diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index e68dd04a4c7..528806a4aab 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -1289,10 +1289,10 @@ AliasResult BasicAAResult::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
   // greater, we know they do not overlap.
   if (GEP1BaseOffset != 0 && DecompGEP1.VarIndices.empty()) {
     if (GEP1BaseOffset >= 0) {
-      if (V2Size != MemoryLocation::UnknownSize) {
+      if (V1Size != MemoryLocation::UnknownSize &&
+          V2Size != MemoryLocation::UnknownSize) {
         if ((uint64_t)GEP1BaseOffset < V2Size)
           return PartialAlias;
-        assert(V1Size != MemoryLocation::UnknownSize);
         return NoAlias;
       }
     } else {