Fix the check on isStoreIndirect in LocalAnalysis

In `hasOldExpressionOnRhs()`, we temporarily change wrtbar to aloadi
for the syntactic comparison in `areSyntacticallyEquivalent()`.
When it’s an indirect store, the number of children of the node is
set to 1, otherwise 0. Because the check on whether not the node
is an indirect store happens after the wrtbar node is recreated as aloadi,
`node->getOpCode().isStoreIndirect()` is false for aloadi, and the
number of children for wrtbar node ends up as 0. It prevents
`areSyntacticallyEquivalent()` from comparing the first child of the two
nodes. It concludes that different expressions as the same.
The fix is to check if it’s an indirect store from the original node.

Fixes eclipse-openj9/openj9#11569

Signed-off-by: Annabelle Huo <Annabelle.Huo@ibm.com>

compiler/optimizer/LocalAnalysis.cpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2020 IBM Corp. and others
+ * Copyright (c) 2000, 2021 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -488,7 +488,7 @@ int TR_LocalAnalysisInfo::hasOldExpressionOnRhs(TR::Node *node, bool recalcConta
 #endif
    bool seenWriteBarrier = false;
    int32_t storeNumChildren = node->getNumChildren();
-
+   bool isStoreIndirect = node->getOpCode().isStoreIndirect();
 
    // If node is a null check, compare the
    // null check reference only to establish syntactic equivalence
@@ -528,7 +528,7 @@ int TR_LocalAnalysisInfo::hasOldExpressionOnRhs(TR::Node *node, bool recalcConta
 #endif
 
          TR::Node::recreate(node, _compilation->il.opCodeForCorrespondingLoadOrStore(node->getOpCodeValue()));
-         if (node->getOpCode().isStoreIndirect())
+         if (isStoreIndirect)
             {
             node->setNumChildren(1);
             }
@@ -548,6 +548,7 @@ int TR_LocalAnalysisInfo::hasOldExpressionOnRhs(TR::Node *node, bool recalcConta
       int32_t hashValue = _hashTable->hash(node);
       HashTable::Cursor cursor(_hashTable, hashValue);
       TR::Node *other;
+      bool tmpIsStoreIndirect = false;
       for (other = cursor.firstNode(); other; other = cursor.nextNode())
          {
          // Convert other node's opcode to be a load temporarily
@@ -566,12 +567,13 @@ int TR_LocalAnalysisInfo::hasOldExpressionOnRhs(TR::Node *node, bool recalcConta
             if (other->getOpCode().isWrtBar())
                seenOtherWriteBarrier = true;
 
+            tmpIsStoreIndirect = other->getOpCode().isStoreIndirect();
 #ifdef J9_PROJECT_SPECIFIC
             seenOtherIndirectBCDStore = other->getType().isBCD();
 #endif
             TR::Node::recreate(other, _compilation->il.opCodeForCorrespondingLoadOrStore(other->getOpCodeValue()));
 
-            if (other->getOpCode().isStoreIndirect())
+            if (tmpIsStoreIndirect)
                {
                other->setNumChildren(1);
                }