Index: lib/Transforms/Scalar/GVN.cpp
===================================================================
--- lib/Transforms/Scalar/GVN.cpp
+++ lib/Transforms/Scalar/GVN.cpp
@@ -2159,15 +2159,10 @@
   // split critical edge, and hence may invalidate the RPO/DT iterator.
   //
   std::vector<BasicBlock *> BBVect;
-  BBVect.reserve(256);
-  // Needed for value numbering with phi construction to work.
-  ReversePostOrderTraversal<Function *> RPOT(&F);
-  for (ReversePostOrderTraversal<Function *>::rpo_iterator RI = RPOT.begin(),
-                                                           RE = RPOT.end();
-       RI != RE; ++RI)
-    BBVect.push_back(*RI);
+  std::copy(po_begin(&F), po_end(&F), std::back_inserter(BBVect));
 
-  for (std::vector<BasicBlock *>::iterator I = BBVect.begin(), E = BBVect.end();
+  // Need to go through the vector in reverse.
+  for (std::vector<BasicBlock *>::reverse_iterator I = BBVect.rbegin(), E = BBVect.rend();
        I != E; I++)
     Changed |= processBlock(*I);