diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 3d1b20bba7a0..369f2f4f90e1 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -120,7 +120,7 @@ AliasAnalysis::getModRefBehavior(CallSite CS,
 AliasAnalysis::ModRefBehavior
 AliasAnalysis::getModRefBehavior(Function *F,
                                  std::vector<PointerAccessInfo> *Info) {
-  if (F->doesNotAccessMemory())
+  if (F && F->doesNotAccessMemory())
     // Can't do better than this.
     return DoesNotAccessMemory;
   return UnknownModRefBehavior;