LoadUint32() doesn't need a scratch register.

src/x64/macro-assembler-x64.h

 // 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.
 
 #ifndef V8_X64_MACRO_ASSEMBLER_X64_H_
 #define V8_X64_MACRO_ASSEMBLER_X64_H_
 
 #include "assembler.h"
 #include "frames.h"
 #include "v8globals.h"
@@ skipping 986 matching lines @@
   void TruncateDoubleToI(Register result_reg, XMMRegister input_reg);
 
   void DoubleToI(Register result_reg, XMMRegister input_reg,
       XMMRegister scratch, MinusZeroMode minus_zero_mode,
       Label* conversion_failed, Label::Distance dst = Label::kFar);
 
   void TaggedToI(Register result_reg, Register input_reg, XMMRegister temp,
       MinusZeroMode minus_zero_mode, Label* lost_precision,
       Label::Distance dst = Label::kFar);
 
-  void LoadUint32(XMMRegister dst, Register src, XMMRegister scratch);
+  void LoadUint32(XMMRegister dst, Register src);
 
   void LoadInstanceDescriptors(Register map, Register descriptors);
   void EnumLength(Register dst, Register map);
   void NumberOfOwnDescriptors(Register dst, Register map);
 
   template<typename Field>
   void DecodeField(Register reg) {
     static const int shift = Field::kShift;
     static const int mask = Field::kMask >> Field::kShift;
     shrp(reg, Immediate(shift));
@@ skipping 577 matching lines @@
     masm->popfq();                                                           \
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_