Chapter renumber, and split ch 17

Renumber chapters 10a, 10b, 11, 12, 13, 14 -> 10, 11, 13, 12, [11,14].
Split ch 17 into a 17a and 17b; shuffle around im/mutable syntax to be consistent, and present it more slowly.
THe new immutable syntax is pushed through all later chapters

63 files changed, 0 insertions, 7401 deletions

diff --git a/chapter17/src/main/java/com/seaofnodes/simple/Ary.java b/chapter17/src/main/java/com/seaofnodes/simple/Ary.java
deleted file mode 100644
index 8654d41e..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/Ary.java
+++ /dev/null
@@ -1,217 +0,0 @@
-package com.seaofnodes.simple;
-
-import java.lang.StringBuilder;
-import java.lang.reflect.Array;
-import java.util.*;
-
-// ArrayList with saner syntax
-public class Ary<E> extends AbstractList<E> implements List<E> {
-    public E[] _es;
-    public int _len;
-
-    public Ary(E[] es) { this(es,es.length); }
-    public Ary(E[] es, int len) { if( es.length==0 ) es=Arrays.copyOf(es,1); _es=es; _len=len; }
-    @SuppressWarnings("unchecked")
-    public Ary(Class<E> clazz) { this((E[]) Array.newInstance(clazz, 1),0); }
-
-    /** @return list is empty */
-    public boolean isEmpty() { return _len==0; }
-    /** @return active list length */
-    public int len() { return _len; }
-    public int size() { return len(); }
-
-    /** @param i element index
-     *  @return element being returned; throws if OOB
-     *  @exception AIOOBE if !(0 <= i < _len)
-     */
-    public E get( int i ) { return at(i); }
-    public E at( int i ) {
-        range_check(i);
-        return _es[i];
-    }
-
-    /** @return last element */
-    public E last( ) { return at(_len-1); }
-
-    /** Add element in amortized constant time
-     *  @param e Element to add at end of list
-     **/
-    public E push( E e ) {
-        if( _len >= _es.length ) _es = Arrays.copyOf(_es,Math.max(1,_es.length<<1));
-        return (_es[_len++] = e);
-    }
-    /** @return remove and return last element */
-    public E pop( ) {
-        range_check(0);
-        return _es[--_len];
-    }
-    @Override public E removeLast() { return pop(); }
-
-
-    /** Add element in amortized constant time
-     *  @param e Element to add at end of list
-     *  @return true */
-    public boolean add( E e ) {
-        if( _len >= _es.length ) _es = Arrays.copyOf(_es,Math.max(1,_es.length<<1));
-        _es[_len++] = e;
-        return true;
-    }
-
-    ///** Slow, linear-time, element insert.  Preserves order.
-    // *  @param i index to insert at, between 0 and _len inclusive.
-    // *  @param e Element to insert
-    // */
-    //public void insert( int i, E e ) {
-    //    if( i < 0 || i>_len )
-    //        throw new ArrayIndexOutOfBoundsException(""+i+" >= "+_len);
-    //    if( _len >= _es.length ) _es = Arrays.copyOf(_es,Math.max(1,_es.length<<1));
-    //    System.arraycopy(_es,i,_es,i+1,(_len++)-i);
-    //    _es[i] = e;
-    //}
-
-    /** Fast, constant-time, element removal.  Does not preserve order
-     *  @param i element to be removed
-     *  @return element removed */
-    public E del( int i ) {
-        range_check(i);
-        E tmp = _es[i];
-        _es[i]=_es[--_len];
-        return tmp;
-    }
-
-    ///** Element removal, using '=='.  Does not preserve order.
-    // *  @param e element to be removed
-    // *  @return element removed */
-    //public E del( E e ) {
-    //    for( int i=0; i<_len; i++ ) {
-    //        E tmp = _es[i];
-    //        if( tmp==e ) {
-    //            _es[i]=_es[--_len];
-    //            return tmp;
-    //        }
-    //    }
-    //    return null;
-    //}
-
-    /** Slow, linear-time, element removal.  Preserves order.
-     *  @param i element to be removed
-     *  @return element removed */
-    @Override public E remove( int i ) {
-        range_check(i);
-        E e = _es[i];
-        System.arraycopy(_es,i+1,_es,i,(--_len)-i);
-        return e;
-    }
-
-    /** Remove all elements */
-    public void clear( ) { _len=0; }
-
-    /** Set existing element
-     *  @param i element to set
-     *  @param e value to set
-     *  @return old value
-     *  @exception AIOOBE if !(0 <= i < _len)
-     */
-    public E set( int i, E e ) {
-        range_check(i);
-        E old = _es[i];
-        _es[i] = e;
-        return old;
-    }
-
-    public Ary<E> setLen( int len ) {
-        if( len > _len )
-            while( len>= _es.length ) _es = Arrays.copyOf(_es,_es.length<<1);
-        _len = len;
-        while( _es.length > (len<<1) ) // Shrink if hugely too large
-            _es = Arrays.copyOf(_es,_es.length>>1);
-        Arrays.fill(_es,len,_es.length,null);
-        return this;
-    }
-
-    /** @param c Collection to be added */
-    public boolean addAll( Collection<? extends E> c ) {
-        if( c==null ) return false;
-        for( E e : c ) add(e);
-        return true;
-    }
-    public Ary<E> addAll( Iterable<? extends E> it ) { for( E e : it ) add(e); return this; }
-
-    /** @param es Array to be added */
-    public <F extends E> Ary<E> addAll( F[] es ) {
-        if( es==null || es.length==0 ) return this;
-        while( _len+es.length > _es.length ) _es = Arrays.copyOf(_es,_es.length<<1);
-        System.arraycopy(es,0,_es,_len,es.length);
-        _len += es.length;
-        return this;
-    }
-
-    /** @param c Collection to be added */
-    public Ary<E> addAll( Ary<? extends E> c ) {
-        if( c==null || c._len==0 ) return this;
-        while( _len+c._len > _es.length ) _es = Arrays.copyOf(_es,_es.length<<1);
-        System.arraycopy(c._es,0,_es,_len,c._len);
-        _len += c._len;
-        return this;
-    }
-
-  /** @return compact array version */
-  public E[] asAry() { return Arrays.copyOf(_es,_len); }
-
-  /** Sorts in-place
-   *  @param c Comparator to sort by */
-  public void sort_update(Comparator<? super E> c ) { Arrays.sort(_es, 0, _len, c);  }
-
-    /** Find the first matching element using ==, or -1 if none.  Note that
-     *  most del calls shuffle the list, so the first element might be random.
-     *  @param e Element to find
-     *  @return index of first matching element, or -1 if none */
-    public int find( E e ) {
-        for( int i=0; i<_len; i++ )  if( _es[i]==e )  return i;
-        return -1;
-    }
-
-
-    /** @return an iterator */
-    @Override public Iterator<E> iterator() { return new Iter(); }
-    private class Iter implements Iterator<E> {
-        int _i=0;
-        @Override public boolean hasNext() { return _i<_len; }
-        @Override public E next() { return _es[_i++]; }
-    }
-
-    @Override public String toString() {
-        StringBuilder sb = new StringBuilder().append('{');
-        for( int i=0; i<_len; i++ ) {
-            if( i>0 ) sb.append(',');
-            if( _es[i] != null ) sb.append(_es[i].toString());
-        }
-        return sb.append('}').toString();
-    }
-
-    private void range_check( int i ) {
-        if( i < 0 || i>=_len )
-            throw new ArrayIndexOutOfBoundsException(""+i+" >= "+_len);
-    }
-
-    // Note that the hashCode() and equals() are not invariant to changes in the
-    // underlying array.  If the hashCode() is used (e.g., inserting into a
-    // HashMap) and the then the array changes, the hashCode() will change also.
-    @Override public boolean equals( Object o ) {
-        if( this==o ) return true;
-        if( !(o instanceof Ary ary) ) return false;
-        if( _len != ary._len ) return false;
-        if( _es == ary._es ) return true;
-        for( int i=0; i<_len; i++ )
-            if( !(_es[i]==null ? (ary._es[i] == null) : _es[i].equals(ary._es[i])) )
-                return false;
-        return true;
-    }
-    @Override public int hashCode( ) {
-        int sum=_len;
-        for( int i=0; i<_len; i++ )
-            sum += _es[i]==null ? 0 : _es[i].hashCode();
-        return sum;
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java b/chapter17/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java
deleted file mode 100644
index eba99128..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java
+++ /dev/null
@@ -1,238 +0,0 @@
- package com.seaofnodes.simple;
-
-import com.seaofnodes.simple.IterPeeps.WorkList;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.*;
-import java.util.*;
-
-public abstract class GlobalCodeMotion {
-
-    // Arrange that the existing isCFG() Nodes form a valid CFG.  The
-    // Node.use(0) is always a block tail (either IfNode or head of the
-    // following block).  There are no unreachable infinite loops.
-    public static void buildCFG( StopNode stop ) {
-        schedEarly();
-        Parser.SCHEDULED = true;
-        schedLate( stop);
-    }
-
-
-    // ------------------------------------------------------------------------
-    // Visit all nodes in CFG Reverse Post-Order, essentially defs before uses
-    // (except at loops).  Since defs are visited first - and hoisted as early
-    // as possible, when we come to a use we place it just after its deepest
-    // input.
-    private static void schedEarly() {
-        ArrayList<CFGNode> rpo = new ArrayList<>();
-        BitSet visit = new BitSet();
-        _rpo_cfg(Parser.START, visit, rpo);
-        // Reverse Post-Order on CFG
-        for( int j=rpo.size()-1; j>=0; j-- ) {
-            CFGNode cfg = rpo.get(j);
-            cfg.loopDepth();
-            for( Node n : cfg._inputs )
-                _schedEarly(n,visit);
-            // In dead infinite loops, entire code blocks may be unreachable
-            // from below.  Reach down from the CFG to their Phis so their
-            // inputs are scheduled too.
-            if( cfg instanceof RegionNode )
-                for( Node phi : cfg._outputs )
-                    if( phi instanceof PhiNode )
-                        _schedEarly(phi,visit);
-        }
-    }
-
-    // Post-Order of CFG
-    private static void _rpo_cfg(Node n, BitSet visit, ArrayList<CFGNode> rpo) {
-        if( !(n instanceof CFGNode cfg) || visit.get(cfg._nid) )
-            return;             // Been there, done that
-        visit.set(cfg._nid);
-        for( Node use : cfg._outputs )
-            _rpo_cfg(use,visit,rpo);
-        rpo.add(cfg);
-    }
-
-    private static void _schedEarly(Node n, BitSet visit) {
-        if( n==null || visit.get(n._nid) ) return; // Been there, done that
-        assert !(n instanceof CFGNode);
-        visit.set(n._nid);
-        // Schedule inputs first, except Phis: following their backedges would
-        // enter a data cycle before its control has been scheduled.
-        for( Node def : n._inputs )
-            if( def!=null && !(def instanceof PhiNode) )
-                _schedEarly(def,visit);
-        // An existing edge 0 already supplies control (or a Phi/Proj binding).
-        if( n.in(0)==null ) {
-            // Schedule at deepest input
-            CFGNode early = Parser.START; // Maximally early, lowest idepth
-            for( int i=1; i<n.nIns(); i++ )
-                if( n.in(i)!=null && n.in(i).cfg0().idepth() > early.idepth() )
-                    early = n.in(i).cfg0(); // Latest/deepest input
-            n.setDef(0,early);              // First place this can go
-        }
-    }
-
-    // ------------------------------------------------------------------------
-    private static void schedLate( StopNode stop) {
-        CFGNode[] late = new CFGNode[Node.UID()];
-        Node[] ns = new Node[Node.UID()];
-        // Record Load NIDs at all their CFG block choices, then check against
-        // Store block choices to force a Load above an anti-dependent Store.
-        int[] anti = new int[Node.UID()];
-        // Breadth-first scheduling
-        breadth(stop,ns,late,anti);
-
-        // Copy the best placement choice into the control slot
-        for( int i=0; i<late.length; i++ )
-            if( ns[i] != null && !(ns[i] instanceof ProjNode) )
-                ns[i].setDef(0,late[i]);
-    }
-
-    private static void breadth(Node stop, Node[] ns, CFGNode[] late, int[] anti) {
-        // Things on the worklist have some (but perhaps not all) uses done.
-        WorkList<Node> work = new WorkList<>();
-        work.push(stop);
-        Node n;
-        outer:
-        while( (n = work.pop()) != null ) {
-            assert late[n._nid]==null; // No double visit
-            // These I know the late schedule of, and need to set early for loops
-            if( n instanceof CFGNode cfg ) late[n._nid] = cfg.blockHead() ? cfg : cfg.cfg(0);
-            else if( n instanceof PhiNode phi ) late[n._nid] = phi.region();
-            else if( n instanceof ProjNode && n.in(0) instanceof CFGNode cfg ) late[n._nid] = cfg;
-            else {
-
-                // All uses done?
-                for( Node use : n._outputs )
-                    if( use!=null && late[use._nid]==null )
-                        continue outer; // Nope, await all uses done
-
-                // Loads need their memory inputs' uses also done
-                if( n instanceof LoadNode ld )
-                    for( Node memuse : ld.antiDeps() )
-                        if( late[memuse._nid]==null )
-                            continue outer;
-
-                // All uses done, schedule
-                _doSchedLate(n,ns,late,anti);
-            }
-
-            // A use just finished; reconsider its inputs and waiting loads,
-            // even when the shared memory input was already scheduled.
-            for( Node def : n._inputs ) {
-                if( def==null ) continue;
-                if( late[def._nid]==null ) work.push(def);
-                wakeLoads(def,late,work,new BitSet());
-            }
-            if( n instanceof LoopNode loop )
-                for( Node phi : loop._outputs )
-                    if( phi instanceof PhiNode && late[phi._nid]==null )
-                        work.push(phi);
-        }
-    }
-
-    private static void _doSchedLate(Node n, Node[] ns, CFGNode[] late, int[] anti) {
-        // Walk uses, gathering the LCA (Least Common Ancestor) of uses
-        CFGNode early = n.in(0) instanceof CFGNode cfg ? cfg : n.in(0).cfg0();
-        assert early != null;
-        CFGNode lca = null;
-        for( Node use : n._outputs )
-            if( use != null )
-              lca = use_block(n,use, late).domLCA(lca,null);
-
-        // Loads may need anti-dependencies, raising their LCA
-        if( n instanceof LoadNode load )
-            lca = find_anti_dep(lca,load,early,late,anti);
-
-        // Walk up from the LCA to the early, looking for best place.  This is
-        // the lowest execution frequency, approximated by least loop depth and
-        // deepest control flow.
-        CFGNode best = lca;
-        lca = lca.idom();       // Already found best for starting LCA
-        for( ; lca != early.idom(); lca = lca.idom() )
-            if( better(lca,best) )
-                best = lca;
-        assert !(best instanceof IfNode);
-        ns  [n._nid] = n;
-        late[n._nid] = best;
-    }
-
-    // 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 PhiNode phi) )
-            return late[use._nid];
-        CFGNode found=null;
-        for( int i=1; i<phi.nIns(); i++ )
-            if( phi.in(i)==n )
-                found = phi.region().cfg(i).domLCA(found,null); // Can be more than one matching input.
-        assert found!=null;
-        return found;
-    }
-
-
-    // Least loop depth first, then largest idepth
-    private static boolean better( CFGNode lca, CFGNode best ) {
-        return lca.loopDepth() < best.loopDepth() ||
-            lca instanceof NeverNode ||
-            lca.idepth() > best.idepth() ||
-            best instanceof IfNode;
-    }
-
-    // An allocation may consume a load's memory through a partial aggregate.
-    private static void wakeLoads(Node def, CFGNode[] late, WorkList<Node> work, BitSet visit) {
-        if( visit.get(def._nid) ) return;
-        visit.set(def._nid);
-        for( Node out : def._outputs )
-            if( out instanceof LoadNode ld && late[ld._nid]==null ) work.push(ld);
-        if( def instanceof MemMergeNode )
-            for( int i=1; i<def.nIns(); i++ )
-                if( def.in(i)!=null ) wakeLoads(def.in(i),late,work,visit);
-    }
-
-    private static CFGNode find_anti_dep(CFGNode lca, LoadNode load, CFGNode early, CFGNode[] late, int[] anti) {
-        // We could skip final-field loads here.
-        // Walk LCA->early, flagging Load's block location choices
-        for( CFGNode cfg=lca; early!=null && cfg!=early.idom(); cfg = cfg.idom() )
-            anti[cfg._nid] = load._nid;
-        // Walk load->mem uses, looking for Stores causing an anti-dep
-        for( Node mem : load.antiDeps() ) {
-            switch( mem ) {
-            case StoreNode st:
-                assert late[st._nid]!=null;
-                lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st,anti);
-                break;
-            case NewNode st:
-                assert late[st._nid]!=null;
-                lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st,anti);
-                break;
-            case PhiNode phi:
-                // Repeat anti-dep for matching Phi inputs.
-                // No anti-dep edges but may raise the LCA.
-                for( int i=1; i<phi.nIns(); i++ )
-                    if( phi.in(i)==load.mem() )
-                        lca = anti_dep(load,phi.region().cfg(i),load.mem().cfg0(),lca,null,anti);
-                break;
-            default: throw Utils.TODO();
-            }
-        }
-        return lca;
-    }
-
-    //
-    private static CFGNode anti_dep( LoadNode load, CFGNode stblk, CFGNode defblk, CFGNode lca, Node st, int[] anti ) {
-        // Preserve the full store range for the earlier evaluator scheduler.
-        // It places nodes independently of GCM and may hoist this store.
-        for( ; stblk != defblk.idom(); stblk = stblk.idom() ) {
-            // Store and Load overlap, need anti-dependence
-            if( anti[stblk._nid]==load._nid ) {
-                lca = stblk.domLCA(lca,null); // Raise Loads LCA
-                if( lca == stblk && st != null && st._inputs.find(load) == -1 ) // And if something moved,
-                    st.addDef(load);   // Add anti-dep as well
-                return lca;            // Cap this stores' anti-dep to here
-            }
-        }
-        return lca;
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/IRPrinter.java b/chapter17/src/main/java/com/seaofnodes/simple/IRPrinter.java
deleted file mode 100644
index 7e93e9da..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/IRPrinter.java
+++ /dev/null
@@ -1,33 +0,0 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.print.IRAdapter;
-import com.seaofnodes.simple.node.*;
-
-/** This chapter's read-only IR facts and the familiar debugger entry points. */
-public final class IRPrinter extends IRAdapter<Node> {
-    private static final com.seaofnodes.print.IRPrinter<Node> PRINT =
-        new com.seaofnodes.print.IRPrinter<>(new IRPrinter());
-    @Override public String type(Node n) { return n._type==null ? "" : n._type.str(); }
-    @Override public String inputMark(Node n, Node def) { return n instanceof MemMergeNode && def instanceof MemMergeNode ? "^" : " "; }
-    @Override public Kind kind(Node n) {
-        if( n instanceof StartNode ) return Kind.START;
-        if( n instanceof StopNode ) return Kind.STOP;
-        if( n instanceof LoopNode ) return Kind.LOOP;
-        if( n instanceof RegionNode ) return Kind.REGION;
-        if( n instanceof PhiNode ) return Kind.PHI;
-        if( n instanceof ReturnNode ) return Kind.RETURN;
-        if( n instanceof ConstantNode ) return Kind.CONSTANT;
-        if( n instanceof CProjNode ) return Kind.CPROJ;
-        if( n instanceof ProjNode ) return n instanceof CFGNode ? Kind.CPROJ : Kind.PROJ;
-        if( n instanceof CFGNode ) return Kind.CTRL;
-        if( n instanceof MultiNode ) return Kind.MULTI;
-        return Kind.DATA;
-    }
-    @Override public int index(Node n) {
-        if( n instanceof ProjNode p ) return p._idx;
-        if( n instanceof CProjNode p ) return p._idx;
-        return n._nid;
-    }
-
-    public static String prettyPrint(Node n, int depth) { return PRINT.prettyPrint(n,depth); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/IterPeeps.java b/chapter17/src/main/java/com/seaofnodes/simple/IterPeeps.java
deleted file mode 100644
index 5a80698a..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/IterPeeps.java
+++ /dev/null
@@ -1,211 +0,0 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.simple.node.*;
-
-import java.util.Arrays;
-import java.util.BitSet;
-import java.util.Random;
-
-/**
- * The IterPeeps runs after parsing. It iterates the peepholes to a fixed point
- * so that no more peepholes apply.  This should be linear because peepholes rarely
- * (never?)  increase code size.  The graph should monotonically reduce in some
- * dimension, which is usually size.  It might also reduce in e.g. number of
- * MulNodes or Load/Store nodes, swapping out more "expensive" Nodes for cheaper
- * ones.
- * <br>
- * The theoretical overall worklist is mindless just grabbing the next thing and
- * doing it.  If the graph changes, put the neighbors on the worklist.
- * <br>
- * Lather, Rinse, Repeat until the worklist runs dry.
- * <p>
- * The main issues we have to deal with:
- *
- * <ul>
- * <li>Nodes have uses; replacing some set of Nodes with another requires more graph
- *   reworking.  Not rocket science, but it can be fiddly.  Its helpful to have a
- *   small set of graph munging utilities, and the strong invariant that the graph
- *   is stable and correct between peepholes.  In our case `Node.subsume` does
- *   most of the munging, building on our prior stable Node utilities.</li>
- *
- * <li>Changing a Node also changes the graph "neighborhood".  The neighbors need to
- *   be checked to see if THEY can also peephole, and so on.  After any peephole
- *   or graph update we put a Nodes uses and defs on the worklist.</li>
- *
- * <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
- *   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
- *   progressOnList(stop);`</li>
- * </ul>
- */
-public abstract class IterPeeps {
-
-    private static final WorkList<Node> WORK = new WorkList<>();
-
-    public static <N extends Node> N add( N n ) {
-        return (N)WORK.push(n);
-    }
-
-    public static void addAll( Ary<Node> ary ) {
-        WORK.addAll(ary);
-    }
-
-    /**
-     * Iterate peepholes to a fixed point
-     */
-    public static StopNode iterate(StopNode stop) {
-        assert progressOnList(stop);
-        int cnt=0;
-
-        Node n;
-        while( (n=WORK.pop()) != null ) {
-            if( n.isDead() )  continue;
-            cnt++;              // Useful for debugging, searching which peephole broke things
-            var obs = Parser.PARSER == null ? null : Parser.PARSER._obs;
-            if( obs != null ) obs.before(n);
-            Node x = n.peepholeOpt();
-            if( x != null ) {
-                if( x.isDead() ) {
-                    if( obs != null ) obs.after(n, x, true);
-                    continue;
-                }
-                // peepholeOpt can return brand-new nodes, needing an initial type set
-                if( x._type==null ) x.setType(x.compute());
-                // Changes require neighbors onto the worklist
-                if( x != n || !(x instanceof ConstantNode) ) {
-                    // All outputs of n (changing node) not x (prior existing node).
-                    for( Node z : n._outputs ) WORK.push(z);
-                    // Everybody gets a free "go again" in case they didn't get
-                    // made in their final form.
-                    WORK.push(x);
-                    // If the result is not self, revisit all inputs (because
-                    // there's a new user), and replace in the graph.
-                    if( x != n ) {
-                        for( Node z : n. _inputs ) WORK.push(z);
-                        n.subsume(x);
-                    }
-                }
-                // If there are distant neighbors, move to worklist
-                n.moveDepsToWorklist();
-                assert progressOnList(stop); // Very expensive assert
-            }
-            if( n.isUnused() && !(n instanceof StopNode) )
-                n.kill();       // Just plain dead
-            if( obs != null ) obs.after(n, x, true);
-        }
-
-        return stop;
-    }
-
-    // Visit ALL nodes and confirm the invariant:
-    //   Either you are on the WORK worklist OR running `iter()` makes no progress.
-
-    // This invariant ensures that no progress is missed, i.e., when the
-    // worklist is empty we have indeed done all that can be done.  To help
-    // with debugging, the {@code assert} is broken out in a place where it is easy to
-    // stop if a change is found.
-
-    // Also, the normal usage of `iter()` may attempt peepholes with distance
-    // neighbors and these should fail, but will then try to add dependencies
-    // {@link #Node.addDep} which is a side effect in an assert.  The {@link
-    // #midAssert} is used to stop this side effect.
-    private static boolean MID_ASSERT;
-    public static boolean midAssert() { return MID_ASSERT; }
-    private static boolean progressOnList(Node stop) {
-        MID_ASSERT = true;
-        int old_cnt = Node.ITER_CNT, old_nop = Node.ITER_NOP_CNT;
-        Node changed = stop.walk( n -> {
-                Node m = n;
-                if( n.compute().isa(n._type) && (!n.iskeep() || n._nid<=5) ) { // Types must be forwards, even if on worklist
-                    if( WORK.on(n) ) return null;
-                    m = n.peepholeOpt();
-                    if( m==null ) return null;
-                }
-                System.err.println("BREAK HERE FOR BUG");
-                return m;
-            });
-        Node.ITER_CNT = old_cnt;  Node.ITER_NOP_CNT = old_nop;
-        MID_ASSERT = false;
-        return changed==null;
-    }
-
-    public static void reset() {
-        WORK.clear();
-    }
-
-    /**
-     * Classic WorkList, with a fast add/remove, dup removal, random pull.
-     * The Node's nid is used to check membership in the worklist.
-     */
-    public static class WorkList<E extends Node> {
-
-        private Node[] _es;
-        private int _len;
-        private final BitSet _on;   // Bit set if Node._nid is on WorkList
-        private final Random _R;    // For randomizing pull from the WorkList
-        private final long _seed;
-
-        /* Useful stat - how many nodes are processed in the post parse iterative opt */
-        private long _totalWork = 0;
-
-        WorkList() { this(123); }
-        WorkList(long seed) {
-            _es = new Node[1];
-            _len=0;
-            _on = new BitSet();
-            _seed = seed;
-            _R = new Random();
-            _R.setSeed(_seed);
-        }
-
-        /**
-         * Pushes a Node on the WorkList, ensuring no duplicates
-         * If Node is null it will not be added.
-         */
-        public E push( E x ) {
-            if( x==null ) return null;
-            int idx = x._nid;
-            if( !_on.get(idx) ) {
-                _on.set(idx);
-                if( _len==_es.length )
-                    _es = Arrays.copyOf(_es,_len<<1);
-                _es[_len++] = x;
-                _totalWork++;
-            }
-            return x;
-        }
-
-        public void addAll( Ary<E> ary ) {
-            for( E n : ary )
-                push(n);
-        }
-
-        /**
-         * True if Node is on the WorkList
-         */
-        boolean on( E x ) { return _on.get(x._nid); }
-
-        /**
-         * Removes a random Node from the WorkList; null if WorkList is empty
-         */
-        E pop() {
-            if( _len == 0 ) return null;
-            int idx = _R.nextInt(_len);
-            E x = (E)_es[idx];
-            _es[idx] = _es[--_len]; // Compress array
-            _on.clear(x._nid);
-            return x;
-        }
-
-        public void clear() {
-            _len = 0;
-            _on.clear();
-            _R.setSeed(_seed);
-            _totalWork = 0;
-        }
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/Parser.java b/chapter17/src/main/java/com/seaofnodes/simple/Parser.java
deleted file mode 100644
index 9f81d556..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/Parser.java
+++ /dev/null
@@ -1,1427 +0,0 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.graph.GraphObserver;
-
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.*;
-
-import java.util.*;
-
-/**
- * The Parser converts a Simple source program to the Sea of Nodes intermediate
- * representation directly in one pass.  There is no intermediate Abstract
- * Syntax Tree structure.
- * <p>
- * This is a simple recursive descent parser. All lexical analysis is done here as well.
- */
-public class Parser {
-
-    // Current compilation context; the observer belongs to the parser.
-    public static Parser PARSER;
-    public GraphObserver<Node> _obs;
-    public int pos() { return _lexer._position; }
-
-
-    /**
-     * A Global Static, unique to each compilation.  This is a public, so we
-     * can make constants everywhere without having to thread the StartNode
-     * through the entire parser and optimizer.
-     * <p>
-     * To make the compiler multithreaded, this field will have to move into a TLS.
-     */
-    public static StartNode START;
-
-    public static ConstantNode ZERO; // Very common node, cached here
-    public static XCtrlNode XCTRL;   // Very common node, cached here
-
-    // Next available memory alias number
-    static int ALIAS;
-
-    public StopNode STOP;
-
-    // Debugger Printing.
-    public static boolean SCHEDULED; // True if debug printer can use schedule info
-
-    // The Lexer.  Thin wrapper over a byte[] buffer with a cursor.
-    private final Lexer _lexer;
-
-    /**
-     * 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
-     * we handle branching. See {@link #parseIf()}.
-     * <p>
-     * Each ScopeNode contains a stack of lexical scopes, each scope is a symbol table that binds
-     * variable names to Nodes.  The top of this stack represents current scope.
-     * <p>
-     * We keep a list of all ScopeNodes so that we can show them in graphs.
-     * @see #parseIf()
-     * @see #_xScopes
-     */
-    public ScopeNode _scope;
-
-    /**
-     * List of keywords disallowed as identifiers
-     */
-    private static final HashSet<String> KEYWORDS = new HashSet<>(){{
-            add("bool");
-            add("break");
-            add("byte");
-            add("continue");
-            add("else");
-            add("f32");
-            add("f64");
-            add("false");
-            add("flt");
-            add("i16");
-            add("i32");
-            add("i64");
-            add("i8");
-            add("if");
-            add("int");
-            add("new");
-            add("null");
-            add("return");
-            add("struct");
-            add("true");
-            add("u1");
-            add("u16");
-            add("u32");
-            add("u8");
-            add("while");
-        }};
-
-
-    /**
-     * We clone ScopeNodes when control flows branch; it is useful to have
-     * a list of all active ScopeNodes for purposes of visualization of the SoN graph
-     */
-    public final Stack<ScopeNode> _xScopes = new Stack<>();
-
-    ScopeNode _continueScope;
-    ScopeNode _breakScope;      // Merge all the while-breaks here
-
-    // Mapping from a type name to a Type.  The string name matches
-    // `type.str()` call.  No TypeMemPtrs are in here, because Simple does not
-    // have C-style '*ptr' references.
-    public static HashMap<String, Type> TYPES;
-
-    // Mapping from a type name to the constructor for a Type.
