Only unset argInfo if value changes

Signed-off-by: Liqun Liu <liqunl@ca.ibm.com>
eclipse · Nov 23, 2020 · 2565771 · 2565771
1 parent f719080
commit 2565771
Showing 1 changed file with 21 additions and 6 deletions.
diff --git a/compiler/optimizer/Inliner.cpp b/compiler/optimizer/Inliner.cpp
@@ -6383,6 +6383,7 @@ OMR_InlinerUtil::clearArgInfoForNonInvariantArguments(TR_CallTarget *target, TR_
       traceMsg(comp(), "Clearing arg info for non invariant arguments\n");
 
    TR::ResolvedMethodSymbol* methodSymbol = target->_calleeSymbol;
+
    TR_PrexArgInfo* argInfo = target->_prexArgInfo;
    if (!argInfo)
       {
@@ -6402,12 +6403,26 @@ OMR_InlinerUtil::clearArgInfoForNonInvariantArguments(TR_CallTarget *target, TR_
 
       TR_ASSERT(storeNode->getSymbolReference(), "stores should have symRefs");
       TR::ParameterSymbol*  parmSymbol = storeNode->getSymbolReference()->getSymbol()->getParmSymbol();
-      if (parmSymbol->getOrdinal() < argInfo->getNumArgs())
-         {
-         if (tracePrex)
-            traceMsg(comp(), "ARGS PROPAGATION: unsetting an arg [%i] of argInfo %p", parmSymbol->getOrdinal(), argInfo);
-         argInfo->set(parmSymbol->getOrdinal(), NULL);
-         cleanedAnything = true;
+      auto ordinal = parmSymbol->getOrdinal();
+      if (ordinal < argInfo->getNumArgs() && argInfo->get(ordinal))
+         {
+         auto prexArg = argInfo->get(ordinal);
+         // If the value to store is the same as the original value, don't unset the arg info
+         auto valueNode = storeNode->getFirstChild();
+         if (valueNode->getOpCode().hasSymbolReference() &&
+             valueNode->getSymbolReference()->hasKnownObjectIndex() &&
+             prexArg->getKnownObjectIndex() == valueNode->getSymbolReference()->getKnownObjectIndex())
+            {
+            if (tracePrex)
+               traceMsg(comp(), "ARGS PROPAGATION: arg %d holds the same value after store node n%dn, keep argInfo %p", ordinal, storeNode->getGlobalIndex(), argInfo);
+            }
+         else
+            {
+            if (tracePrex)
+               traceMsg(comp(), "ARGS PROPAGATION: unsetting an arg [%i] of argInfo %p", parmSymbol->getOrdinal(), argInfo);
+            argInfo->set(parmSymbol->getOrdinal(), NULL);
+            cleanedAnything = true;
+            }
          }
       }