Don't double smi-tag the mask used to check read-only / field mode in the dictionary-store-stub on …

src/ic/x64/ic-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 "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/codegen.h"
 #include "src/ic/ic.h"
@@ skipping 101 matching lines @@
 
   // If probing finds an entry in the dictionary, scratch0 contains the
   // index into the dictionary. Check that the value is a normal
   // property that is not read only.
   __ bind(&done);
   const int kElementsStartOffset =
       NameDictionary::kHeaderSize +
       NameDictionary::kElementsStartIndex * kPointerSize;
   const int kDetailsOffset = kElementsStartOffset + 2 * kPointerSize;
   const int kTypeAndReadOnlyMask =
-      (PropertyDetails::TypeField::kMask |
-       PropertyDetails::AttributesField::encode(READ_ONLY))
-      << kSmiTagSize;
+      PropertyDetails::TypeField::kMask |
+      PropertyDetails::AttributesField::encode(READ_ONLY);
   __ Test(Operand(elements, scratch1, times_pointer_size,
                   kDetailsOffset - kHeapObjectTag),
           Smi::FromInt(kTypeAndReadOnlyMask));
   __ j(not_zero, miss_label);
 
   // Store the value at the masked, scaled index.
   const int kValueOffset = kElementsStartOffset + kPointerSize;
   __ leap(scratch1, Operand(elements, scratch1, times_pointer_size,
                             kValueOffset - kHeapObjectTag));
   __ movp(Operand(scratch1, 0), value);
@@ skipping 835 matching lines @@
   Condition cc =
       (check == ENABLE_INLINED_SMI_CHECK)
           ? (*jmp_address == Assembler::kJncShortOpcode ? not_zero : zero)
           : (*jmp_address == Assembler::kJnzShortOpcode ? not_carry : carry);
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64