*** old/src/share/vm/opto/chaitin.hpp	Tue Jan 20 09:42:50 2015
--- new/src/share/vm/opto/chaitin.hpp	Tue Jan 20 09:42:50 2015

*** 576,585 ****
--- 576,611 ----
                                    Block *current_block, Node_List& value, Node_List &regnd,
                                    OptoReg::Name nreg, OptoReg::Name nreg2);
    // Extend the node to LRG mapping
    void add_reference( const Node *node, const Node *old_node);
  
+   // Record the first use of a def in the block for a register.
+   class RegDefUse {
+     Node* _def;
+     Node* _first_use;
+   public:
+     RegDefUse() : _def(NULL), _first_use(NULL) { }
+     Node* def() const       { return _def;       }
+     Node* first_use() const { return _first_use; }
+ 
+     void update(Node* def, Node* use) {
+       if (_def != def) {
+         _def = def;
+         _first_use = use;
+       }
+     }
+     void clear() {
+       _def = NULL;
+       _first_use = NULL;
+     }
+   };
+   typedef GrowableArray<RegDefUse> RegToDefUseMap;
+   int possibly_merge_multidef(Node *n, uint k, Block *block, RegToDefUseMap& reg2defuse);
+ 
+   // Merge nodes that are a part of a multidef lrg and produce the same value within a block.
+   void merge_multidefs();
+ 
  private:
  
    static int _final_loads, _final_stores, _final_copies, _final_memoves;
    static double _final_load_cost, _final_store_cost, _final_copy_cost, _final_memove_cost;
    static int _conserv_coalesce, _conserv_coalesce_pair;