--- old/src/hotspot/share/gc/g1/heapRegionType.hpp	2018-10-05 11:11:07.555645800 -0700
+++ new/src/hotspot/share/gc/g1/heapRegionType.hpp	2018-10-05 11:11:06.653946600 -0700
@@ -74,8 +74,9 @@
     ContinuesHumongousTag = HumongousMask | PinnedMask + 1,
 
     OldMask               = 16,
+    PreMatureOldMask      = OldMask + 1,
     OldTag                = OldMask,
-
+    PreMatureOldTag       = PreMatureOldMask,
     // Archive regions are regions with immutable content (i.e. not reclaimed, and
     // not allocated into during regular operation). They differ in the kind of references
     // allowed for the contained objects:
@@ -137,6 +138,8 @@
   // is_old regions may or may not also be pinned
   bool is_old() const { return (get() & OldMask) != 0; }
 
+  bool is_premature_old() const { return get() == PreMatureOldTag; }
+
   bool is_old_or_humongous() const { return (get() & (OldMask | HumongousMask)) != 0; }
 
   bool is_old_or_humongous_or_archive() const { return (get() & (OldMask | HumongousMask | ArchiveMask)) != 0; }
@@ -157,6 +160,8 @@
 
   void set_old() { set(OldTag); }
 
+  void set_premature_old() { set(PreMatureOldTag); }
+
   // Change the current region type to be of an old region type if not already done so.
   // Returns whether the region type has been changed or not.
   bool relabel_as_old() {