[GR-33496] Better guarded replacements in read elimination

PullRequest: graal/9711

Author: gergo-

compiler/src/org.graalvm.compiler.virtual/src/org/graalvm/compiler/virtual/phases/ea/ReadEliminationClosure.java

@@ -107,7 +107,7 @@ protected boolean processNode(Node node, ReadEliminationBlockState state, GraphE
                 LoadCacheEntry identifier = new LoadCacheEntry(object, new FieldLocationIdentity(access.field()));
                 ValueNode cachedValue = state.getCacheEntry(identifier);
                 if (node instanceof LoadFieldNode) {
-                    if (cachedValue != null && access.stamp(NodeView.DEFAULT).isCompatible(cachedValue.stamp(NodeView.DEFAULT))) {
+                    if (cachedValue != null && areValuesReplaceable(access, cachedValue, considerGuards)) {
                         effects.replaceAtUsages(access, cachedValue, access);
                         addScalarAlias(access, cachedValue);
                         deleted = true;
@@ -224,7 +224,7 @@ protected boolean processNode(Node node, ReadEliminationBlockState state, GraphE
         return deleted;
     }
 
-    private static boolean areValuesReplaceable(ValueNode originalValue, ValueNode replacementValue, boolean considerGuards) {
+    protected static boolean areValuesReplaceable(ValueNode originalValue, ValueNode replacementValue, boolean considerGuards) {
         return originalValue.stamp(NodeView.DEFAULT).isCompatible(replacementValue.stamp(NodeView.DEFAULT)) &&
                         (!considerGuards || (getGuard(originalValue) == null || getGuard(originalValue) == getGuard(replacementValue)));
     }