Fix an iterator invalidation bug I induced.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40830 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index d2892de..4622441 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -217,8 +217,7 @@
   // Add a new tree node for this BasicBlock, and link it as a child of
   // IDomNode
   DomTreeNode *C = new DomTreeNode(BB, IPDomNode);
-  DomTreeNodes[BB] = C;
-  return BBNode = IPDomNode->addChild(C);
+  return DomTreeNodes[BB] = IPDomNode->addChild(C);
 }
 
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