<int[]> xss = FREES.atX(len);
+        if( xss==null )
+            FREES.setX(len, xss = new Ary<>(int[].class));
+        return xss;
+    }
+    // Pull free array from free list
+    static int[] free(int len) {
+        int[] xs = _xss(len).pop();
+        if( xs==null )
+            { NEWS++;  xs = new int[len];  }
+        assert isMutable(xs);
+        return xs;
+    }
+    // Return ys.  Put xs on free list
+    static int[] _free(int[] xs, int[] ys) {
+        Arrays.fill(xs,0);      // Mutable again
+        _xss(xs.length).push(xs);
+        return ys;
+    }
+
+    // Meet: Set union
+    public static int[] meet(int[] xs, int[] ys) {
+        if( xs==ys ) return xs;
+        boolean isX=true, isY=true;
+        int min = Math.min(xs.length,ys.length);
+        for( int i=1; i<min; i++ ) {
+            if( (xs[i] | ys[i])!=xs[i] ) isX=false;
+            if( (xs[i] | ys[i])!=ys[i] ) isY=false;
+        }
+        if( !isHigh(xs) && min < ys.length )
+            isX = false; // YS has *some* more bits set, and XS does not
+        if( !isHigh(ys) && min < xs.length )
+            isY = false; // XS has *some* more bits set, and YS does not
+        if( isX ) return xs;
+        if( isY ) return ys;
+        // Get a free one
+        int[] ms = free(Math.max(xs.length,ys.length));
+        for( int i=1; i<min; i++ )
+            ms[i] = xs[i] | ys[i];
+        if( min < xs.length )  System.arraycopy(xs,min,ms,min,xs.length-min);
+        if( min < ys.length )  System.arraycopy(ys,min,ms,min,ys.length-min);
+        return intern(ms);
+    }
+
+    // Dual: flip all the bits
+    public static int[] dual(int[] xs) {
+        int[] ds = free(xs.length);
+        for( int i=1; i<xs.length; i++ )
+            ds[i] = ~xs[i];
+        return intern(ds);
+    }
+
+
+    public static void packed(BAOS baos, int[] xs) {
+        baos.packed1(xs.length);
+        for( int i=1; i<xs.length; i++ )
+            baos.packed4(xs[i]);
+    }
+    public static int[] packed(BAOS bais) {
+        int len = bais.packed1();
+        int[] xs = free(len);
+        for( int i=1; i<len; i++ )
+            xs[i] = bais.packed4();
+        return intern(xs);
+    }
+
+    // Next set bit, or -1
+    // for( int bit = XInt.next(bits,0); bit >=0; bit = XInt.next(bits,bit) ) {...bit...}
+    public static int next(int[] xs, int x) {
+        assert !isHigh(xs);     // No iterating infinite bitsets
+        x++;                    // Skip current
+        for( ; !bit(xs,x); x++ )
+            if( idx(x)>=xs.length )
+                return -1;
+        return x;
+    }
+
+    // Remap all bits
+    public static int[] remap( int[] xs, AryInt map ) {
+        if( xs==FULL ) return xs;
+        assert !isHigh(xs);
+        int[] ys = free(xs.length);
+        for( int bit = next(xs,0); bit >=0; bit = next(xs,bit) ) {
+            int bat = map.at(bit);
+            ys[idx(bat)] |= mask(bat);
+        }
+        return intern(ys);
+    }
+
+
+
+    public static String str(int[] xs) { return str(new SB(),xs).toString(); }
+    public static SB str(SB sb, int[] xs) {
+        sb.p("[ ");
+        // Printing ranges;
+        //   1,2,3 prints 1-3
+        //   1,2,4 prints 1,2,4
+        //
+        int max = (xs.length-1)<<5;
+        int low = 0;   // No low range
+        for( int i=1; i<max; i++ ) {
+            if( bit(xs,i) ) {       // Set bit, start or extend range
+                if( low==0 ) low=i; // No range, start one
+            } else {                // Break in sequence, ending a range
+                range(sb,low,i-1);  // Print prior range, and start new one
+                low=0;              // Reset range
+            }
+        }
+        // Print any partial range
+        range(sb,low,max-1).unchar();
+        if( isHigh(xs) )
+            sb.p(",...");
+        return sb.p("]");
+    }
+
+    private static SB range( SB sb, int low, int mid ) {
+        if( low==0 ) ;
+        else if( low==mid ) sb.p(low).p(',');
+        else if( low==mid-1 ) sb.p(low).p(',').p(mid).p(',');
+        else sb.p(low).p('-').p(mid).p(',');
+        return sb;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/util/BAOS.java b/src/main/java/com/seaofnodes/simple/util/BAOS.java
new file mode 100644
index 00000000..61ce7387
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/util/BAOS.java
@@ -0,0 +1,162 @@
+package com.seaofnodes.simple.util;
+
+import java.util.HashMap;
+import java.util.Arrays;
+
+// "ByteArrayOutputStream", and Input Stream and not synchronized and has
+// matching pack/unpack strategies.
