Index: lib/Transforms/Utils/MemorySSA.cpp
===================================================================
--- lib/Transforms/Utils/MemorySSA.cpp
+++ lib/Transforms/Utils/MemorySSA.cpp
@@ -1044,6 +1044,14 @@
   if (isa<FenceInst>(I))
     return StartingAccess;
 
+  // Start with the thing we already think clobbers this location
+  MemoryAccess *DefiningAccess = StartingAccess->getDefiningAccess();
+
+  // At this point, DefiningAccess may be the live on entry def.
+  // If it is, we will not get a better result.
+  if (MSSA->isLiveOnEntryDef(DefiningAccess))
+    return DefiningAccess;
+
   UpwardsMemoryQuery Q;
   Q.OriginalAccess = StartingAccess;
   Q.IsCall = bool(ImmutableCallSite(I));
@@ -1051,17 +1059,9 @@
     Q.StartingLoc = MemoryLocation::get(I);
   Q.Inst = I;
   Q.DL = &Q.Inst->getModule()->getDataLayout();
-  if (auto CacheResult = doCacheLookup(StartingAccess, Q, Q.StartingLoc))
+  if (auto CacheResult = doCacheLookup(DefiningAccess, Q, Q.StartingLoc))
     return CacheResult;
 
-  // Start with the thing we already think clobbers this location
-  MemoryAccess *DefiningAccess = StartingAccess->getDefiningAccess();
-
-  // At this point, DefiningAccess may be the live on entry def.
-  // If it is, we will not get a better result.
-  if (MSSA->isLiveOnEntryDef(DefiningAccess))
-    return DefiningAccess;
-
   MemoryAccess *Result = getClobberingMemoryAccess(DefiningAccess, Q);
   doCacheInsert(Q.OriginalAccess, Result, Q, Q.StartingLoc);
   // TODO: When this implementation is more mature, we may want to figure out