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

src/x64/ic-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 490 matching lines @@
 
   // Check that the key is a smi.
   __ JumpIfNotSmi(rax, &check_string);
   __ bind(&index_smi);
   // Now the key is known to be a smi. This place is also jumped to from below
   // where a numeric string is converted to a smi.
 
   GenerateKeyedLoadReceiverCheck(
       masm, rdx, rcx, Map::kHasIndexedInterceptor, &slow);
 
-  // Check the "has fast elements" bit in the receiver's map which is
-  // now in rcx.
-  __ testb(FieldOperand(rcx, Map::kBitField2Offset),
-           Immediate(1 << Map::kHasFastElements));
-  __ j(zero, &check_number_dictionary);
+  // Check the receiver's map to see if it has fast elements.
+  __ CheckFastElements(rcx, &check_number_dictionary);
 
   GenerateFastArrayLoad(masm,
                         rdx,
                         rax,
                         rcx,
                         rbx,
                         rax,
                         NULL,
                         &slow);
   Counters* counters = masm->isolate()->counters();
@@ skipping 1078 matching lines @@
   Condition cc = *jmp_address == Assembler::kJncShortOpcode
       ? not_zero
       : zero;
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64