+public class BAOS {
+
+    private byte[] _buf;
+    private int _len;
+
+    public BAOS() { _buf = new byte[1]; }
+    public BAOS(byte[] buf) { _buf = buf; }
+    public BAOS(byte[] buf, int x) { _buf = buf; _len = x; }
+
+    public byte[] toByteArray() {
+        return Arrays.copyOf(_buf,_len);
+    }
+
+    public byte[] buf() { return _buf; }
+    public int size() { return _len; }
+    public void set( byte[] buf, int len ) { _buf=buf; _len=len; }
+    public void clear() { _len=0; }
+
+    // -----------------------------------------------------------------------
+    // Basic read, write (expand)
+
+    private void grow(int len) {
+        while( _len+len >= _buf.length )
+            _buf = Arrays.copyOf(_buf,_buf.length*2);
+    }
+
+    // Write a byte, grow as needed; silent chop
+    public BAOS write(int b) {
+        grow(1);
+        _buf[_len++] = (byte)b; // Silent chop
+        return this;
+    }
+
+    // Read an UNSIGNED bytes at INDEX, AIOOBE if off end
+    public int read1(int idx) { return _buf[idx] & 0xFF; }
+
+    // Read an UNSIGNED byte, AIOOBE if off end
+    public int read() { return read1(_len++); }
+
+    // write 2 bytes
+    public BAOS write2( int x ) {
+        grow(2);
+        _buf[_len++] = (byte)(x>> 0);
+        _buf[_len++] = (byte)(x>> 8);
+        return this;
+    }
+
+    // Read a u16 in 2 bytes
+    public int read2(int idx) { return read1(idx) | (read1(idx+1)<<8);  }
+    public int read2() { int rez = read2(_len); _len+=2; return rez; }
+
+    // write 4 bytes
+    public BAOS write4( int x ) {
+        grow(4);
+        _buf[_len++] = (byte)(x>> 0);
+        _buf[_len++] = (byte)(x>> 8);
+        _buf[_len++] = (byte)(x>>16);
+        _buf[_len++] = (byte)(x>>24);
+        return this;
+    }
+
+    // Read a i32 in 4 bytes
+    public int read4(int idx) { return read2(idx) | (read2(idx+2)<<16);  }
+    public int read4() { int rez = read4(_len); _len+=4; return rez; }
+
+    // write 8 bytes
+    public BAOS write8( long x ) {
+        write4((int) x     );
+        write4((int)(x>>32));
+        return this;
+    }
+
+    // Read a i64 in 8 bytes
+    public long read8(int idx) { return ((long)read4(idx) & 0xFFFFFFFFL) | ((long)read4(idx+4)<<32); }
+    public long read8() { long rez = read8(_len); _len+=8; return rez; }
+
+    // Write byte array
+    public void write( byte[] bs ) {
+        grow(bs.length);
+        System.arraycopy(bs,0,_buf,_len,bs.length);
+        _len += bs.length;
+    }
+
+    // Read/fill byte array
+    public byte[] read( byte[] bs ) {
+        System.arraycopy(_buf,_len,bs,0,bs.length);
+        _len += bs.length;
+        return bs;
+    }
+
+    // -----------------------------------------------------------------------
+    // Write a packed integer to the BAOS.  Track a histogram to make more
+    // intelligent choices in the future.
