MIPS: Improve constant element index access code generation

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 1465 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);
 }
 
 
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
-  LOperand* value = UseRegisterAtStart(instr->index());
+  LOperand* value = UseRegisterOrConstantAtStart(instr->index());
   LOperand* length = UseRegister(instr->length());
   return AssignEnvironment(new(zone()) LBoundsCheck(value, length));
 }
 
 
 LInstruction* LChunkBuilder::DoAbnormalExit(HAbnormalExit* instr) {
   // The control instruction marking the end of a block that completed
   // abruptly (e.g., threw an exception).  There is nothing specific to do.
   return NULL;
 }
@@ skipping 272 matching lines @@
   return DefineAsRegister(new(zone()) LLoadExternalArrayPointer(input));
 }
 
 
 LInstruction* LChunkBuilder::DoLoadKeyedFastElement(
     HLoadKeyedFastElement* instr) {
   ASSERT(instr->representation().IsTagged());
   ASSERT(instr->key()->representation().IsInteger32() ||
          instr->key()->representation().IsTagged());
   LOperand* obj = UseRegisterAtStart(instr->object());
-  LOperand* key = UseRegisterAtStart(instr->key());
+  LOperand* key = UseRegisterOrConstantAtStart(instr->key());
   LLoadKeyedFastElement* result = new(zone()) LLoadKeyedFastElement(obj, key);
   if (instr->RequiresHoleCheck()) AssignEnvironment(result);
   return DefineAsRegister(result);
 }
 
 
 LInstruction* LChunkBuilder::DoLoadKeyedFastDoubleElement(
     HLoadKeyedFastDoubleElement* instr) {
   ASSERT(instr->representation().IsDouble());
   ASSERT(instr->key()->representation().IsInteger32() ||
@@ skipping 430 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