From d5770b4022c35e069fca9b8ba42c163b70b9de27 Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Tue, 14 Jan 2025 09:35:56 -0800
Subject: 2 more fuzzer bugs

---
 .../src/main/java/com/seaofnodes/simple/Parser.java     |  2 ++
 .../main/java/com/seaofnodes/simple/node/LoopNode.java  | 17 -----------------
 .../java/com/seaofnodes/simple/node/RegionNode.java     | 13 +++++++++----
 3 files changed, 11 insertions(+), 21 deletions(-)

(limited to 'chapter18/src/main/java/com')

diff --git a/chapter18/src/main/java/com/seaofnodes/simple/Parser.java b/chapter18/src/main/java/com/seaofnodes/simple/Parser.java
index 4f19dda2..03ae978a 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/Parser.java
@@ -1301,6 +1301,7 @@ public class Parser {
         if( matchx("++") || matchx("--") ) {
             if( f._final && !f._fname.equals("[]") )
                 throw error("Cannot reassign final '"+f._fname+"'");
+            load.keep();
             int delta = _lexer.peek(-1)=='+' ? 1 : -1; // Pre vs post
             Node val = f._type instanceof TypeFloat
                 ?        peep(new AddFNode(load,con(TypeFloat.constant(delta))))
@@ -1311,6 +1312,7 @@ public class Parser {
             // done via the type system.
             if( base.isAry() )  st.setDef(0,ctrl());
             memAlias(f._alias, peep(st));
+            load.unkeep();
             // And use the original loaded value as the result
         } else expr.unkill();
         off.unkill();
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/chapter18/src/main/java/com/seaofnodes/simple/node/LoopNode.java
index a31c8ac8..f70a1012 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/LoopNode.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/LoopNode.java
@@ -23,23 +23,6 @@ public class LoopNode extends RegionNode {
         return entry()._type;
     }
 
-    @Override
-    public Node idealize() {
-        if( inProgress() ) return null;
-        // Dead infinite loops with NO control flow out stick around - as a
-        // dead infinite loop, to signal that control stops and spins here.
-        if( nIns()==2 && !hasPhi() && !hasCFG() )
-            return null;
-        return super.idealize();
-    }
-
-    private boolean hasCFG() {
-        for( Node phi : _outputs )
-            if( phi instanceof CFGNode )
-                return true;
-        return false;
-    }
-
     // Bypass Region idom, same as the default idom() using use in(1) instead of in(0)
     @Override public int idepth() { return _idepth==0 ? (_idepth=idom().idepth()+1) : _idepth; }
     // Bypass Region idom, same as the default idom() using use in(1) instead of in(0)
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/RegionNode.java b/chapter18/src/main/java/com/seaofnodes/simple/node/RegionNode.java
index d8e24964..ea053c02 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/RegionNode.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/RegionNode.java
@@ -68,13 +68,18 @@ public class RegionNode extends CFGNode {
             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( !_disablePeephole &&
-            !hasPhi() &&       // No Phi users, just a control user
+        if( !_disablePeephole && // Optional
+            !hasPhi() &&         // No Phi users, just a control user
             in(1) instanceof CProjNode p1 &&
             in(2) instanceof CProjNode p2 &&
             p1.in(0).addDep(this)==p2.in(0).addDep(this) &&
-            p1.in(0) instanceof IfNode iff )
-            return iff.ctrl();
+            p1.in(0) instanceof IfNode iff ) {
+            // Replace with the iff.ctrl directly
+            if( nIns()==3 ) return iff.ctrl();
+            // Just delete the path for fat Regions
+            setDef(1,iff.ctrl());
+            return delDef(2);
+        }
 
         return null;
     }
-- 
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