+    private static final HashMap<Long,Integer> PACKED_HISTOGRAM = new HashMap<>();
+    private BAOS histo(long x) {
+        Integer cnt = PACKED_HISTOGRAM.get(x);
+        PACKED_HISTOGRAM.put(x,cnt==null ? 1 : cnt+1);
+        return this;
+    }
+
+    // Write a u8 (checked)
+    public void packed1(int x) {
+        assert 0 <= x && x <= 255;
+        histo(x).write(x);
+    }
+
+    public int packed1() { return read(); }
+
+    // Write a u16 (checked)
+    public void packed2(int x) {
+        assert 0 <= x && x <= 65535;
+        (( x <= 254 ) ? write(x) : write(0xFF).write2(x)).histo(x);
+    }
+
+    // Read a packed u16
+    public int packed2() {
+        int x = read();
+        return x==0xFF ? read2() : x;
+    }
+
+    // Write a packed i32
+    public void packed4(int x) {
+        ((-127 <= x && x <= 127 ) ? write(x) : write(-128).write4(x)).histo(x);
+    }
+
+    // Read a packed i32
+    public int packed4() {
+        int x = _buf[_len++];   // Signed byte read
+        return x== -128 ? read4() : x;
+    }
+
+    // Write a packed i64
+    public void packed8(long x) {
+        ((-127 <= x && x <= 127 ) ? write((int)x) : write(-128).write8(x)).histo(x);
+    }
+
+    // Read a packed i64
+    public long packed8() {
+        int x = _buf[_len++];   // Signed byte read
+        return x== -128 ? read8() : x;
+    }
+
+    public void packedS(String s) {
+        packed4(s.length());
+        for( int i=0; i<s.length(); i++ )
+            packed4(s.charAt(i));
+    }
+
+    public String packedS() {
+        int len = packed4();
+        String s = new String(_buf,_len,len).intern();
+        _len += len;
+        return s;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/util/IntHashMap.java b/src/main/java/com/seaofnodes/simple/util/IntHashMap.java
new file mode 100644
index 00000000..55aaa9f9
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/util/IntHashMap.java
@@ -0,0 +1,65 @@
+package com.seaofnodes.simple.util;
+
+import java.util.Arrays;
+
+// Int-Int Hash Map
+public class IntHashMap {
+    private int[] _es;
+    private int _size;
+    private final int _sentinel;
+
+    // Pick a sentinel value; not allowed for keys or values.  Sentinel is
+    // returned on a miss.  Writing sentinel counts as a remove.
+    public IntHashMap(int sentinel) {
+        _sentinel = sentinel;
+        _es = new int[4];
+        Arrays.fill(_es,sentinel);
+    }
+
+    public int size() { return _size; }
+    public void clear() {
+        _size = 0;
+        Arrays.fill(_es,_sentinel);
+    }
+
+    private int cap() { return _es.length>>1; }
+
+    public int put( int key, int val ) {
+        int slot = probe(key);
+        int old = _es[(slot<<1)+1];
+        if( old == _sentinel && val != _sentinel ) _size++;
+        if( old != _sentinel && val == _sentinel ) _size--;
+        // Check cap
+        if( _size > ((cap()>>1) + (cap()>>2)) ) {
+            grow();
+            slot = probe(key);
+        }
+
+        _es[ slot<<1   ] = key;
+        _es[(slot<<1)+1] = val;
+        return old;
+    }
+
+    public int get( int key ) {
+        int slot = probe(key);
+        return _es[(slot<<1)+1];
+    }
+
+    int probe( int key ) {
+        int mask = cap()-1;
+        int slot = key & mask;
+        while( _es[slot<<1] != _sentinel && _es[slot<<1] != key )
+            slot = (slot + (key|1)) & mask;
+        return slot;
+    }
+
+    // Double underlying array size
+    private void grow() {
+        int[] old = _es;
+        _es = new int[_es.length<<1];
+        Arrays.fill(_es,_sentinel);
+        for( int i=0; i<old.length; i+=2 )
+            if( old[i] != _sentinel )
+                put(old[i],old[i+1]);
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/util/SB.java b/src/main/java/com/seaofnodes/simple/util/SB.java
index d7afd6eb..cc59f2a6 100644
--- a/src/main/java/com/seaofnodes/simple/util/SB.java
+++ b/src/main/java/com/seaofnodes/simple/util/SB.java
@@ -42,7 +42,7 @@ public final class SB {
   // 4 bytes, 8 hex digits, 32 bits, Big Endian
   public SB hex4(int s) { return hex2(s>>16).hex2(s); }
   // 8 bytes, 16 hex digits, 64 bits, Big Endian
-    public SB hex8(long s) { return hex4((int)(s>>32)).hex4((int)s); }
+  public SB hex8(long s) { return hex4((int)(s>>32)).hex4((int)s); }
 
   // Fixed width field
   public SB fix( int sz, String s ) {