From 385db70abc590215a6af0ef53cbb9eefc5405759 Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Fri, 11 Sep 2026 19:47:39 -0700
Subject: More robust on broken inputs

---
 .../src/main/java/com/seaofnodes/simple/codegen/Opto.java     |  9 +++++++--
 .../src/main/java/com/seaofnodes/simple/node/ArithNode.java   |  4 ++++
 .../src/main/java/com/seaofnodes/simple/node/BoolNode.java    |  4 ++++
 .../src/main/java/com/seaofnodes/simple/node/CallNode.java    | 11 +++++++----
 .../src/main/java/com/seaofnodes/simple/node/MinusNode.java   |  2 ++
 5 files changed, 24 insertions(+), 6 deletions(-)

(limited to 'chapter25/src/main')

diff --git a/chapter25/src/main/java/com/seaofnodes/simple/codegen/Opto.java b/chapter25/src/main/java/com/seaofnodes/simple/codegen/Opto.java
index 690ae3ad..6e00d02c 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/codegen/Opto.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/codegen/Opto.java
@@ -304,7 +304,11 @@ abstract public class Opto {
                 int mode = 0;
                 for( int i=1; i<n.nIns(); i++ )
                     mode |= numericEvidence(n.in(i),visited);
-                assert mode != 0;
+                // A closed recursive numeric component can have no remaining
+                // concrete evidence after SCCP, e.g. dead all-integer loops.
+                // With no float evidence, settle to integer.
+                if( mode == 0 )
+                    mode = 1;
                 if( mode != 0 )  {
                     // If both evidence, FP wins
                     modeNode.setMode((byte)((mode&2)==2 ? 2 : 1)).init();
@@ -330,8 +334,9 @@ abstract public class Opto {
 
         int evidence = 0;
         assert !(n instanceof ConvertNode); // No test case
-        assert !(n instanceof    ModeNode);
         switch( n ) {
+        case ModeNode modeNode when modeNode.mode() != 0 -> { return modeNode.mode(); }
+        case ModeNode modeNode -> {}
         case PhiNode phi -> {}
         case ReturnNode ret -> {}
         case ProjNode proj when proj.in(0) instanceof CallEndNode cend -> {
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/ArithNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/ArithNode.java
index 8c21aef7..995b4743 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/node/ArithNode.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/node/ArithNode.java
@@ -57,6 +57,8 @@ public abstract class ArithNode extends Node implements ModeNode {
         Type bad = null;
         for( int i=1; i<n.nIns(); i++ ) {
             Type t = n.in(i)._type;
+            if( t==null )
+                return null;
             if( t.isHigh() )
                 return null;
             // A weak input is not evidence of a bad mode while the graph is
@@ -97,6 +99,8 @@ public abstract class ArithNode extends Node implements ModeNode {
     @Override
     public final Type compute() {
         Type t1 = in(1)._type, t2 = in(2)._type;
+        if( t1==null || t2==null )
+            return Type.TOP;
         if( t1.isHigh() || t2.isHigh() )
             return _mode==0 ? Type.TOP :
                 _mode==1 ? TypeInteger.TOP :
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/BoolNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/BoolNode.java
index ef71983e..ac3b0bc0 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/node/BoolNode.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/node/BoolNode.java
@@ -37,6 +37,8 @@ abstract public class BoolNode extends Node implements ModeNode {
     public TypeInteger compute() {
         Type t1 = in(1)._type;
         Type t2 = in(2)._type;
+        if( t1==null || t2==null )
+            return BOOL;
         // Exactly equals?
         if( t1.isHigh() || t2.isHigh() )
             return (TypeInteger)BOOL.dual();
@@ -79,6 +81,8 @@ abstract public class BoolNode extends Node implements ModeNode {
             return this instanceof LT ? CodeGen.CODE.ZERO : ConstantNode.make(TRUE);
         // Can we decide int vs flt?
         Type t1 = in(1)._type, t2 = in(2)._type;
+        if( t1==null || t2==null )
+            return null;
         if( _mode==0 ) {
             byte mode = ArithNode.mode(t1,t2);
             if( mode!=0 ) return setMode(mode).init();
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/CallNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/CallNode.java
index 90d7e379..9ce97ac6 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/node/CallNode.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/node/CallNode.java
@@ -153,11 +153,14 @@ public class CallNode extends CFGNode {
         fun.delDef(path);
         CodeGen.CODE.add(fun);
         CallEndNode cend = cend();
-        ReturnNode ret = fun.ret().keep();
-        cend.delDef(cend._inputs.find(ret));
-        CodeGen.CODE.add(cend);
+        ReturnNode ret = fun.ret();
+        if( cend != null ) {
+            ret.keep();
+            cend.delDef(cend._inputs.find(ret));
+            CodeGen.CODE.add(cend);
+            ret.unkeep();
+        }
         assert !linked(fun);
-        ret.unkeep();
     }
 
 
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/MinusNode.java
index 6101fba2..642fc2b2 100644
--- a/chapter25/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ b/chapter25/src/main/java/com/seaofnodes/simple/node/MinusNode.java
@@ -37,6 +37,8 @@ public class MinusNode extends Node implements ModeNode {
     @Override
     public Type compute() {
         Type t = in(1)._type;
+        if( t==null )
+            return Type.TOP;
         if( t.isHigh() )
             return _mode==0 ? Type.TOP :
                 _mode==1 ? TypeInteger.TOP :
-- 
cgit v1.2.3