[GR-56000] Don't allow IntegerExactOverflowNode as condition in ConditionalNode

PullRequest: graal/19919

Author: gergo-

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/IfNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -84,6 +84,7 @@
 import jdk.graal.compiler.nodes.spi.SimplifierTool;
 import jdk.graal.compiler.nodes.spi.SwitchFoldable;
 import jdk.graal.compiler.nodes.util.GraphUtil;
+import jdk.graal.compiler.replacements.nodes.arithmetic.IntegerExactOverflowNode;
 import jdk.vm.ci.code.CodeUtil;
 import jdk.vm.ci.meta.Constant;
 import jdk.vm.ci.meta.JavaConstant;
@@ -1706,6 +1707,13 @@ private ValueNode canonicalizeConditionalCascade(SimplifierTool tool, ValueNode
         if (trueValue.getStackKind() != JavaKind.Int && trueValue.getStackKind() != JavaKind.Long) {
             return null;
         }
+        if (condition() instanceof IntegerExactOverflowNode) {
+            /*
+             * An exact overflow node is tightly coupled to the if node that uses it. It must not be
+             * used as the condition in a conditional node.
+             */
+            return null;
+        }
         if (isSafeConditionalInput(trueValue, trueSuccessor) && isSafeConditionalInput(falseValue, falseSuccessor)) {
             return graph().unique(new ConditionalNode(condition(), trueValue, falseValue));
         }

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/replacements/nodes/arithmetic/IntegerExactOverflowNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,9 +31,12 @@
 import java.util.List;
 
 import jdk.graal.compiler.core.common.type.Stamp;
+import jdk.graal.compiler.graph.Node;
 import jdk.graal.compiler.graph.NodeClass;
 import jdk.graal.compiler.nodeinfo.NodeInfo;
 import jdk.graal.compiler.nodes.AbstractBeginNode;
+import jdk.graal.compiler.nodes.FixedGuardNode;
+import jdk.graal.compiler.nodes.GuardNode;
 import jdk.graal.compiler.nodes.IfNode;
 import jdk.graal.compiler.nodes.LogicNode;
 import jdk.graal.compiler.nodes.NodeView;
@@ -65,6 +68,14 @@ public ValueNode getY() {
         return y;
     }
 
+    @Override
+    protected boolean verifyNode() {
+        for (Node usage : usages()) {
+            assertTrue(usage instanceof GuardNode || usage instanceof FixedGuardNode || usage instanceof IfNode, "exact overflow node must only be used by guards or ifs, found: %s", usage);
+        }
+        return super.verifyNode();
+    }
+
     /**
      * Make sure the overflow detection nodes have the same order of inputs as the exact arithmetic
      * nodes.
@@ -119,5 +130,12 @@ public void simplify(SimplifierTool tool) {
 
             coupledNodes.forEach(n -> n.replaceAndDelete(split));
         }
+        if (hasNoUsages()) {
+            /*
+             * We don't want GVN during canonicalization to find this node and give it usages again,
+             * since the canonicalizer would not call this simplify method again.
+             */
+            safeDelete();
+        }
     }
 }