-    public final HashMap<String, StructNode> INITS;
-
-
-    public Parser(String source, TypeInteger arg) {
-        PARSER = this;
-        Node.reset();
-        IterPeeps.reset();
-        SCHEDULED = false;
-        _lexer = new Lexer(source);
-        _scope = new ScopeNode();
-        _continueScope = _breakScope = null;
-        START = new StartNode(arg);
-        STOP = new StopNode(source);
-        ZERO = con(0).keep();
-        XCTRL= new XCtrlNode().peephole().keep();
-        ALIAS = 2; // alias 0 for the control, 1 for memory
-        TYPES = defaultTypes();
-        INITS = new HashMap<>();
-    }
-
-    public Parser(String source) {
-        this(source, TypeInteger.BOT);
-    }
-
-    @Override
-    public String toString() { return _lexer.toString(); }
-
-    public static HashMap<String, Type> defaultTypes() {
-        return new HashMap<>() {{
-            put("bool",TypeInteger.U1 );
-            put("byte",TypeInteger.U8 );
-            put("f32" ,TypeFloat  .B32);
-            put("f64" ,TypeFloat  .BOT);
-            put("flt" ,TypeFloat  .BOT);
-            put("i16" ,TypeInteger.I16);
-            put("i32" ,TypeInteger.I32);
-            put("i64" ,TypeInteger.BOT);
-            put("i8"  ,TypeInteger.I8 );
-            put("int" ,TypeInteger.BOT);
-            put("u1"  ,TypeInteger.U1 );
-            put("u16" ,TypeInteger.U16);
-            put("u32" ,TypeInteger.U32);
-            put("u8"  ,TypeInteger.U8 );
-            put("val" ,Type.TOP);    // Marker type, indicates type inference
-            put("var" ,Type.BOTTOM); // Marker type, indicates type inference
-        }};
-    }
-
-    // Debugging utility to find a Node by index
-    public static Node find(int nid) { return START.find(nid); }
-
-    private Node ctrl() { return _scope.ctrl(); }
-    private <N extends Node> N ctrl(N n) { return _scope.ctrl(n); }
-
-    public StopNode parse() {
-        _xScopes.push(_scope);
-        // Enter a new scope for the initial control and arguments
-        _scope.push();
-        _scope.define(ScopeNode.CTRL, Type.CONTROL   , false, new CProjNode(START, 0, ScopeNode.CTRL).peephole());
-        _scope.define(ScopeNode.MEM0, TypeMem.BOT    , false, new  ProjNode(START, 1, ScopeNode.MEM0).peephole());
-        _scope.define(ScopeNode.ARG0, TypeInteger.BOT, false, new  ProjNode(START, 2, ScopeNode.ARG0).peephole());
-
-        // Parse whole program
-        parseBlock(false);
-
-        if( ctrl()._type==Type.CONTROL )
-            STOP.addReturn(new ReturnNode(ctrl(), ZERO, _scope).peephole());
-        _scope.kill();
-        _xScopes.pop();
-        for( StructNode init : INITS.values() )
-            init.unkeep().kill();
-        INITS.clear();
-        if (!_lexer.isEOF()) throw error("Syntax error, unexpected " + _lexer.getAnyNextToken());
-        STOP.peephole();
-        return STOP;
-    }
-
-    /**
-     * Parses a block
-     *
-     * <pre>
-     *     '{' statements '}'
-     * </pre>
-     * Does not parse the opening or closing '{}'
-     * @return a {@link Node} or {@code null}
-     */
-    private Node parseBlock(boolean inCon) {
-        // Enter a new scope
-        _scope.push(inCon);
-        while (!peek('}') && !_lexer.isEOF())
-            parseStatement();
-        // Exit scope
-        _scope.pop();
-        return null;
-    }
-
-    /**
-     * Parses a statement
-     *
-     * <pre>
-     *     returnStatement | declStatement | blockStatement | ifStatement | expressionStatement
-     * </pre>
-     * @return a {@link Node} or {@code null}
-     */
-    private Node parseStatement() {
-        if( false ) return null;
-        else if (matchx("return")  ) return parseReturn();
-        else if (match ("{")       ) return require(parseBlock(false),"}");
-        else if (matchx("if")      ) return parseIf();
-        else if (matchx("while")   ) return parseWhile();
-        else if (matchx("for")     ) return parseFor();
-        else if (matchx("break")   ) return parseBreak();
-        else if (matchx("continue")) return parseContinue();
-        else if (matchx("struct")  ) return parseStruct();
-        else if (matchx(";")       ) return null; // Empty statement
-        // Declaration or normal assignment/expression
-        else return parseDeclarationStatement();
-    }
-
-    /**
-     * Parses a while statement
-     *
-     * <pre>
-     *     while ( expression ) statement
-     * </pre>
-     * @return a {@link Node}, never {@code null}
-     */
-    private Node parseWhile() {
-        require("(");
-        return parseLooping(false);
-    }
-
-
-    /**
-     * Parses a for statement
-     *
-     * <pre>
-     *     for( var x=init; test; incr ) body
-     * </pre>
-     * @return a {@link Node}, never {@code null}
-     */
-    private Node parseFor() {
-        // {   var x=init,y=init,...;
-        //     while( pred ) {
-        //         body;
-        //         next;
-        //     }
-        // }
-        require("(");
-        _scope.push();          // Scope for the index variables
-        if( !match(";") )       // Can be empty init "for(;test;next) body"
-            parseDeclarationStatement(); // Non-empty init
-        Node rez = parseLooping(true);
-        _scope.pop();           // Exit index variable scope
-        return rez;
-    }
-
-    // Shared by `for` and `while`
-    private Node parseLooping( boolean doFor ) {
-
-        var savedContinueScope = _continueScope;
-        var savedBreakScope    = _breakScope;
-
-        // Loop region has two control inputs, the first is the entry
-        // point, and second is back edge that is set after loop is parsed
-        // (see end_loop() call below).  Note that the absence of back edge is
-        // used as an indicator to switch off peepholes of the region and
-        // associated phis; see {@code inProgress()}.
-
-        ctrl(new LoopNode(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).
-        // We create phis eagerly for all the names we find, see dup().
-
-        // Save the current scope as the loop head
-        ScopeNode head = _scope.keep();
-        // Clone the head Scope to create a new Scope for the body.
-        // Create phis eagerly as part of cloning
-        _xScopes.push(_scope = _scope.dup(true)); // The true argument triggers creating phis
-
-        // Parse predicate
-        var pred = peek(';') ? con(1) : parseAsgn();
-        require( doFor ? ";" : ")" );
-
-        // IfNode takes current control and predicate
-        Node ifNode = new IfNode(ctrl(), pred.keep()).peephole();
-        // Setup projection nodes
-        Node ifT = new CProjNode(ifNode.  keep(), 0, "True" ).peephole().keep();
-        Node ifF = new CProjNode(ifNode.unkeep(), 1, "False").peephole();
-
-        // for( ;;next ) body
-        int nextPos = -1, nextEnd = -1;
-        if( doFor ) {
-            // Skip the next expression and parse it later
-            nextPos = pos();
-            skipAsgn();
-            nextEnd = pos();
-            require(")");
-        }
-
-        // Clone the body Scope to create the break/exit Scope which accounts for any
-        // side effects in the predicate.  The break/exit Scope will be the final
-        // scope after the loop, and its control input is the False branch of
-        // the loop predicate.  Note that body Scope is still our current scope.
-        ctrl(ifF);
-        _xScopes.push(_breakScope = _scope.dup());
-        _breakScope.addGuards(ifF,pred,true); // Up-cast predicate
-
-        // No continues yet
-        _continueScope = null;
-
-        // Parse the true side, which corresponds to loop body
-        // Our current scope is the body Scope
-        ctrl(ifT.unkeep());     // set ctrl token to ifTrue projection
-        _scope.addGuards(ifT,pred.unkeep(),false); // Up-cast predicate
-        parseStatement();       // Parse loop body
-        _scope.removeGuards(ifT);
-
-        // Merge the loop bottom into other continue statements
-        if (_continueScope != null) {
-            _continueScope = jumpTo(_continueScope);
-            _scope.kill();
-            _scope = _continueScope;
-        }
-
-        // Now append the next code onto the body code
-        if( doFor ) {
-            int old = pos(nextPos);
-            if( !peek(')') )
-              parseAsgn();
-            if( pos() != nextEnd )
-                throw errorSyntax( "Unexpected code after expression" );
-            pos(old);
-        }
-
-        // The true branch loops back, so whatever is current _scope.ctrl gets
-        // added to head loop as input.  endLoop() updates the head scope, and
-        // goes through all the phis that were created earlier.  For each phi,
-        // it sets the second input to the corresponding input from the back
-        // edge.  If the phi is redundant, it is replaced by its sole input.
-        var exit = _breakScope;
-        head.endLoop(_scope, exit);
-        head.unkeep().kill();
-
-        _xScopes.pop();       // Cleanup
-        _xScopes.pop();       // Cleanup
-
-        _continueScope = savedContinueScope;
-        _breakScope = savedBreakScope;
-
-        // At exit the false control is the current control, and
-        // the scope is the exit scope after the exit test.
-        _xScopes.pop();
-        _xScopes.push(exit);
-        _scope = exit;
-        return _scope;
-    }
-
-    private ScopeNode jumpTo(ScopeNode toScope) {
-        ScopeNode cur = _scope.dup();
-        ctrl(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._lexSize.size() > _breakScope._lexSize.size() )
-            cur.pop();
-        // If this is a continue then first time the target is null
-        // So we just use the pruned current scope as the base for the
-        // "continue"
-        if( toScope == null )
-            return cur;
-        // toScope is either the break scope, or a scope that was created here
-        assert toScope._lexSize.size() <= _breakScope._lexSize.size();
-        toScope.ctrl(toScope.mergeScopes(cur).peephole());
-        return toScope;
-    }
-
-    private void checkLoopActive() { if (_breakScope == null) throw Parser.error("No active loop for a break or continue"); }
-
-    private Node parseContinue() { checkLoopActive(); return (_continueScope = require(jumpTo( _continueScope ),";"));  }
-    private Node parseBreak   () {
-        checkLoopActive();
-        // At the time of the break, and loop-exit conditions are only valid if
-        // they are ALSO valid at the break.  It is the intersection of
-        // conditions here, not the union.
-        _breakScope.removeGuards(_breakScope.ctrl());
-        _breakScope = require(jumpTo(_breakScope ),";");
-        _breakScope.addGuards(_breakScope.ctrl(), null, false);
-        return _breakScope;
-    }
-
-    // Look for an unbalanced `)`, skipping balanced
-    private Type skipAsgn() {
-        int paren=0;
-        while( true )
-            // Next X char handles skipping complex comments
-            switch( _lexer.nextXChar() ) {
-            case Character.MAX_VALUE:
-                throw Utils.TODO();
-            case ')':
-                if( --paren<0 )
-                    return posT(pos()-1); // Leave the `)` behind
-                break;
-            case '(': paren ++; break;
-            default: break;
-            }
-    }
-
-
-    /**
-     * Parses a statement
-     *
-     * <pre>
-     *     if ( expression ) statement [else statement]
-     * </pre>
-     * @return a {@link Node}, never {@code null}
-     */
-    private Node parseIf() {
-        // Parse predicate
-        require("(");
-        var pred = require(parseAsgn(), ")");
-        return parseTrinary(pred,true,"else");
-    }
-
-    // Parse a conditional expression, merging results.
-    private Node parseTrinary( Node pred, boolean stmt, String fside ) {
-        pred.keep();
-
-        // IfNode takes current control and predicate
-        Node ifNode = new IfNode(ctrl(), pred).peephole();
-        // Setup projection nodes
-        Node ifT = new CProjNode(ifNode.  keep(), 0, "True" ).peephole().keep();
-        Node ifF = new CProjNode(ifNode.unkeep(), 1, "False").peephole().keep();
-        // In if true branch, the ifT proj node becomes the ctrl
-        // But first clone the scope and set it as current
-        int ndefs = _scope.nIns();
-        ScopeNode fScope = _scope.dup(); // Duplicate current scope
-        fScope.ctrl(ifF);       // The pending arm already starts at False
-        _xScopes.push(fScope); // For graph visualization we need all scopes
-
-        // Parse the true side
-        ctrl(ifT.unkeep());     // set ctrl token to ifTrue projection
-        _scope.addGuards(ifT,pred,false); // Up-cast predicate
-        Node lhs = stmt ? parseStatement() : parseAsgn().keep(); // Parse true-side
-        _scope.removeGuards(ifT);
-
-        ScopeNode tScope = _scope;
-
-        // Parse the false side
-        _scope = fScope;        // Restore scope, then parse else block if any
-        ifF.unkeep();           // fScope already owns the false control
-        // Up-cast predicate, even if not else clause, because predicate can
-        // remain true if the true clause exits: `if( !ptr ) return 0; return ptr.fld;`
-        _scope.addGuards(ifF,pred,true);
-        boolean doRHS = match(fside);
-        Node rhs = doRHS
-            ? (stmt ? parseStatement() : parseAsgn())
-            : (stmt ? null             : con(lhs._type.makeZero()));
-        _scope.removeGuards(ifF);
-        if( doRHS )
-            fScope = _scope;
-        pred.unkeep();
-
-        // Check for `if(pred) int x=17;`
-        if( tScope.nIns() != ndefs || fScope.nIns() != ndefs )
-            throw error("Cannot define a new name on one arm of an if");
-
-        // Check the trinary widening int/flt
-        if( !stmt ) {
-            rhs = widenInt( rhs, lhs._type ).keep();
-            lhs = widenInt( lhs.unkeep(), rhs._type ).keep();
-            rhs.unkeep();
-        }
-
-        // Merge results
-        _scope = tScope;
-        _xScopes.pop();       // Discard pushed from graph display
-
-        RegionNode r = ctrl(tScope.mergeScopes(fScope));
-        Node ret = stmt ? r : peep(new PhiNode("",lhs._type.meet(rhs._type),r,lhs.unkeep(),rhs));
-        r.peephole();
-        return ret;
-    }
-
-    /**
-     * Parses a return statement; "return" already parsed.
-     * The $ctrl edge is killed.
-     *
-     * <pre>
-     *     'return' expr ;
-     * </pre>
-     * @return an expression {@link Node}, never {@code null}
-     */
-    private Node parseReturn() {
-        var expr = require(parseAsgn(), ";");
-        Node ret = STOP.addReturn(new ReturnNode(ctrl(), expr, _scope).peephole());
-        ctrl(XCTRL);            // Kill control
-        return ret;
-    }
-
-
-
-    /** Parse: [name '='] expr
-     */
-    private Node parseAsgn() {
-        int old = pos();
-        String name = _lexer.matchId();
-        // Just a plain expression, no assignment.
-        // Distinguish `var==expr` from `var=expr`
-        if( name==null || KEYWORDS.contains(name) || !matchOpx('=','=') )
-            {  pos(old);  return parseExpression();  }
-
-        // Parse assignment expression
-        Node expr = parseAsgn();
-
-        // Final variable to update
-        ScopeNode.Var def = _scope.lookup(name);
-        if( def==null )
-            throw error("Undefined name '" + 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 && !_scope.inCon() )
-            throw error("Cannot reassign final '"+name+"'");
-
-        // Lift expression, based on type
-        Node lift = liftExpr(expr, def.type(), def._final);
-        // Update
-        _scope.update(name,lift);
-        // Return un-lifted expr
-        return expr;
-    }
-
-    // Make finals deep; 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 ) {
-        assert !(expr._type instanceof TypeMemPtr tmp) || !tmp.isFRef();
-        // Final is deep on ptrs
-        if( xfinal && t instanceof TypeMemPtr tmp ) {
-            t = tmp.makeRO();
-            expr = peep(new ReadOnlyNode(expr));
-        }
-        // Auto-widen int to float
-        expr = widenInt( expr, t );
-        // Auto-narrow wide ints to narrow ints
-        expr = zsMask(expr,t);
-        // Type is sane
-        if( !expr._type.isa(t) )
-            throw error("Type " + expr._type.str() + " is not of declared type " + t.str());
-        return expr;
-    }
-
-    private Node widenInt( Node expr, Type t ) {
-        return expr._type instanceof TypeInteger && t instanceof TypeFloat
-            ? peep(new ToFloatNode(expr)) : expr;
-    }
-
-    /**
-     * Parse declaration or expression statement
-     * declStmt = type var['=' exprAsgn][, var['=' exprAsgn]]* ';' | exprAsgn ';'
-     * <p>
-     * exprAsgn = var '=' exprAsgn | expr
-     */
-    private Node parseDeclarationStatement() {
-        Type t = type();
-        if( t == null )
-            return require(parseAsgn(),";");
-
-        // now parse var['=' asgnexpr] in a loop
-        Node n = parseDeclaration(t);
-        while( match(",") )
-            n = parseDeclaration(t);
-        return require(n,";");
-    }
-
-    /** Parse final: [!]var['=' asgn]
-     */
-    private Node parseDeclaration(Type t) {
-        assert t!=null;
-        // Has var/val instead of a user-declared type
-        boolean inferType = t==Type.TOP || t==Type.BOTTOM;
-        boolean hasBang = match("!");
-        String name = requireId();
-
-        // Optional initializing expression follows
-        boolean xfinal = false;
-        Node expr;
-        if( match("=") ) {
-            expr = parseAsgn();
-            // `val` is always final
-            xfinal = (t==Type.TOP) ||
-                // var is always not-final, final if no Bang AND TMP since primitives are not-final by default
-                (t!=Type.BOTTOM && !hasBang && (t instanceof TypeMemPtr));
-            // var/val, then type comes from expression
-            if( inferType )
-                t = expr._type.glb();
-
-        } else {
-            if( inferType && !_scope.inCon() )
-                throw errorSyntax("=expression");
-            expr = con(t.makeInit());
-        }
-
-        // Lift expression, based on type
-        Node lift = liftExpr(expr, t, xfinal);
-        if( xfinal && t instanceof TypeMemPtr tmp )
-            t = tmp.makeRO();
-
-        // Define a new name,
-        if( !_scope.define(name,t,xfinal,lift) )
-            throw error("Redefining name '" + name + "'");
-        return null;
-    }
-
-
-
-    /**
-     * Parse a struct declaration, and return the following statement.
-     * Only allowed in top level scope.
-     * Structs cannot be redefined.
-     *
-     * @return The statement following the struct
-     */
-    private Node parseStruct() {
-        if (_xScopes.size() > 1) throw errorSyntax("struct declarations can only appear in top level scope");
-        String typeName = requireId();
-        Type t = TYPES.get(typeName);
-        if( t!=null && !(t instanceof TypeMemPtr tmp && tmp.isFRef() ) )
-            throw errorSyntax("struct '" + typeName + "' cannot be redefined");
-
-        // A Block scope parse, and inspect the scope afterward for fields.
-        _scope.push(true);
-        _xScopes.push(_scope);
-        require("{");
-        while (!peek('}') && !_lexer.isEOF())
-            parseStatement();
-
-        // Grab the declarations and build fields and a Struct
-        int lexlen = _scope._lexSize.last();
-        int varlen = _scope._vars._len;
-        StructNode s = new StructNode();
-        Field[] fs = new Field[varlen-lexlen];
-        for( int i=lexlen; i<varlen; i++ ) {
-            s.addDef(_scope.in(i));
-            ScopeNode.Var v = _scope._vars.at(i);
-            fs[i-lexlen] = Field.make(v._name,v.type(),ALIAS++,v._final);
-        }
-        TypeStruct ts = s._ts = TypeStruct.make(typeName, fs);
-        TYPES.put(typeName, TypeMemPtr.make(ts));
-        INITS.put(typeName,s.peephole().keep());
-        // Done with struct/block scope
-        require("}");
-        require(";");
-        _xScopes.pop();
-        _scope.pop();
-        return null;
-    }
-
-
-    // Parse and return a type or null.  Valid types always are followed by an
-    // 'id' which the caller must parse.  This lets us distinguish forward ref
-    // types (which ARE valid here) from local vars in an (optional) forward
-    // ref type position.
-
-    // t = int|i8|i16|i32|i64|u8|u16|u32|u64|byte|bool | flt|f32|f64 | val | var | struct[?]
-    private Type type() {
-        int old1 = pos();
-        String tname = _lexer.matchId();
-        if( tname==null ) return null;
-        // Convert the type name to a type.
-        Type t0 = TYPES.get(tname);
-        // No new types as keywords
-        if( t0 == null && KEYWORDS.contains(tname) )
-            return posT(old1);
-        Type t1 = t0 == null ? TypeMemPtr.make(TypeStruct.makeFRef(tname)) : t0; // Null: assume a forward ref type
-        // Nest arrays and '?' as needed
-        Type t2 = t1;
-        while( true ) {
-            assert !(t2 instanceof TypeStruct);
-            if( match("?") ) {
-                if( !(t2 instanceof TypeMemPtr tmp) )
-                    throw error("Type "+t0+" cannot be null");
-                if( tmp._nil ) throw error("Type "+t2+" already allows null");
-                t2 = TypeMemPtr.make(tmp._obj,true);
-            } else if( match("[]") ) {
-                t2 = typeAry(t2);
-            } else
-                break;
-        }
-
-        // Check no forward ref
-        if( t0 != null ) return t2;
-        // Check valid forward ref, after parsing all the type extra bits.
-        // Cannot check earlier, because cannot find required 'id' until after "[]?" syntax
-        int old2 = pos();
-        String id = _lexer.matchId();
-        pos(old2);              // Reset lexer to reparse
-        if( id==null || _scope.lookup(id)!=null )
-            return posT(old1);  // Reset lexer to reparse
-        // Yes a forward ref, so declare it
-        TYPES.put(tname,t1);
-        return t2;
-    }
-
-    // Make an array type of t
-    private TypeMemPtr typeAry( Type t ) {
-        if( t instanceof TypeMemPtr tmp && !tmp._nil )
-            throw error("Arrays of reference types must always be nullable");
-        String tname = "["+t.str()+"]";
-        Type ta = TYPES.get(tname);
-        if( ta != null ) return (TypeMemPtr)ta;
-        // Need make an array type.
-        TypeStruct ts = TypeStruct.makeAry(TypeInteger.BOT,ALIAS++,t,ALIAS++);
-        assert ts.str().equals(tname);
-        TypeMemPtr tary = TypeMemPtr.make(ts);
-        TYPES.put(tname,tary);
-        return tary;
-    }
-
-    /**
-     * Parse an expression of the form:
-     *
-     * <pre>
-     *     expr : bitwise [? expr [: expr]]
-     * </pre>
-     * @return an expression {@link Node}, never {@code null}
-     */
-    private Node parseExpression() {
-        Node expr = parseBitwise();
-        return match("?") ? parseTrinary(expr,false,":") : expr;
-    }
-
-    /**
-     * Parse an bitwise expression
-     *
-     * <pre>
-     *     bitwise : compareExpr (('&' | '|' | '^') compareExpr)*
-     * </pre>
-     * @return a bitwise expression {@link Node}, never {@code null}
-     */
-    private Node parseBitwise() {
-        Node lhs = parseComparison();
-        while( true ) {
-            if( false ) ;
-            else if( match("&") ) lhs = new AndNode(lhs,null);
-            else if( match("|") ) lhs = new  OrNode(lhs,null);
-            else if( match("^") ) lhs = new XorNode(lhs,null);
-            else break;
-            lhs.setDef(2,parseComparison());
-            lhs = peep(lhs);
-        }
-        return lhs;
-    }
-
-    /**
-     * Parse an expression of the form:
-     *
-     * <pre>
-     *     expr : additiveExpr op additiveExpr
-     * </pre>
-     * @return an comparator expression {@link Node}, never {@code null}
-     */
-    private Node parseComparison() {
-        var lhs = parseShift();
-        while( true ) {
-            int idx=0;  boolean negate=false;
-            // Test for any local nodes made, and "keep" lhs during peepholes
-            if( false ) ;
-            else if( match("==") ) { idx=2;  lhs = new BoolNode.EQ(lhs, null); }
-            else if( match("!=") ) { idx=2;  lhs = new BoolNode.EQ(lhs, null); negate=true; }
-            else if( match("<=") ) { idx=2;  lhs = new BoolNode.LE(lhs, null); }
-            else if( match("<" ) ) { idx=2;  lhs = new BoolNode.LT(lhs, null); }
-            else if( match(">=") ) { idx=1;  lhs = new BoolNode.LE(null, lhs); }
-            else if( match(">" ) ) { idx=1;  lhs = new BoolNode.LT(null, lhs); }
-            else break;
-            // Peepholes can fire, but lhs is already "hooked", kept alive
-            lhs.setDef(idx,parseShift());
-            lhs = peep(lhs.widen());
-            if( negate )        // Extra negate for !=
-                lhs = peep(new NotNode(lhs));
-        }
-        return lhs;
-    }
-
-    /**
-     * Parse an additive expression
-     *
-     * <pre>
-     *     shiftExpr : additiveExpr (('<<' | '>>' | '>>>') additiveExpr)*
-     * </pre>
-     * @return a shift expression {@link Node}, never {@code null}
-     */
-    private Node parseShift() {
-        Node lhs = parseAddition();
-        while( true ) {
-            if( false ) ;
-            else if( match("<<") ) lhs = new ShlNode(lhs,null);
-            else if( match(">>>")) lhs = new ShrNode(lhs,null);
-            else if( match(">>") ) lhs = new SarNode(lhs,null);
-            else break;
-            lhs.setDef(2,parseAddition());
-            lhs = peep(lhs.widen());
-        }
-        return lhs;
-    }
-
-    /**
-     * Parse an additive expression
-     *
-     * <pre>
-     *     additiveExpr : multiplicativeExpr (('+' | '-') multiplicativeExpr)*
-     * </pre>
-     * @return an add expression {@link Node}, never {@code null}
-     */
-    private Node parseAddition() {
-        Node lhs = parseMultiplication();
-        while( true ) {
-            if( false ) ;
-            else if( match("+") ) lhs = new AddNode(lhs,null);
-            else if( match("-") ) lhs = new SubNode(lhs,null);
-            else break;
-            lhs.setDef(2,parseMultiplication());
-            lhs = peep(lhs.widen());
-        }
-        return lhs;
-    }
-
-    /**
-     * Parse an multiplicativeExpr expression
-     *
-     * <pre>
-     *     multiplicativeExpr : unaryExpr (('*' | '/') unaryExpr)*
-     * </pre>
-     * @return a multiply expression {@link Node}, never {@code null}
-     */
-    private Node parseMultiplication() {
-        var lhs = parseUnary();  boolean mul;
-        while( true ) {
-            if( false ) ;
-            else if( match("*") ) lhs = new MulNode(lhs,null);
-            else if( match("/") ) lhs = new DivNode(lhs,null);
-            else break;
-            lhs.setDef(2,parseUnary());
-            lhs = peep(lhs.widen());
-        }
-        return lhs;
-    }
-
-    /**
-     * Parse a unary minus expression.
-     *
-     * <pre>
-     *     unaryExpr : ('-') unaryExpr | '!') unaryExpr | postfixExpr | primaryExpr | '--' Id | '++' Id
-     * </pre>
-     * @return a unary expression {@link Node}, never {@code null}
-     */
-    private Node parseUnary() {
-        // Pre-dec/pre-inc
-        int old = pos();
-        if( match("--") || match("++") ) {
-            int delta = _lexer.peek(-1)=='+' ? 1 : -1; // Pre vs post
-            String name = _lexer.matchId();
-            if( name!=null ) {
-                ScopeNode.Var n = _scope.lookup(name);
-                if( n != null ) {
-                    if( n._final )
-                        throw error("Cannot reassign final '"+n._name+"'");
-                    Node expr = zsMask(peep(new AddNode(_scope.in(n),con(delta))),n.type());
-                    _scope.update(n,expr);
-                    return expr;
-                }
-            }
-            // Reset, try again
-            pos(old);
-        }
-        if (match("-")) return peep(new MinusNode(parseUnary()).widen());
-        if (match("!")) return peep(new   NotNode(parseUnary()));
-        return parsePostfix(parsePrimary());
-    }
-
-    /**
-     * Parse a primary expression:
-     *
-     * <pre>
-     *     primaryExpr : integerLiteral | true | false | null | new Type | '(' expression ')' | Id['++','--']
-     * </pre>
-     * @return a primary {@link Node}, never {@code null}
-     */
-    private Node parsePrimary() {
-        if( _lexer.isNumber(_lexer.peek()) ) return parseLiteral();
-        if( matchx("true" ) ) return con(1);
-        if( matchx("false") ) return ZERO;
-        if( matchx("null" ) ) return con(TypeMemPtr.NULLPTR);
-        if( match("(") ) return require(parseAsgn(), ")");
-        if( matchx("new"  ) ) return alloc();
-        // Expect an identifier now
-        ScopeNode.Var n = requireLookupId("an identifier or expression");
-        Node rvalue = _scope.in(n);
-        if( rvalue._type == Type.BOTTOM )
-            throw error("Cannot read uninitialized field '"+n._name+"'");
-        // Check for assign-update, x += e0;
-        char ch = _lexer.matchOperAssign();
-        if( ch==0  ) return rvalue;
-        if( n._final )
-            throw error("Cannot reassign final '"+n._name+"'");
-        Node op = switch(ch) {
-        case '+'        -> new AddNode(rvalue,null);
-        case '-'        -> new SubNode(rvalue,null);
-        case '*'        -> new MulNode(rvalue,null);
-        case '/'        -> new DivNode(rvalue,null);
-        case '&'        -> new AndNode(rvalue,null);
-        case '|'        -> new  OrNode(rvalue,null);
-        case '^'        -> new XorNode(rvalue,null);
-        case Lexer.SHL  -> new ShlNode(rvalue,null);
-        case Lexer.SAR  -> new SarNode(rvalue,null);
-        case Lexer.SHR  -> new ShrNode(rvalue,null);
-        case        1   -> new AddNode(rvalue,con( 1));
-        case (char)-1   -> new AddNode(rvalue,con(-1));
-        default         -> throw Utils.TODO();
-        };
-        // Return pre-value (x+=1) or post-value (x++)
-        boolean pre = op.in(2)==null;
-        // Parse RHS argument as needed
-        if( pre )
-            { op.keep().setDef(2,parseAsgn());  op.unkeep(); }
-        else rvalue.keep();     // Keep post-value across peeps
-        op = zsMask(peep(op),n.type());
-        _scope.update(n,op);
-        return pre ? op : rvalue.unkeep();
-    }
-
-    ScopeNode.Var requireLookupId(String msg) {
-        String id = _lexer.matchId();
-        if( id == null || KEYWORDS.contains(id) )
-            throw errorSyntax(msg);
-        ScopeNode.Var n = _scope.lookup(id);
-        if( n==null )
-            throw error("Undefined name '" + id + "'");
-        return n;
-    }
-
-    /**
-       Parse an allocation
-     */
-    private Node alloc() {
-        Type t = type();
-        if( t==null ) throw error("Expected a type");
-        // Parse ary[ length_expr ]
-        if( match("[") ) {
-            Node len = parseAsgn();
-            if( !(len._type instanceof TypeInteger) )
-                throw error("Cannot allocate an array with length "+len._type);
-            require("]");
-            TypeMemPtr tmp = typeAry(t);
-            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();
-            for( int i=0; i<fs.length; i++ )
-                _scope.define(fs[i]._fname, fs[i]._type, fs[i]._final, s.in(i)._type==Type.TOP ? con(Type.BOTTOM) : s.in(i));
-            // Parse the constructor body
-            parseBlock(true);
-            require("}");
-            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, con(tmp._obj.offset(fs.length)), idx, init );
-        if( hasConstructor )
-            _scope.pop();
-        return ptr;
-    }
-
-
-    /**
-     * 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 + "'");
-        Node prior = mem().keep();
-        MemMergeNode input = new MemMergeNode(null);
-        for( Field f : fs ) input.alias(f._alias,prior);
-        // Constructor values follow control, memory, and allocation size.
