diff --git a/lib/Analysis/IPA/CallGraph.cpp b/lib/Analysis/IPA/CallGraph.cpp
index 74a28d8..70bf2c4 100644
--- a/lib/Analysis/IPA/CallGraph.cpp
+++ b/lib/Analysis/IPA/CallGraph.cpp
@@ -126,6 +126,7 @@
     delete I->second;
   FunctionMap.clear();
   delete CallsExternalNode;
+  CallsExternalNode = 0;
 }
 
 static void WriteToOutput(const CallGraphNode *CGN, std::ostream &o) {