MIPS64: Refine 'Remove unused byte from Map::instance_sizes field.'

src/mips64/builtins-mips64.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 "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS64
 
@@ skipping 465 matching lines @@
       __ LoadRoot(t3, Heap::kUndefinedValueRootIndex);
 
       if (!is_api_function) {
         Label no_inobject_slack_tracking;
 
         // Check if slack tracking is enabled.
         __ Branch(&no_inobject_slack_tracking, lt, a6,
                   Operand(static_cast<int64_t>(Map::kSlackTrackingCounterEnd)));
 
         // Allocate object with a slack.
-        __ lwu(a0, FieldMemOperand(a2, Map::kInstanceSizesOffset));
-        __ Ext(a0, a0, Map::kInObjectPropertiesByte * kBitsPerByte,
-               kBitsPerByte);
-        __ lwu(a2, FieldMemOperand(a2, Map::kInstanceAttributesOffset));
-        __ Ext(a2, a2, Map::kUnusedPropertyFieldsByte * kBitsPerByte,
-               kBitsPerByte);
+        __ lbu(a0, FieldMemOperand(a2, Map::kInObjectPropertiesOffset));
+        __ lbu(a2, FieldMemOperand(a2, Map::kUnusedPropertyFieldsOffset));
         __ dsubu(a0, a0, a2);
         __ dsll(at, a0, kPointerSizeLog2);
         __ daddu(a0, t1, at);
         // a0: offset of first field after pre-allocated fields
         if (FLAG_debug_code) {
           __ dsll(at, a3, kPointerSizeLog2);
           __ Daddu(t2, t0, Operand(at));   // End of object.
           __ Assert(le, kUnexpectedNumberOfPreAllocatedPropertyFields,
               a0, Operand(t2));
         }
@@ skipping 1256 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64