-        Node[] ns = new Node[3+fs.length];
-        ns[0] = ctrl();
-        ns[1] = input.peephole();
-        ns[2] = size;
-        for( int i=0; i<fs.length; i++ ) ns[3+i] = init.get(idx+i);
-        Node nnn = new NewNode(TypeMemPtr.make(obj),ns).peephole().keep();
-        Node ptr = new ProjNode(nnn,0,obj._name).peephole().keep();
-        Node out = new ProjNode(nnn,1,"$mem").peephole().keep();
-        MemMergeNode after = new MemMergeNode(prior);
-        for( Field f : fs ) after.alias(f._alias,out);
-        mem(after.peephole());
-        out.unkeep();
-        nnn.unkeep();
-        prior.unkeep();
-        return ptr.unkeep();
-    }
-
-    private static final Ary<Node> ALTMP = new Ary<>(Node.class);
-    private Node newArray(TypeStruct ary, Node len) {
-        int base = ary.aryBase ();
-        int scale= ary.aryScale();
-        Node size = peep(new AddNode(con(base),peep(new ShlNode(len.keep(),con(scale)))));
-        ALTMP.clear();  ALTMP.add(len.unkeep()); ALTMP.add(con(ary._fields[1]._type.makeInit()));
-        return newStruct(ary,size,0,ALTMP);
-    }
-
-    // Memory is one hidden SSA variable, including across branches and loops.
-    private Node mem() { return _scope.mem(); }
-    private void mem(Node n) { _scope.mem(n); }
-
-    private void store(String name, int alias, Type glb, Node ptr, Node off, Node val, boolean init, Node ctrl) {
-        Node prior = mem().keep();
-        Node st = new StoreNode(name,alias,glb,prior,ptr,off,val,init);
-        st.setDef(0,ctrl);
-        st = st.peephole();
-        mem(new MemMergeNode(prior,alias,st).peephole());
-        prior.unkeep();
-    }
-
-    /**
-     * Parse postfix expression. For now this is just a field
-     * expression, but in future could be array index too.
-     *
-     * <pre>
-     *     expr ('.' IDENTIFIER)* [ = expr ]
-     *     expr #
-     *     expr ('[' expr ']')* = [ = expr ]
-     * </pre>
-     */
-    private Node parsePostfix(Node expr) {
-        String name = null;
-        if( match(".") )      name = requireId();
-        else if( match("#") ) name = "#";
-        else if( match("[") ) name = "[]";
-        else return expr;       // No postfix
-
-        // Sanity check expr for being a reference
-        if( !(expr._type instanceof TypeMemPtr ptr) )
-            throw error("Expected reference but got " + expr._type.str());
-
-        // Happens when parsing known dead code, which often has other typing
-        // issues.  Since the code is dead, possibly due to inlining, lets not
-        // spoil the user experience with error messages.
-        if( ctrl()._type==Type.XCONTROL )
-            // Exit out via parsing the trailing expression
-            return matchOpx('=','=') ? parseAsgn() : parsePostfix(con(Type.TOP));
-
-        // Sanity check field name for existing
-        TypeMemPtr tmp = (TypeMemPtr)TYPES.get(ptr._obj._name);
-        if( tmp == null ) throw error("Accessing unknown field '" + name + "' from '" + ptr + "'");
-        TypeStruct base = tmp._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._type;
-        if( tf instanceof TypeMemPtr ftmp && ftmp.isFRef() )
-            tf = ftmp.makeFrom(((TypeMemPtr)(TYPES.get(ftmp._obj._name)))._obj);
-
-        expr.keep();
-        // Field offset; fixed for structs, computed for arrays
-        Node off = (name.equals("[]")       // If field is an array body
-            // Array index math
-            ? peep(new AddNode(con(base.aryBase()),peep(new ShlNode(require(parseAsgn(),"]"),con(base.aryScale())))))
-            // Struct field offsets are hardwired
-            : con(base.offset(fidx))).keep();
-
-        // Disambiguate "obj.fld==x" boolean test from "obj.fld=x" field assignment
-        if( matchOpx('=','=') ) {
-            Node val = parseAsgn().keep();
-            Node lift = liftExpr( val, tf, f._final );
-
-            store(name,f._alias,tf,expr.unkeep(),off.unkeep(),lift,false,base.isAry() ? ctrl() : null);
-            return val.unkeep();        // "obj.a = expr" returns the expression while updating memory
-        }
-
-        Node load = new LoadNode(name, f._alias, tf.glb(), mem(), 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() ) load.setDef(0,ctrl());
-        load = peep(load);
-
-        // ary[idx]++ or ptr.fld++
-        if( matchx("++") || matchx("--") ) {
-            if( f._final && !f._fname.equals("[]") )
-                throw error("Cannot reassign final '"+f._fname+"'");
-            Node inc = peep(new AddNode(load,con( _lexer.peek(-1)=='+' ? 1 : -1)));
-            Node val = zsMask(inc,tf);
-            store(name,f._alias,tf,expr.unkeep(),off,val,false,base.isAry() ? ctrl() : null);
-            // And use the original loaded value as the result
-        } else expr.unkill();
-        off.unkill();
-
-        return parsePostfix(load);
-    }
-
-
-    // zero/sign extend.  "i" is limited to either classic unsigned (min==0) or
-    // classic signed (min=minus-power-of-2); max=power-of-2-minus-1.
-    private Node zsMask(Node val, Type t ) {
-        if( !(val._type instanceof TypeInteger tval && t instanceof TypeInteger t0 && !tval.isa(t0)) ) {
-            if( !(val._type instanceof TypeFloat tval && t instanceof TypeFloat t0 && !tval.isa(t0)) )
-                return val;
-            // Float rounding
-            return peep(new RoundF32Node(val));
-        }
-        if( t0._min==0 )        // Unsigned
-            return peep(new AndNode(val,con(t0._max)));
-        // Signed extension
-        int shift = Long.numberOfLeadingZeros(t0._max)-1;
-        Node shf = con(shift);
-        if( shf._type==TypeInteger.ZERO )
-            return val;
-        return peep(new SarNode(peep(new ShlNode(val,shf.keep())),shf.unkeep()));
-    }
-
-
-    /**
-     * Parse integer literal
-     *
-     * <pre>
-     *     integerLiteral: [1-9][0-9]* | [0]
-     *     floatLiteral: [digits].[digits]?[e [digits]]?
-     * </pre>
-     */
-    private ConstantNode parseLiteral() { return con(_lexer.parseNumber()); }
-    public static Node con( long con ) { return con(TypeInteger.constant(con));  }
-    public static ConstantNode con( Type t ) { return (ConstantNode)new ConstantNode(t).peephole();  }
-    public Node peep( Node n ) {
-        // Peephole, then improve with lexically scoped guards
-        return _scope.upcastGuard(n.peephole());
-    }
-
-    //////////////////////////////////
-    // Utilities for lexical analysis
-
-    // Return true and skip if "syntax" is next in the stream.
-    private boolean match (String syntax) { return _lexer.match (syntax); }
-    // Match must be "exact", not be followed by more id letters
-    private boolean matchx(String syntax) { return _lexer.matchx(syntax); }
-    private boolean matchOpx(char c0, char c1) { return _lexer.matchOpx(c0,c1);  }
-    // Return true and do NOT skip if 'ch' is next
-    private boolean peek(char ch) { return _lexer.peek(ch); }
-    private boolean peekIsId() { return _lexer.peekIsId(); }
-
-    private int pos(int pos) {
-        int old = _lexer._position;
-        _lexer._position = pos;
-        return old;
-    }
-    private Type posT(int pos) { _lexer._position = pos; return null; }
-
-    // Require and return an identifier
-    private String requireId() {
-        String id = _lexer.matchId();
-        if (id != null && !KEYWORDS.contains(id) ) return id.intern();
-        throw error("Expected an identifier, found '"+id+"'");
-    }
-
-    private String matchId() {
-        int old = pos();
-        String id = _lexer.matchId();
-        if( id==null ) return null;
-        if( !KEYWORDS.contains(id) ) return id;
-        pos(old);
-        return null;
-    }
-
-    // Require an exact match
-    private Parser require(String syntax) { require(null, syntax); return this; }
-    private <N> N require(N n, String syntax) {
-        if (match(syntax)) return n;
-        throw errorSyntax(syntax);
-    }
-
-    RuntimeException errorSyntax(String syntax) {
-        return error("Syntax error, expected " + syntax + ": " + _lexer.getAnyNextToken());
-    }
-
-    public static RuntimeException error( String errorMessage ) {
-        return new RuntimeException(errorMessage);
-    }
-
-    ////////////////////////////////////
-    // Lexer components
-
-    private static class Lexer {
-
-        // Input buffer; an array of text bytes read from a file or a string
-        private final byte[] _input;
-        // Tracks current position in input buffer
-        private int _position = 0;
-
-        /**
-         * Record the source text for lexing
-         */
-        public Lexer(String source) {
-            this(source.getBytes());
-        }
-
-        /**
-         * Direct from disk file source
-         */
-        public Lexer(byte[] buf) {
-            _input = buf;
-        }
-
-        // Very handy in the debugger, shows the unparsed program
-        @Override
-        public String toString() {
-            return new String(_input, _position, _input.length - _position);
-        }
-
-        // True if at EOF
-        private boolean isEOF() {
-            return _position >= _input.length;
-        }
-
-        // Peek next character, or report EOF
-        private char peek() {
-            return isEOF() ? Character.MAX_VALUE   // Special value that causes parsing to terminate
-                    : (char) _input[_position];
-        }
-        // Just crash if misused
-        public byte peek(int off) { return _input[_position+off]; }
-
-        private char nextChar() {
-            char ch = peek();
-            _position++;
-            return ch;
-        }
-
-        // True if a white space
-        private boolean isWhiteSpace() {
-            return peek() <= ' '; // Includes all the use space, tab, newline, CR
-        }
-
-        /**
-         * Return the next non-white-space character
-         */
-        private void skipWhiteSpace() {
-            while( true ) {
-                if( isWhiteSpace() ) _position++;
-                // Skip // to end of line
-                else if( _position+2 < _input.length &&
-                         _input[_position  ] == '/' &&
-                         _input[_position+1] == '/') {
-                    _position += 2;
-                    while( !isEOF() && _input[_position] != '\n' ) _position++;
-                } else break;
-            }
-        }
-
-        // Next non-white-space character, or EOF
-        public char nextXChar() { skipWhiteSpace(); return nextChar(); }
-
-        // Return true, if we find "syntax" after skipping white space; also
-        // then advance the cursor past syntax.
-        // Return false otherwise, and do not advance the cursor.
-        boolean match(String syntax) {
-            skipWhiteSpace();
-            int len = syntax.length();
-            if (_position + len > _input.length) return false;
-            for (int i = 0; i < len; i++)
-                if ((char) _input[_position + i] != syntax.charAt(i))
-                    return false;
-            _position += len;
-            return true;
-        }
-
-        // Match must be exact and not followed by more ID characters.
-        // Prevents identifier "ifxy" from matching an "if" statement.
-        boolean matchx(String syntax) {
-            if( !match(syntax) ) return false;
-            if( !isIdLetter(peek()) ) return true;
-            _position -= syntax.length();
-            return false;
-        }
-        boolean matchOpx(char c0, char c1) {
-            skipWhiteSpace();
-            if( _position+1 >= _input.length || _input[_position]!=c0 || _input[_position+1]==c1 )
-                return false;
-            _position++;
-            return true;
-        }
-
-        private boolean peek(char ch) {
-            skipWhiteSpace();
-            return peek()==ch;
-        }
-
-        boolean peekIsId() {
-            skipWhiteSpace();
-            return isIdStart(peek());
-        }
-
-        // Return an identifier or null
-        String matchId() {
-            return peekIsId() ? parseId() : null;
-        }
-
-        // Used for errors
-        String getAnyNextToken() {
-            if (isEOF()) return "";
-            if (isIdStart(peek())) return parseId();
-            if (isNumber(peek())) return parseNumberString();
-            if (isPunctuation(peek())) return parsePunctuation();
-            return String.valueOf(peek());
-        }
-
-
-        boolean isNumber(char ch) {return Character.isDigit(ch);}
-
-        // Return a constant Type, either TypeInteger or TypeFloat
-        private Type parseNumber() {
-            int old = _position;
-            int len = isLongOrDouble();
-            if( len > 0 ) {
-                if( len > 1 && _input[old]=='0' )
-                    throw error("Syntax error: integer values cannot start with '0'");
-                return TypeInteger.constant(Long.parseLong(new String(_input,old,len)));
-            }
-            return TypeFloat.constant(Double.parseDouble(new String(_input,old,-len)));
-        }
-        private String parseNumberString() {
-            int old = _position;
-            int len = Math.abs(isLongOrDouble());
-            _position += len;
-            return new String(_input,old,len);
-        }
-
-        // Return +len that ends a long
-        // Return -len that ends a double
-        private int isLongOrDouble() {
-            int old = _position;
-            char c;
-            while( Character.isDigit(c=nextChar()) ) ;
-            if( !(c=='e' || c=='.') )
-                return --_position - old;
-            while( Character.isDigit(c=nextChar()) || c=='e' || c=='.' ) ;
-            return -(--_position - old);
-        }
-
-        // First letter of an identifier
-        private boolean isIdStart(char ch) {
-            return Character.isAlphabetic(ch) || ch == '_';
-        }
-
-        // All characters of an identifier, e.g. "_x123"
-        private boolean isIdLetter(char ch) {
-            return Character.isLetterOrDigit(ch) || ch == '_';
-        }
-
-        private String parseId() {
-            int start = _position;
-            while (isIdLetter(nextChar())) ;
-            return new String(_input, start, --_position - start);
-        }
-
-        //
-        private boolean isPunctuation(char ch) {
-            return "=;[]<>()+-/*&|^".indexOf(ch) != -1;
-        }
-
-        private String parsePunctuation() {
-            int start = _position;
-            return new String(_input, start, 1);
-        }
-
-        // Next oper= character, or 0.
-        // As a convenience, mark "++" as a char 1 and "--" as char -1 (65535)
-        // Disallow e.g. "arg--1" which should parse as "arg - -1"
-        // Distinct tags for the multi-character compound operators.
-        static final char SHL = 2, SAR = 3, SHR = 4;
-
-        public char matchOperAssign() {
-            skipWhiteSpace();
-            if( match("<<=" ) ) return SHL;
-            if( match(">>>=") ) return SHR;
-            if( match(">>=" ) ) return SAR;
-            if( _position+2 >= _input.length ) return 0;
-            char ch0 = (char)_input[_position];
-            if( "+-/*&|^".indexOf(ch0) == -1 ) return 0;
-            char ch1 = (char)_input[_position+1];
-            if(               ch1 == '=' ) { _position += 2; return ch0; }
-            if( isIdLetter((char)_input[_position+2]) ) return 0;
-            if( ch0 == '+' && ch1 == '+' ) { _position += 2; return (char) 1; }
-            if( ch0 == '-' && ch1 == '-' ) { _position += 2; return (char)-1; }
-            return 0;
-        }
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/Utils.java b/chapter17/src/main/java/com/seaofnodes/simple/Utils.java
deleted file mode 100644
index 1346c3ea..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/Utils.java
+++ /dev/null
@@ -1,53 +0,0 @@
-package com.seaofnodes.simple;
-
-import java.util.ArrayList;
-
-public class Utils {
-    public static RuntimeException TODO() { return TODO("Not yet implemented"); }
-    public static RuntimeException TODO(String msg) { return new RuntimeException(msg); }
-
-    /**
-     *  Fast, constant-time, element removal.  Does not preserve order
-     *
-     *  @param array ArrayList to modify
-     *  @param i element to be removed
-     *  @return element removed
-     */
-    public static <E> void del(ArrayList<E> array, int i) {
-        E last = array.removeLast();
-        if (i < array.size()) array.set(i, last);
-    }
-
-    /**
-     * Search a list for an element by reference
-     *
-     * @param ary List to search in
-     * @param x Object to be searched
-     * @return >= 0 on success, -1 on failure
-     */
-    public static <E> int find( ArrayList<E> ary, E x ) {
-        for( int i=0; i<ary.size(); i++ )
-            if( ary.get(i)==x )
-                return i;
-        return -1;
-    }
-    /**
-     * Search a list for an element by reference
-     *
-     * @param ary List to search in
-     * @param x Object to be searched
-     * @return >= 0 on success, -1 on failure
-     */
-    public static <E> int find( E[] ary, E x ) {
-        for( int i=0; i<ary.length; i++ )
-            if( ary[i]==x )
-                return i;
-        return -1;
-    }
-
-    // Rotate a long, nice for hashes
-    public static long rot( long x, int n ) { return (x<<n) | (x>>>n); }
-
-    // Fold a 64bit hash into 32 bits
-    public static int fold( long x ) { return (int)((x>>32) ^ x); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/AddFNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/AddFNode.java
deleted file mode 100644
index fd713156..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/AddFNode.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-
-public class AddFNode extends Node {
-    public AddFNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "AddF"; }
-
-    @Override protected String format() { return "(%1+%2)"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeFloat i0 &&
-            in(2)._type instanceof TypeFloat i1) {
-            if (i0.isConstant() && i1.isConstant())
-                return TypeFloat.constant(i0.value()+i1.value());
-        }
-        return in(1)._type.meet(in(2)._type);
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Type t2 = in(2)._type;
-
-        // Add of 0.
-        if ( t2.isConstant() && t2 instanceof TypeFloat i && i.value()==0 )
-            return lhs;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new AddFNode(lhs,rhs); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/AddNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/AddNode.java
deleted file mode 100644
index 5eb0b0a3..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/AddNode.java
+++ /dev/null
@@ -1,186 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.*;
-
-
-public class AddNode extends Node {
-    public AddNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Add"; }
-
-    @Override protected String format() { return "(%1+%2)"; }
-
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i1 &&
-            t2 instanceof TypeInteger i2 ) {
-            if (i1.isConstant() && i2.isConstant())
-                return TypeInteger.constant(i1.value()+i2.value());
-            // Fold ranges like {0-1} + {2-3} into {2-4}.
-            if( !overflow(i1._min,i2._min) &&
-                !overflow(i1._max,i2._max) )
-                return TypeInteger.make(i1._min+i2._min,i1._max+i2._max);
-        }
-        return TypeInteger.BOT;
-    }
-
-    static boolean overflow( long x, long y ) {
-        if( (x ^    y ) < 0 ) return false; // unequal signs, never overflow
-        return (x ^ (x + y)) < 0; // sum has unequal signs, so overflow
-    }
-    @Override
-    public Node idealize () {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        if( rhs.err() != null ) return null;
-        Type t2 = rhs._type;
-
-        // Add of 0.  We do not check for (0+x) because this will already
-        // canonicalize to (x+0)
-        if( t2 instanceof TypeInteger i && i.isConstant() && i.value()==0 )
-            return lhs;
-
-        // Add of same to a multiply by 2
-        if( lhs==rhs )
-            return new MulNode(lhs,new ConstantNode(TypeInteger.constant(2)).peephole());
-
-        // Goal: a left-spine set of adds, with constants on the rhs (which then fold).
-
-        // Move non-adds to RHS
-        if( !(lhs instanceof AddNode) && rhs instanceof AddNode )
-            return swap12();
-
-        // x+(-y) becomes x-y
-        if( rhs instanceof MinusNode minus )
-            return new SubNode(lhs,minus.in(1));
-
-        // Now we might see (add add non) or (add non non) or (add add add) but never (add non add)
-
-        // Do we have  x + (y + z) ?
-        // 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));
-
-        // Now we might see (add add non) or (add non non) but never (add non add) nor (add add add)
-        if( !(lhs instanceof AddNode) )
-            // Rotate; look for (add (phi cons) con/(phi cons))
-            return spine_cmp(lhs,rhs,this) ? swap12() : phiCon(this,true);
-
-        // 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 )
-            return null;
-
-        // Do we have (x + con1) + con2?
-        // Replace with (x + (con1+con2) which then fold the constants
-        // lhs.in(2) is con1 here
-        // If lhs.in(2) is not a constant, we add ourselves as a dependency
-        // because if it later became a constant then we could make this
-        // transformation.
-        if( lhs.in(2).addDep(this)._type.isConstant() && rhs._type.isConstant() )
-            return new AddNode(lhs.in(1),new AddNode(lhs.in(2),rhs).peephole());
-
-
-        // Do we have ((x + (phi cons)) + con) ?
-        // Do we have ((x + (phi cons)) + (phi cons)) ?
-        // Push constant up through the phi: x + (phi con0+con0 con1+con1...)
-        Node phicon = phiCon(this,true);
-        if( phicon!=null ) return phicon;
-
-        // Now we sort along the spine via rotates, to gather similar things together.
-
-        // 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 null;
-    }
-
-    // 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)) ?
-    // Push constant up through the phi: x + (phi con0+con0 con1+con1...)
-    static Node phiCon(Node op, boolean rotate) {
-        Node lhs = op.in(1);
-        Node rhs = op.in(2);
-        if( rhs._type==TypeInteger.TOP ) return null;
-        // LHS is either a Phi of constants, or another op with Phi of constants
-        PhiNode lphi = pcon(lhs,op);
-        if( rotate && lphi==null && lhs.nIns() > 2 ) {
-            // Only valid to rotate constants if both are same associative ops
-            if( lhs.getClass() != op.getClass() ) return null;
-            lphi = pcon(lhs.in(2),op); // Will rotate with the Phi push
-        }
-        if( lphi==null ) return null;
-
-        // RHS is a constant or a Phi of constants
-        if( !(rhs instanceof ConstantNode) && pcon(rhs,op)==null )
-            return null;
-
-        // If both are Phis, must be same Region
-        if( rhs instanceof PhiNode && lphi.in(0) != rhs.in(0) )
-            return null;
-
-        // Note that this is the exact reverse of Phi pulling a common op down
-        // to reduce total op-count.  We don't get in an endless push-up
-        // push-down peephole cycle because the constants all fold first.
-        Node[] ns = new Node[lphi.nIns()];
-        ns[0] = lphi.in(0);
-        // Push constant up through the phi: x + (phi con0+con0 con1+con1...)
-        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._declaredType,ns).peephole();
-        // Rotate needs another op, otherwise just the phi
-        return lhs==lphi ? phi : op.copy(lhs.in(1),phi);
-    }
-
-    /**
-     * Tests if the op is a phi and has all constant inputs.
-     * If not, returns null.
-     * If op is a phi, but its inputs are not all constants, then dep is added as
-     * a dependency to the phi's non-const input, because if later the input turn into a constant
-     * dep can make progress.
-     */
-    static PhiNode pcon(Node op, Node dep) {
-        return op instanceof PhiNode phi && phi.allCons(dep) ? phi : null;
-    }
-
-    // Compare two off-spine nodes and decide what order they should be in.
-    // Do we rotate ((x + hi) + lo) into ((x + lo) + hi) ?
-    // Generally constants always go right, then Phi-of-constants, then muls, then others.
-    // Ties with in a category sort by node ID.
-    // TRUE if swapping hi and lo.
-    static boolean spine_cmp( Node hi, Node lo, Node dep ) {
-        if( lo._type.isConstant() ) return false;
-        if( hi._type.isConstant() ) return true ;
-
-        if( lo instanceof PhiNode lphi && lphi.region()._type==Type.XCONTROL ) return false;
-        if( hi instanceof PhiNode hphi && hphi.region()._type==Type.XCONTROL ) return false;
-
-        if( lo instanceof PhiNode && lo.allCons(dep) ) return false;
-        if( hi instanceof PhiNode && hi.allCons(dep) ) return true ;
-
-        if( lo instanceof PhiNode && !(hi instanceof PhiNode) ) return true;
-        if( hi instanceof PhiNode && !(lo instanceof PhiNode) ) return false;
-
-        // Same category of "others"
-        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 public String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '"+label()+"' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '"+label()+"' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/AndNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/AndNode.java
deleted file mode 100644
index bd03d6cb..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/AndNode.java
+++ /dev/null
@@ -1,61 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class AndNode extends Node {
-    public AndNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "And"; }
-
-    @Override protected String format() { return "(%1&%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i0 &&
-            t2 instanceof TypeInteger i1 ) {
-            if( i0.isConstant() && i1.isConstant() )
-                return TypeInteger.constant(i0.value()&i1.value());
-            // Sharpen allowed bits if either value is narrowed
-            long mask = i0.mask() & i1.mask();
-            return mask < 0 ? TypeInteger.BOT : TypeInteger.make(0,mask);
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t1 = lhs._type;
-        Type t2 = rhs._type;
-
-        // And of -1.  We do not check for (-1&x) because this will already
-        // canonicalize to (x&-1)
-        if( t2.isConstant() && t2 instanceof TypeInteger i && i.value()==-1 )
-            return lhs;
-
-        // Move constants to RHS: con*arg becomes arg*con
-        if ( t1.isConstant() && !t2.isConstant() )
-            return swap12();
-
-        // Do we have ((x & (phi cons)) & con) ?
-        // Do we have ((x & (phi cons)) & (phi cons)) ?
-        // Push constant up through the phi: x & (phi con0&con0 con1&con1...)
-        Node phicon = AddNode.phiCon(this,true);
-        if( phicon!=null ) return phicon;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new AndNode(lhs,rhs); }
-    @Override String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '&' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '&' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/BoolNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/BoolNode.java
deleted file mode 100644
index 6efde623..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/BoolNode.java
+++ /dev/null
@@ -1,114 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeMemPtr;
-
-import static com.seaofnodes.simple.type.TypeInteger.*;
-
-abstract public class BoolNode extends Node {
-
-    public BoolNode(Node lhs, Node rhs) {
-        super(null, lhs, rhs);
-    }
-
-    abstract String op();       // String opcode name
-
-    @Override
-    public String label() { return getClass().getSimpleName(); }
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.open().n(in(1)).p(op()).n(in(2)).close();
-    }
-
-    @Override
-    public TypeInteger compute() {
-        Type t1 = in(1)._type;
-        Type t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return BOOL.dual();
-        if( t1 instanceof TypeInteger i1 &&
-            t2 instanceof TypeInteger i2 )
-            return doOp(i1,i2);
-        if( t1 instanceof TypeFloat f1 &&
-            t2 instanceof TypeFloat f2 &&
-            f1.isConstant() && f2.isConstant() )
-            return TypeInteger.constant(doOp(f1.value(), f2.value()) ? 1 : 0);
-        return BOOL;
-    }
-
-    TypeInteger doOp(TypeInteger t1, TypeInteger t2) { throw Utils.TODO(); }
-    boolean doOp(double lhs, double rhs) { throw Utils.TODO(); }
-
-    @Override
-    public Node idealize() {
-        // Compare of same
-        if( in(1)==in(2) )
-            return new ConstantNode(doOp(ZERO,ZERO));
-
-        // 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 X==0 becomes a !X
-            if( (in(2)._type == ZERO || in(2)._type == TypeMemPtr.NULLPTR) )
-                return new NotNode(in(1));
-        }
-
-        // Do we have ((phi cons) cmp con) ?
-        // Do we have ((phi cons) cmp (phi cons)) ?
-        // Push the compare up through the phi: (phi con0 cmp con, con1 cmp con...)
-        Node phicon = AddNode.phiCon(this,this instanceof EQ);
-        if( phicon!=null ) return phicon;
-
-        return null;
-    }
-
-    public static class EQ extends BoolNode {
-        public EQ(Node lhs, Node rhs) { super(lhs,rhs); }
-        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); }
-    }
-    public static class LT extends BoolNode {
-        public LT(Node lhs, Node rhs) { super(lhs,rhs); }
-        String op() { return "<" ; }
-        TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
-            if( i1._max <  i2._min ) return TRUE;
-            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); }
-    }
-    public static class LE extends BoolNode {
-        public LE(Node lhs, Node rhs) { super(lhs,rhs); }
-        String op() { return "<="; }
-        TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
-            if( i1._max <= i2._min ) return TRUE;
-            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); } boolean doOp(double lhs, double rhs) { return lhs == rhs; } }
-    public static class LTF extends LT { public LTF(Node lhs, Node rhs) { super(lhs,rhs); } boolean doOp(double lhs, double rhs) { return lhs <  rhs; } }
-    public static class LEF extends LE { public LEF(Node lhs, Node rhs) { super(lhs,rhs); } boolean doOp(double lhs, double rhs) { return lhs <= rhs; } }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/BulkMemPhiNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/BulkMemPhiNode.java
deleted file mode 100644
index 84f97189..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/BulkMemPhiNode.java
+++ /dev/null
@@ -1,237 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
-import java.util.BitSet;
-
-/**
- * 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.
-    // Each split clones the exclusions; published sets are never mutated.
-    public final BitSet _aliases;
-
-    public BulkMemPhiNode(String label, Node... inputs) {
-        this(label,EMPTY,inputs);
-    }
-
-    private BulkMemPhiNode(String label, BitSet aliases, Node... inputs) {
-        super(label,TypeMem.BOT,inputs);
-        _aliases = aliases;
-    }
-
-    public boolean isSplit(int alias) { return _aliases.get(alias); }
-
-    @Override public String label() { return "BulkPhi"+_aliases; }
-
-    @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( ((RegionNode)region()).inProgress() || region().nIns()<=1 )
-            return null;        // Input is in-progress
-
-        // "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,IterPeeps.add(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<_outputs.size(); i++ ) {
-            int alias = outputAlias(_outputs.get(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 mmm.in(1)!=null && missingAlias(mmm)==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 ProjNode proj -> 0;
-        case ConstantNode con -> 0;
-        case MemMergeNode mmm -> missingAlias(mmm);
-        case MemOpNode mem -> unsplit(mem._alias);
-        case BulkMemPhiNode bulk -> missingAlias(bulk);
-        default -> throw new AssertionError("Unexpected memory input "+n);
-        };
-    }
-
-    // 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(this);
-        return switch(use) {
-        case ScopeNode scope -> 0;
-        case MemMergeNode mmm -> missingAlias(mmm);
-        case BulkMemPhiNode bulk -> missingAlias(bulk);
-        case MemOpNode mem -> unsplit(mem._alias);
-        case MemPhiNode phi -> unsplit(phi._alias);
-        default -> {
-            assert use instanceof ReturnNode
-                : "Unexpected bulk-memory user "+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) {
-        if( alias <= 1 ) return 0;
-        assert !_aliases.get(alias);
-        return 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;
-    }
-
-    // Every explicit slot requests that alias, including a partial allocation
-    // input whose slot still points to this bulk Phi.
