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

src/ia32/macro-assembler-ia32.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_IA32
 
 #include "bootstrapper.h"
 #include "codegen.h"
@@ skipping 3312 matching lines @@
   j(cc, condition_met, condition_met_distance);
 }
 
 
 void MacroAssembler::CheckMapDeprecated(Handle<Map> map,
                                         Register scratch,
                                         Label* if_deprecated) {
   if (map->CanBeDeprecated()) {
     mov(scratch, map);
     mov(scratch, FieldOperand(scratch, Map::kBitField3Offset));
-    and_(scratch, Immediate(Smi::FromInt(Map::Deprecated::kMask)));
+    and_(scratch, Immediate(Map::Deprecated::kMask));
     j(not_zero, if_deprecated);
   }
 }
 
 
 void MacroAssembler::JumpIfBlack(Register object,
                                  Register scratch0,
                                  Register scratch1,
                                  Label* on_black,
                                  Label::Distance on_black_near) {
@@ skipping 157 matching lines @@
     Check(less_equal, kLiveBytesCountOverflowChunkSize);
   }
 
   bind(&done);
 }
 
 
 void MacroAssembler::EnumLength(Register dst, Register map) {
   STATIC_ASSERT(Map::EnumLengthBits::kShift == 0);
   mov(dst, FieldOperand(map, Map::kBitField3Offset));
-  and_(dst, Immediate(Smi::FromInt(Map::EnumLengthBits::kMask)));
+  and_(dst, Immediate(Map::EnumLengthBits::kMask));
+  SmiTag(dst);
 }
 
 
 void MacroAssembler::CheckEnumCache(Label* call_runtime) {
   Label next, start;
   mov(ecx, eax);
 
   // Check if the enum length field is properly initialized, indicating that
   // there is an enum cache.
   mov(ebx, FieldOperand(ecx, HeapObject::kMapOffset));
@@ skipping 90 matching lines @@
   if (ms.shift() > 0) sar(edx, ms.shift());
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32