LoadUint32() doesn't need a scratch register.

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 "v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "bootstrapper.h"
 #include "codegen.h"
@@ skipping 3305 matching lines @@
   bind(&conv_failure);
   Set(result_reg, 0);
   ucomisd(input_reg, temp_xmm_reg);
   j(below, &done, Label::kNear);
   Set(result_reg, 255);
   bind(&done);
 }
 
 
 void MacroAssembler::LoadUint32(XMMRegister dst,
-                                Register src,
-                                XMMRegister scratch) {
+                                Register src) {
   if (FLAG_debug_code) {
     cmpq(src, Immediate(0xffffffff));
     Assert(below_equal, kInputGPRIsExpectedToHaveUpper32Cleared);
   }
   cvtqsi2sd(dst, src);
 }
 
 
 void MacroAssembler::SlowTruncateToI(Register result_reg,
                                      Register input_reg,
@@ skipping 1897 matching lines @@
   if (ms.shift() > 0) sarl(rdx, Immediate(ms.shift()));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64