-    private int missingAlias(MemMergeNode mmm) {
-        for( int alias=2; alias<mmm.nIns(); alias++ )
-            if( mmm.in(alias)!=null &&
-                mmm.alias(alias)!=mmm.in(1) &&
-                !_aliases.get(alias) )
-                return alias;
-        return 0;
-    }
-
-    // Slice out given alias
-    private MemMergeNode slice( int alias ) {
-        assert !_aliases.get(alias);
-        // Inputs are the same; MemPhi will sharpen his own inputs.  If a
-        // parallel precise Phi already exists, reuse it instead of building a
-        // duplicate for the same Region/alias pair.
-        Node mem = precisePhi(alias);
-
-        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++ )
-            IterPeeps.add(bphi.in(i));
-        // Do not peephole bphi here, as BulkMemPhi can recursively start a
-        // second bulk rewrite before this one has finished.  Let the worklist
-        // discover any further splits
-        bphi.setType(TypeMem.BOT);
-        Node bulk = bphi;
-        IterPeeps.add(bulk);
-        IterPeeps.add(mem);
-        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(bulk);
-        for( int old = _aliases.nextSetBit(0); old >= 0; old = _aliases.nextSetBit(old+1) )
-            { assert old != alias; mmm.alias(old,precisePhi(old));}
-        mmm.alias(alias,precise);
-        assert checkMerge(mmm);
-        return mmm;
-    }
-
-    // Find or make the precise Phi parallel to this bulk Phi at the same merge.
-    private Node precisePhi(int alias) {
-        MemPhiNode mphi = _findPhi(alias);
-        if( mphi!=null ) return mphi;
-
-        mphi = new MemPhiNode("$"+alias,alias);
-        mphi.addDef(region());
-        // Due to cycles, must set before calling peephole
-        mphi.setType(TypeMem.make(alias,Type.BOTTOM));
-        for( int i=1; i<nIns(); i++ )
-            mphi.addDef(IterPeeps.add(preciseInput(in(i),alias)));
-        return IterPeeps.add(mphi);
-    }
-
-    MemPhiNode _findPhi(int alias) {
-        for( Node use : region()._outputs )
-            if( use instanceof MemPhiNode mphi && mphi._alias==alias )
-                return mphi;
-        return null;
-    }
-
-    // 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;
-    }
-
-    @Override public boolean eq(Node n) {
-        return _aliases.equals(((BulkMemPhiNode)n)._aliases) && super.eq(n);
-    }
-
-    @Override int hash() { return _aliases.hashCode(); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/CFGNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/CFGNode.java
deleted file mode 100644
index e85fc6ae..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/CFGNode.java
+++ /dev/null
@@ -1,136 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.Utils;
-
-import java.util.BitSet;
-import java.util.HashSet;
-import java.util.HashMap;
-
-/** Control Flow Graph Nodes
- * <p>
- *  CFG nodes have a immediate dominator depth (idepth) and a loop nesting
- *  depth(loop_depth).
- * <p>
- *  idepth is computed lazily upon first request, and is valid even in the
- *  Parser, and is used by peepholes during parsing and afterward.
- * <p>
- *  loop_depth is computed after optimization as part of scheduling.
- *
- */
-public abstract class CFGNode extends Node {
-
-    public CFGNode(Node... nodes) { super(nodes); }
-
-    public CFGNode cfg(int idx) { return (CFGNode)in(idx); }
-
-    // Block head is Start, Region, CProj, but not e.g. If, Return, Stop
-    public boolean blockHead() { return false; }
-
-    // ------------------------------------------------------------------------
-    /**
-     * Immediate dominator tree depth, used to approximate a real IDOM during
-     * parsing where we do not have the whole program, and also peepholes
-     * change the CFG incrementally.
-     * <p>
-     * See {@link <a href="https://en.wikipedia.org/wiki/Dominator_(graph_theory)">...</a>}
-     */
-    public char _idepth;
-    public int idepth() { return _idepth!=0 ? _idepth : cacheIDepth(idom().idepth()+1); }
-    // Zero depth means uncached. Check before narrowing so overflow cannot wrap.
-    final int cacheIDepth(int depth) {
-        assert 0 <= depth && depth <= Character.MAX_VALUE : "Dominator depth exceeds 65535";
-        return _idepth = (char)depth;
-    }
-
-
-    // Return the immediate dominator of this Node and compute dom tree depth.
-    public CFGNode idom(Node dep) { return cfg(0); }
-    public final CFGNode idom() { return idom(null); }
-
-    // Return the LCA of two idoms
-    public CFGNode domLCA(CFGNode rhs, Node dep) {
-        if( rhs==null ) return this;
-        CFGNode lhs = this;
-        while( lhs != rhs ) {
-            if( lhs==null || rhs==null ) return null;
-            int comp = lhs.idepth() - rhs.idepth();
-            if( comp >= 0 ) lhs = (dep==null ? lhs : (CFGNode)lhs.addDep(dep)).idom();
-            if( comp <= 0 ) rhs = (dep==null ? rhs : (CFGNode)rhs.addDep(dep)).idom();
-        }
-        return lhs;
-    }
-
-    // ------------------------------------------------------------------------
-    // Loop nesting
-    public LoopNode loop() { return _ltree._head; }
-    public int loopDepth() { return _ltree==null ? 0 : _ltree.depth(); }
-
-    LoopTree _ltree;
-    int _pre;                   // Pre-order numbers for loop tree finding
-    private static class LoopTree {
-        LoopTree _par;
-        final LoopNode _head;
-        int _depth;
-        LoopTree(LoopNode head) { _head = head; }
-        @Override public String toString() { return "LOOP"+_head._nid; }
-        int depth() {
-            return _depth==0 ? (_par==null ? 0 : (_depth = _par.depth()+1)) : _depth;
-        }
-    }
-
-    // ------------------------------------------------------------------------
-    // 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(StopNode stop) {
-        _ltree = stop._ltree = Parser.XCTRL._ltree = new LoopTree((StartNode)this);
-        _bltWalk(2,stop, new BitSet());
-    }
-    private int _bltWalk(int pre, StopNode stop, BitSet post) {
-        // Pre-walked?
-        if( _pre!=0 ) return pre;
-        _pre = pre++;
-        // Pre-walk
-        for( Node use : _outputs )
-            if( use instanceof CFGNode usecfg )
-                pre = usecfg._bltWalk(pre,stop,post);
-
-        // Post-order work: find innermost loop
-        LoopTree inner = null, ltree;
-        for( Node use : _outputs ) {
-            if( !(use instanceof CFGNode usecfg) ) 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(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;
-        // Tag as post-walked
-        post.set(_nid);
-        return pre;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/CProjNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/CProjNode.java
deleted file mode 100644
index 53348b5a..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/CProjNode.java
+++ /dev/null
@@ -1,61 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
-import com.seaofnodes.simple.type.TypeTuple;
-
-public class CProjNode extends CFGNode {
-
-    // Which slice of the incoming multipart value
-    public final int _idx;
-
-    // Debugging label
-    public final String _label;
-
-    public CProjNode(Node ctrl, int idx, String label) {
-        super(ctrl);
-        _idx = idx;
-        _label = label;
-    }
-
-    @Override public String label() { return _label; }
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) { return p.p(_label); }
-
-    @Override public boolean isMultiTail() { return in(0).isMultiHead(); }
-    @Override public boolean blockHead() { return true; }
-
-    public CFGNode ctrl() { return cfg(0); }
-
-    @Override
-    public Type compute() {
-        Type t = ctrl()._type;
-        return t instanceof TypeTuple tt ? tt._types[_idx] : Type.BOTTOM;
-    }
-
-    @Override
-    public Node idealize() {
-        if( ctrl()._type instanceof TypeTuple tt ) {
-            if( tt._types[_idx]==Type.XCONTROL )
-                return Parser.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 && iff.pred().addDep(this) instanceof NotNode not )
-            return new CProjNode(new IfNode(iff.ctrl(),not.in(1)).peephole(),1-_idx,_idx==0 ? "False" : "True");
-
-        return null;
-    }
-
-    @Override
-    boolean eq( Node n ) { return _idx == ((CProjNode)n)._idx; }
-
-    @Override
-    int hash() { return _idx; }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/CastNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/CastNode.java
deleted file mode 100644
index 9ade5a50..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/CastNode.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import com.seaofnodes.simple.IterPeeps;
-
-
-// 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 {
-    private final Type _t;
-    public CastNode(Type t, Node ctrl, Node in) {
-        super(ctrl, in);
-        _t = t;
-        setType(compute());
-    }
-
-    @Override public String label() { return "("+_t.str()+")"; }
-
-
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.p(label()).n(in(1));
-    }
-
-    @Override
-    public Type compute() {
-        return in(1)._type.join(_t);
-    }
-
-    @Override
-    public Node idealize() {
-        return in(1)._type.isa(_t) ? in(1) : null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
deleted file mode 100644
index 426736ed..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
+++ /dev/null
@@ -1,56 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-
-
-/**
- * A Constant node represents a constant value.  At present, the only constants
- * that we allow are integer literals; therefore Constants contain an integer
- * value.  As we add other types of constants, we will refactor how we represent
- * Constants.
- * <p>
- * Constants have no semantic inputs. However, we set Start as an input to
- * Constants to enable a forward graph walk.  This edge carries no semantic
- * meaning, and it is present <em>solely</em> to allow visitation.
- * <p>
- * The Constant's value is the value stored in it.
- */
-public class ConstantNode extends Node {
-    final Type _con;
-    public ConstantNode( Type type ) {
-        super(Parser.START);
-        _con = type;
-    }
-
-    @Override protected String repeatName() {
-        return _con==null || _con.toString().length()<=32 ? null : uniqueName();
-    }
-
-    @Override
-    public String label() { return "Con"; }
-
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.p(_con);
-    }
-
-    @Override public boolean isMultiTail() { return true; }
-
-    @Override
-    public Type compute() { return _con; }
-
-    @Override
-    public Node idealize() { return null; }
-
-    @Override
-    boolean eq(Node n) {
-        ConstantNode con = (ConstantNode)n; // Contract
-        return _con==con._con;
-    }
-
-    @Override
-    int hash() { return _con.hashCode(); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/DivFNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/DivFNode.java
deleted file mode 100644
index a3f4318d..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/DivFNode.java
+++ /dev/null
@@ -1,39 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-
-public class DivFNode extends Node {
-    public DivFNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "DivF"; }
-
-    @Override protected String format() { return "(%1/%2)"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeFloat i0 &&
-            in(2)._type instanceof TypeFloat i1) {
-            if (i0.isConstant() && i1.isConstant())
-                return TypeFloat.constant(i0.value()/i1.value());
-        }
-        return in(1)._type.meet(in(2)._type);
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t1 = lhs._type;
-        Type t2 = rhs._type;
-
-        // Div of 1.  
-        if ( t2.isConstant() && t2 instanceof TypeFloat i && i.value()==1 )
-            return lhs;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new DivFNode(lhs,rhs); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/DivNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/DivNode.java
deleted file mode 100644
index cd749a03..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/DivNode.java
+++ /dev/null
@@ -1,40 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class DivNode extends Node {
-    public DivNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Div"; }
-
-    @Override protected String format() { return "(%1/%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i1 &&
-            t2 instanceof TypeInteger i2 ) {
-            if (i1.isConstant() && i2.isConstant())
-                return i2.value() == 0
-                    ? TypeInteger.ZERO
-                    : TypeInteger.constant(i1.value()/i2.value());
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        // Div of 1.
-        if( in(2)._type == TypeInteger.TRUE )
-            return in(1);
-        return null;
-    }
-
-    @Override Node copy(Node lhs, Node rhs) { return new DivNode(lhs,rhs); }
-    @Override Node copyF() { return new DivFNode(null,null); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/IfNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/IfNode.java
deleted file mode 100644
index 2b53b3a3..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/IfNode.java
+++ /dev/null
@@ -1,62 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import com.seaofnodes.simple.type.TypeTuple;
-import java.util.HashSet;
-
-public class IfNode extends CFGNode implements MultiNode {
-
-    public IfNode(Node ctrl, Node pred) {
-        super(ctrl, pred);
-        IterPeeps.add(this);    // Because idoms are complex, just add it
-    }
-
-    @Override
-    public String label() { return "If"; }
-
-    @Override protected String format() { return "if( %1 )"; }
-
-    @Override public boolean isMultiHead() { return true; }
-
-    public Node ctrl() { return in(0); }
-    public Node pred() { return in(1); }
-
-    @Override
-    public Type compute() {
-        // If the If node is not reachable then neither is any following Proj
-        if (ctrl()._type != Type.CONTROL && ctrl()._type != Type.BOTTOM )
-            return TypeTuple.IF_NEITHER;
-        Node pred = pred();
-        Type t = pred._type;
-        // High types mean NEITHER side is reachable.
-        // Wait until the type falls to decide which way to go.
-        if( t == Type.TOP || t == TypeInteger.TOP )
-            return TypeTuple.IF_NEITHER;
-        // If constant is 0 then false branch is reachable
-        // Else true branch is reachable
-        if( t.isConstant() )
-            return t.makeInit()==t ? TypeTuple.IF_FALSE : TypeTuple.IF_TRUE;
-        // Integers allow non-zero ranges: "1-65535"
-        if( t.makeZero().meet(t) != t )
-            return TypeTuple.IF_TRUE;
-
-        return TypeTuple.IF_BOTH;
-    }
-
-    @Override
-    public Node idealize() {
-        // 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( dom.addDep(this) instanceof IfNode iff && iff.pred().addDep(this)==pred() && prior instanceof CProjNode prj ) {
-                    setDef(1,new ConstantNode(TypeInteger.make(true,prj._idx==0?1:0)).peephole());
-                    return this;
-                }
-        return null;
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/LoadNode.java
deleted file mode 100644
index c5cc381a..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ /dev/null
@@ -1,221 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.type.*;
-import java.util.BitSet;
-import java.util.ArrayList;
-
-/**
- * Load represents extracting a value from inside a memory object,
- * in chapter 10 this means Struct fields.
- */
-public class LoadNode extends MemOpNode {
-
-    /**
-     * Load a value from a ptr.field.
-     *
-     * @param name  The field we are loading
-     * @param mem   The memory alias node - this is updated after a Store
-     * @param ptr   The ptr to the struct base from where we load a field
-     * @param off   The offset inside the struct base
-     */
-    public LoadNode(String name, int alias, Type glb, Node mem, Node ptr, Node off) {
-        super(name, alias, glb, mem, ptr, off);
-    }
-
-    @Override boolean canDrop(MemOpNode other, Node dep) {
-        return super.canDrop(other,dep) && !clobbered(dep);
-    }
-
-    // Check only immediate memory users. Stores clobber memory; Phis and
-    // aggregates might lead to a clobber, so stop rather than search further.
-    private boolean clobbered(Node dep) {
-        Node mem = mem();
-        mem.addDepForwards(dep);
-        for( Node use : mem._outputs ) {
-            if( use==null ) continue;
-            use.addDepForwards(dep);
-            if( use instanceof StoreNode || use instanceof PhiNode ||
-                use instanceof MemMergeNode ||
-                use instanceof NewNode ) return true;
-        }
-        return false;
-    }
-
-    // Debugger label
-    @Override public String  label() { return "ld_"+mlabel(); }
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) { return p.p(".").p(_name); }
-
-    @Override
-    public Type compute() {
-        Type t = MemMergeNode.contents(mem(),_alias,this);
-        // Update declared forward ref to the actual.
-        if( _declaredType.isFRef() && t instanceof TypeMemPtr tmp && !tmp.isFRef() )
-            _declaredType = tmp;
-        return err()==null ? _declaredType.join(t) : _declaredType;
-    }
-
-    @Override
-    public Node idealize() {
-        if( mem() instanceof MemMergeNode merge ) {
-            setDef(1,IterPeeps.add(merge.alias(_alias)));
-            return this;
-        }
-        Node ptr = ptr();
-
-        // Simple Load-after-Store on same address.
-        if( mem() instanceof StoreNode st &&
-            _alias==st._alias && ptr == st.ptr() && off() == st.off() ) { // Must check same object
-            assert _name.equals(st._name); // Equiv class aliasing is perfect
-            return st.val();
-        }
-
-        // Simple Load-after-New on same address.
-        if( mem() instanceof ProjNode p && p.in(0) instanceof NewNode nnn &&
-            ptr == nnn.proj(0) ) // Must check same object
-            return nnn.in(nnn.findAlias(_alias)); // Load from New init
-
-        // Load-after-Store on same address, but bypassing provably unrelated
-        // stores.  This is a more complex superset of the above two peeps.
-        // "Provably unrelated" is really weak.
-        if( ptr instanceof ReadOnlyNode ro )
-            ptr = ro.in(1);
-        Node mem = mem();
-        outer:
-        while( true ) {
-            mem.addDep(this);
-            switch( mem ) {
-            case MemMergeNode merge:
-                mem = merge.alias(_alias);
-                break;
-            case StoreNode st:
-                if( _alias==st._alias && ptr == st.ptr() && off() == st.off() )
-                    return castRO(st.val()); // Proved equal
-                // Can we prove unequal?  Offsets do not overlap?
-                if( _alias==st._alias && !off()._type.join(st.off()._type).isHigh() && // Offsets overlap
-                    !neverAlias(ptr,st.ptr()) )                   // And might alias
-                    break outer; // Cannot tell, stop trying
-                // Pointers cannot overlap
-                mem = st.mem(); // Proved never equal
-                break;
-            case PhiNode phi:      break outer;  // Assume related
-            case ConstantNode top: break outer;  // Assume shortly dead
-            case ProjNode mproj:
-                if( mproj.in(0) instanceof NewNode nnn1 ) {
-                    if( ptr instanceof ProjNode pproj && pproj.in(0) == mproj.in(0) )
-                        return castRO(nnn1.in(nnn1.findAlias(_alias))); // Load from New init
-                    if( !(ptr instanceof ProjNode pproj && pproj.in(0) instanceof NewNode nnn2) )
-                        break outer; // Cannot tell, ptr not related to New
-                    mem = nnn1.mem();// Bypass unrelated New
-                    break;
-                } else break outer;
-            default:
-                break outer;
-            }
-        }
-
-        // Push a Load up through a Phi, as long as it collapses on at least
-        // one arm.  If at a Loop, the backedge MUST collapse - else we risk
-        // spinning the same transform around the loop indefinitely.
-        //   BEFORE (2 Sts, 1 Ld):          AFTER (1 St, 0 Ld):
-        //   if( pred ) ptr.x = e0;         val = pred ? e0
-        //   else       ptr.x = e1;                    : e1;
-        //   val = ptr.x;                   ptr.x = val;
-        if( mem() instanceof MemPhiNode memphi && memphi.region()._type == Type.CONTROL && memphi.nIns()== 3 &&
-            // Offset can be hoisted
-            off() instanceof ConstantNode &&
-            // Pointer can be hoisted
-            hoistPtr(ptr,memphi)  ) {
-
-            // Profit on RHS/Loop backedge
-            if( profit(memphi,2) ||
-                // Else must not be a loop to count profit on LHS.
-                (!(memphi.region() instanceof LoopNode) && profit(memphi,1)) ) {
-                Node ld1 = ld(1);
-                Node ld2 = ld(2);
-                return new PhiNode(_name,_declaredType,memphi.region(),ld1,ld2);
-            }
-        }
-
-        return null;
-    }
-
-    private Node ld( int idx ) {
-        Node mem = mem(), ptr = ptr();
-        LoadNode ld = new LoadNode(_name,_alias,_declaredType,mem.in(idx),ptr instanceof PhiNode && ptr.in(0)==mem.in(0) ? ptr.in(idx) : ptr,off());
-        ld.setDef(0,in(0));
-        return ld.peephole();
-    }
-
-    private static boolean neverAlias( Node ptr1, Node ptr2 ) {
-        return ptr1.in(0) != ptr2.in(0) &&
-            // Unrelated allocations
-            ptr1 instanceof ProjNode && ptr1.in(0) instanceof NewNode &&
-            ptr2 instanceof ProjNode && ptr2.in(0) instanceof NewNode;
-    }
-
-    private static boolean hoistPtr(Node ptr, PhiNode memphi ) {
-        // Can I hoist ptr above the Region?
-        if( !(memphi.region() instanceof RegionNode r) )
-            return false;       // Dead or dying Region/Phi
-        // If ptr from same Region, then yes, just use hoisted split pointers
-        if( ptr instanceof PhiNode pphi && pphi.region() == r )
-            return true;
-
-        // No, so can we lift this ptr?
-        CFGNode cptr = ptr.cfg0();
-        if( cptr != null )
-            // Pointer is controlled high
-            // TODO: Really needs to be the LCA of all inputs is high
-            return cptr.idepth() <= r.idepth();
-
-        // Dunno without a longer walk
-        return false;
-    }
-
-    // Profitable if we find a matching Store on this Phi arm.
-    private boolean profit(PhiNode phi, int idx) {
-        Node px = phi.in(idx);
-        if( px==null ) return false;
-        px.addDep(this);
-        if( px._type instanceof TypeMem mem && mem._t.isHighOrConst() ) return true;
-        if( px instanceof StoreNode st1 && _alias==st1._alias && ptr()==st1.ptr() && off()==st1.off() ) return true;
-        return false;
-    }
-
-    // Read-Only is a deep property, and cannot be cast-away
-    private Node castRO(Node rez) {
-        if( ptr()._type.isFinal() && !rez._type.isFinal() )
-            return new ReadOnlyNode(rez).peephole();
-        return rez;
-    }
-
-    // Memory writers which must follow this read. A packaging node is not a
-    // write, but can hide New's input, so follow this alias through aggregates.
-    public ArrayList<Node> antiDeps() {
-        ArrayList<Node> deps = new ArrayList<>();
-        antiDeps(mem(),deps,new BitSet());
-        return deps;
-    }
-
-    private void antiDeps(Node mem, ArrayList<Node> deps, BitSet visit) {
-        if( visit.get(mem._nid) ) return;
-        visit.set(mem._nid);
-        for( Node use : mem._outputs ) {
-            if( use instanceof MemMergeNode merge ) {
-                Node slice = _alias<merge.nIns() ? merge.in(_alias) : null;
-                if( (slice==mem) || (slice==null && merge.in(1)==mem) )
-                    antiDeps(merge,deps,visit);
-            } else if( (use instanceof StoreNode st && st._alias==_alias) ||
-                       (use instanceof NewNode nnn && nnn.field(_alias)!=null) ||
-                       (use instanceof MemPhiNode phi && phi._alias==_alias) ||
-                       (use instanceof BulkMemPhiNode phi && !phi.isSplit(_alias)) ) {
-                if( !deps.contains(use) ) deps.add(use);
-            }
-        }
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/LoopNode.java
deleted file mode 100644
index 8fb6a4ce..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/LoopNode.java
+++ /dev/null
@@ -1,61 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.util.BitSet;
-import java.util.HashSet;
-
-public class LoopNode extends RegionNode {
-    public LoopNode( Node entry ) { super(null,entry,null); }
-
-    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;
-    }
-
-    @Override
-    public Node idealize() {
-        return inProgress() ? null : super.idealize();
-    }
-
-    // Bypass Region idom, same as the default idom() using use in(1) instead of in(0)
-    @Override public int idepth() { return _idepth!=0 ? _idepth : cacheIDepth(entry().idepth()+1); }
-    // Bypass Region idom, same as the default idom() using use in(1) instead of in(0)
-    @Override public CFGNode idom(Node dep) { return entry(); }
-
-    // If this is an unreachable loop, it may not have an exit.  If it does not
-    // (i.e., infinite loop), force an exit to make it reachable.
-    public StopNode forceExit( StopNode stop ) {
-        // Walk the backedge, then immediate dominator tree util we hit this
-        // Loop again.  If we ever hit a CProj from an If (as opposed to
-        // directly on the If) we found our exit.
-        CFGNode x = back();
-        while( x != this ) {
-            if( x instanceof CProjNode exit && exit.in(0) instanceof IfNode iff ) {
-                CFGNode other = iff.cproj(1-exit._idx);
-                if( other.loopDepth() < loopDepth() )
-                    return stop; // Found an exit, not an infinite loop
-            }
-            x = x.idom();
-        }
-        // Found a no-exit loop.  Insert an exit
-        NeverNode iff = new NeverNode(back());
-        for( Node use : _outputs )
-            if( use instanceof PhiNode phi )
-                iff.addDef(use);
-        CProjNode t = new CProjNode(iff,0,"True" );
-        CProjNode f = new CProjNode(iff,1,"False");
-        setDef(2,f);
-        stop.addDef(new ReturnNode(t,Parser.ZERO,null));
-        return stop;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
deleted file mode 100644
index faf456de..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
+++ /dev/null
@@ -1,90 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
-
-/** A default slice and explicit alias overrides. A null default means partial
- *  memory: absent aliases are not covered, rather than having unknown contents.
- */
-public class MemMergeNode extends Node {
-    public MemMergeNode(Node bulk) { super(null,bulk); _type = TypeMem.BOT; }
-    public MemMergeNode(Node bulk, int alias, Node precise) {
-        this(bulk);
-        alias(alias,precise);
-    }
-
-    public Node alias(int alias) {
-        Node n = alias < nIns() ? in(alias) : null;
-        assert n!=null || !(in(1) instanceof BulkMemPhiNode bulk) || !bulk.isSplit(alias);
-        n = n==null ? in(1) : n;
-        assert n!=null : "Alias not covered: "+alias;
-        return n;
-    }
-
-    public void alias(int alias, Node mem) {
-        assert alias > 1;
-        while( nIns()<=alias ) addDef(null);
-        setDef(alias,mem);
-    }
-
-    // Scalar contents of one alias. New's field inputs supply the initialized type;
-    // join it with the incoming contents for all previously allocated objects.
-    // Phis use their cached types, so this query does not recurse around loops.
-    static Type contents(Node mem, int alias, Node dep) {
-        mem.addDep(dep);
-        if( mem instanceof MemMergeNode merge )
-            return contents(merge.alias(alias),alias,dep);
-        if( mem instanceof ProjNode proj && proj.in(0) instanceof NewNode nnn ) {
-            assert proj._idx==1 && nnn.field(alias)!=null;
-            nnn.addDep(dep);
-            Node init = nnn.in(nnn.findAlias(alias)).addDep(dep);
-            return contents(nnn.mem(),alias,dep).meet(init._type);
-        }
-        // There are no heap arguments in this chapter. Before the first New,
-        // the set of allocated objects (and hence stored values) is empty.
-        if( mem instanceof ProjNode proj && proj.in(0) instanceof StartNode ) return Type.TOP;
-        if( mem._type==Type.TOP || mem._type==TypeMem.TOP ) return Type.TOP;
-        if( mem._type instanceof TypeMem mt && mt._alias==alias ) return mt._t;
-        return Type.BOTTOM;
-    }
-
-    @Override public String label() { return "MemMerge"; }
-    @Override public boolean isMem() { return true; }
-    @Override public Type compute() { return TypeMem.BOT; }
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        p.p("MEM[");
-        for( int i=1; i<nIns(); i++ )
-            if( in(i)!=null ) {
-                p.p(i==1 ? "default:" : i+":");
-                p.n(in(i)).p(" ");
-            }
-        return p.p("]");
-    }
-
-    @Override public Node idealize() {
-        boolean progress=false, allDefault=true;
-        for( int i=2; i<nIns(); i++ ) {
-            if( in(i)!=null && in(i)==in(1) ) { setDef(i,null); progress=true; }
-            if( in(i) instanceof MemMergeNode mem ) {
-                setDef(i,IterPeeps.add(mem.alias(i)));
-                progress=true;
-            }
-            if( in(i)!=null ) allDefault=false;
-        }
-        if( allDefault && in(1)!=null ) return in(1);
-
-        if( in(1) instanceof MemMergeNode mem ) {
-            for( int i=2; i<mem.nIns(); i++ )
-                if( mem.in(i)!=null && (i>=nIns() || in(i)==null) )
-                    alias(i,mem.in(i));
-            IterPeeps.add(mem.in(1));
-            setDef(1,mem.in(1));
-            return this;
-        }
-        assert BulkMemPhiNode.checkMerge(this);
-        return progress ? this : null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
deleted file mode 100644
index 0bf9b6ac..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ /dev/null
@@ -1,62 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMemPtr;
-
-/**
- * Convenience common base for Load and Store.
- */
-public abstract class MemOpNode extends Node {
-
-    public final String _name;
-    public final int _alias;
-    // Declared type; not final because it might be a forward-reference
-    // which will be lazily improved when the reference is declared.
-    public Type _declaredType;
-
-    public MemOpNode(String name, int alias, Type glb, Node mem, Node ptr, Node off) {
-        super(null, mem, ptr, off);
-        _name  = name;
-        _alias = alias;
-        _declaredType = glb;
-    }
-    public MemOpNode(String name, int alias, Type glb, Node mem, Node ptr, Node off, Node value) {
-        this(name, alias, glb, mem, ptr, off);
-        addDef(value);
-    }
-
-    //
-    static String mlabel(String name) { return name.equals("[]") ? "ary" : (name.equals("#") ? "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); }
-
-    // Extra conditions for factoring matching memory operations through a Phi.
-    // The caller has already checked the opcode, input shape and control.
