Introduce MoveDouble to the X64 MacroAssembler

src/x64/macro-assembler-x64.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 828 matching lines @@
 
   // Emit code to discard a non-negative number of pointer-sized elements
   // from the stack, clobbering only the rsp register.
   void Drop(int stack_elements);
 
   void Call(Label* target) { call(target); }
   void Push(Register src) { push(src); }
   void Pop(Register dst) { pop(dst); }
   void PushReturnAddressFrom(Register src) { push(src); }
   void PopReturnAddressTo(Register dst) { pop(dst); }
+  void MoveDouble(Register dst, const Operand& src) { movq(dst, src); }
+  void MoveDouble(const Operand& dst, Register src) { movq(dst, src); }
 
   // Control Flow
   void Jump(Address destination, RelocInfo::Mode rmode);
   void Jump(ExternalReference ext);
   void Jump(Handle<Code> code_object, RelocInfo::Mode rmode);
 
   void Call(Address destination, RelocInfo::Mode rmode);
   void Call(ExternalReference ext);
   void Call(Handle<Code> code_object,
             RelocInfo::Mode rmode,
@@ skipping 744 matching lines @@
     masm->popfq();                                                           \
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_