Replace our home-grown BitCast with bit_cast from Chrome/Google3.

src/x64/macro-assembler-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/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 3377 matching lines @@
 
   bind(&maybe_nan);
   // Could be NaN or Infinity. If fraction is not zero, it's NaN, otherwise
   // it's an Infinity, and the non-NaN code path applies.
   j(greater, &is_nan, Label::kNear);
   cmpl(FieldOperand(maybe_number, HeapNumber::kValueOffset), Immediate(0));
   j(zero, &not_nan);
   bind(&is_nan);
   // Convert all NaNs to the same canonical NaN value when they are stored in
   // the double array.
-  Set(kScratchRegister, BitCast<uint64_t>(
-      FixedDoubleArray::canonical_not_the_hole_nan_as_double()));
+  Set(kScratchRegister,
+      bit_cast<uint64_t>(
+          FixedDoubleArray::canonical_not_the_hole_nan_as_double()));
   movq(xmm_scratch, kScratchRegister);
   jmp(&have_double_value, Label::kNear);
 
   bind(&smi_value);
   // Value is a smi. convert to a double and store.
   // Preserve original value.
   SmiToInteger32(kScratchRegister, maybe_number);
   Cvtlsi2sd(xmm_scratch, kScratchRegister);
   movsd(FieldOperand(elements, index, times_8,
                      FixedDoubleArray::kHeaderSize - elements_offset),
@@ skipping 1969 matching lines @@
   if (mag.shift > 0) sarl(rdx, Immediate(mag.shift));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64