Make LiveRange objects 1 word smaller by using a bool instead of enum for register kind.

src/lithium-allocator.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 128 matching lines @@
   // Code relies on kStep being a power of two.
   STATIC_ASSERT(IS_POWER_OF_TWO(kStep));
 
   explicit LifetimePosition(int value) : value_(value) { }
 
   int value_;
 };
 
 
 enum RegisterKind {
-  NONE,
   GENERAL_REGISTERS,
   DOUBLE_REGISTERS
 };
 
 
 // A register-allocator view of a Lithium instruction. It contains the id of
 // the output operand and a list of input operand uses.
 
 class LInstruction;
 class LEnvironment;
@@ skipping 152 matching lines @@
 
   // Can this live range be spilled at this position.
   bool CanBeSpilled(LifetimePosition pos);
 
   // Split this live range at the given position which must follow the start of
   // the range.
   // All uses following the given position will be moved from this
   // live range to the result live range.
   void SplitAt(LifetimePosition position, LiveRange* result);
 
-  bool IsDouble() const { return assigned_register_kind_ == DOUBLE_REGISTERS; }
+  bool IsDouble() const { return is_double_; }
   bool HasRegisterAssigned() const {
     return assigned_register_ != kInvalidAssignment;
   }
   bool IsSpilled() const { return spilled_; }
   UsePosition* FirstPosWithHint() const;
 
   LOperand* FirstHint() const {
     UsePosition* pos = FirstPosWithHint();
     if (pos != NULL) return pos->hint();
     return NULL;
@@ skipping 37 matching lines @@
 #endif
 
  private:
   void ConvertOperands();
   UseInterval* FirstSearchIntervalForPosition(LifetimePosition position) const;
   void AdvanceLastProcessedMarker(UseInterval* to_start_of,
                                   LifetimePosition but_not_past) const;
 
   int id_;
   bool spilled_;
+  bool is_double_;
   int assigned_register_;
-  RegisterKind assigned_register_kind_;
   UseInterval* last_interval_;
   UseInterval* first_interval_;
   UsePosition* first_pos_;
   LiveRange* parent_;
   LiveRange* next_;
   // This is used as a cache, it doesn't affect correctness.
   mutable UseInterval* current_interval_;
   UsePosition* last_processed_use_;
   LOperand* spill_operand_;
   int spill_start_index_;
@@ skipping 229 matching lines @@
 
   bool has_osr_entry_;
 
   DISALLOW_COPY_AND_ASSIGN(LAllocator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_ALLOCATOR_H_