[x64] simply tweak materialization of float/double constants

src/x64/assembler-x64-inl.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_ASSEMBLER_X64_INL_H_
 #define V8_X64_ASSEMBLER_X64_INL_H_
 
 #include "src/x64/assembler-x64.h"
 
 #include "src/base/cpu.h"
@@ skipping 161 matching lines @@
   byte rex_bits =  (reg.code() & 0x8) >> 1 | (base.code() & 0x8) >> 3;
   if (rex_bits != 0) emit(0x40 | rex_bits);
 }
 
 
 void Assembler::emit_optional_rex_32(Register rm_reg) {
   if (rm_reg.high_bit()) emit(0x41);
 }
 
 
+void Assembler::emit_optional_rex_32(XMMRegister rm_reg) {
+  if (rm_reg.high_bit()) emit(0x41);
+}
+
+
 void Assembler::emit_optional_rex_32(const Operand& op) {
   if (op.rex_ != 0) emit(0x40 | op.rex_);
 }
 
 
 Address Assembler::target_address_at(Address pc,
                                      ConstantPoolArray* constant_pool) {
   return Memory::int32_at(pc) + pc + 4;
 }
 
@@ skipping 362 matching lines @@
   DCHECK(len_ == 1 || len_ == 2);
   int32_t* p = reinterpret_cast<int32_t*>(&buf_[len_]);
   *p = disp;
   len_ += sizeof(int32_t);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_INL_H_