-    boolean canDrop(MemOpNode other, Node dep) {
-        ptr().addDep(dep);
-        return _alias==other._alias && _declaredType==other._declaredType && err()==null;
-    }
-
-    @Override
-    boolean eq(Node n) {
-        MemOpNode mem = (MemOpNode)n; // Invariant
-        return _alias==mem._alias;    // When comparing types error to use "equals"; always use "=="
-    }
-
-    @Override
-    int hash() { return _alias; }
-
-    @Override
-    String err() {
-        Type ptr = ptr()._type;
-        // Already an error, but better error messages come from elsewhere
-        if( ptr == Type.BOTTOM ) return null;
-        // Better be a not-nil TMP
-        if( ptr instanceof TypeMemPtr tmp && !tmp._nil )
-            return null;
-        return "Might be null accessing '" + _name + "'";
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MemPhiNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MemPhiNode.java
deleted file mode 100644
index 6aae00f9..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MemPhiNode.java
+++ /dev/null
@@ -1,42 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
-
-/** A Phi for one field alias, parallel to a bulk Phi at the same Region. */
-public class MemPhiNode extends PhiNode {
-    public final int _alias;
-
-    public MemPhiNode(String label, int alias, Node... inputs) {
-        super(label,TypeMem.make(alias,Type.BOTTOM),inputs);
-        assert alias > 1;
-        _alias = alias;
-    }
-
-    @Override public String label() { return "MemPhi_"+_alias; }
-
-    @Override public Type compute() {
-        assert BulkMemPhiNode.checkMem(this,_alias);
-        if( !(region() instanceof RegionNode r) )
-            return region()._type==Type.XCONTROL ? TypeMem.TOP : _type;
-        if( r.inProgress() ) return _declaredType;
-        Type t = Type.TOP;
-        for( int i=1; i<nIns(); i++ )
-            if( r.in(i).addDep(this)._type!=Type.XCONTROL )
-                t = t.meet(MemMergeNode.contents(in(i),_alias,this));
-        return TypeMem.make(_alias,t);
-    }
-
-    @Override public Node idealize() {
-        for( int i=1; i<nIns(); i++ )
-            if( in(i) instanceof MemMergeNode mem ) {
-                setDef(i,IterPeeps.add(mem.alias(_alias)));
-                return this;
-            }
-        return super.idealize();
-    }
-
-    @Override boolean eq(Node n) { return _alias==((MemPhiNode)n)._alias && super.eq(n); }
-    @Override int hash() { return _alias; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MinusFNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
deleted file mode 100644
index 1b45c7c5..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
+++ /dev/null
@@ -1,30 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-
-public class MinusFNode extends Node {
-    public MinusFNode(Node in) { super(null, in); }
-
-    @Override public String label() { return "MinusF"; }
-
-    @Override protected String format() { return "(-%1)"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeFloat i0)
-            return i0.isConstant() ? TypeFloat.constant(-i0.value()) : i0;
-        return TypeFloat.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        // -(-x) is x
-        if( in(1) instanceof MinusFNode minus )
-            return minus.in(1);
-
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java
deleted file mode 100644
index b85af74e..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import com.seaofnodes.simple.Utils;
-
-
-public class MinusNode extends Node {
-    public MinusNode(Node in) { super(null, in); }
-
-    @Override public String label() { return "Minus"; }
-
-    @Override protected String format() { return "(-%1)"; }
-
-    @Override
-    public Type compute() {
-        if( in(1)._type instanceof TypeInteger i0 ) {
-            if( i0.isHigh() ) return TypeInteger.TOP;
-            if( i0==TypeInteger.BOT || i0._min == Long.MIN_VALUE || i0._max == Long.MIN_VALUE )
-                return TypeInteger.BOT;
-            return TypeInteger.make(-i0._max,-i0._min);
-        }
-        return in(1)._type.isHigh() ? TypeInteger.TOP : TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        // -(-x) is x
-        if( in(1) instanceof MinusNode minus )
-            return minus.in(1);
-
-        return null;
-    }
-    @Override Node copyF() { return new MinusFNode(null); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MulFNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MulFNode.java
deleted file mode 100644
index 6a57f3c5..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MulFNode.java
+++ /dev/null
@@ -1,44 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-
-public class MulFNode extends Node {
-    public MulFNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "MulF"; }
-
-    @Override protected String format() { return "(%1*%2)"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeFloat i0 &&
-            in(2)._type instanceof TypeFloat i1) {
-            if (i0.isConstant() && i1.isConstant())
-                return TypeFloat.constant(i0.value()*i1.value());
-        }
-        return in(1)._type.meet(in(2)._type);
-    }
-
-    @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/chapter17/src/main/java/com/seaofnodes/simple/node/MulNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MulNode.java
deleted file mode 100644
index a9ac07e6..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MulNode.java
+++ /dev/null
@@ -1,61 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class MulNode extends Node {
-    public MulNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Mul"; }
-
-    @Override protected String format() { return "(%1*%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i1 &&
-            t2 instanceof TypeInteger i2 ) {
-            if( i1==TypeInteger.ZERO || i2==TypeInteger.ZERO)
-                return TypeInteger.ZERO;
-            if (i1.isConstant() && i2.isConstant())
-                return TypeInteger.constant(i1.value()*i2.value());
-        }
-        return TypeInteger.BOT;
-    }
-
-    @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 TypeInteger i && i.value()==1 )
-            return lhs;
-
-        // Move constants to RHS: con*arg becomes arg*con
-        if ( t1.isConstant() && !t2.isConstant() )
-            return swap12();
-
-        // Do we have ((x * (phi cons)) * con) ?
-        // Do we have ((x * (phi cons)) * (phi cons)) ?
-        // Push constant up through the phi: x * (phi con0*con0 con1*con1...)
-        Node phicon = AddNode.phiCon(this,true);
-        if( phicon!=null ) return phicon;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new MulNode(lhs,rhs); }
-    @Override Node copyF() { return new MulFNode(null,null); }
-    @Override public String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '"+label()+"' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '"+label()+"' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MultiNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MultiNode.java
deleted file mode 100644
index ac9c0045..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MultiNode.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package com.seaofnodes.simple.node;
-
-public interface MultiNode extends OutNode {
-
-    // Find a projection by index
-    default ProjNode proj( int idx ) {
-        for( Node out : outs() )
-            if( out instanceof ProjNode prj && prj._idx==idx )
-                return prj;
-        return null;
-    }
-
-    // Find a projection by index
-    default CProjNode cproj( int idx ) {
-        for( Node out : outs() )
-            if( out instanceof CProjNode prj && prj._idx==idx )
-                return prj;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/NeverNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/NeverNode.java
deleted file mode 100644
index 7e42ccf9..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/NeverNode.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.TypeInteger;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeTuple;
-
-
-// "Never true" for infinite loop exits
-public class NeverNode extends IfNode {
-    public NeverNode(Node ctrl) { super(ctrl,Parser.ZERO); }
-
-    @Override public String label() { return "Never"; }
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) { return p.p("Never"); }
-
-    @Override public Type compute() { return TypeTuple.IF_BOTH; }
-
-    @Override public Node idealize() { return null; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/NewNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/NewNode.java
deleted file mode 100644
index 51341c41..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/NewNode.java
+++ /dev/null
@@ -1,60 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.*;
-
-/** Allocate and initialize an object. Inputs {ctrl, $mem, size, fields...};
- *  results {ptr, $mem}.
- *  The memory input and result cover only the aliases in the allocated struct.
- */
-public class NewNode extends Node implements MultiNode {
-
-    public final TypeMemPtr _ptr;
-
-    public NewNode(TypeMemPtr ptr, Node... nodes) {
-        super(nodes);
-        _ptr = ptr;
-        assert nodes.length==3+ptr._obj._fields.length;
-        assert nodes[0]._type==Type.CONTROL || nodes[0]._type==Type.XCONTROL;
-        assert nodes[1]._type instanceof TypeMem;
-        assert nodes[2]._type instanceof TypeInteger;
-        for( int i=3; i<nodes.length; i++ ) assert nodes[i]._type!=null;
-    }
-
-    public Node mem() { return in(1); }
-    public Node size() { return in(2); }
-
-    public Field field(int alias) {
-        for( Field f : _ptr._obj._fields )
-            if( f._alias==alias ) return f;
-        return null;
-    }
-
-    @Override public String label() {
-        return "new_"+(_ptr._obj.isAry() ? "ary_"+_ptr._obj._fields[1]._type.str() : _ptr._obj.str());
-    }
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.p("new ").p(_ptr._obj.str());
-    }
-
-    // Find matching alias input
-    int findAlias(int alias) {
-        return 3+_ptr._obj.findAlias(alias);
-    }
-
-
-    @Override
-    public TypeTuple compute() {
-        return TypeTuple.make(_ptr,TypeMem.BOT);
-    }
-
-    @Override
-    public Node idealize() { return null; }
-
-    @Override
-    boolean eq(Node n) { return this == n; }
-
-    @Override
-    int hash() { return _ptr.hashCode(); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter17/src/main/java/com/seaofnodes/simple/node/Node.java
deleted file mode 100644
index bd1fdffa..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/Node.java
+++ /dev/null
@@ -1,611 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.BaseNode;
-
-import com.seaofnodes.simple.Parser;
-
-import com.seaofnodes.simple.Ary;
-import com.seaofnodes.simple.IRPrinter;
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-import java.util.*;
-import java.util.function.Function;
-
-/**
- * All Nodes in the Sea of Nodes IR inherit from the Node class.
- * The Node class provides common functionality used by all subtypes.
- * Subtypes of Node specialize by overriding methods.
- */
-public abstract class Node extends BaseNode<Node> implements OutNode, Cloneable {
-
-    /**
-     * Inputs to the node. These are use-def references to Nodes.
-     * <p>
-     * Generally fixed length, ordered, nulls allowed, no unused trailing space.
-     * Ordering is required because e.g. "a/b" is different from "b/a".
-     * The first input (offset 0) is often a {@link CFGNode} node.
-     */
-    public Ary<Node> _inputs;
-
-    /**
-     * Outputs reference Nodes that are not null and have this Node as an
-     * input.  These nodes are users of this node, thus these are def-use
-     * references to Nodes.
-     * <p>
-     * Outputs directly match inputs, making a directed graph that can be
-     * walked in either direction.  These outputs are typically used for
-     * efficient optimizations but otherwise have no semantics meaning.
-     */
-    public Ary<Node> _outputs;
-
-    /**
-     * Current computed type for this Node.  This value changes as the graph
-     * changes and more knowledge is gained about the program.
-     */
-    public Type _type;
-
-    /**
-     * A private Global Static mutable counter, for unique node id generation.
-     * To make the compiler multithreaded, this field will have to move into a TLS.
-     * Starting with value 1, to avoid bugs confusing node ID 0 with uninitialized values.
-     * */
-    private static int UNIQUE_ID = 1;
-    public static int UID() { return UNIQUE_ID; }
-
-    protected Node(Node... inputs) {
-        super(UNIQUE_ID++); // allocate unique dense ID
-        _inputs = new Ary<>(Node.class);
-        Collections.addAll(_inputs,inputs);
-        _outputs = new Ary<>(Node.class);
-        for( Node n : _inputs )
-            if( n != null )
-                n.addUse( this );
-    }
-
-    // Easy reading label for debugger, e.g. "Add" or "Region" or "EQ"
-    public abstract String label();
-
-    public String p(int depth) { return IRPrinter.prettyPrint(this,depth); }
-
-    public boolean isMultiHead() { return false; }
-    public boolean isMultiTail() { return false; }
-
-    // ------------------------------------------------------------------------
-    // Graph Node & Edge manipulation
-
-    @Override public String typeName() { return _type==null ? null : _type.toString(); }
-
-    /**
-     * Gets the ith input node
-     * @param i Offset of the input node
-     * @return Input node or null
-     */
-    public Node in(int i) { return _inputs.get(i); }
-    public Node out(int i) { return _outputs.get(i); }
-    @Override public Ary<Node> outs() { return _outputs; }
-
-    public int nIns() { return _inputs.size(); }
-
-    public int nOuts() { return _outputs.size(); }
-
-    public boolean isUnused() { return nOuts() == 0; }
-
-    public CFGNode cfg0() { return (CFGNode)in(0); }
-
-    /**
-     * Change a <em>def</em> into a Node.  Keeps the edges correct, by removing
-     * the corresponding <em>use->def</em> edge.  This may make the original
-     * <em>def</em> go dead.  This function is co-recursive with {@link #kill}.
-     * <p>
-
-     * This method is the normal path for altering a Node, because it does the
-     * proper default edge maintenance.  It also <em>immediately</em> kills
-     * Nodes that lose their last use; at times care must be taken to avoid
-     * killing Nodes that are being used without having an output Node.  This
-     * definitely happens in the middle of recursive {@link #peephole} calls.
-     *
-     * @param idx which def to set
-     * @param new_def the new definition
-     * @return new_def for flow coding
-     */
-    public <N extends Node> N setDef(int idx, N new_def ) {
-        unlock();
-        Node old_def = in(idx);
-        if( old_def == new_def ) return new_def; // No change
-        // If new def is not null, add the corresponding def->use edge
-        // This needs to happen before removing the old node's def->use edge as
-        // the new_def might get killed if the old node kills it recursively.
-        if( new_def != null )
-            new_def.addUse(this);
-        // Set the new_def over the old (killed) edge
-        _inputs.set(idx,new_def);
-        if( old_def != null &&  // If the old def exists, remove a def->use edge
-            old_def.delUse(this) ) // If we removed the last use, the old def is now dead
-            old_def.kill();     // Kill old def
-        moveDepsToWorklist();
-        // Return new_def for easy flow-coding
-        return new_def;
-    }
-
-    // Remove the numbered input, compressing the inputs in-place.  This
-    // shuffles the order deterministically - which is suitable for Region and
-    // Phi, but not for every Node.  If the def goes dead, it is recursively
-    // killed, which may include 'this' Node.
-    Node delDef(int idx) {
-        unlock();
-        Node old_def = in(idx);
-        _inputs.del(idx);
-        if( old_def.delUse(this) ) // If we removed the last use, the old def is now dead
-            old_def.kill();     // Kill old def
-        old_def.moveDepsToWorklist();
-        return this;
-    }
-
-    // Insert the numbered input, sliding other inputs to the right
-    Node insertDef(int idx, Node new_def) {
-        _inputs.add(idx,null);
-        return setDef(idx,new_def);
-    }
-
-    /**
-     * Add a new def to an existing Node.  Keep the edges correct by
-     * adding the corresponding <em>def->use</em> edge.
-     *
-     * @param new_def the new definition, appended to the end of existing definitions
-     * @return new_def for flow coding
-     */
-    public Node addDef(Node new_def) {
-        unlock();
-        // Add use->def edge
-        _inputs.add(new_def);
-        // If new def is not null, add the corresponding def->use edge
-        if( new_def != null )
-            new_def.addUse(this);
-        return new_def;
-    }
-
-    // Breaks the edge invariants, used temporarily
-    protected <N extends Node> void addUse(N n) { _outputs.add(n); }
-
-    // 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.
-    // Error is 'use' does not exist; ok for 'use' to be null.
-    protected boolean delUse( Node use ) {
-        _outputs.del(_outputs.find(use));
-        moveDepsToWorklist(); // User-count and anti-dependence queries can now change.
-        return _outputs.isEmpty();
-    }
-
-    // Shortcut for "popping" until n nodes.  A "pop" is basically a
-    // setDef(last,null) followed by lowering the nIns() count.
-    void popUntil(int n) {
-        unlock();
-        while( nIns() > n ) {
-            Node old_def = _inputs.pop();
-            if( old_def != null &&     // If it exists and
-                old_def.delUse(this) ) // If we removed the last use, the old def is now dead
-                old_def.kill();        // Kill old def
-        }
-    }
-
-    /**
-     * Kill a Node with no <em>uses</em>, by setting all of its <em>defs</em>
-     * to null.  This may recursively kill more Nodes, and is basically dead
-     * code elimination.
-     */
-    public void kill( ) {
-        unlock();
-        moveDepsToWorklist();
-        assert isUnused();      // Has no uses, so it is dead
-        _type=null;             // Flag as dead
-        while( nIns()>0 ) { // Set all inputs to null, recursively killing unused Nodes
-            Node old_def = _inputs.removeLast();
-            if( old_def != null ) {
-                IterPeeps.add(old_def);// Revisit neighbor because removed use
-                if( old_def.delUse(this) ) // If we removed the last use, the old def is now dead
-                    old_def.kill();        // Kill old def
-            }
-        }
-        assert isDead();        // Really dead now
-    }
-
-    // Mostly used for asserts and printing.
-    public boolean isDead() { return isUnused() && nIns()==0 && _type==null; }
-
-    // Shortcuts to stop DCE mid-parse
-    // Add bogus null use to keep node alive
-    public <N extends Node> N keep() { addUse(null); return (N)this; }
-    // Remove bogus null.
-    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() {
-        if( unkeep().isUnused() )
-            kill();
-    }
-
-    // Replace self with nnn in the graph, making 'this' go dead
-    public void subsume( Node nnn ) {
-        assert nnn!=this;
-        while( nOuts() > 0 ) {
-            Node n = _outputs.removeLast();
-            n.unlock();
-            int idx = n._inputs.find(this);
-            n._inputs.set(idx,nnn);
-            n.moveDepsToWorklist(); // Rewiring can change a dependent query without changing type.
-            nnn.addUse(n);
-            IterPeeps.addAll(n._outputs);
-        }
-        kill();
-    }
-
-    // ------------------------------------------------------------------------
-    // Graph-based optimizations
-
-    /**
-     * Try to peephole at this node and return a better replacement Node.
-     * Always returns some not-null Node (often this).
-     */
-    public final Node peephole() {
-        var obs = IterPeeps.midAssert() ? null : Parser.PARSER == null ? null : Parser.PARSER._obs;
-        if( obs != null ) obs.before(this);
-        Node n = peepholeOpt();
-        Node rez = n == null ? this : deadCodeElim(n.peephole());
-        if( obs != null ) obs.after(this, n == null ? null : rez, false);
-        return rez;
-    }
-
-    /**
-     * Try to peephole at this node and return a better replacement Node if
-     * possible.  We compute a {@link Type} and then check and replace:
-     * <ul>
-     * <li>if the Type {@link Type#isConstant}, we replace with a {@link ConstantNode}</li>
-     * <li>in a future chapter we will look for a
-     * <a href="https://en.wikipedia.org/wiki/Common_subexpression_elimination">Common Subexpression</a>
-     * to eliminate.</li>
-     * <li>we ask the Node for a better replacement.  The "better replacement"
-     * is things like {@code (1+2)} becomes {@code 3} and {@code (1+(x+2))} becomes
-     * {@code (x+(1+2))}.  By canonicalizing expressions we fold common addressing
-     * math constants, remove algebraic identities and generally simplify the
-     * code. </li>
-     *
-     * Unlike peephole above, this explicitly returns null for no-change, or not-null
-     * for a better replacement (which can be this).
-     * </ul>
-     */
-    public final Node peepholeOpt( ) {
-        ITER_CNT++;
-        // Compute initial or improved Type
-        Type old = setType(compute());
-
-        // Replace constant computations from non-constants with a constant node
-        if( !(this instanceof ConstantNode) && !(this instanceof XCtrlNode) && _type.isHighOrConst() )
-            return (_type==Type.XCONTROL ? new XCtrlNode() : new ConstantNode(_type)).peepholeOpt();
-
-        // Global Value Numbering
-        if( _hash==0 ) {
-            Node n = GVN.get(this); // Will set _hash as a side effect
-            if( n==null )
-                GVN.put(this,this);  // Put in table now
-            else {
-                // Because of random worklist ordering, the two equal nodes
-                // might have different types.  Because of monotonicity, both
-                // types are valid.  To preserve monotonicity, the resulting
-                // shared Node has to have the best of both types.
-                n.setType(n._type.join(_type));
-                _hash = 0; // Clear, since it never went in the table
-                return deadCodeElim(n);// Return previous; does Common Subexpression Elimination
-            }
-        }
-
-        // Ask each node for a better replacement
-        Node n = idealize();
-        if( n != null )         // Something changed
-            return n;           // Report progress
-
-        if( old==_type ) ITER_NOP_CNT++;
-        return old==_type ? null : this; // Report progress
-    }
-    public static int ITER_CNT, ITER_NOP_CNT;
-
-    // m is the new Node, self is the old.
-    // Return 'm', which may have zero uses but is alive nonetheless.
-    // If self has zero uses (and is not 'm'), {@link #kill} self.
-    private Node deadCodeElim(Node m) {
-        // If self is going dead and not being returned here (Nodes returned
-        // from peephole commonly have no uses (yet)), then kill self.
-        if( m != this && isUnused() && !isDead() ) {
-            // Killing self - and since self recursively kills self's inputs we
-            // might end up killing 'm', which we are returning as a live Node.
-            // So we add a bogus extra null output edge to stop kill().
-            m.keep();      // Keep m alive
-            kill();        // Kill self because replacing with 'm'
-            m.unkeep();    // Okay to peephole m
-        }
-        return m;
-    }
-
-    /**
-     * This function needs to be
-     * <a href="https://en.wikipedia.org/wiki/Monotonic_function">Monotonic</a>
-     * as it is part of a Monotone Analysis Framework.
-     * <a href="https://www.cse.psu.edu/~gxt29/teaching/cse597s21/slides/08monotoneFramework.pdf">See for example this set of slides</a>.
-     * <p>
-     * For Chapter 2, all our Types are really integer constants, and so all
-     * the needed properties are trivially true, and we can ignore the high
-     * theory.  Much later on, this will become important and allow us to do
-     * many fancy complex optimizations trivially... because theory.
-     * <p>
-     * {@link #compute()} needs to be stand-alone, and cannot recursively call compute
-     * on its inputs, because programs are cyclic (have loops!) and this will just
-     * infinitely recurse until stack overflow.  Instead, compute typically
-     * computes a new type from the {@link #_type} field of its inputs.
-     */
-    public abstract Type compute();
-
-    // Set the type.  Assert monotonic progress.
-    // If changing, add users to worklist.
-    public Type setType(Type type) {
-        Type old = _type;
-        assert old==null || type.isa(old); // Since _type not set, can just re-run this in assert in the debugger
-        if( old == type ) return old;
-        _type = type;       // Set _type late for easier assert debugging
-        IterPeeps.addAll(_outputs);
-        moveDepsToWorklist();
-        return old;
-    }
-
-    /**
-     * This function rewrites the current Node into a more "idealized" form.
-     * This is the bulk of our peephole rewrite rules, and we use this to
-     * e.g. turn arbitrary collections of adds and multiplies with mixed
-     * constants into a normal form that's easy for hardware to implement.
-     * Example: An array addressing expression:
-     * <pre>   ary[idx+1]</pre>
-     * might turn into Sea-of-Nodes IR:
-     * <pre>   (ary+12)+((idx+1) * 4)</pre>
-     * This expression can then be idealized into:
-     * <pre>   ary + ((idx*4) + (12 + (1*4)))</pre>
-     * And more folding:
-     * <pre>   ary + ((idx<<2) + 16)</pre>
-     * And during code-gen:
-     * <pre>   MOV4 Rary,[Ridx<<2 +16] // or some such hardware-specific notation </pre>
-     * <p>
-     * {@link #idealize} has a very specific calling convention:
-     * <ul>
-     * <li>If NO change is made, return {@code null}
-     * <li>If ANY change is made, return not-null; this can be {@code this}
-     * <li>The returned Node does NOT call {@link #peephole} on itself; the {@link #peephole} call will recursively peephole it.
-     * <li>Any NEW nodes that are not directly returned DO call {@link #peephole}.
-     * </ul>
-     * <p>
-     * Examples:
-     * <table border="3">
-     * <tr><th>    before       </th><th>       after     </th><th>return </th><th>comment  </th></tr>
-     * <tr><td>{@code (x+5)    }</td><td>{@code   (x+5)  }</td><td>{@code null  }</td><td>No change</td></tr>
-     * <tr><td>{@code (5+x)    }</td><td>{@code   (x+5)  }</td><td>{@code this  }</td><td>Swapped arguments</td></tr>
-     * <tr><td>{@code ((x+1)+2)}</td><td>{@code (x+(1+2))}</td><td>{@code (x+_) }</td><td>Returns 2 new Nodes</td></tr>
-     * </table>
-     *
-     * The last entry deserves more discussion.  The new Node {@code (1+2)}
-     * created in {@link #idealize} calls {@link #peephole} (which then folds
-     * into a constant).  The other new Node {@code (x+3)} does not call
-     * peephole, because it is returned and peephole itself will recursively
-     * call peephole.
-     * <p>
-     * Since idealize calls peephole and peephole calls idealize, you must be
-     * careful that all idealizations are <em>monotonic</em>: all transforms
-     * remove some feature, so that the set of available transforms always
-     * shrinks.  If you don't, you risk an infinite peephole loop!
-     *
-     * @return Either a new or changed node, or null for no changes.
-     */
-    public abstract Node idealize();
-
-    // Some of the peephole rules get complex, and search further afield than
-    // just the nearest neighbor.  These peepholes can fail the pattern match
-    // on a node some distance away, and if that node ever changes we should
-    // retry the peephole.  Track a set of Nodes dependent on `this`, and
-    // revisit them if `this` changes.
-    Ary<Node> _deps;
-    public int nDeps() { return _deps == null ? 0 : _deps.size(); }
-    public Node dep(int idx) { return _deps.get(idx); }
-
-    /**
-     * Add a node to the list of dependencies.  Only add it if its 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.
-     */
-    Node addDep( Node dep ) {
-        return addDep(dep,false);
-    }
-
-    // A bulk Phi inspects its users' partitions. Def-to-use propagation does
-    // not revisit that producer when an immediate user's partition changes.
-    Node addDepForwards(Node dep) { return addDep(dep,true); }
-
-    private Node addDep(Node dep, boolean forwards) {
-        // Running peepholes during the big assert cannot have side effects
-        // like adding dependencies.
-        if( IterPeeps.midAssert() ) return this;
-        var obs = IterPeeps.midAssert() ? null : Parser.PARSER == null ? null : Parser.PARSER._obs;
-        if( obs != null ) obs.dep(this, dep);
-        if( _deps==null ) _deps = new Ary<>(Node.class);
-        if( _deps   .find(dep) != -1 ) return this; // Already on list
-        if( !forwards && _inputs .find(dep) != -1 ) return this; // No need for deps on immediate neighbors
-        if( !forwards && _outputs.find(dep) != -1 ) return this;
-        _deps.add(dep);
-        return this;
-    }
-
-    // Move the dependents onto a worklist, and clear for future dependents.
-    public void moveDepsToWorklist( ) {
-        if( _deps==null ) return;
-        IterPeeps.addAll(_deps);
-        _deps.clear();
-    }
-
-    // Global Value Numbering.  Hash over opcode and inputs; hits in this table
-    // are structurally equal.
-    public static final HashMap<Node,Node> GVN = new HashMap<>();
-
-    // 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 ) {
-        if( o==this ) return true;
-        if( o.getClass() != getClass() ) return false;
-        Node n = (Node)o;
-        int len = _inputs.size();
-        if( len != n._inputs.size() ) return false;
-        for( int i=0; i<len; i++ )
-            if( in(i) != n.in(i) )
-                return false;
-        return eq(n);
-    }
-    // Subclasses add extra checks (such as ConstantNodes have same constant),
-    // and can assume "this!=n" and has the same Java class.
-    boolean eq( Node n ) { return true; }
-
-    // Cached hash.  If zero, then not computed AND this Node is NOT in the GVN
-    // table - and can have its edges hacked (which will change his hash
-    // anyway).  If Non-Zero then this Node is IN the GVN table, or is being
-    // probed to see if it can be inserted.  His edges are "locked", because
-    // hacking his edges will change his hash.
-    int _hash;
-
-    // If the _hash is set, then the Node is in the GVN table; remove it.
-    void unlock() {
-        if( _hash==0 ) return;
-        Node old = GVN.remove(this); // Pull from table
-        assert old==this;
-        _hash=0;                // Out of table now
-    }
-
-    // Hash of opcode and inputs
-    @Override public final int hashCode() {
-        if( _hash != 0 ) return _hash;
-        int hash = hash();
-        for( Node n : _inputs )
-            if( n != null )
-                hash = hash ^ (hash<<17) ^ (hash>>13) ^ n._nid;
-        if( hash==0 ) hash = 0xDEADBEEF; // Bad hash, so use some junky thing
-        return (_hash=hash);
-    }
-    // Subclasses add extra hash info (such as ConstantNodes constant)
-    int hash() { return 0; }
-
-    // ------------------------------------------------------------------------
-    //
-
-    /** Is this Node Memory related */
-    public boolean isMem() { 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
-
-    // Swap inputs without letting either input go dead during the swap.
-    Node swap12() {
-        unlock();               // Hash is order dependent
-        Node tmp = in(1);
-        _inputs.set(1,in(2));
-        _inputs.set(2,tmp);
-        return this;
-    }
-
-    /**
-     * Does this node contain all constants?  Ignores in(0), as is usually
-     * control.  In an input is not a constant, we add dep as a dependency to
-     * it because dep can make progress if the input becomes a constant later.
-     * It is sufficient for one of the non-const inputs to have the dependency,
-     * so we don't bother checking the rest.
-     */
-    boolean allCons(Node dep) {
-        for( int i=1; i<nIns(); i++ )
-            if( !(in(i)._type.isConstant()) ) {
-                in(i).addDep(dep); // If in(i) becomes a constant later, will trigger some peephole
-                return false;
-            }
-        return true;
-    }
-
-    // Make a shallow copy (same class) of this Node, with given inputs and
-    // empty outputs and a new Node ID.  The original inputs are ignored.
-    // Does not need to be implemented in isCFG() nodes.
-    Node copy(Node lhs, Node rhs) { throw Utils.TODO("Binary ops need to implement copy"); }
-
-    // Exact-class copy preserving operation attributes, with fresh identity
-    // and no edges, dependencies, or GVN membership.
-    public final Node copyEmpty() {
-        Node n;
-        try { n = (Node)clone(); }
-        catch( CloneNotSupportedException e ) { throw new AssertionError(e); }
-        n._nid = UNIQUE_ID++;
-        n._inputs = new Ary<>(Node.class);
-        n._outputs = new Ary<>(Node.class);
-        n._deps = null;
-        n._hash = 0;
-        return n;
-    }
-
-    // Report any post-optimize errors
-    String err() { return null; }
-
-    /**
-     * Used to allow repeating tests in the same JVM.  This just resets the
-     * Node unique id generator, and is done as part of making a new Parser.
-     */
-    public static void reset() {
-        UNIQUE_ID = 1;
-        GVN.clear();
-        ITER_CNT = ITER_NOP_CNT = 0;
-    }
-
-    // Utility to walk the entire graph applying a function; return the first
-    // not-null result.
-    private static final BitSet WVISIT = new BitSet();
-    final public <E> E walk( Function<Node,E> pred ) {
-        assert WVISIT.isEmpty();
-        E rez = _walk(pred);
-        WVISIT.clear();
-        return rez;
-    }
-
-    private <E> E _walk( Function<Node,E> pred ) {
-        if( WVISIT.get(_nid) ) return null; // Been there, done that
-        WVISIT.set(_nid);
-        E x = pred.apply(this);
-        if( x != null ) return x;
-        for( Node def : _inputs  )  if( def != null && (x = def._walk(pred)) != null ) return x;
-        for( Node use : _outputs )  if( use != null && (x = use._walk(pred)) != null ) return x;
-        return null;
-    }
-
-    /**
-     * Debugging utility to find a Node by index
-     */
-    public Node find(int nid) {
-        return walk( n -> n._nid==nid ? n : null );
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/NotNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/NotNode.java
deleted file mode 100644
index b9cf4904..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/NotNode.java
+++ /dev/null
@@ -1,39 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.type.*;
-
-public class NotNode extends Node {
-    public NotNode(Node in) { super(null, in); }
-
-    @Override public String label() { return "Not"; }
-
-    @Override protected String format() { return "(!%1)"; }
-
-    @Override
-    public Type compute() {
-        Type t0 = in(1)._type;
-        if( t0.isHigh() ) return TypeInteger.BOOL.dual();
-        switch( t0 ) {
-        case TypeInteger i0:  return i0._max < 0 || i0._min > 0 ? TypeInteger.FALSE : (i0==TypeInteger.ZERO ? TypeInteger.TRUE : TypeInteger.BOOL);
-        case TypeFloat   i0:
-            return i0.isConstant() ? TypeInteger.constant(i0.value()==0 ? 1 : 0) : TypeInteger.BOOL;
-        case TypeMemPtr p0:
-            // top->top, bot->bot, null->1, *void->0, not-null ptr->0, ptr/nil->bot
-            // If input in null then true
-            // If input is not null ptr then false
-            if( p0 == TypeMemPtr.NULLPTR ) return TypeInteger.TRUE;
-            if( !p0._nil )                 return TypeInteger.FALSE;
-            return TypeInteger.BOOL;
-        case Type t:
-            if( t0.getClass() != Type.class )
-                // Only doing NOT on ints and ptrs
-                throw Utils.TODO();
-            return TypeInteger.BOOL;
-        }
-    }
-
-    @Override
-    public Node idealize() { return null; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/OrNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/OrNode.java
deleted file mode 100644
index 5be31b88..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/OrNode.java
+++ /dev/null
@@ -1,58 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class OrNode extends Node {
-    public OrNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Or"; }
-
-    @Override protected String format() { return "(%1|%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i0 &&
-            t2 instanceof TypeInteger i1 ) {
-            if( i0.isConstant() && i1.isConstant() )
-                return TypeInteger.constant(i0.value()|i1.value());
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t1 = lhs._type;
-        Type t2 = rhs._type;
-
-        // Or of 0.  We do not check for (0|x) because this will already
-        // canonicalize to (x|0)
-        if( t2.isConstant() && t2 instanceof TypeInteger i && i.value()==0 )
-            return lhs;
-
-        // Move constants to RHS: con*arg becomes arg*con
-        if ( t1.isConstant() && !t2.isConstant() )
-            return swap12();
-
-        // Do we have ((x | (phi cons)) | con) ?
