Add complete ElementKind information directly to Map for objects with elements.

src/x64/full-codegen-x64.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 3312 matching lines @@
   // other stack fields, and clear the direction flag in anticipation
   // of calling CopyBytes.
   __ subq(rsp, Immediate(2 * kPointerSize));
   __ cld();
   // Check that the array is a JSArray
   __ JumpIfSmi(array, &bailout);
   __ CmpObjectType(array, JS_ARRAY_TYPE, scratch);
   __ j(not_equal, &bailout);
 
   // Check that the array has fast elements.
-  __ testb(FieldOperand(scratch, Map::kBitField2Offset),
-           Immediate(1 << Map::kHasFastElements));
-  __ j(zero, &bailout);
+  __ CheckFastElements(scratch, &bailout);
 
   // Array has fast elements, so its length must be a smi.
   // If the array has length zero, return the empty string.
   __ movq(array_length, FieldOperand(array, JSArray::kLengthOffset));
   __ SmiCompare(array_length, Smi::FromInt(0));
   __ j(not_zero, &non_trivial_array);
   __ LoadRoot(rax, Heap::kEmptyStringRootIndex);
   __ jmp(&return_result);
 
   // Save the array length on the stack.
@@ skipping 963 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64