Fix the ASSERT in RegDepCopyRemoval

Fix the assert added in RegDepCopyRemoval to consider missing case
where child of GlRegDeps is PassThrough with the regLoad child and
both uses same register.

Fixes: eclipse-openj9/openj9#10630

Signed-off-by: Rahil Shah <rahil@ca.ibm.com>

compiler/optimizer/RegDepCopyRemoval.cpp

@@ -437,8 +437,14 @@ TR::RegDepCopyRemoval::makeFreshCopy(TR_GlobalRegisterNumber reg)
    NodeChoice &choice = getNodeChoice(reg);
    if (choice.regStoreNode == NULL)
       {
-      // As we walk down in Extended Basic Block, for each register, if exists, we record a regStore node, if we do not have one found for given register, node should be regLoad. 
-      TR_ASSERT_FATAL(dep.node->getOpCode().isLoadReg(), "Only PassThrough (with a corresponding regStore appeared before) or regLoad is expected as children of GlRegDeps, Unexpected Node is n%dn OpCode %s",dep.node->getGlobalIndex(), dep.node->getOpCode().getName());
+      // As we walk down in Extended Basic Block, for each register, if exists, we record a regStore node, if we do not have one found for given register, node should be regLoad.
+      // It is possible that the child node of GlRegDep is PassThrough with regLoad child where both uses same register. In this case, it won't have the corresponding regStore.
+      TR_ASSERT_FATAL_WITH_NODE(dep.node,
+                                 dep.node->getOpCode().isLoadReg()
+                                 || (dep.node->getOpCodeValue() == TR::PassThrough
+                                    && dep.node->getFirstChild()->getOpCode().isLoadReg()
+                                    && dep.node->getGlobalRegisterNumber() == dep.node->getFirstChild()->getGlobalRegisterNumber()),
+                                 "Only PassThrough (with corresponding regStore appeared before or using same Global Register as child) or regLoad nodes are expected as children of GlRegDeps.");
       choice.regStoreNode = TR::Node::create(dep.node, comp()->il.opCodeForRegisterStore(dep.node->getDataType()), 1, copyNode);
       _treetop->insertBefore(TR::TreeTop::create(comp(), choice.regStoreNode));
       choice.regStoreNode->setGlobalRegisterNumber(dep.node->getGlobalRegisterNumber());