diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -327,6 +327,7 @@
   OW_End,
   OW_PartialEarlierWithFullLater,
   OW_MaybePartial,
+  OW_None,
   OW_Unknown
 };
 
@@ -1055,7 +1056,7 @@
 
     // Can reach here only if accesses are known not to overlap. There is no
     // dedicated code to indicate no overlap so signal "unknown".
-    return OW_Unknown;
+    return OW_None;
   }
 
   bool isInvisibleToCallerAfterRet(const Value *V) {
@@ -1455,7 +1456,7 @@
                               DepWriteOffset, InstWriteOffset);
         // If Current does not write to the same object as KillingDef, check
         // the next candidate.
-        if (OR == OW_Unknown)
+        if (OR == OW_Unknown || OR == OW_None)
           continue;
         else if (OR == OW_MaybePartial) {
           // If KillingDef only partially overwrites Current, check the next
@@ -1464,6 +1465,7 @@
           // which are less likely to be removable in the end.
           if (PartialLimit <= 1) {
             WalkerStepLimit -= 1;
+            LLVM_DEBUG(dbgs() << "   ... reached partial limit ... continue with next access\n");
             continue;
           }
           PartialLimit -= 1;