From 2eba63966bdc3d9cfdf41ee085f35cbb6d529bbc Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Wed, 7 Oct 2026 19:10:51 -0700
Subject: Towrds getting RA spill counts comparable

Ignore JIGs.  Get test suites more conical, so reg alloc spill counts are comparable
---
 .../java/com/seaofnodes/simple/codegen/IFG.java    |  7 ++++
 .../com/seaofnodes/simple/node/CallEndNode.java    | 43 ++++++++++++++++++++--
 .../java/com/seaofnodes/simple/node/FunNode.java   |  7 +++-
 3 files changed, 52 insertions(+), 5 deletions(-)

(limited to 'chapter25/src/main')

diff --git a/chapter25/src/main/java/com/seaofnodes/simple/codegen/IFG.java b/chapter25/src/main/java/com/seaofnodes/simple/codegen/IFG.java
index 6145910c..bcdb14bf 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/codegen/IFG.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/codegen/IFG.java
@@ -457,6 +457,13 @@ abstract public class IFG {
             int area = cfg != use.cfg0()
                 ? functionArea(lrg._fun,alloc)
                 : cfg._outputs.find(use)-cfg._outputs.find(def)-1;
+            // A single-use function address can move next to its use without
+            // adding an instruction.  Prefer that to saving a callee-save
+            // register just to hold the address.  Stay in the same block and
+            // require a gap so the clone makes progress.
+            if( def instanceof FunPtrNode && !lrg._multiUse &&
+                cfg == use.cfg0() && area > 0 )
+                return 1000000;
             if( area > 0 )
                 return areaScore(area,loopCost(use));
         }
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/CallEndNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
index 162f9c24..35180fea 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
@@ -179,10 +179,12 @@ public class CallEndNode extends CFGNode implements MultiNode {
             { addDep(fptr); return -1; }
 
         // Encouraged inlining because small size and constructor.
-        int maxSize = fun._name!=null && fun.isInit() && !fun.isClz() ? 200 : 100;
-        if( fun._approxUIDs >= maxSize )
-            return -2;          // Try later (if shrinking helps)
-        if( fun.body().cardinality() >= maxSize )
+        int maxSize = fun.inlineLimit();
+        // A large parse can leave only a tiny initializer.  Recognize that
+        // without repeatedly walking the whole body while it shrinks.
+        if( fun._approxUIDs >= maxSize ) {
+            if( !smallBody(fun) ) return -1;
+        } else if( fun.body().cardinality() >= maxSize )
             return -1;          // Try later (if cleanup makes the real body small enough)
 
         // Can be cloned but not trivial
@@ -192,6 +194,39 @@ public class CallEndNode extends CFGNode implements MultiNode {
         return 1;
     }
 
+    // Bounded, conservative recognition of straight-line initializer boilerplate.
+    // Walk uses from the entry and stop at Return, never following callers or
+    // constant inputs.  This also avoids scanning sparse MemMerge input arrays.
+    // Watch only this small prefix, including an unsupported node that may fold.
+    private static final Node[] TINYBODY = new Node[15]; // Tiny worklist
+    private boolean smallBody(FunNode fun) {
+        ReturnNode ret = fun.ret();
+        for( Node in : ret._inputs )
+            if( in!=null ) addDep(in);
+        if( ret.ctrl()!=fun ) return false;
+        TINYBODY[0] = fun;
+        int len=1;
+        for( int i=0; i<len; i++ ) {
+            Node n = TINYBODY[i];
+            addDep(n);
+            if( n==ret ) continue;
+            if( n instanceof ParmNode parm && parm.region()!=fun ) return false;
+            if( n!=fun && !(n instanceof ParmNode) &&
+                !(n instanceof StoreNode) && !(n instanceof MemMergeNode) )
+                return false;                             // Something unexpected
+            if( n.nOuts()>TINYBODY.length ) return false; // Too big
+            for( Node use : n._outputs ) {
+                if( use==null ) continue;
+                int j=0;
+                while( j<len && TINYBODY[j]!=use ) j++;
+                if( j<len ) continue; // Already in TINYBODY
+                if( len==TINYBODY.length ) { addDep(use); return false; } // Too big
+                TINYBODY[len++] = use;  // Add to worklist
+            }
+        }
+        return true;
+    }
+
     public void doInline() {
         assert _inline > 0;    // Only called when possible to inline
 
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/FunNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/FunNode.java
index 29e9900a..b74f9e6b 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/node/FunNode.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/node/FunNode.java
@@ -221,6 +221,11 @@ public class FunNode extends RegionNode {
     public static boolean isInit(String name ) { return name!=null && name.endsWith("init>"); }
     public static boolean isInstance(String name ) { return name!=null && name.endsWith(".<init>"); }
 
+    // Allocation factories and instance initializers carry extra memory boilerplate.
+    public int inlineLimit() {
+        return isInstance() || (_name!=null && _name.endsWith(".<new>")) ? 200 : 100;
+    }
+
     // Function is public (callable from Start directly).
     public boolean isPublic( ) {
         // Never true for anonymous functions
@@ -316,7 +321,7 @@ public class FunNode extends RegionNode {
     FunNode copyBody() {
         // Build the function body BitSet
         BitSet body = body();
-        assert body.cardinality() < 100;
+        assert body.cardinality() < inlineLimit();
         // Walk the body, cloning
         IdentityHashMap<Node,Node> map = new IdentityHashMap<>();
         BitSet visit = CodeGen.CODE.visit();
-- 
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