-        // Do we have ((x | (phi cons)) | (phi cons)) ?
-        // Push constant up through the phi: x | (phi con0|con0 con1|con1...)
-        Node phicon = AddNode.phiCon(this,true);
-        if( phicon!=null ) return phicon;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new OrNode(lhs,rhs); }
-    @Override String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '|' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '|' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/OutNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/OutNode.java
deleted file mode 100644
index dbac136b..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/OutNode.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.simple.Ary;
-
-public interface OutNode {
-    Ary<Node> outs();
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/PhiNode.java
deleted file mode 100644
index 942748e7..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/PhiNode.java
+++ /dev/null
@@ -1,201 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
-import com.seaofnodes.simple.Utils;
-
-
-public class PhiNode extends Node {
-
-    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.
-    final Type _declaredType;
-
-    public PhiNode(String label, Type declaredType, Node... inputs) { super(inputs); _label = label;  assert declaredType!=null; _declaredType = declaredType; }
-
-    public static PhiNode make(String label, Type type, Node... inputs) {
-        return type instanceof TypeMem ? new BulkMemPhiNode(label,inputs) : new PhiNode(label,type,inputs);
-    }
-
-    @Override public String label() { return "Phi_"+MemOpNode.mlabel(_label); }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        if( !(region() instanceof RegionNode r) || r.inProgress() )
-            p.p("Z");
-        p.p("Phi(");
-        for( Node in : _inputs ) p.n(in).p(",");
-        return p.unchar(',').close();
-    }
-
-    public CFGNode region() { return (CFGNode)in(0); }
-    @Override public boolean isMultiTail() { return true; }
-    @Override public boolean isMem() { return _declaredType instanceof TypeMem; }
-
-    @Override
-    public Type compute() {
-        if( !(region() instanceof RegionNode r) )
-            return region()._type==Type.XCONTROL ? (_type instanceof TypeMem ? TypeMem.TOP : Type.TOP) : _type;
-        // During parsing Phis have to be computed type pessimistically.
-        if( r.inProgress() ) return _declaredType;
-        // Set type to local top of the starting type
-        Type t = _declaredType.lub();
-        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.
-            if( r.in(i).addDep(this)._type != Type.XCONTROL )
-                t = t.meet(in(i)._type);
-        return t;
-    }
-
-    @Override
-    public Node idealize() {
-        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 we have only a single unique input, become it.
-        Node live = singleUniqueInput();
-        if (live != null)
-            return live;
-
-        // Phi(op(a,b,...),op(c,d,...)) -> op(Phi(a,c),Phi(b,d),...).
-        Node down;
-        if( same_op() && (down=drop_same_op())!=null ) return down;
-
-        // If merging Phi(N, cast(N)) - we are losing the cast JOIN effects, so just remove.
-        if( nIns()==3 ) {
-            if( in(1) instanceof CastNode cast && cast.in(1).addDep(this)==in(2) ) return in(2);
-            if( in(2) instanceof CastNode cast && cast.in(1).addDep(this)==in(1) ) return 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.
-        if( nIns()==3 ) {
-            int nullx = -1;
-            if( in(1)._type == in(1)._type.makeInit() ) nullx = 1;
-            if( in(2)._type == in(2)._type.makeInit() ) nullx = 2;
-            if( nullx != -1 ) {
-                Node val = in(3-nullx);
-                if( r.idom(this).addDep(this) instanceof IfNode iff && iff.pred().addDep(this)==val ) {
-                    // Must walk the idom on the null side to make sure we hit False.
-                    CFGNode idom = (CFGNode)r.in(nullx);
-                    while( idom.nIns() > 0 && idom.in(0) != iff ) idom = idom.idom();
-                    if( idom instanceof CProjNode proj && proj._idx==1 )
-                        return val;
-                }
-            }
-        }
-
-        return null;
-    }
-
-    private boolean same_op() {
-        Node op = in(1);
-        if( op instanceof CFGNode || op instanceof ConstantNode || op instanceof PhiNode ||
-            op instanceof ProjNode || op instanceof NewNode || op instanceof ScopeNode || op instanceof MemMergeNode ) return false;
-        // A bulk Phi must split its aliases before factoring precise Stores.
-        if( this instanceof BulkMemPhiNode ) return false;
-        // Bulk splitting currently identifies parallel slices by Region/alias.
-        // Factoring can introduce another slice at a different memory point;
-        // wait until that Region's bulk partitioning has finished.
-        if( op instanceof MemOpNode )
-            for( Node use : region()._outputs )
-                if( use instanceof BulkMemPhiNode ) {
-                    use.addDepForwards(this);
-                    return false;
-                }
-        Node busy = null;
-        for( int i=1; i<nIns(); i++ ) {
-            Node n = in(i);
-            if( region().in(i).addDep(this)._type==Type.XCONTROL ||
-                op.getClass()!=n.getClass() || n.nIns()!=op.nIns() || n.in(0)!=null || !op.eq(n) ) return false;
-            if( n instanceof MemOpNode mem && !mem.canDrop((MemOpNode)op,this) ) return false;
-            // Moving a Store must remove the old effect, not duplicate it.
-            // Allow one shared arm: the other arms disappear into the single
-            // factored operation, usually reducing the total operation count.
-            n.addDepForwards(this);
-            if( n.nOuts()>1 ) {
-                for( Node use : n._outputs )
-                    if( use!=null && use!=this ) use.addDepForwards(this);
-                if( n instanceof StoreNode || busy!=null ) return false;
-                busy=n;
-            }
-            for( int j=1; j<n.nIns(); j++ )
-                if( n.in(j) instanceof ScopeNode || ((n.in(j)==null) != (op.in(j)==null)) ) return false;
-        }
-        return true;
-    }
-
-    private Node drop_same_op() {
-        Node op = in(1), cp = op.copyEmpty();
-        cp._type = null;
-        cp.addDef(null);
-        for( int j=1; j<op.nIns(); j++ ) {
-            Node x = op.in(j);
-            boolean different = false;
-            for( int i=2; i<nIns(); i++ )
-                if( in(i).in(j)!=x ) different=true;
-            if( different ) {
-                Node[] ins = new Node[nIns()];
-                ins[0] = region();
-                Type t = Type.TOP;
-                for( int i=1; i<nIns(); i++ ) {
-                    ins[i] = in(i).in(j);
-                    t = t.meet(ins[i]._type);
-                }
-                PhiNode phi = j==1 && op instanceof MemOpNode mem
-                    ? new MemPhiNode(_label,mem._alias,ins)
-                    : PhiNode.make(_label,t.glb(),ins);
-                x = phi.peephole();
-            }
-            cp.addDef(x);
-        }
-        // Factoring must not widen the result (e.g. correlated And operands).
-        if( cp.compute().isa(compute()) ) return cp;
-        cp.kill();
-        return null;
-    }
-
-    /**
-     * If only single unique input, return it
-     */
-    private Node singleUniqueInput() {
-        if( region() instanceof LoopNode loop && loop.entry()._type == Type.XCONTROL )
-            return null;    // Dead entry loops just ignore and let the loop collapse
-        Node live = null;
-        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.
-            if( region().in(i).addDep(this)._type != Type.XCONTROL && in(i) != this )
-                if( live == null || live == in(i) ) live = in(i);
-                else return null;
-        }
-        return live;
-    }
-
-    @Override
-    boolean allCons(Node dep) {
-        if( !(region() instanceof RegionNode r) ) return false;
-        // When the region completes (is no longer in progress) the Phi can
-        // become a "all constants" Phi, and the "dep" might make progress.
-        addDep(dep);
-        if( r.inProgress() ) return false;
-        return super.allCons(dep);
-    }
-
-    // True if last input is null
-    public final boolean inProgress() {
-        return in(nIns()-1) == null;
-    }
-
-    // Never equal if inProgress
-    @Override boolean eq( Node n ) {
-        return !inProgress();
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ProjNode.java
deleted file mode 100644
index 668e20ad..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ProjNode.java
+++ /dev/null
@@ -1,47 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
-import com.seaofnodes.simple.type.TypeTuple;
-
-
-public class ProjNode extends Node {
-
-    // Which slice of the incoming multipart value
-    public final int _idx;
-
-    // Debugging label
-    public final String _label;
-
-    public ProjNode(Node ctrl, int idx, String label) {
-        super(ctrl);
-        _idx = idx;
-        _label = label;
-    }
-
-    @Override public String label() { return _label; }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) { return p.p(_label); }
-
-    @Override public CFGNode cfg0() { return in(0).cfg0(); }
-
-    @Override public boolean isMultiTail() { return in(0).isMultiHead(); }
-    @Override public boolean isMem() { return _type instanceof TypeMem; }
-
-    @Override
-    public Type compute() {
-        Type t = in(0)._type;
-        return t instanceof TypeTuple tt ? tt._types[_idx] : Type.BOTTOM;
-    }
-
-    @Override public Node idealize() { return null; }
-
-    @Override
-    boolean eq( Node n ) { return _idx == ((ProjNode)n)._idx; }
-
-    @Override
-    int hash() { return _idx; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
deleted file mode 100644
index fa4e0242..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMemPtr;
-
-
-/**
- * Cast a pointer to read-only
- */
-public class ReadOnlyNode extends Node {
-    public ReadOnlyNode( Node n ) { super(null,n); }
-    @Override public String label() { return "ReadOnly"; }
-
-    @Override protected String format() { return "(const)%1"; }
-    @Override public Type compute() {
-        Type t = in(1)._type;
-        return t instanceof TypeMemPtr tmp ? tmp.makeRO() : t;
-    }
-
-    @Override public Node idealize() {
-        if( in(1)._type instanceof TypeMemPtr tmp && tmp.isFinal() )
-            return in(1);
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/RegionNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/RegionNode.java
deleted file mode 100644
index 27866139..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/RegionNode.java
+++ /dev/null
@@ -1,119 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.type.Type;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashSet;
-
-public class RegionNode extends CFGNode {
-
-    public RegionNode(Node... nodes) { super(nodes); }
-
-    @Override
-    public String label() { return "Region"; }
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.p(label());
-    }
-
-    @Override public boolean isMultiHead() { return true; }
-    @Override public boolean blockHead() { return true; }
-
-    @Override
-    public Type compute() {
-        if( inProgress() ) return Type.CONTROL;
-        Type t = Type.XCONTROL;
-        for (int i = 1; i < nIns(); i++)
-            t = t.meet(in(i)._type);
-        return t;
-    }
-
-    @Override
-    public Node idealize() {
-        if( inProgress() ) return null;
-        // Delete dead paths into a Region
-        int path = findDeadInput();
-        if( path != 0 &&
-            // Do not delete the entry path of a loop (ok to remove the back
-            // edge and make the loop a single-entry Region which folds away
-            // the Loop).  Folding the entry path confused the loop structure,
-            // moving the backedge to the entry point.
-            !(this instanceof LoopNode loop && loop.entry()==in(path)) ) {
-            // Cannot use the obvious output iterator here, because a Phi
-            // deleting an input might recursively delete *itself*.  This
-            // shuffles the output array, and we might miss iterating an
-            // unrelated Phi. So on rare occasions we repeat the loop to get
-            // all the Phis.
-            int nouts = 0;
-            while( nouts != nOuts() ) {
-                nouts = nOuts();
-                for( int i=0; i<nOuts(); i++ )
-                    if( out(i) instanceof PhiNode phi && phi.nIns()==nIns() ) {
-                        phi.delDef(path);
-                        IterPeeps.addAll(phi._outputs);
-                    }
-            }
-            return isDead() ? Parser.XCTRL : delDef(path);
-        }
-        // If down to a single input, become that input
-        if( nIns()==2 && !hasPhi() )
-            return in(1);       // Collapse if no Phis; 1-input Phis will collapse on their own
-
-        // If a CFG diamond with no merging, delete: "if( pred ) {} else {};"
-        if( !hasPhi() &&       // No Phi users, just a control user
-            in(1) instanceof CProjNode p1 &&
-            in(2) instanceof CProjNode p2 &&
-            p1.addDepForwards(this).in(0)==p2.addDepForwards(this).in(0) &&
-            p1.in(0) instanceof IfNode iff )
-            return iff.ctrl();
-
-        return null;
-    }
-
-    private int findDeadInput() {
-        for( int i=1; i<nIns(); i++ )
-            if( in(i)._type==Type.XCONTROL )
-                return i;
-        return 0;               // All inputs alive
-    }
-
-    private boolean hasPhi() {
-        for( Node phi : _outputs )
-            if( phi instanceof PhiNode )
-                return true;
-        return false;
-    }
-
-    // Immediate dominator of Region is a little more complicated.
-    @Override public int idepth() {
-        if( _idepth!=0 ) return _idepth;
-        int depth=0;
-        for( Node n : _inputs )
-            if( n!=null )
-                depth = Math.max(depth,((CFGNode)n).idepth()+1);
-        return cacheIDepth(depth);
-    }
-
-    @Override public CFGNode idom(Node dep) {
-        CFGNode lca = null;
-        // Recompute from predecessors: CFG edits can change the dominator.
-        for( int i=1; i<nIns(); i++ )
-            lca = cfg(i).domLCA(lca,dep);
-        return lca;
-    }
-
-    // True if last input is null
-    public final boolean inProgress() {
-        return nIns()>1 && in(nIns()-1) == null;
-    }
-
-    // Never equal if inProgress
-    @Override boolean eq( Node n ) {
-        return !inProgress();
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ReturnNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
deleted file mode 100644
index 6c773c42..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
+++ /dev/null
@@ -1,42 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.*;
-
-
-/** Keeps all preceding memory effects and the return value alive: {ctrl, $mem, value}. */
-public class ReturnNode extends CFGNode {
-
-    public ReturnNode(Node ctrl, Node data, ScopeNode scope) {
-        // A synthetic never-taken loop exit has no source scope.
-        super(ctrl, scope == null ? null : scope.mem(), data);
-    }
-
-    public Node ctrl() { return in(0); }
-    public Node mem () { return in(1); }
-    public Node expr() { return in(2); }
-
-    @Override
-    public String label() { return "Return"; }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        p.p("return ");
-        p.n(expr());
-        return p.p(";");
-    }
-
-    @Override
-    public Type compute() {
-        // Return exposes the complete memory state.
-        return TypeTuple.make(ctrl()._type,TypeMem.BOT,expr()._type);
-    }
-
-    @Override
-    public Node idealize() {
-        if( ctrl()._type==Type.XCONTROL )
-            return ctrl();
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java b/chapter17/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
deleted file mode 100644
index 78e7698c..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
+++ /dev/null
@@ -1,33 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-
-public class RoundF32Node extends Node {
-    public RoundF32Node(Node lhs) { super(null, lhs); }
-
-    @Override public String label() { return "RoundF32"; }
-
-    @Override protected String format() { return "((f32)%1)"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeFloat i0 && i0.isConstant() )
-            return TypeFloat.constant((float)i0.value());
-        return in(1)._type;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Type t1 = lhs._type;
-
-        // RoundF32 of float
-        if( t1 instanceof TypeFloat tf && tf._sz==32 )
-            return lhs;
-
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/SarNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/SarNode.java
deleted file mode 100644
index 44233b3d..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/SarNode.java
+++ /dev/null
@@ -1,54 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class SarNode extends Node {
-    public SarNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Sar"; }
-
-    @Override protected String format() { return "(%1>>%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if (t1 instanceof TypeInteger i0 &&
-            t2 instanceof TypeInteger i1) {
-            if( i0 == TypeInteger.ZERO )
-                return TypeInteger.ZERO;
-            if( i0.isConstant() && i1.isConstant() )
-                return TypeInteger.constant(i0.value()>>i1.value());
-            if( i1.isConstant() ) {
-                int log = (int)i1.value();
-                return TypeInteger.make(-1L<<(63-log),(1L<<(63-log))-1);
-            }
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t2 = rhs._type;
-
-        // Sar of 0.
-        if( t2.isConstant() && t2 instanceof TypeInteger i && (i.value()&63)==0 )
-            return lhs;
-
-        // TODO: x >> 3 >> (y ? 1 : 2) ==> x >> (y ? 4 : 5)
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new SarNode(lhs,rhs); }
-    @Override String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '>>' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '>>' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ScopeNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
deleted file mode 100644
index b539ff87..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
+++ /dev/null
@@ -1,407 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.Ary;
-import com.seaofnodes.simple.type.*;
-import java.util.*;
-
-/**
- * The Scope node is purely a parser helper - it tracks names to nodes with a
- * stack of variable records.
- */
-public class ScopeNode extends Node {
-
-    /**
-     * The control is a name that binds to the currently active control
-     * node in the graph
-     */
-    public static final String CTRL = "$ctrl";
-    public static final String ARG0 = "arg";
-    public static final String MEM0 = "$mem";
-
-    /** The tracked fields are now complex enough to deserve a array-of-structs layout
-     */
-    public static class Var {
-        public final int _idx;       // index in containing scope
-        public final String _name;   // Declared name
-        private Type _type;          // Declared type
-        public final boolean _final; // Final field
-        public Var(int idx, String name, Type type, boolean xfinal) {
-            _idx = idx;
-            _name = name;
-            _type = type;
-            _final = xfinal;
-        }
-        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 lazyGLB() {
-            Type t = type();
-            return t instanceof TypeMemPtr ? t : t.glb();
-        }
-        @Override public String toString() {
-            return _type.toString()+(_final ? " ": " !")+_name;
-        }
-    }
-
-    public Node in(Var v) { return in(v._idx); }
-
-    @Override public Type compute() { return Type.BOTTOM; }
-    @Override public Node idealize() { return null; }
-
-    // All active/live variables in all nested scopes, all run together
-    public final Ary<Var> _vars;
-
-    // Size of each nested lexical scope
-    public final Ary<Integer> _lexSize;
-
-    // True if parsing inside of a constructor
-    public final Ary<Boolean> _inCons;
-
-    // Extra guards; tested predicates and casted results
-    private final Ary<Node> _guards;
-
-    // A new ScopeNode
-    public ScopeNode() {
-        _type = Type.BOTTOM;
-        _vars   = new Ary<>(Var    .class);
-        _lexSize= new Ary<>(Integer.class);
-        _inCons = new Ary<>(Boolean.class);
-        _guards = new Ary<>(Node   .class);
-    }
-
-    @Override public String label() { return "Scope"; }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        p.p("Scope[ ");
-        int j=1;
-        for( int i=0; i<nIns(); i++ ) {
-            if( j < _lexSize._len && i == _lexSize.at(j) ) { p.p("| "); j++; }
-            Var v = _vars.get(i);
-            p.p(v.type());
-            p.p(" ");
-            if( v._final ) p.p("!");
-            p.p(v._name);
-            p.p("=");
-            Node n = in(i);
-            while( n instanceof ScopeNode loop ) {
-                p.p("Lazy_");
-                n = loop.in(i);
-            }
-            p.n(n);
-            p.p(", ");
-        }
-        return p.unchar(", ").p("]");
-    }
-
-
-    public Node ctrl() { return in(0); }
-    public Node mem() { return in(lookup(MEM0)); }
-    public void mem(Node n) { update(MEM0,n); }
-
-    /**
-     * The ctrl of a ScopeNode is always bound to the currently active
-     * control node in the graph, via a special name '$ctrl' that is not
-     * a valid identifier in the language grammar and hence cannot be
-     * referenced in Simple code.
-     *
-     * @param n The node to be bound to '$ctrl'
-     *
-     * @return Node that was bound
-     */
-    public <N extends Node> N ctrl(N n) { return setDef(0,n); }
-
-    public void push() { push(false); }
-    public void push(boolean inCon) {
-        assert _lexSize._len==_inCons._len;
-        _lexSize.push(_vars.size());
-        _inCons.push(inCon);
-    }
-    public void pop() {
-        assert _lexSize._len==_inCons._len;
-        int n = _lexSize.pop();
-        _inCons.pop();
-        popUntil(n);
-        _vars.setLen(n);
-    }
-
-    public boolean inCon() { return _inCons.last(); }
-
-    // Find name in reverse, return an index into _vars or -1.  Linear scan
-    // instead of hashtable, but probably doesn't matter until the scan
-    // typically hits many dozens of variables.
-    int find( String name ) {
-        for( int i=_vars.size()-1; i>=0; i-- )
-            if( _vars.get(i)._name.equals(name) )
-                return i;
-        return -1;
-    }
-
-    /**
-     * Create a new variable name in the current scope
-     */
-    public boolean define( String name, Type declaredType, boolean xfinal, Node init ) {
-        assert name.charAt(0)!='$' || _lexSize.size()==1; // Later scopes do not define memory
-        if( _lexSize._len > 1 )
-            for( int i=_vars.size()-1; i>=_lexSize.last(); i-- )
-                if( _vars.get(i)._name.equals(name) )
-                    return false;   // Double define
-        _vars.add(new Var(nIns(),name,declaredType,xfinal));
-        addDef(init);
-        return true;
-    }
-
-    /**
-     * Lookup a name in all scopes starting from most deeply nested.
-     *
-     * @param name Name to be looked up
-     * @return null if not found, or the implementing Node
-     */
-    public Var lookup( String name ) {
-        int idx = find(name);
-        // -1 is missed in all scopes, not found
-        return idx == -1 ? null : update(_vars.at(idx),null);
-    }
-
-    /**
-     * If the name is present in any scope, then redefine else null
-     *
-     * @param name Name being redefined
-     * @param n    The node to bind to the name
-     */
-    public void update( String name, Node n ) {
-        int idx = find(name);
-        assert idx>=0;
-        update(_vars.at(idx),n);
-    }
-
-    public Var update( ScopeNode.Var v, Node st ) {
-        Node old = in(v._idx);
-        if( old instanceof ScopeNode loop ) {
-            // Lazy Phi!
-            Node def = loop.in(v._idx);
-            old = def instanceof PhiNode phi && loop.ctrl()==phi.region()
-                // Loop already has a real Phi, use it
-                ? def
-                // 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,PhiNode.make(v._name, v.lazyGLB(), loop.ctrl(), loop.in(loop.update(v,null)._idx),null).peephole());
-            setDef(v._idx,old);
-        }
-        if( st!=null ) setDef(v._idx,st); // Set new value
-        return v;
-    }
-
-    /**
-     * Duplicate a ScopeNode; including all levels, up to Nodes.  So this is
-     * neither shallow (would dup the Scope but not the internal HashMap
-     * tables), nor deep (would dup the Scope, the HashMap tables, but then
-     * also the program Nodes).
-     * <p>
-     * If the {@code loop} flag is set, the edges are filled in as the original
-     * Scope, as an indication of Lazy Phis at loop heads.  The goal here is to
-     * not make Phis at loop heads for variables which are never touched in the
-     * loop body.
-     * <p>
-     * The new Scope is a full-fledged Node with proper use<->def edges.
-     */
-    public ScopeNode dup() { return dup(false); }
-    public ScopeNode dup(boolean loop) {
-        ScopeNode dup = new ScopeNode();
-        // Our goals are:
-        // 1) duplicate the name bindings of the ScopeNode across all stack levels
-        // 2) Make the new ScopeNode a user of all the nodes bound
-        // 3) Ensure that the order of defs is the same to allow easy merging
-        dup._vars   .addAll(_vars   );
-        dup._lexSize.addAll(_lexSize);
-        dup._inCons .addAll(_inCons );
-        dup._guards .addAll(_guards );
-        // The dup'd guards all need dup'd keepers, to keep proper accounting
-        // when later removing all guards
-        for( Node n : _guards )
-            if( !(n instanceof CFGNode) )
-                n.keep();
-        dup.addDef(ctrl());     // Control input is just copied
-
-        // Memory is one binding, with the same lazy loop Phi as scalar names.
-        for( int i=1; i<nIns(); i++ )
-            dup.addDef(loop ? this : in(i));
-        return dup;
-    }
-
-    /**
-     * Merges the names whose node bindings differ, by creating Phi node for such names
-     * The names could occur at all stack levels, but a given name can only differ in the
-     * innermost stack level where the name is bound.
-     *
-     * @param that The ScopeNode to be merged into this
-     * @return A new node representing the merge point
-     */
-    public RegionNode mergeScopes(ScopeNode that) {
-        RegionNode r = (RegionNode) ctrl(new RegionNode(null,ctrl(), that.ctrl()).keep());
-        _merge(that,r);
-        that.kill();            // Kill merged scope
-        IterPeeps.add(r);
-        return r.unkeep();
-    }
-
-    private void _merge(ScopeNode that, RegionNode r) {
-        for( int i = 1; i < nIns(); 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 = _vars.at(i);
-                Node lhs = this.in(this.update(v,null));
-                Node rhs = that.in(that.update(v,null));
-                setDef(i, PhiNode.make(v._name, v.type(), r, lhs, rhs).peephole());
-            }
-    }
-
-    // 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 ) {
-        Node ctrl = ctrl();
-        assert ctrl instanceof LoopNode loop && loop.inProgress();
-        ctrl.setDef(2,back.ctrl());
-
-        _endLoop(this,back,exit);
-        back.kill();            // Loop backedge is dead
-        // Now one-time do a useless-phi removal
-        _useless();
-    }
-
-    // Fill in the backedge of any inserted Phis
-    void _endLoop( ScopeNode scope, Node back, Node exit ) {
-        for( int i=1; i<nIns(); i++ ) {
-            if( back.in(i) != scope ) {
-                PhiNode phi = (PhiNode)in(i);
-                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));
-        }
-    }
-
-
-    // Now one-time do a useless-phi removal
-    void _useless( ) {
-        for( int i=1; i<nIns(); i++ ) {
-            if( in(i) instanceof PhiNode phi ) {
-                // Do an eager useless-phi removal
-                Node in = phi.peephole();
-                IterPeeps.addAll(phi._outputs);
-                phi.moveDepsToWorklist();
-                if( in != phi ) {
-                    if( !phi.iskeep() ) // Keeping phi around for parser elsewhere
-                        phi.subsume(in);
-                    setDef(i,in); // Set the update back into Scope
-                }
-            }
-        }
-    }
-
-    // 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 ) {
-        assert ctrl instanceof CFGNode;
-        _guards.add(ctrl);      // Marker between guard sets
-        // add pred & its cast to the normal input list, with special Vars
-        if( ctrl._type == Type.XCONTROL || pred==null || pred.isDead() )
-            return;           // Dead, do not add any guards
-        _addGuards(ctrl,pred,invert);
-    }
-
-    private void _addGuards( Node ctrl, Node pred, boolean invert ) {
-        if( pred==null || pred.isDead() )
-            return;
-        // A single negation is handled below. For !!p (including p != null),
-        // also refine the underlying p without changing the Boolean result.
-        if( pred instanceof NotNode not && not.in(1) instanceof NotNode ) {
-            pred.keep();        // Recursive peepholes may rediscover this Not.
-            _addGuards(ctrl,not.in(1),!invert);
-            pred.unkeep();
-        }
-        // Invert the If conditional
-        if( invert )
-            pred = pred instanceof NotNode not ? not.in(1) : IterPeeps.add(new NotNode(pred).peephole());
-        // This is a zero/null test.
-        // Compute the positive test type.
-        Type tnz   = pred._type.nonZero();
-        Type tcast = tnz.join(pred._type);
-        if( tcast != pred._type ) {
-            Node cast = new CastNode(tnz,ctrl,pred.keep()).peephole().keep();
-            _guards.add(pred);
-            _guards.add(cast);
-            replace(pred,cast);
-        }
-
-        // Compute the negative test type.
-        if( pred instanceof NotNode not ) {
-            Node npred = not.in(1);
-            Type tzero = npred._type.makeZero();
-            Type tzcast= tzero.join(npred._type);
-            if( tzcast != npred._type ) {
-                Node cast = new CastNode(tzero,ctrl,npred.keep()).peephole().keep();
-                _guards.add(npred);
-                _guards.add( cast);
-                replace(npred,cast);
-            }
-        }
-    }
-
-    // Remove matching pred/cast pairs from this guarded region.
-    public void removeGuards( Node ctrl ) {
-        assert ctrl instanceof CFGNode;
-        // Pop the guards up to this region's marker.
-        while( true ) {
-            Node g = _guards.pop();
-            if( g == ctrl ) break;
-            if( g instanceof CFGNode ) continue;
-            g            .unkill(); // Pop/kill cast
-            _guards.pop().unkill(); // Pop/kill pred
-        }
-    }
-
-    // If we find a guarded instance of pred, replace with the upcasted version
-    public Node upcastGuard( Node pred ) {
-        // If finding an instanceof pred, replace with cast.
-        // Otherwise, just pred itself.
-        int i = _guards._len;
-        while( i > 0 ) {
-            Node  cast = _guards.at(--i);
-            if( cast instanceof CFGNode ) continue; // Marker between guard sets
-            Node xpred = _guards.at(--i);
-            if( xpred == pred )
-                return cast;
-        }
-        return pred;
-    }
-
-    // Kill guards also
-    @Override public void kill() {
-        for( Node n : _guards )
-            if( !(n instanceof CFGNode) )
-                n.unkill();
-        _guards.clear();
-        super.kill();
-    }
-
-
-    private Node replace( Node old, Node cast ) {
-        assert old!=null && old!=cast;
-        for( int i=0; i<nIns(); i++ )
-            if( in(i)==old )
-                setDef(i,cast);
-        return cast;
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ShlNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ShlNode.java
deleted file mode 100644
index 65dfe684..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ShlNode.java
+++ /dev/null
@@ -1,57 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-public class ShlNode extends Node {
-    public ShlNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Shl"; }
-
-    @Override protected String format() { return "(%1<<%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if (t1 instanceof TypeInteger i0 &&
-            t2 instanceof TypeInteger i1 ) {
-            if( i0 == TypeInteger.ZERO )
-                return TypeInteger.ZERO;
-            if( i0.isConstant() && i1.isConstant() )
-                return TypeInteger.constant(i0.value()<<i1.value());
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-
-        if( rhs._type instanceof TypeInteger shl && shl.isConstant() ) {
-            // Shl of 0.
