Make BitField3 a raw uint32 field, and move to the start of the map.

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "bootstrapper.h"
 #include "codegen.h"
@@ skipping 3466 matching lines @@
 }
 
 
 void MacroAssembler::LoadInstanceDescriptors(Register map,
                                              Register descriptors) {
   movp(descriptors, FieldOperand(map, Map::kDescriptorsOffset));
 }
 
 
 void MacroAssembler::NumberOfOwnDescriptors(Register dst, Register map) {
-  movp(dst, FieldOperand(map, Map::kBitField3Offset));
+  movl(dst, FieldOperand(map, Map::kBitField3Offset));
   DecodeField<Map::NumberOfOwnDescriptorsBits>(dst);
 }
 
 
 void MacroAssembler::EnumLength(Register dst, Register map) {
   STATIC_ASSERT(Map::EnumLengthBits::kShift == 0);
-  movp(dst, FieldOperand(map, Map::kBitField3Offset));
-  Move(kScratchRegister, Smi::FromInt(Map::EnumLengthBits::kMask));
-  andp(dst, kScratchRegister);
+  movl(dst, FieldOperand(map, Map::kBitField3Offset));
+  andl(dst, Immediate(Map::EnumLengthBits::kMask));
+  Integer32ToSmi(dst, dst);
 }
 
 
 void MacroAssembler::DispatchMap(Register obj,
                                  Register unused,
                                  Handle<Map> map,
                                  Handle<Code> success,
                                  SmiCheckType smi_check_type) {
   Label fail;
   if (smi_check_type == DO_SMI_CHECK) {
@@ skipping 1445 matching lines @@
   }
   j(cc, condition_met, condition_met_distance);
 }
 
 
 void MacroAssembler::CheckMapDeprecated(Handle<Map> map,
                                         Register scratch,
                                         Label* if_deprecated) {
   if (map->CanBeDeprecated()) {
     Move(scratch, map);
-    movp(scratch, FieldOperand(scratch, Map::kBitField3Offset));
-    SmiToInteger32(scratch, scratch);
-    andp(scratch, Immediate(Map::Deprecated::kMask));
+    movl(scratch, FieldOperand(scratch, Map::kBitField3Offset));
+    andl(scratch, Immediate(Map::Deprecated::kMask));
     j(not_zero, if_deprecated);
   }
 }
 
 
 void MacroAssembler::JumpIfBlack(Register object,
                                  Register bitmap_scratch,
                                  Register mask_scratch,
                                  Label* on_black,
                                  Label::Distance on_black_distance) {
@@ skipping 260 matching lines @@
   if (ms.shift() > 0) sarl(rdx, Immediate(ms.shift()));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64