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

src/x64/full-codegen-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 "code-stubs.h"
 #include "codegen.h"
@@ skipping 2958 matching lines @@
 
   // Skip loop if no descriptors are valid.
   __ NumberOfOwnDescriptors(rcx, rbx);
   __ cmpp(rcx, Immediate(0));
   __ j(equal, &done);
 
   __ LoadInstanceDescriptors(rbx, r8);
   // rbx: descriptor array.
   // rcx: valid entries in the descriptor array.
   // Calculate the end of the descriptor array.
-  __ imulp(rcx, rcx, Immediate(DescriptorArray::kDescriptorSize));
-  SmiIndex index = masm_->SmiToIndex(rdx, rcx, kPointerSizeLog2);
-  __ leap(rcx,
-         Operand(
-             r8, index.reg, index.scale, DescriptorArray::kFirstOffset));
+  __ imull(rcx, rcx, Immediate(DescriptorArray::kDescriptorSize));
+  __ leal(rcx, Operand(r8, rcx, times_4, DescriptorArray::kFirstOffset));
   // Calculate location of the first key name.
   __ addp(r8, Immediate(DescriptorArray::kFirstOffset));
   // Loop through all the keys in the descriptor array. If one of these is the
   // internalized string "valueOf" the result is false.
   __ jmp(&entry);
   __ bind(&loop);
   __ movp(rdx, FieldOperand(r8, 0));
   __ Cmp(rdx, isolate()->factory()->value_of_string());
   __ j(equal, if_false);
   __ addp(r8, Immediate(DescriptorArray::kDescriptorSize * kPointerSize));
@@ skipping 1839 matching lines @@
   ASSERT_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64