Add an IC for CompareNil operations

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 1557 matching lines @@
 }
 
 
 LInstruction* LChunkBuilder::DoCompareConstantEqAndBranch(
     HCompareConstantEqAndBranch* instr) {
   return new(zone()) LCmpConstantEqAndBranch(
       UseRegisterAtStart(instr->value()));
 }
 
 
-LInstruction* LChunkBuilder::DoIsNilAndBranch(HIsNilAndBranch* instr) {
-  ASSERT(instr->value()->representation().IsTagged());
-  return new(zone()) LIsNilAndBranch(UseRegisterAtStart(instr->value()));
-}
-
-
 LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* temp = TempRegister();
   return new(zone()) LIsObjectAndBranch(UseRegisterAtStart(instr->value()),
                                         temp);
 }
 
 
 LInstruction* LChunkBuilder::DoIsStringAndBranch(HIsStringAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
@@ skipping 875 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