diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index fb9ece2..e68dd04a 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -1292,6 +1292,7 @@
       if (V2Size != MemoryLocation::UnknownSize) {
         if ((uint64_t)GEP1BaseOffset < V2Size)
           return PartialAlias;
+        assert(V1Size != MemoryLocation::UnknownSize);
         return NoAlias;
       }
     } else {