diff --git a/clang/include/clang/Parse/Ownership.h b/clang/include/clang/Parse/Ownership.h
index ed1b068f8140..5eb9635f06a1 100644
--- a/clang/include/clang/Parse/Ownership.h
+++ b/clang/include/clang/Parse/Ownership.h
@@ -166,7 +166,7 @@ namespace llvm {
 // conversions.
 
 // Flip this switch to measure performance impact of the smart pointers.
-#define DISABLE_SMART_POINTERS
+//#define DISABLE_SMART_POINTERS
 
 namespace llvm {
   template<>