-            if( (shl.value()&63)==0 )
-                return lhs;
-            // (x + c) << i  =>  (x << i) + (c << i)
-            if( lhs instanceof AddNode add && add.addDep(this).in(2)._type instanceof TypeInteger c && c.isConstant() && c!=TypeInteger.ZERO ) {
-                long sum = c.value() << shl.value();
-                if( Integer.MIN_VALUE <= sum  && sum <= Integer.MAX_VALUE )
-                    return new AddNode( new ShlNode(add.in(1),rhs).peephole(), Parser.con(sum) );
-            }
-        }
-
-        // TODO: x << 3 << (y ? 1 : 2) ==> x << (y ? 4 : 5)
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new ShlNode(lhs,rhs); }
-    @Override String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '<<' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '<<' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ShrNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ShrNode.java
deleted file mode 100644
index 757fd69e..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ShrNode.java
+++ /dev/null
@@ -1,50 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class ShrNode extends Node {
-    public ShrNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Shr"; }
-
-    @Override protected String format() { return "(%1>>>%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if (t1 instanceof TypeInteger i0 &&
-            t2 instanceof TypeInteger i1 ) {
-            if( i0 == TypeInteger.ZERO )
-                return TypeInteger.ZERO;
-            if( i0.isConstant() && i1.isConstant() )
-                return TypeInteger.constant(i0.value()>>>i1.value());
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t2 = rhs._type;
-
-        // Shr of 0.
-        if( t2.isConstant() && t2 instanceof TypeInteger i && (i.value()&63)==0 )
-            return lhs;
-
-        // TODO: x >>> 3 >>> (y ? 1 : 2) ==> x >>> (y ? 4 : 5)
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new ShrNode(lhs,rhs); }
-    @Override String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '>>>' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '>>>' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/StartNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/StartNode.java
deleted file mode 100644
index cefa2d72..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/StartNode.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.*;
-import java.util.HashSet;
-import static com.seaofnodes.simple.Utils.TODO;
-
-/** Start supplies control, whole memory, and the argument, in that order. */
-public class StartNode extends LoopNode implements MultiNode {
-
-    final Type _arg;
-
-    public StartNode(Type arg) { super(null); _arg = arg; _type = compute(); }
-
-    @Override public String label() { return "Start"; }
-
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.p(label());
-    }
-
-    @Override public boolean isMultiHead() { return true; }
-    @Override public boolean blockHead() { return true; }
-    @Override public CFGNode cfg0() { return this; }
-
-    @Override public TypeTuple compute() {
-        return TypeTuple.make(Type.CONTROL,TypeMem.BOT,_arg);
-    }
-
-    @Override public Node idealize() { return null; }
-
-    // No immediate dominator, and idepth==0
-    @Override public int idepth() { return 0; }
-    @Override public CFGNode idom(Node dep) { return null; }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/StopNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/StopNode.java
deleted file mode 100644
index d0eb5750..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/StopNode.java
+++ /dev/null
@@ -1,89 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.GlobalCodeMotion;
-
-
-public class StopNode extends CFGNode {
-
-    public final String _src;
-
-    public StopNode(String src) {
-        super();
-        _src = src;
-    }
-
-    @Override
-    public String label() {
-        return "Stop";
-    }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        if( ret()!=null ) return p.n(ret());
-        p.p("Stop[ ");
-        for( Node ret : _inputs )
-            p.n(ret).p(" ");
-        return p.p("]");
-    }
-
-    @Override public boolean blockHead() { return true; }
-
-    // If a single Return, return it.
-    // Otherwise, null because ambiguous.
-    public ReturnNode ret() {
-        return nIns()==1 ? (ReturnNode)in(0) : null;
-    }
-
-    @Override
-    public Type compute() {
-        return Type.BOTTOM;
-    }
-
-    @Override
-    public Node idealize() {
-        int len = nIns();
-        for( int i=0; i<nIns(); i++ )
-            if( in(i)._type==Type.XCONTROL )
-                delDef(i--);
-        if( len != nIns() ) return this;
-        return null;
-    }
-
-    @Override public int idepth() {
-        if( _idepth!=0 ) return _idepth;
-        int d=0;
-        for( Node n : _inputs )
-            if( n!=null )
-                d = Math.max(d,((CFGNode)n).idepth()+1);
-        return cacheIDepth(d);
-    }
-    @Override public CFGNode idom(Node dep) { return null; }
-
-    public Node addReturn(Node node) {
-        return addDef(node);
-    }
-
-    public StopNode iterate() { return IterPeeps.iterate(this).typeCheck().GCM(); }
-    public StopNode typeCheck() {
-        var obs = Parser.PARSER == null ? null : Parser.PARSER._obs;
-        String err = walk(n -> {
-            String msg = n.err();
-            if( msg != null && obs != null ) obs.error(n, msg);
-            return msg;
-        });
-        if( err != null ) throw new RuntimeException(err);
-        if( obs != null ) obs.phase("TypeCheck");
-        return this;
-    }
-    StopNode GCM() {
-        Parser.START.buildLoopTree(this);
-
-        GlobalCodeMotion.buildCFG(this);
-        return this;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/StoreNode.java
deleted file mode 100644
index 48c8927f..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ /dev/null
@@ -1,125 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.type.*;
-
-
-/**
- * Store represents setting a value to a memory based object, in chapter 10
- * this means a field inside a struct.
- */
-public class StoreNode extends MemOpNode {
-
-    private final boolean _init; // Initializing writes are allowed to write null
-
-    /**
-     * @param name  The struct field we are assigning to
-     * @param mem   The memory alias node - this is updated after a Store
-     * @param ptr   The ptr to the struct base where we will store a value
-     * @param off   The offset inside the struct base
-     * @param value Value to be stored
-     */
-    public StoreNode(String name, int alias, Type glb, Node mem, Node ptr, Node off, Node value, boolean init) {
-        super(name, alias, glb, mem, ptr, off, value);
-        _init = init;
-    }
-
-    // Debugger label
-    @Override boolean canDrop(MemOpNode other, Node dep) {
-        return super.canDrop(other,dep) && _init==((StoreNode)other)._init;
-    }
-
-    @Override public String  label() { return "st_"+mlabel(); }
-    @Override public boolean isMem() { return true; }
-
-    public Node val() { return in(4); }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        return p.p(".").p(_name).p("=").p( val()).p(";");
-    }
-
-    @Override
-    public Type compute() {
-        Type val = val()._type;
-        if( _declaredType.isFRef() && val instanceof TypeMemPtr tmp && !tmp.isFRef() )
-            _declaredType = tmp;
-        Type t = val.join(_declaredType).meet(MemMergeNode.contents(mem(),_alias,this));
-        return TypeMem.make(_alias,t);
-    }
-
-    @Override
-    public Node idealize() {
-        if( mem() instanceof MemMergeNode merge ) {
-            setDef(1,IterPeeps.add(merge.alias(_alias)));
-            return this;
-        }
-
-
-        // Simple store-after-store on same address.  Should pick up the
-        // required init-store being stomped by a first user store.
-        if( mem() instanceof StoreNode st &&
-            ptr()==st.ptr() && _alias==st._alias &&  // Must check same object
-            off()==st.off() &&  // And same offset
-            ptr()._type instanceof TypeMemPtr && // No bother if weird dead pointers
-            // 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
-            setDef(1,st.mem());
-            return this;
-        }
-
-        // Simple store-after-new on same address.  Should pick up the
-        // an init-store being stomped by a first user store.
-        if( mem() instanceof ProjNode st  && st .in(0) instanceof NewNode nnn &&
-            ptr() instanceof ProjNode ptr && ptr.in(0) == nnn &&
-            ptr()._type instanceof TypeMemPtr tmp && // No bother if weird dead pointers
-            // Cannot fold a store of a single element over the array body initializer value
-            !(tmp._obj.isAry() && tmp._obj._fields[1]._alias==_alias) &&
-            // Very sad strong cutout: val has to be legal to hoist to a New
-            // input, which means it cannot depend on the New.  Many many
-            // things are legal here but difficult to check without doing a
-            // full dominator check.  Example failure:
-            // "struct C { C? c; }; C self = new C { c=self; }"
-            val()._type.isHighOrConst() &&
-            // Must have exactly one use of "this" or you get weird
-            // non-serializable memory effects in the worse case.
-            checkOnlyUse(st) &&
-            // Folding away a broken store
-            err()==null ) {
-            nnn.setDef(nnn.findAlias(_alias),val());
-            // Must retype the NewNode
-            nnn  ._type = nnn.  compute();
-            mem()._type = mem().compute();
-            return st;
-        }
-
-        return null;
-    }
-
-    // Check that "mem" has no uses except "this"
-    private boolean checkOnlyUse(Node mem) {
-        if( mem.nOuts()==1 ) return true;
-        // Add deps on the other uses (can be e.g. ScopeNode mid-parse) so that
-        // when the other uses go away we can retry.
-        for( Node use : mem._outputs )
-            if( use != this )
-                use.addDep(this);
-        return false;
-    }
-
-    @Override
-    String err() {
-        String err = super.err();
-        if( err != null ) return err;
-        TypeMemPtr tmp = (TypeMemPtr)ptr()._type;
-        if( tmp._obj.field(_name)._final )
-            return "Cannot modify final field '"+_name+"'";
-        Type t = val()._type;
-        return _init || t.isa(_declaredType) ? null : "Cannot store "+t+" into field "+_declaredType+" "+_name;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/StructNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/StructNode.java
deleted file mode 100644
index 429b49cc..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/StructNode.java
+++ /dev/null
@@ -1,45 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.type.*;
-
-/**
- * Build a compound object
- */
-public class StructNode extends Node {
-
-    public TypeStruct _ts;
-
-    @Override public String label() { return _ts==null ? "STRUCT?" : _ts.str(); }
-
-    @Override
-    protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
-        if( _ts==null ) return p.p("STRUCT?");
-        p.p(_ts._name).p(" {");
-        for( int i=0; i<nIns(); i++ ) {
-            p.p(_ts._fields[i]._fname).p(":");
-            p.p(in(i)==null ? Type.BOTTOM : in(i)._type);
-            p.p("; ");
-        }
-        return p.unchar("; ").p("}");
-    }
-
-    @Override
-    public TypeStruct compute() {
-        if( _ts==null ) return TypeStruct.BOT;
-        Field[] fs = new Field[_ts._fields.length];
-        for( int i=0; i<fs.length; i++ )
-            fs[i] = _ts._fields[i].makeFrom(in(i)==null ? Type.TOP : in(i)._type);
-        return TypeStruct.make(_ts._name,fs);
-    }
-
-    @Override
-    public Node idealize() { return null; }
-
-    @Override
-    boolean eq(Node n) { return _ts == ((StructNode)n)._ts; }
-
-    @Override
-    int hash() { return _ts==null ? 0 : _ts.hashCode(); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/SubFNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/SubFNode.java
deleted file mode 100644
index 2d218a03..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/SubFNode.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-
-
-public class SubFNode extends Node {
-    public SubFNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "SubF"; }
-
-    @Override protected String format() { return "(%1-%2)"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeFloat i0 &&
-            in(2)._type instanceof TypeFloat i1) {
-            if (i0.isConstant() && i1.isConstant())
-                return TypeFloat.constant(i0.value()-i1.value());
-        }
-        return in(1)._type.meet(in(2)._type);
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Type t2 = in(2)._type;
-
-        // Sub of 0.
-        if ( t2.isConstant() && t2 instanceof TypeFloat i && i.value()==0 )
-            return lhs;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new SubFNode(lhs,rhs); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/SubNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/SubNode.java
deleted file mode 100644
index 768cb2bf..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/SubNode.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class SubNode extends Node {
-    public SubNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Sub"; }
-
-    @Override protected String format() { return "(%1-%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i1 &&
-            t2 instanceof TypeInteger i2 ) {
-            if (i1.isConstant() && i2.isConstant())
-                return TypeInteger.constant(i1.value()-i2.value());
-            // Fold ranges like {2-3} - {0-1} into {1-3}.
-            if( !AddNode.overflow(i1._min,-i2._max) &&
-                !AddNode.overflow(i1._max,-i2._min) &&
-                i2._min != Long.MIN_VALUE  )
-                return TypeInteger.make(i1._min-i2._max,i1._max-i2._min);
-        }
-        // Sub of same is 0
-        if( in(1)==in(2) )
-            return TypeInteger.ZERO;
-
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t1 = lhs._type;
-        Type t2 = rhs._type;
-
-        // Keep invalid operands for type checking.
-        if( t1 instanceof TypeInteger x && t2 instanceof TypeInteger y ) {
-            if( y.isConstant() && y.value()==0 ) return lhs;
-            if( x.isConstant() && x.value()==0 ) return new MinusNode(rhs);
-        }
-
-        // x - (-y) is x+y
-        if( rhs instanceof MinusNode minus )
-            return new AddNode(lhs,minus.in(1));
-
-        // (-x) - y is -(x+y)
-        if( lhs instanceof MinusNode minus )
-            return new MinusNode(new AddNode(minus.in(1),rhs).peephole());
-
-        return null;
-    }
-
-    @Override Node copy(Node lhs, Node rhs) { return new SubNode(lhs,rhs); }
-    @Override Node copyF() { return new SubFNode(null,null); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
deleted file mode 100644
index 26cf50e1..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
+++ /dev/null
@@ -1,25 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class ToFloatNode extends Node {
-    public ToFloatNode(Node lhs) { super(null, lhs); }
-
-    @Override public String label() { return "ToFloat"; }
-
-    @Override protected String format() { return "(flt)%1"; }
-
-    @Override
-    public Type compute() {
-        if (in(1)._type instanceof TypeInteger i0 && i0.isConstant() )
-            return TypeFloat.constant(i0.value());
-        return TypeFloat.BOT;
-    }
-
-    @Override public Node idealize() { return null; }
-    @Override Node copy(Node lhs, Node rhs) { return new ToFloatNode(lhs); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
deleted file mode 100644
index 056dfba1..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package com.seaofnodes.simple.node;
-
-import com.seaofnodes.print.ExprPrinter;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.type.Type;
-
-public class XCtrlNode extends CFGNode {
-    public XCtrlNode( ) { super(Parser.START); }
-    @Override public String label() { return "Xctrl"; }
-    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) { return p.p("Xctrl"); }
-    @Override  public Type compute() { return Type.XCONTROL; }
-    @Override public Node idealize() { return null; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/XorNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/XorNode.java
deleted file mode 100644
index ef7273b8..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/XorNode.java
+++ /dev/null
@@ -1,58 +0,0 @@
-package com.seaofnodes.simple.node;
-
-
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
-
-public class XorNode extends Node {
-    public XorNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
-
-    @Override public String label() { return "Xor"; }
-
-    @Override protected String format() { return "(%1^%2)"; }
-
-    @Override
-    public Type compute() {
-        Type t1 = in(1)._type, t2 = in(2)._type;
-        if( t1.isHigh() || t2.isHigh() )
-            return TypeInteger.TOP;
-        if( t1 instanceof TypeInteger i0 &&
-            t2 instanceof TypeInteger i1 ) {
-            if( i0.isConstant() && i1.isConstant() )
-                return TypeInteger.constant(i0.value()^i1.value());
-        }
-        return TypeInteger.BOT;
-    }
-
-    @Override
-    public Node idealize() {
-        Node lhs = in(1);
-        Node rhs = in(2);
-        Type t1 = lhs._type;
-        Type t2 = rhs._type;
-
-        // Xor of 0.  We do not check for (0^x) because this will already
-        // canonicalize to (x^0)
-        if( t2.isConstant() && t2 instanceof TypeInteger i && i.value()==0 )
-            return lhs;
-
-        // Move constants to RHS: con*arg becomes arg*con
-        if ( t1.isConstant() && !t2.isConstant() )
-            return swap12();
-
-        // Do we have ((x ^ (phi cons)) ^ con) ?
-        // Do we have ((x ^ (phi cons)) ^ (phi cons)) ?
-        // Push constant up through the phi: x ^ (phi con0^con0 con1^con1...)
-        Node phicon = AddNode.phiCon(this,true);
-        if( phicon!=null ) return phicon;
-
-        return null;
-    }
-    @Override Node copy(Node lhs, Node rhs) { return new XorNode(lhs,rhs); }
-    @Override String err() {
-        if( !(in(1)._type instanceof TypeInteger) ) return "Cannot '^' " + in(1)._type;
-        if( !(in(2)._type instanceof TypeInteger) ) return "Cannot '^' " + in(2)._type;
-        return null;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/print/SimpleGraphAdapter.java b/chapter17/src/main/java/com/seaofnodes/simple/print/SimpleGraphAdapter.java
deleted file mode 100644
index 7ba58e6f..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/print/SimpleGraphAdapter.java
+++ /dev/null
@@ -1,42 +0,0 @@
-package com.seaofnodes.simple.print;
-
-import com.seaofnodes.graph.GraphAdapter;
-import com.seaofnodes.graph.GraphSnapshot.*;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeMem;
-
-/** Chapter 17's view of the IR; browser, transport and layout are shared. */
-public class SimpleGraphAdapter extends GraphAdapter<Node> {
-
-    @Override protected String edgeName(Node n, int i) {
-        return n instanceof ScopeNode scope && i < scope._vars.size()
-                ? scope._vars.get(i)._name : null;
-    }
-    @Override protected int projectionIndex(Node n) { return n instanceof ProjNode p ? p._idx : n instanceof CProjNode p ? p._idx : -1; }
-
-    @Override protected Kind kind(Node n) {
-        if( n instanceof StopNode ) return Kind.STOP;
-        if( n instanceof ScopeNode ) return Kind.SCOPE;
-        if( n instanceof StartNode ) return Kind.CTRL;
-        if( n instanceof LoopNode ) return Kind.LOOP;
-        if( n instanceof RegionNode ) return Kind.REGION;
-        if( n instanceof PhiNode ) return Kind.PHI;
-        return n instanceof CFGNode ? Kind.CTRL : isMem(n) ? Kind.MEM : Kind.DATA;
-    }
-
-    @Override protected Role role(Node n, int i) {
-        if( n instanceof ScopeNode || n instanceof ConstantNode || n instanceof XCtrlNode ) return Role.ASSOC;
-        if( n instanceof PhiNode ) return i == 0 ? Role.ASSOC : isMem(n) ? Role.MEM : Role.DATA;
-        if( n instanceof ProjNode || n instanceof CProjNode )
-            return n instanceof CFGNode ? Role.CTRL : isMem(n) ? Role.MEM : Role.DATA;
-        if( n instanceof RegionNode && i == 0 ) return Role.ASSOC;
-        if( i == 0 || n instanceof RegionNode || n instanceof StopNode ) return Role.CTRL;
-        if( i == 1 && (n instanceof MemOpNode || n instanceof ReturnNode || n instanceof NewNode) ) return Role.MEM;
-        Node def = n.in(i);
-        if( def != null && isMem(def) ) return Role.MEM;
-        return Role.DATA;
-    }
-
-    private boolean isMem(Node n) { return n.isMem() || n._type instanceof TypeMem; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/print/SimpleGraphObserver.java b/chapter17/src/main/java/com/seaofnodes/simple/print/SimpleGraphObserver.java
deleted file mode 100644
index d774967b..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/print/SimpleGraphObserver.java
+++ /dev/null
@@ -1,45 +0,0 @@
-package com.seaofnodes.simple.print;
-
-import com.seaofnodes.graph.GraphCapture;
-import com.seaofnodes.graph.GraphViewer;
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.node.Node;
-import java.util.ArrayList;
-import java.io.IOException;
-
-/** Chapter 17's compilation context; capture and event bookkeeping are shared. */
-public class SimpleGraphObserver extends GraphCapture<Node> {
-    private Parser _parser;
-    private Node _ret;
-    private String _phase;
-    public SimpleGraphObserver() { super(new SimpleGraphAdapter()); }
-    public static void main(String[] args) throws IOException {
-        GraphViewer.run(new SimpleGraphObserver());
-    }
-    @Override protected void compile(String src) {
-        _parser = new Parser(src);
-        _parser._obs = this;
-        _phase = "Parse";
-        _ret = _parser.parse();
-        phase(_phase);
-        _phase = "Iter";
-        com.seaofnodes.simple.IterPeeps.iterate(_parser.STOP);
-        phase(_phase);
-        _phase = "TypeCheck";
-        _parser.STOP.typeCheck();
-    }
-    @Override protected String phase() { return _phase; }
-    @Override protected int pos() { return "Parse".equals(_phase) ? _parser.pos() : -1; }
-    @Override protected void detach() {
-        if( _parser != null ) _parser._obs = null;
-        _parser = null;
-        _ret = null;
-    }
-    @Override protected Node scope() { return _parser._scope; }
-    @Override protected void roots(ArrayList<Node> roots) {
-        roots.add(Parser.START);
-        roots.add(_parser.STOP);
-        roots.addAll(_parser._xScopes);
-        roots.add(_ret);
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/Field.java b/chapter17/src/main/java/com/seaofnodes/simple/type/Field.java
deleted file mode 100644
index 349c1fb0..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/Field.java
+++ /dev/null
@@ -1,77 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import com.seaofnodes.simple.Utils;
-import java.util.ArrayList;
-
-/**
- * Represents a field in a struct. This is not a Type in the type system.
- */
-public class Field extends Type {
-
-    // The pair {fieldName,type} uniquely identifies a field.
-
-    // Field name
-    public final String _fname;
-    // Type of the field
-    public final Type _type;
-    // Unique memory alias, not sensibly part of a "type" but very convenient here.
-    public final int _alias;
-    // Field must be written to exactly once, no more, no less
-    public final boolean _final;
-
-    private Field(String fname, Type type, int alias, boolean xfinal ) {
-        super(TFLD);
-        _fname = fname;
-        _type  = type;
-        _alias = alias;
-        _final = xfinal;
-    }
-    // Make with existing alias
-    public static Field make( String fname, Type type, int alias, boolean xfinal ) {
-        return new Field(fname,type,alias,xfinal).intern();
-    }
-    public Field makeFrom( Type type ) {
-        return type == _type ? this : new Field(_fname,type,_alias,_final).intern();
-    }
-    @Override public Field makeRO() { return _final ? this : make(_fname,_type.makeRO(),_alias,true);  }
-    @Override public boolean isFinal() { return _final && _type.isFinal(); }
-
-    public static final Field TEST = make("test",TypeInteger.ZERO,-2,false);
-    public static void gather(ArrayList<Type> ts) { ts.add(TEST); }
-
-    @Override Field xmeet( Type that ) {
-        Field fld = (Field)that; // Invariant
-        assert _fname.equals(fld._fname);
-        assert _alias==fld._alias;
-        return make(_fname,_type.meet(fld._type),_alias,_final | fld._final);
-    }
-
-    @Override
-    public Field dual() { return make(_fname,_type.dual(),_alias,!_final); }
-
-    @Override public Field glb() {
-        Type glb = _type.glb();
-        return glb==_type ? this : make(_fname,glb,_alias,_final);
-    }
-
-    @Override public Field lub() {
-        Type lub = _type.lub();
-        return lub==_type ? this : make(_fname,lub,_alias,_final);
-    }
-
-    // Override in subclasses
-    int hash() { return _fname.hashCode() ^ _type.hashCode() ^ _alias ^ (_final ? 1024 : 0); }
-
-    boolean eq(Type t) {
-        Field f = (Field)t;
-        return _fname.equals(f._fname) && _type==f._type && _alias==f._alias && _final==f._final;
-    }
-
-
-    @Override
-    public StringBuilder print( StringBuilder sb ) {
-        return _type.print(sb.append(_final?"":"!").append(_fname).append(":").append(_alias).append(" : "));
-    }
-
-    @Override public String str() { return _fname; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/Type.java b/chapter17/src/main/java/com/seaofnodes/simple/type/Type.java
deleted file mode 100644
index 4ebb2b6d..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/Type.java
+++ /dev/null
@@ -1,218 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import com.seaofnodes.simple.Utils;
-
-import java.util.ArrayList;
-import java.util.HashMap;
-
-/**
- * These types are part of a Monotone Analysis Framework,
- * @see <a href="https://www.cse.psu.edu/~gxt29/teaching/cse597s21/slides/08monotoneFramework.pdf">see for example this set of slides</a>.
- * <p>
- * The types form a lattice; @see <a href="https://en.wikipedia.org/wiki/Lattice_(order)">a symmetric complete bounded (ranked) lattice.</a>
- * <p>
- * This wild lattice theory will be needed later to allow us to easily beef up
- * the analysis and optimization of the Simple compiler... but we don't need it
- * now, just know that it is coming along in a later Chapter.
- * <p>g
- * One of the fun things here is that while the theory is deep and subtle, the
- * actual implementation is darn near trivial and is generally really obvious
- * what we're doing with it.  Right now, it's just simple integer math to do
- * simple constant folding e.g. 1+2 == 3 stuff.
- */
-
-public class Type {
-    static final HashMap<Type,Type> INTERN = new HashMap<>();
-
-    // ----------------------------------------------------------
-    // Simple types are implemented fully here.  "Simple" means: the code and
-    // type hierarchy are simple, not that the Type is conceptually simple.
-    static final byte TBOT    = 0; // Bottom (ALL)
-    static final byte TTOP    = 1; // Top    (ANY)
-    static final byte TCTRL   = 2; // Ctrl flow bottom
-    static final byte TXCTRL  = 3; // Ctrl flow top (mini-lattice: any-xctrl-ctrl-all)
-    static final byte TSIMPLE = 4; // End of the Simple Types
-    static final byte TINT    = 5; // All Integers; see TypeInteger
-    static final byte TFLT    = 6; // All Integers; see TypeInteger
-    static final byte TTUPLE  = 7; // Tuples; finite collections of unrelated Types, kept in parallel
-    static final byte TMEM    = 8; // All memory (alias 0) or A slice of memory - with specific alias
-    static final byte TMEMPTR = 9; // Memory pointer type
-    static final byte TSTRUCT =10; // Structs; tuples with named fields
-    static final byte TFLD    =11; // Fields into struct
-    static final byte TARRAY  =12; // Array
-
-    public final byte _type;
-
-    public boolean is_simple() { return _type < TSIMPLE; }
-    private static final String[] STRS = new String[]{"Bot","Top","Ctrl","~Ctrl"};
-    protected Type(byte type) { _type = type; }
-
-    public static final Type BOTTOM   = new Type( TBOT   ).intern(); // ALL
-    public static final Type TOP      = new Type( TTOP   ).intern(); // ANY
-    public static final Type CONTROL  = new Type( TCTRL  ).intern(); // Ctrl
-    public static final Type XCONTROL = new Type( TXCTRL ).intern(); // ~Ctrl
-    public static Type[] gather() {
-        ArrayList<Type> ts = new ArrayList<>();
-        ts.add(BOTTOM);
-        ts.add(CONTROL);
-        Field.gather(ts);
-        TypeInteger.gather(ts);
-        TypeFloat.gather(ts);
-        TypeMem.gather(ts);
-        TypeMemPtr.gather(ts);
-        TypeStruct.gather(ts);
-        TypeTuple.gather(ts);
-        int sz = ts.size();
-        for( int i = 0; i < sz; i++ )
-            ts.add(ts.get(i).dual());
-        return ts.toArray(new Type[ts.size()]);
-    }
-
-    // Is high or on the lattice centerline.
-    public boolean isHigh       () { return _type==TTOP || _type==TXCTRL; }
-    public boolean isHighOrConst() { return _type==TTOP || _type==TXCTRL; }
-
-    // Strict constant values, things on the lattice centerline.
-    // Excludes both high and low values
-    public boolean isConstant() { return false; }
-
-    /**
-     * Display Type name in a format that's good for IR printer
-     */
-    public StringBuilder typeName( StringBuilder sb) { return print(sb); }
-
-
-    // ----------------------------------------------------------
-
-    // Notes on Type interning: At the moment it is not easy to reset the
-    // interned types because we hold static references to several types and
-    // these are scattered around.  This means the INTERN cache will retain all
-    // types from every run of the Parser.  For this to work correctly types
-    // must be rigorous about defining when they are the same.  Also types need
-    // to be immutable once defined.  The rationale for interning is
-    // *correctness* with cyclic type definitions.  Simple structural recursive
-    // checks go exponential with merely sharing, but with cycles they will
-    // stack overflow and crash.  Intering means we do not need to have sharing
-    // checks with every type compare, only during interning.
-
-    // Factory method which interns "this"
-    public  <T extends Type> T intern() {
-        T nnn = (T)INTERN.get(this);
-        if( nnn==null )
-            INTERN.put(nnn=(T)this,this);
-        return nnn;
-    }
-
-    private int _hash;          // Hash cache; not-zero when set.
-    @Override
-    public final int hashCode() {
-        if( _hash!=0 ) return _hash;
-        _hash = hash();
-        if( _hash==0 ) _hash = 0xDEADBEEF; // Bad hash from subclass; use some junk thing
-        return _hash;
-    }
-    // Override in subclasses
-    int hash() { return _type; }
-
-    @Override
-    public final boolean equals( Object o ) {
-        if( o==this ) return true;
-        if( !(o instanceof Type t)) return false;
-        if( _type != t._type ) return false;
-        return eq(t);
-    }
-    // Overridden in subclasses; subclass can assume "this!=t" and java classes are same
-    boolean eq(Type t) { return true; }
-
-
-    // ----------------------------------------------------------
-    public final Type meet(Type t) {
-        // Shortcut for the self case
-        if( t == this ) return this;
-        // Same-type is always safe in the subclasses
-        if( _type==t._type ) return xmeet(t);
-        // 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
-    }
-
-    // Compute meet right now.  Overridden in subclasses.
-    // Handle cases where 'this.is_simple()' and unequal to 't'.
-    // Subclassed xmeet calls can assert that '!t.is_simple()'.
-    Type xmeet(Type t) {
-        assert is_simple(); // Should be overridden in subclass
-        // ANY meet anything is thing; thing meet ALL is ALL
-        if( _type==TBOT || t._type==TTOP ) return this;
-        if( _type==TTOP || t._type==TBOT ) return    t;
-        // 'this' is {TCTRL,TXCTRL}
-        if( !t.is_simple() ) return BOTTOM;
-        // 't' is {TCTRL,TXCTRL}
-        return _type==TCTRL || t._type==TCTRL ? CONTROL : XCONTROL;
-    }
-
-    public Type dual() {
-        return switch( _type ) {
-        case TBOT -> TOP;
-        case TTOP -> BOTTOM;
-        case TCTRL -> XCONTROL;
-        case TXCTRL -> CONTROL;
-        default -> throw Utils.TODO(); // Should not reach here
-        };
-    }
-
-    // ----------------------------------------------------------
-    // Our lattice is defined with a MEET and a DUAL.
-    // JOIN is dual of meet of both duals.
