diff --git a/include/llvm/DerivedTypes.h b/include/llvm/DerivedTypes.h
index fa951bf70d0..b5824f8f815 100644
--- a/include/llvm/DerivedTypes.h
+++ b/include/llvm/DerivedTypes.h
@@ -50,6 +50,10 @@ protected:
   ///
   void dropAllTypeUses();
 
+  /// unlockedRefineAbstractTypeTo - Internal version of refineAbstractTypeTo
+  /// that performs no locking.  Only used for internal recursion.
+  void unlockedRefineAbstractTypeTo(const Type *NewType);
+  
 public:
 
   //===--------------------------------------------------------------------===//