Clean up some uses of std::distance, now that we have allnodes_size.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52545 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 883ba38..3be3377 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -313,8 +313,7 @@
   }
 
   assert(Order.size() == Visited.size() &&
-         Order.size() == 
-         (unsigned)std::distance(DAG.allnodes_begin(), DAG.allnodes_end()) &&
+         Order.size() == DAG.allnodes_size() &&
          "Error: DAG is cyclic!");
 }