--- a/src/hotspot/share/oops/accessBackend.hpp	Wed Jan 10 10:21:25 2018 +0100
+++ b/src/hotspot/share/oops/accessBackend.hpp	Wed Jan 10 18:04:56 2018 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,7 @@
 #include "metaprogramming/conditional.hpp"
 #include "metaprogramming/enableIf.hpp"
 #include "metaprogramming/integralConstant.hpp"
+#include "metaprogramming/isSame.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/globalDefinitions.hpp"
 
@@ -54,11 +55,11 @@
     BARRIER_CLONE
   };
 
-  template <DecoratorSet decorators>
+  template <DecoratorSet decorators, typename T>
   struct MustConvertCompressedOop: public IntegralConstant<bool,
     HasDecorator<decorators, INTERNAL_VALUE_IS_OOP>::value &&
-    HasDecorator<decorators, INTERNAL_CONVERT_COMPRESSED_OOP>::value &&
-    HasDecorator<decorators, INTERNAL_RT_USE_COMPRESSED_OOPS>::value> {};
+    IsSame<typename HeapOopType<decorators>::type, narrowOop>::value &&
+    IsSame<T, oop>::value> {};
 
   // This metafunction returns an appropriate oop type if the value is oop-like
   // and otherwise returns the same type T.
@@ -172,13 +173,13 @@
   // Only encode if INTERNAL_VALUE_IS_OOP
   template <DecoratorSet idecorators, typename T>
   static inline typename EnableIf<
-    AccessInternal::MustConvertCompressedOop<idecorators>::value,
+    AccessInternal::MustConvertCompressedOop<idecorators, T>::value,
     typename HeapOopType<idecorators>::type>::type
   encode_internal(T value);
 
   template <DecoratorSet idecorators, typename T>
   static inline typename EnableIf<
-    !AccessInternal::MustConvertCompressedOop<idecorators>::value, T>::type
+    !AccessInternal::MustConvertCompressedOop<idecorators, T>::value, T>::type
   encode_internal(T value) {
     return value;
   }
@@ -192,12 +193,12 @@
   // Only decode if INTERNAL_VALUE_IS_OOP
   template <DecoratorSet idecorators, typename T>
   static inline typename EnableIf<
-    AccessInternal::MustConvertCompressedOop<idecorators>::value, T>::type
+    AccessInternal::MustConvertCompressedOop<idecorators, T>::value, T>::type
   decode_internal(typename HeapOopType<idecorators>::type value);
 
   template <DecoratorSet idecorators, typename T>
   static inline typename EnableIf<
-    !AccessInternal::MustConvertCompressedOop<idecorators>::value, T>::type
+    !AccessInternal::MustConvertCompressedOop<idecorators, T>::value, T>::type
   decode_internal(T value) {
     return value;
   }