PR6880: Don't dereference CallsExternalNode if it's NULL.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101897 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/IPA/CallGraph.cpp b/lib/Analysis/IPA/CallGraph.cpp
index c59c31c..62a4c31 100644
--- a/lib/Analysis/IPA/CallGraph.cpp
+++ b/lib/Analysis/IPA/CallGraph.cpp
@@ -158,9 +158,11 @@
   // destroy - Release memory for the call graph
   virtual void destroy() {
     /// CallsExternalNode is not in the function map, delete it explicitly.
-    CallsExternalNode->allReferencesDropped();
-    delete CallsExternalNode;
-    CallsExternalNode = 0;
+    if (CallsExternalNode) {
+      CallsExternalNode->allReferencesDropped();
+      delete CallsExternalNode;
+      CallsExternalNode = 0;
+    }
     CallGraph::destroy();
   }
 };