Fix
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070416/047971.html


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36236 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index f93190c..b239596 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -284,7 +284,7 @@
     for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB);
          SI != SE; ++SI)
       // Does Node immediately dominate this predecessor?
-      if (DT[*SI]->getIDom() != Node)
+      if (DT[*SI] && DT[*SI]->getIDom() != Node)
         S.insert(*SI);
 
   // At this point, S is DFlocal.  Now we union in DFup's of our children...