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

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 17db9bf1a50205d8a4d002c83042d291151ce23c..e1ce8cbf7950334aefeba5af80918f82e8fa3bc9 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -3484,16 +3484,16 @@ void MacroAssembler::LoadInstanceDescriptors(Register map,
 
 
 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);
 }
 
 
@@ -4959,9 +4959,8 @@ void MacroAssembler::CheckMapDeprecated(Handle<Map> map,
                                         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);
   }
 }