MIPS: Improve SeqStringSetChar implementation.

src/mips/lithium-mips.cc

 // Copyright 2012 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 1765 matching lines @@
 LInstruction* LChunkBuilder::DoDateField(HDateField* instr) {
   LOperand* object = UseFixed(instr->value(), a0);
   LDateField* result =
       new(zone()) LDateField(object, FixedTemp(a1), instr->index());
   return MarkAsCall(DefineFixed(result, v0), instr, CAN_DEOPTIMIZE_EAGERLY);
 }
 
 
 LInstruction* LChunkBuilder::DoSeqStringSetChar(HSeqStringSetChar* instr) {
   LOperand* string = UseRegister(instr->string());
-  LOperand* index = UseRegister(instr->index());
-  LOperand* value = UseTempRegister(instr->value());
-  LSeqStringSetChar* result =
-      new(zone()) LSeqStringSetChar(instr->encoding(), string, index, value);
-  return DefineAsRegister(result);
+  LOperand* index = UseRegisterOrConstant(instr->index());
+  LOperand* value = UseRegister(instr->value());
+  return new(zone()) LSeqStringSetChar(instr->encoding(), string, index, value);
 }
 
 
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
   LOperand* value = UseRegisterOrConstantAtStart(instr->index());
   LOperand* length = UseRegister(instr->length());
   return AssignEnvironment(new(zone()) LBoundsCheck(value, length));
 }
 
 
@@ skipping 725 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal