improve portability to avoid conflicting with std::next in c++'0x.
Patch by Howard Hinnant!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 273dbf0..25eb637 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -232,7 +232,7 @@
   // node is only legalized after all of its operands are legalized.
   DAG.AssignTopologicalOrder();
   for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
-       E = prior(DAG.allnodes_end()); I != next(E); ++I)
+       E = prior(DAG.allnodes_end()); I != llvm::next(E); ++I)
     LegalizeOp(SDValue(I, 0));
 
   // Finally, it's possible the root changed.  Get the new root.