Fix index register assignment in LoadFieldByIndex for arm, arm64, and mips.

src/arm/lithium-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "lithium-allocator-inl.h"
 #include "arm/lithium-arm.h"
 #include "arm/lithium-codegen-arm.h"
 #include "hydrogen-osr.h"
@@ skipping 2538 matching lines @@
 
 LInstruction* LChunkBuilder::DoCheckMapValue(HCheckMapValue* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   LOperand* map = UseRegisterAtStart(instr->map());
   return AssignEnvironment(new(zone()) LCheckMapValue(value, map));
 }
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
-  LOperand* index = UseRegister(instr->index());
+  LOperand* index = UseTempRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 } }  // namespace v8::internal