Subzero. X86. Refactors initRegisterSet.

src/IceRegistersX8664.h

 //===- subzero/src/IceRegistersX8664.h - Register information ---*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// \brief Declares the registers and their encodings for x86-64.
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICEREGISTERSX8664_H
 #define SUBZERO_SRC_ICEREGISTERSX8664_H
 
 #include "IceDefs.h"
 #include "IceInstX8664.def"
 #include "IceTypes.h"
 
 namespace Ice {
 
 class RegX8664 {
 public:
   /// An enum of every register. The enum value may not match the encoding used
   /// to binary encode register operands in instructions.
   enum AllRegisters {
+    Reg_Invalid,
 #define X(val, encode, name, base, scratch, preserved, stackptr, frameptr,     \
           isGPR, is64, is32, is16, is8, isXmm, is64To8, is32To8, is16To8,      \
           isTrunc8Rcvr, isAhRcvr, aliases)                                     \
   val,
     REGX8664_TABLE
 #undef X
         Reg_NUM
   };
 
   /// An enum of GPR Registers. The enum value does match the encoding used to
@@ skipping 29 matching lines @@
   Encoded_8_##val = encode,
     REGX8664_BYTEREG_TABLE
 #undef X
         Encoded_Not_ByteReg = -1
   };
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEREGISTERSX8664_H