-    public final Type join(Type t) {
-        if( this==t ) return this;
-        return dual().meet(t.dual()).dual();
-    }
-
-    // True if this "isa" t; e.g. 17 isa TypeInteger.BOT
-    public boolean isa( Type t ) { return meet(t)==t; }
-
-    /** Compute greatest lower bound in the lattice */
-    public Type glb() { return _type==TCTRL ? CONTROL : BOTTOM; }
-    /** Compute least upper bound in the lattice */
-    public Type lub() { return _type==TCTRL ? XCONTROL : TOP; }
-
-    // Make an initial/default version of this type.  Typically, 0 for integers
-    // and null for nullable pointers.
-    public Type makeInit() { return this; }
-    // Make a zero version of this type, 0 for integers and null for pointers.
-    public Type makeZero() { return null; }
-    // Make a non-zero version of this type, if possible.  Integers attempt to
-    // exclude zero from their range and pointers become not-null.
-    public Type nonZero() { return glb(); }
-
-    // Is forward-reference
-    public boolean isFRef() { return false; }
-
-    // All reachable struct Fields are final
-    public boolean isFinal() { return true; }
-
-    // Make all reachable struct Fields final
-    public Type makeRO() { return this; }
-
-    // ----------------------------------------------------------
-
-    // Size in bits to hold an instance of this type.
-    // Sizes are expected to be between 1 and 64 bits.
-    // Size 0 means this either takes no space (such as a known-zero field)
-    // or isn't a scalar to be stored in memory.
-    public int log_size() { throw Utils.TODO(); }
-
-    // ----------------------------------------------------------
-    // Useful in the debugger, which calls toString everywhere.
-    // This is a more verbose dev-friendly print.
-    @Override
-    public final String toString() {
-        return print(new StringBuilder()).toString();
-    }
-
-    public StringBuilder print(StringBuilder sb) { return is_simple() ? sb.append(STRS[_type]) : sb;}
-
-    // This is used by error messages, and is a shorted print.
-    public String str() { return STRS[_type]; }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeFloat.java b/chapter17/src/main/java/com/seaofnodes/simple/type/TypeFloat.java
deleted file mode 100644
index f85abbed..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeFloat.java
+++ /dev/null
@@ -1,120 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import java.util.ArrayList;
-
-/**
- * Float Type
- */
-public class TypeFloat extends Type {
-
-    public final static TypeFloat TOP = make((byte)-64, 0);
-    public final static TypeFloat T32 = make((byte)-32, 0);
-    public final static TypeFloat ZERO= make((byte)  0, 0);
-    public final static TypeFloat B32 = make((byte) 32, 0);
-    public final static TypeFloat BOT = make((byte) 64, 0);
-
-    /** +/-64 for double; +/-32 for float, or 0 for constants */
-    public final byte _sz;
-
-    /**
-     * The constant value or 0
-     */
-    public final double _con;
-
-    private TypeFloat(byte sz, double con) {
-        super(TFLT);
-        _sz  = sz ;
-        _con = con;
-    }
-    private static TypeFloat make(byte sz, double con) {
-        return new TypeFloat(sz,con).intern();
-    }
-
-    public static TypeFloat constant(double con) { return make((byte)0, con); }
-
-    public static void gather(ArrayList<Type> ts) { ts.add(ZERO); ts.add(BOT); ts.add(B32); ts.add(constant(3.141592653589793)); }
-
-    // FIXME this display format is problematic
-    // In visualizer '#' gets prepended if its a constant
-    @Override
-    public StringBuilder print(StringBuilder sb) {
-        if( this==TOP ) return sb.append("FltTop");
-        if( this==T32 ) return sb.append("F32Top");
-        if( this==B32 ) return sb.append("F32Bot");
-        if( this==BOT ) return sb.append("FltBot");
-        return sb.append(_con);
-    }
-
-    @Override public String str() {
-        if( this==TOP ) return "~flt";
-        if( this==T32 ) return "~f32";
-        if( this==B32 ) return  "f32";
-        if( this==BOT ) return  "flt";
-        return ""+_con+(isF32() ? "f" : "");
-    }
-
-    /**
-     * Display Type name in a format that's good for IR printer
-     */
-    @Override
-    public StringBuilder typeName(StringBuilder sb) {
-        if( this==TOP ) return sb.append("FltTop");
-        if( this==T32 ) return sb.append("F32Top");
-        if( this==B32 ) return sb.append("F32Bot");
-        if( this==BOT ) return sb.append("FltBot");
-        return sb.append(isF32() ? "F32" : "Flt");
-    }
-
-    boolean isF32() { return ((float)_con)==_con; }
-    @Override public boolean isHigh()        { return _sz< 0; }
-    @Override public boolean isHighOrConst() { return _sz<=0; }
-    @Override public boolean isConstant()    { return _sz==0; }
-
-    @Override public int log_size() {
-        int sz = _sz==0 ? (isF32() ? 32 : 64) : Math.abs(_sz);
-        return _sz==32 ? 2 : 3;
-    }
-
-    public double value() { return _con; }
-
-    @Override
-    public Type xmeet(Type other) {
-        // Invariant from caller: 'this' != 'other' and same class (TypeFloat)
-        TypeFloat i = (TypeFloat)other; // Contract
-        // Larger size in i1, smaller in i0
-        TypeFloat i0 = _sz < i._sz ? this : i;
-        TypeFloat i1 = _sz < i._sz ? i : this;
-
-        if( i1._sz== 64 ) return BOT;
-        if( i0._sz==-64 ) return i1;
-        if( i1._sz== 32 )
-            return i0._sz==0 && !i0.isF32() ? BOT : B32;
-        if( i1._sz!=  0 ) return i1;
-        // i1 is a constant
-        if( i0._sz==-32 )
-            return i1.isF32() ? i1 : BOT;
-        // Since both are constants, and are never equals (contract) unequals
-        // constants fall to bottom
-        return i0.isF32() && i1.isF32() ? B32 : BOT;
-    }
-
-    @Override
-    public Type dual() {
-        if( _sz==0 ) return this; // Constants are a self-dual
-        return make((byte)-_sz,0);
-    }
-
-    @Override public Type glb() { return BOT; }
-    @Override public Type lub() { return TOP; }
-    @Override public TypeFloat makeInit() { return ZERO; }
-    @Override public TypeFloat makeZero() { return ZERO; }
-
-    @Override
-    int hash() { return (int)(Double.hashCode(_con) ^ _sz); }
-    @Override
-    public boolean eq( Type t ) {
-        TypeFloat i = (TypeFloat)t; // Contract
-        return _con==i._con && _sz==i._sz;
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeInteger.java b/chapter17/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
deleted file mode 100644
index b2979d7b..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
+++ /dev/null
@@ -1,133 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import com.seaofnodes.simple.Utils;
-import java.util.ArrayList;
-
-/**
- * Integer Type
- */
-public class TypeInteger extends Type {
-
-    public final static TypeInteger TOP = make(false, 0);
-    public final static TypeInteger BOT = make(false, 1);
-    public final static TypeInteger ZERO= make(0,0);
-    public final static TypeInteger U1  = make(0,1);
-    public final static TypeInteger BOOL= U1;
-    public final static TypeInteger FALSE=ZERO;
-    public final static TypeInteger TRUE= make(1,1);
-    public final static TypeInteger I8  = make(-128,127);
-    public final static TypeInteger I16 = make(-32768,32767);
-    public final static TypeInteger I32 = make(-1L<<31,(1L<<31)-1);
-
-    public final static TypeInteger U8  = make(0,255);
-    public final static TypeInteger U16 = make(0,65535);
-    public final static TypeInteger U32 = make(0,(1L<<32)-1);
-
-    /**
-     * Describes an integer *range* - everything from min to max; both min and
-     * max are inclusive.  If min==max, this is a constant.
-     *
-     * If min <= max, this is a  below center (towards bottom).
-     * If min >  max, this is an above center (towards top).
-     */
-    public final long _min, _max;
-
-    private TypeInteger(long min, long max) { super(TINT); _min = min; _max = max; }
-    public static TypeInteger make(long lo, long hi) {  return new TypeInteger(lo,hi).intern();  }
-    public static TypeInteger make(boolean is_con, long con) {
-        return make(is_con ? con : (con==0 ? Long.MAX_VALUE : Long.MIN_VALUE),
-                    is_con ? con : (con==0 ? Long.MIN_VALUE : Long.MAX_VALUE));
-    }
-
-    public static TypeInteger constant(long con) { return make(true, con); }
-
-    public static void gather(ArrayList<Type> ts) { ts.add(ZERO); ts.add(BOT); ts.add(U1); ts.add(U8); }
-
-    // FIXME this display format is problematic
-    // In visualizer '#' gets prepended if its a constant
-    @Override
-    public StringBuilder print(StringBuilder sb) { return sb.append(str()); }
-
-    @Override public String str() {
-        if( this==TOP ) return "~int";
-        if( this==BOT ) return  "int";
-        if( this==BOOL) return ("bool");
-        if( this==I8  ) return ("i8");
-        if( this==I16 ) return ("i16");
-        if( this==I32 ) return ("i32");
-        if( this==U8  ) return ("u8");
-        if( this==U16 ) return ("u16");
-        if( this==U32 ) return ("u32");
-        if( isConstant() ) return ""+_min;
-        return "["+_min+"-"+_max+"]";
-    }
-
-    /**
-     * Display Type name in a format that's good for IR printer
-     */
-    @Override
-    public StringBuilder typeName(StringBuilder sb) {
-        if( this==TOP ) return sb.append("IntTop");
-        if( this==BOT ) return sb.append("IntBot");
-        return sb.append("Int");
-    }
-
-    @Override public boolean isHigh       () { return _min >  _max; }
-    @Override public boolean isHighOrConst() { return _min >= _max; }
-    @Override public boolean isConstant   () { return _min == _max; }
-
-    @Override public int log_size() {
-        if( this==I8  || this==U8 || this==BOOL ) return 0; // 1<<0 == 1 bytes
-        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( isHighOrConst() ) return 0;
-        throw Utils.TODO();
-    }
-
-    public long value() { assert isConstant(); return _min; }
-
-    // AND-mask of forced zeros.  e.g. unsigned types will return their mask;
-    // u8 will return 0xFF.  But also a range of 16-18 (0x10-0x12) will return
-    // 0x13 - no value in the range {16,17,18} will allow bit 0x04 to be set.
-    public long mask() {
-        if( isHigh() ) return 0;
-        if( isConstant() ) return _min;
-        //if( _min<0 ) return -1L;
-        //if( _max==Long.MAX_VALUE ) return -1L;
-        // Those bit positions which differ min to max
-        long x = _min ^ _max;
-        // Highest '1' bit in the differ set.  Since the range is from min to
-        // max, all values below here are possible.
-        long ff1 = Long.highestOneBit(x);
-        // Make a all-1's mask from ff1, and set over the same bits (either min
-        // or max is ok).
-        long mask = _min | (ff1-1) | ff1;
-        return mask;
-    }
-
-    @Override
-    public Type xmeet(Type other) {
-        // 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));
-    }
-
-    @Override public TypeInteger dual() { return make(_max,_min); }
-    @Override public TypeInteger glb() { return BOT; }
-    @Override public TypeInteger lub() { return TOP; }
-    @Override public TypeInteger makeInit() { return ZERO; }
-    @Override public TypeInteger makeZero() { return ZERO; }
-    @Override public TypeInteger nonZero() {
-        if( isHigh() ) return this;
-        if( _min==0 ) return make(1,Math.max(_max,1)); // specifically good on BOOL
-        if( _max==0 ) return make(_min,-1);
-        return this;
-    }
-    @Override int hash() { return (int)((_min ^ (_min>>32)) *(_max ^ (_max>>32))); }
-    @Override
-    public boolean eq( Type t ) {
-        TypeInteger i = (TypeInteger)t; // Contract
-        return _min==i._min && _max==i._max;
-    }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeMem.java b/chapter17/src/main/java/com/seaofnodes/simple/type/TypeMem.java
deleted file mode 100644
index 6dcd401a..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeMem.java
+++ /dev/null
@@ -1,69 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import com.seaofnodes.simple.Utils;
-import java.lang.Long;
-import java.util.BitSet;
-import java.util.ArrayList;
-
-
-/**
- * Represents a slice of memory corresponding to a set of aliases
- */
-public class TypeMem extends Type {
-
-    // Which slice of memory?
-    //  0 means TOP, no slice.
-    // -1 means BOT, all memory.
-    //  N means slice#N.
-    public final int _alias;
-    public final Type _t;       // Memory contents, some scalar type
-
-    private TypeMem(int alias, Type t) { super(TMEM); _alias = alias; _t = t; }
-
-    public static TypeMem make(int alias, Type t) { return new TypeMem(alias,t).intern(); }
-    public static final TypeMem TOP = make(-1, Type.TOP   );
-    public static final TypeMem BOT = make(-1, Type.BOTTOM);
-
-    public static void gather(ArrayList<Type> ts) { ts.add(make(1,TypeInteger.ZERO)); ts.add(BOT); }
-
-    @Override
-    TypeMem xmeet(Type t) {
-        TypeMem that = (TypeMem) t; // Invariant: TypeMem and unequal
-        if( this==TOP ) return that;
-        if( that==TOP ) return this;
-        if( this==BOT ) return BOT;
-        if( that==BOT ) return BOT;
-        int alias = _alias==that._alias ? _alias : -1;
-        Type mt = _t.meet(that._t);
-        return make(alias,mt);
-    }
-
-    @Override
-    public Type dual() {
-        return make(_alias,_t.dual());
-    }
-
-    @Override public Type glb() { return make(_alias,_t.glb()); }
-    @Override public Type lub() { return make(_alias,_t.lub()); }
-
-    @Override
-    int hash() { return 9876543 + _alias + _t.hashCode(); }
-
-    @Override
-    boolean eq(Type t) {
-        TypeMem that = (TypeMem) t; // Invariant
-        return _alias == that._alias && _t == that._t;
-    }
-
-    @Override
-    public StringBuilder print(StringBuilder sb) {
-        if( this==BOT ) return sb.append("MemBot");
-        if( this==TOP ) return sb.append("MemTop");
-        sb.append("MEM#");
-        if( _alias== 0 ) return sb.append("TOP");
-        if( _alias==-1 ) return sb.append("BOT");
-        return _t.print(sb.append(_alias).append(":"));
-    }
-
-    @Override public String str() { return toString(); }
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java b/chapter17/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
deleted file mode 100644
index 9e33e15d..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
+++ /dev/null
@@ -1,102 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import java.util.ArrayList;
-
-/**
- * Represents a Pointer to memory.
- *
- * Null is generic pointer to non-existent memory.
- * *void is a non-Null pointer to all possible refs, both structs and arrays.
- * Pointers can be to specific struct and array types, or a union with Null.
- * The distinguished *$BOT ptr represents union of *void and Null.
- * The distinguished *$TOP ptr represents the dual of *$BOT.
- */
-public class TypeMemPtr extends Type {
-    // A TypeMemPtr is pair (obj,nil)
-    // where obj is a TypeStruct, possibly TypeStruct.BOT
-    // where nil is an explicit null is allowed or not
-
-    // Examples:
-    // (Person,false) - a not-nil Person
-    // (Person,true ) - a Person or a nil
-    // (BOT   ,false) - a not-nil void* (unspecified struct)
-    // (TOP   ,true ) - a nil
-
-    public final TypeStruct _obj;
-    public final boolean _nil;
-
-    private TypeMemPtr(TypeStruct obj, boolean nil) {
-        super(TMEMPTR);
-        assert obj!=null;
-        _obj = obj;
-        _nil = nil;
-    }
-    public static TypeMemPtr make(TypeStruct obj, boolean nil) { return new TypeMemPtr(obj, nil).intern(); }
-    public static TypeMemPtr make(TypeStruct obj) { return make(obj, false); }
-    public TypeMemPtr makeFrom(TypeStruct obj) { return obj==_obj ? this : make(obj, _nil); }
-    public TypeMemPtr makeFrom(boolean nil) { return nil==_nil ? this : make(_obj, nil); }
-    @Override public TypeMemPtr makeRO() { return makeFrom(_obj.makeRO()); }
-    @Override public boolean isFinal() { return _obj.isFinal(); }
-
-    // An abstract pointer, pointing to either a Struct or an Array.
-    // Can also be null or not.
-    public static final TypeMemPtr BOT = make(TypeStruct.BOT,true);
-    public static final TypeMemPtr TOP = BOT.dual();
-    // An abstract null (can be Struct or Array) or not-null C void*
-    public static final TypeMemPtr NULLPTR = make(TypeStruct.TOP,true);
-    public static final TypeMemPtr VOIDPTR = NULLPTR.dual(); // A bottom mix of not-null ptrs, like C's void* but not null
-
-    public static final TypeMemPtr TEST= make(TypeStruct.TEST,false);
-    public static void gather(ArrayList<Type> ts) { ts.add(NULLPTR); ts.add(BOT); ts.add(TEST); }
-
-    @Override
-    Type xmeet(Type t) {
-        TypeMemPtr that = (TypeMemPtr) t;
-        return TypeMemPtr.make((TypeStruct)_obj.meet(that._obj), _nil | that._nil);
-    }
-
-    @Override
-    public TypeMemPtr dual() { return TypeMemPtr.make(_obj.dual(), !_nil); }
-
-    @Override public TypeMemPtr glb() { return make(_obj.glb(),true ); }
-    @Override public TypeMemPtr lub() { return make(_obj.lub(),false); }
-    // Is forward-reference
-    @Override public boolean isFRef() { return _obj.isFRef(); }
-    @Override public Type makeInit() { return _nil ? NULLPTR : Type.TOP; }
-    @Override public Type makeZero() { return NULLPTR; }
-    @Override public Type nonZero() { return VOIDPTR; }
-
-    @Override public boolean isHigh() { return this==TOP; }
-    @Override public boolean isConstant() { return this==NULLPTR; }
-    @Override public boolean isHighOrConst() { return this==TOP || this==NULLPTR; }
-
-    @Override public int log_size() { return 2; } // (1<<2)==4-byte pointers
-
-    @Override
-    int hash() { return _obj.hashCode() ^ (_nil ? 1024 : 0); }
-
-    @Override
-    boolean eq(Type t) {
-        TypeMemPtr ptr = (TypeMemPtr)t; // Invariant
-        return _obj == ptr._obj  && _nil == ptr._nil;
-    }
-
-    // [void,name,MANY]*[,?]
-    @Override
-    public StringBuilder print(StringBuilder sb) {
-        if( this==BOT ) return sb.append("PtrBot");
-        if( this==TOP ) return sb.append("PtrTop");
-        if( this== NULLPTR) return sb.append("null");
-        if( this== VOIDPTR) return sb.append("*void");
-        return _obj.print(sb.append("*")).append(_nil ? "?" : "");
-    }
-
-    @Override public String str() {
-        if( this==BOT ) return "PtrBot";
-        if( this==TOP ) return "PtrTop";
-        if( this== NULLPTR) return "null";
-        if( this== VOIDPTR) return "*void";
-        return "*"+_obj.str()+(_nil ? "?" : "");
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeStruct.java b/chapter17/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
deleted file mode 100644
index 97664e3c..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
+++ /dev/null
@@ -1,262 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import com.seaofnodes.simple.Utils;
-import java.util.ArrayList;
-
-/**
- * Represents a struct type.
- */
-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.  Briefly during parsing a Struct can be a
-    // forward-ref; in this case the _fields array is null.
-
-    // Its illegal to attempt to load a field from a forward-ref struct.
-
-    // Example: "int rez = new S.x; struct S { int x; } return rez;" // Error, S not defined
-    // Rewrite: "struct S { int x; } int rez = new S.x; return rez;" // Ok, no forward ref
-    //
-    // During the normal optimization run, struct types "bottom out" at further
-    // struct references, so we don't have to handle e.g. cyclic types.  The
-    // "bottom out" is again the forward-ref struct.
-    public final String _name;
-    public final Field[] _fields;
-
-    TypeStruct(String name, Field[] fields) {
-        super(TSTRUCT);
-        _name = name;
-        _fields = fields;
-    }
-
-    // All fields directly listed
-    public static TypeStruct make(String name, Field... fields) { return new TypeStruct(name, fields).intern(); }
-    public static final TypeStruct TOP = make("$TOP",new Field[0]);
-    public static final TypeStruct BOT = make("$BOT",new Field[0]);
-    public static final TypeStruct TEST = make("test",new Field[]{Field.TEST});
-    // Forward-ref version
-    public static TypeStruct makeFRef(String name) { return make(name, (Field[])null); }
-    // Make a read-only version
-    @Override public TypeStruct makeRO() {
-        if( isFinal() ) return this;
-        Field[] flds = new Field[_fields.length];
-        for( int i=0; i<flds.length; i++ )
-            flds[i] = _fields[i].makeRO();
-        return make(_name,flds);
-    }
-
-    // Array
-    public static TypeStruct makeAry(TypeInteger len, int lenAlias, Type body, int bodyAlias) {
-        assert !(body instanceof TypeMemPtr tmp && !tmp._nil);
-        return make("[" + body.str() + "]",
-                    Field.make("#" ,len , lenAlias,true ),
-                    Field.make("[]",body,bodyAlias,false));
-    }
-
-    // A pair of self-cyclic types
-    private static final TypeStruct S1F = makeFRef("S1");
-    private static final TypeStruct S2F = makeFRef("S2");
-    public  static final TypeStruct S1  = make("S1", Field.make("a", TypeInteger.BOT, -1, false), Field.make("s2",TypeMemPtr.make(S2F,false),-2, false) );
-    private static final TypeStruct S2  = make("S2", Field.make("b", TypeFloat  .BOT, -3, false), Field.make("s1",TypeMemPtr.make(S1F,false),-4, false) );
-
-    private static final TypeStruct ARY = makeAry(TypeInteger.BOT,-1,TypeFloat.BOT,-2);
-
-    public static void gather(ArrayList<Type> ts) { ts.add(TEST); ts.add(BOT); ts.add(S1); ts.add(S2); ts.add(ARY); }
-
-    // Find field index by name
-    public int find(String fname) {
-        for( int i=0; i<_fields.length; i++ )
-            if( _fields[i]._fname.equals(fname) )
-                return i;
-        return -1;
-    }
-    public Field field(String fname) {
-        int idx = find(fname);
-        return idx== -1 ? null : _fields[idx];
-    }
-
-    // Find field index by alias
-    public int findAlias( int alias ) {
-        for( int i=0; i<_fields.length; i++ )
-            if( _fields[i]._alias==alias )
-                return i;
-        return -1;
-    }
-
-
-    @Override
-    Type xmeet(Type t) {
-        TypeStruct that = (TypeStruct) t;
-        if( this==TOP ) return that;
-        if( that==TOP ) return this;
-        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( this._fields==null ) return that;
-        if( that._fields==null ) return this;
-        if( _fields.length != that._fields.length ) return BOT;
-        // Just do field meets
-        Field[] flds = new Field[_fields.length];
-        for( int i=0; i<_fields.length; i++ ) {
-            Field f0 = _fields[i], f1 = that._fields[i];
-            if( !f0._fname.equals(f1._fname) || f0._alias != f1._alias )
-                return BOT;
-            flds[i] = (Field)f0.meet(f1);
-        }
-        return make(_name,flds);
-    }
-
-    @Override
-    public TypeStruct dual() {
-        if( this==TOP ) return BOT;
-        if( this==BOT ) return TOP;
-        if( _fields == null ) return this;
-        Field[] flds = new Field[_fields.length];
-        for( int i=0; i<_fields.length; i++ )
-            flds[i] = _fields[i].dual();
-        return make(_name,flds);
-    }
-
-    // Keeps the same struct, but lower-bounds all fields.
-    @Override public TypeStruct glb() {
-        if( _glb() ) return this;
-        // Need to glb each field
-        Field[] flds = new Field[_fields.length];
-        for( int i=0; i<_fields.length; i++ )
-            flds[i] = _fields[i].glb();
-        return make(_name,flds);
-    }
-    private boolean _glb() {
-        if( _fields!=null )
-          for( Field f : _fields )
-              if( f.glb() != f )
-                 return false;
-        return true;
-    }
-    @Override public TypeStruct lub() {
-        if( _lub() ) return this;
-        // Need to glb each field
-        Field[] flds = new Field[_fields.length];
-        for( int i=0; i<_fields.length; i++ )
-            flds[i] = _fields[i].lub();
-        return make(_name,flds);
-    }
-    private boolean _lub() {
-        if( _fields!=null )
-          for( Field f : _fields )
-              if( f.lub() != f )
-                 return false;
-        return true;
-    }
-
-
-    // Is forward-reference
-    @Override public boolean isFRef() { return _fields==null; }
-    // All fields are final
-    @Override public boolean isFinal() {
-        if( _fields==null ) return true;
-        for( Field fld : _fields )
-            if( !fld.isFinal() )
-                return false;
-        return true;
-    }
-
-    @Override
-    boolean eq(Type t) {
-        TypeStruct ts = (TypeStruct)t; // Invariant
-        if( !_name.equals(ts._name) )
-            return false;
-        if( _fields == ts._fields ) return true;
-        if( _fields==null || ts._fields==null ) return false;
-        if( _fields.length!=ts._fields.length )
-            return false;
-        for( int i = 0; i < _fields.length; i++ )
-            if( _fields[i] != ts._fields[i] )
-                return false;
-        return true;
-    }
-
-    @Override
-    int hash() {
-        long hash = _name.hashCode();
-        if( _fields != null )
-            for( Field f : _fields )
-                hash = Utils.rot(hash,13) ^ f.hashCode();
-        return Utils.fold(hash);
-    }
-
-    @Override
-    public StringBuilder print(StringBuilder sb) {
-        if( this==BOT ) return sb.append("StructBot");
-        if( this==TOP ) return sb.append("StructTop");
-        sb.append(_name);
-        if( _fields == null ) return sb; // Forward reference struct, just print the name
-        sb.append(" {");
-        for( Field f : _fields )
-            f._type.print(sb).append(f._final ? " " : " !").append(f._fname).append("; ");
-        return sb.append("}");
-    }
-
-    @Override public String str() {
-        if( this==BOT ) return "StructBot";
-        if( this==TOP ) return "StructTop";
-        return _name;
-    }
-
-
-    public boolean isAry() { return _fields.length==2 && _fields[1]._fname.equals("[]"); }
-
-    public int aryBase() {
-        assert isAry();
-        if( _offs==null ) _offs = offsets();
-        return _offs[1];
-    }
-    public int aryScale() {
-        assert isAry();
-        return _fields[1]._type.log_size();
-    }
-
-
-    // Field offsets as packed byte offsets
-    private int[] _offs;  // Lazily computed and not part of the type semantics
-    public int offset(int idx) {
-        if( _offs==null ) _offs = offsets();
-        return _offs[idx];
-    }
-    private int[] offsets() {    // Field byte offsets
-        // Compute a layout for a collection of fields
-        assert _fields != null; // No forward refs
-        // Compute a layout
-        int[] cnts = new int[4]; // Count of fields at log field size
-        for( Field f : _fields )
-            cnts[f._type.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];
-        for( int i=3; i>=0; i-- ) {
-            offs[i] = off;
-            off += cnts[i]<<i;
-        }
-        // Assign offsets to all fields.
-        // Really a hidden radix sort.
-        _offs = new int[_fields.length+1];
-        for( Field f : _fields ) {
-            int log = f._type.log_size();
-            _offs[idx++] = offs[log]; // Field offset
-            offs[log] += 1<<log;      // Next field offset at same alignment
-            cnts[log]--;              // Count down, should be all zero at end
-        }
-        _offs[_fields.length] = (off+7)& ~7; // Round out to max alignment
-        return _offs;
-    }
-
-}
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeTuple.java b/chapter17/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
deleted file mode 100644
index a34c64db..00000000
--- a/chapter17/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
+++ /dev/null
@@ -1,95 +0,0 @@
-package com.seaofnodes.simple.type;
-
-import java.util.ArrayList;
-
-public class TypeTuple extends Type {
-
-    public final Type[] _types;
-
-    private TypeTuple(Type[] types) { super(TTUPLE); _types = types; }
-    public  static TypeTuple make(Type... types) { return new TypeTuple(types).intern(); }
-
-    private static final TypeTuple TEST = make(TypeInteger.BOT,TypeMemPtr.TEST);
-    public  static final TypeTuple START = make(Type.CONTROL,TypeMem.TOP,TypeInteger.BOT);
-    public  static void gather(ArrayList<Type> ts) {  ts.add(TEST); ts.add(START); }
-
-    @Override
-    Type xmeet(Type other) {
-        TypeTuple tt = (TypeTuple)other;     // contract from xmeet
-        if( _types.length != tt._types.length )
-            return BOTTOM;
-        Type[] ts = new Type[_types.length];
-        for( int i=0; i<_types.length; i++ )
-            ts[i] = _types[i].meet(tt._types[i]);
-        return make(ts);
-    }
-
-    @Override public Type dual() {
-        Type[] ts = new Type[_types.length];
-        for( int i=0; i<_types.length; i++ )
-            ts[i] = _types[i].dual();
-        return make(ts);
-    }
-
-    @Override
-    public Type glb() {
-        Type[] ts = new Type[_types.length];
-        for( int i=0; i<_types.length; i++ )
-            ts[i] = _types[i].glb();
-        return make(ts);
-    }
-
-    @Override public StringBuilder print(StringBuilder sb) {
-        sb.append("[  ");
-        for( Type t : _types )
-            t.print(sb).append(", ");
-        sb.setLength(sb.length()-2);
-        sb.append("]");
-        return sb;
-    }
-
-    @Override public String str() {
-        StringBuilder sb = new StringBuilder();
-        sb.append("[  ");
-        for( Type t : _types )
-            sb.append(t.str()).append(", ");
-        sb.setLength(sb.length()-2);
-        return sb.append("]").toString();
-    }
-
-    /**
-     * Display Type name in a format that's good for IR printer
-     */
-    @Override
-    public StringBuilder typeName(StringBuilder sb) {
-        sb.append("[");
-        for( Type t : _types )
-            t.typeName(sb).append(",");
-        sb.setLength(sb.length()-1);
-        return sb.append("]");
-    }
-
-    public static final TypeTuple IF_BOTH    = make(new Type[]{Type. CONTROL,Type. CONTROL});
-    public static final TypeTuple IF_NEITHER = make(new Type[]{Type.XCONTROL,Type.XCONTROL});
-    public static final TypeTuple IF_TRUE    = make(new Type[]{Type. CONTROL,Type.XCONTROL});
-    public static final TypeTuple IF_FALSE   = make(new Type[]{Type.XCONTROL,Type. CONTROL});
-
-    @Override
-    int hash() {
-        int sum = 0;
-        for( Type type : _types ) sum ^= type.hashCode();
-        return sum;
-    }
-
-    @Override
-    boolean eq( Type t ) {
-        TypeTuple tt = (TypeTuple)t; // Contract
-        if( _types.length != tt._types.length ) return false;
-        for( int i=0; i<_types.length; i++ )
-            if( _types[i]!=tt._types[i] )
-                return false;
-        return true;
-    }
-
-
-}