Fix ARM build for gcc-4.6

src/arm/lithium-arm.cc

 // 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 1381 matching lines @@
       UseFixed(instr->right(), r0);
   LPower* result = new LPower(left, right);
   return MarkAsCall(DefineFixedDouble(result, d3),
                     instr,
                     CAN_DEOPTIMIZE_EAGERLY);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareGeneric(HCompareGeneric* instr) {
   Token::Value op = instr->token();
-  Representation r = instr->GetInputRepresentation();
   ASSERT(instr->left()->representation().IsTagged());
   ASSERT(instr->right()->representation().IsTagged());
   bool reversed = (op == Token::GT || op == Token::LTE);
   LOperand* left = UseFixed(instr->left(), reversed ? r0 : r1);
   LOperand* right = UseFixed(instr->right(), reversed ? r1 : r0);
   LCmpT* result = new LCmpT(left, right);
   return MarkAsCall(DefineFixed(result, r0), instr);
 }
 
 
@@ skipping 769 matching lines @@
 
 LInstruction* LChunkBuilder::DoIn(HIn* instr) {
   LOperand* key = UseRegisterAtStart(instr->key());
   LOperand* object = UseRegisterAtStart(instr->object());
   LIn* result = new LIn(key, object);
   return MarkAsCall(DefineFixed(result, r0), instr);
 }
 
 
 } }  // namespace v8::internal