[crankshaft] Remove the useless HMapEnumLength instruction.

src/crankshaft/mips/lithium-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.7
 // 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 1633 matching lines @@
 }
 
 
 void LCodeGen::DoConstantT(LConstantT* instr) {
   Handle<Object> object = instr->value(isolate());
   AllowDeferredHandleDereference smi_check;
   __ li(ToRegister(instr->result()), object);
 }
 
 
-void LCodeGen::DoMapEnumLength(LMapEnumLength* instr) {
-  Register result = ToRegister(instr->result());
-  Register map = ToRegister(instr->value());
-  __ EnumLength(result, map);
-}
-
-
 MemOperand LCodeGen::BuildSeqStringOperand(Register string,
                                            LOperand* index,
                                            String::Encoding encoding) {
   if (index->IsConstantOperand()) {
     int offset = ToInteger32(LConstantOperand::cast(index));
     if (encoding == String::TWO_BYTE_ENCODING) {
       offset *= kUC16Size;
     }
     STATIC_ASSERT(kCharSize == 1);
     return FieldMemOperand(string, SeqString::kHeaderSize + offset);
@@ skipping 3931 matching lines @@
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8