Avoid re-tagging of the index register in optimized byte array access.

runtime/vm/locations.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_LOCATIONS_H_
 #define VM_LOCATIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/bitfield.h"
@@ skipping 259 matching lines @@
   }
 
   // Return a memory operand for stack slot locations.
   Address ToStackSlotAddress() const;
 
   // Constants.
   static Location RegisterOrConstant(Value* value);
   static Location RegisterOrSmiConstant(Value* value);
   static Location FixedRegisterOrConstant(Value* value, Register reg);
   static Location FixedRegisterOrSmiConstant(Value* value, Register reg);
+  static Location WritableRegisterOrSmiConstant(Value* value);

[Vyacheslav Egorov (Google), 2013/02/13 17:43:04]

I think you don't actually need this.

[Florian Schneider, 2013/02/14 10:35:01]

Done.

   static Location AnyOrConstant(Value* value);
 
   const char* Name() const;
   void PrintTo(BufferFormatter* f) const;
   void Print() const;
 
   // Compare two locations.
   bool Equals(Location other) const {
     return value_ == other.value_;
   }
@@ skipping 195 matching lines @@
   BitmapBuilder* stack_bitmap_;
 
   const ContainsCall contains_call_;
   RegisterSet live_registers_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_LOCATIONS_H_