*** old/src/share/vm/gc_implementation/parallelScavenge/psScavenge.hpp	Thu May 30 11:15:51 2013
--- new/src/share/vm/gc_implementation/parallelScavenge/psScavenge.hpp	Thu May 30 11:15:51 2013

*** 66,78 ****
--- 66,81 ----
    static PSIsAliveClosure     _is_alive_closure;     // Closure used for reference processing
    static CardTableExtension*  _card_table;           // We cache the card table for fast access.
    static bool                 _survivor_overflow;    // Overflow this collection
    static uint                 _tenuring_threshold;   // tenuring threshold for next scavenge
    static elapsedTimer         _accumulated_time;     // total time spent on scavenge
-   static HeapWord*           _young_generation_boundary; // The lowest address possible for the young_gen.
    // This is used to decide if an oop should be scavenged,
    // cards should be marked, etc.
+   static HeapWord*            _young_generation_boundary;
+   // Used to optimize compressed oops young gen boundary checking.
+   static uintptr_t            _young_generation_boundary_compressed;
    static Stack<markOop, mtGC> _preserved_mark_stack; // List of marks to be restored after failed promotion
    static Stack<oop, mtGC>     _preserved_oop_stack;  // List of oops that need their mark restored.
    static CollectorCounters*   _counters;             // collector performance counters
    static bool                 _promotion_failed;
  

*** 110,119 ****
--- 113,125 ----
    }
    // Adaptive size policy support.  When the young generation/old generation
    // boundary moves, _young_generation_boundary must be reset
    static void set_young_generation_boundary(HeapWord* v) {
      _young_generation_boundary = v;
+     if (UseCompressedOops) {
+       _young_generation_boundary_compressed = (uintptr_t)oopDesc::encode_heap_oop((oop)v);
+     }
    }
  
    // Called by parallelScavengeHeap to init the tenuring threshold
    static void initialize();
  

*** 138,151 ****
--- 144,165 ----
      inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p);
  
    static void copy_and_push_safe_barrier_from_klass(PSPromotionManager* pm, oop* p);
  
    // Is an object in the young generation
!   // This assumes that the HeapWord argument is in the heap,
!   // This assumes that the 'o' is in the heap,
    // so it only checks one side of the complete predicate.
+ 
+   inline static bool is_obj_in_young(oop o) {
+     return (HeapWord*)o >= _young_generation_boundary;
+   }
+ 
+   inline static bool is_obj_in_young(narrowOop o) {
+     return (uintptr_t)o >= _young_generation_boundary_compressed;
+   }
+ 
    inline static bool is_obj_in_young(HeapWord* o) {
!     const bool result = (o >= _young_generation_boundary);
      return result;
!     return o >= _young_generation_boundary;
    }
  };
  
  #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_HPP