--- old/src/hotspot/share/memory/universe.hpp	2018-05-07 15:52:03.272367261 +0200
+++ new/src/hotspot/share/memory/universe.hpp	2018-05-07 15:52:02.988362450 +0200
@@ -195,6 +195,9 @@
   static struct NarrowPtrStruct _narrow_klass;
   static address _narrow_ptrs_base;
 
+  // value type using klass alignment encoded as oop metadata
+  static int     _oop_metadata_valuetype_mask;
+
   // array of dummy objects used with +FullGCAlot
   debug_only(static objArrayOop _fullgc_alot_dummy_array;)
   // index of next entry to clear
@@ -436,8 +439,13 @@
   static void     set_narrow_klass_shift(int shift)       {
     assert(shift == 0 || shift == LogKlassAlignmentInBytes, "invalid shift for klass ptrs");
     _narrow_klass._shift   = shift;
+    if (shift == LogKlassAlignmentInBytes) {
+      _oop_metadata_valuetype_mask = 1;
+    }
   }
 
+  static int oop_metadata_valuetype_mask() { return _oop_metadata_valuetype_mask; }
+
   // Reserve Java heap and determine CompressedOops mode
   static ReservedSpace reserve_heap(size_t heap_size, size_t alignment);