diff --git a/lib/Bytecode/Writer/SlotCalculator.h b/lib/Bytecode/Writer/SlotCalculator.h
index 1dc0cc37bd3..8bb87dd434a 100644
--- a/lib/Bytecode/Writer/SlotCalculator.h
+++ b/lib/Bytecode/Writer/SlotCalculator.h
@@ -50,7 +50,7 @@ class SlotCalculator {
   typedef std::vector<const Value*> TypePlane;
   std::vector<TypePlane> Table;
   TypeList Types;
-  typedef std::map<const Value*, unsigned> NodeMapType;
+  typedef DenseMap<const Value*, unsigned> NodeMapType;
   NodeMapType NodeMap;
 
   typedef std::map<const Type*, unsigned> TypeMapType;