diff --git a/lib/Analysis/AliasSetTracker.cpp b/lib/Analysis/AliasSetTracker.cpp
index 0fb419266ce..303d7987b79 100644
--- a/lib/Analysis/AliasSetTracker.cpp
+++ b/lib/Analysis/AliasSetTracker.cpp
@@ -101,7 +101,7 @@ void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
       return;
     else if (AA.onlyReadsMemory(F)) {
       AliasTy = MayAlias;
-      AccessTy = Refs;
+      AccessTy |= Refs;
       return;
     }
   }