Remove the unused HElementsKind instruction.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 1556 matching lines @@
 }
 
 
 void LCodeGen::DoMapEnumLength(LMapEnumLength* instr) {
   Register result = ToRegister(instr->result());
   Register map = ToRegister(instr->value());
   __ EnumLength(result, map);
 }
 
 
-void LCodeGen::DoElementsKind(LElementsKind* instr) {
-  Register result = ToRegister(instr->result());
-  Register input = ToRegister(instr->value());
-
-  // Load map into |result|.
-  __ movp(result, FieldOperand(input, HeapObject::kMapOffset));
-  // Load the map's "bit field 2" into |result|. We only need the first byte.
-  __ movzxbq(result, FieldOperand(result, Map::kBitField2Offset));
-  // Retrieve elements_kind from bit field 2.
-  __ and_(result, Immediate(Map::kElementsKindMask));
-  __ shr(result, Immediate(Map::kElementsKindShift));
-}
-
-
 void LCodeGen::DoValueOf(LValueOf* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
   ASSERT(input.is(result));
   Label done;
 
   if (!instr->hydrogen()->value()->IsHeapObject()) {
     // If the object is a smi return the object.
     __ JumpIfSmi(input, &done, Label::kNear);
   }
@@ skipping 3992 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64