Add sanity check


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5489 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index 80c64d1..badc9c0 100644
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -1029,6 +1029,7 @@
     if (AuxFCallsAlive[i])
       AuxFunctionCalls[CurIdx++].swap(AuxFunctionCalls[i]);
   if (!(Flags & DSGraph::RemoveUnreachableGlobals)) {
+    assert(GlobalsGraph && "No globals graph available??");
     // Move the unreachable call nodes to the globals graph...
     GlobalsGraph->AuxFunctionCalls.insert(GlobalsGraph->AuxFunctionCalls.end(),
                                           AuxFunctionCalls.begin()+CurIdx,