[GR-39650] Floating div nodes: fixes for stamps.

PullRequest: graal/12590

Author: davleopo

compiler/src/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/GuardNode.java

@@ -183,4 +183,16 @@ public NodeSourcePosition getNoDeoptSuccessorPosition() {
     public void setNoDeoptSuccessorPosition(NodeSourcePosition noDeoptSuccessorPosition) {
         this.noDeoptSuccessorPosition = noDeoptSuccessorPosition;
     }
+
+    /**
+     * Determine if the this guard will lead to an unconditional {@link DeoptimizeNode} because its
+     * condition is a constant.
+     */
+    public boolean willDeoptUnconditionally() {
+        if (getCondition() instanceof LogicConstantNode) {
+            LogicConstantNode c = (LogicConstantNode) getCondition();
+            return c.getValue() == negated;
+        }
+        return false;
+    }
 }

compiler/src/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/calc/FloatingIntegerDivRemNode.java

@@ -36,6 +36,7 @@
 import org.graalvm.compiler.nodeinfo.InputType;
 import org.graalvm.compiler.nodeinfo.NodeInfo;
 import org.graalvm.compiler.nodes.GraphState.StageFlag;
+import org.graalvm.compiler.nodes.GuardNode;
 import org.graalvm.compiler.nodes.NodeView;
 import org.graalvm.compiler.nodes.ValueNode;
 import org.graalvm.compiler.nodes.extended.GuardedNode;
@@ -121,8 +122,14 @@ private boolean overflowVisibleSideEffect() {
 
     @Override
     public boolean verify() {
-        GraalError.guarantee((!canDivideByZero() && !overflowVisibleSideEffect()) || graph().isAfterStage(StageFlag.FIXED_READS),
-                        "Floating irem must never create an exception or trap");
+        /*
+         * Special case unconditionally deopting rem operations: Other optimziations can lead to
+         * graphs where the rem operation will unconditionally deopt.
+         */
+        boolean guardWillAlwaysDeopt = getGuard() != null && getGuard() instanceof GuardNode && ((GuardNode) getGuard()).willDeoptUnconditionally();
+        boolean cannotDeopt = (!canDivideByZero() && !overflowVisibleSideEffect());
+        boolean isAfterStage = graph().isAfterStage(StageFlag.FIXED_READS);
+        GraalError.guarantee(guardWillAlwaysDeopt || cannotDeopt || isAfterStage, "Floating irem must never create an exception or trap");
         return super.verify();
     }
 }