Fix PR491 and testcase Transforms/DeadStoreElimination/2004-12-28-PartialStore.ll
llvm-svn: 19180
diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index 27a0b0a..e29bad5 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -111,7 +111,8 @@
if (AliasSet *AS = KillLocs.getAliasSetForPointerIfExists(Ptr, ValSize))
for (AliasSet::iterator ASI = AS->begin(), E = AS->end(); ASI != E; ++ASI)
- if (AA.alias(ASI.getPointer(), ASI.getSize(), Ptr, ValSize)
+ if (ASI.getSize() >= ValSize && // Overwriting all of this store.
+ AA.alias(ASI.getPointer(), ASI.getSize(), Ptr, ValSize)
== AliasAnalysis::MustAlias) {
// If we found a must alias in the killed set, then this store really
// is dead. Remember that the various operands of the store now have