Subzero: Remove unneeded ScratchRegs.

src/IceTargetLoweringX86Base.h

 //===- subzero/src/IceTargetLoweringX86Base.h - x86 lowering ----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 884 matching lines @@
   bool IsEbpBasedFrame = false;
   bool NeedsStackAlignment = false;
   size_t SpillAreaSizeBytes = 0;
   size_t FixedAllocaSizeBytes = 0;
   size_t FixedAllocaAlignBytes = 0;
   bool PrologEmitsFixedAllocas = false;
   uint32_t MaxOutArgsSizeBytes = 0;
   static std::array<llvm::SmallBitVector, RCX86_NUM> TypeToRegisterSet;
   static std::array<llvm::SmallBitVector, Traits::RegisterSet::Reg_NUM>
       RegisterAliases;
-  static llvm::SmallBitVector ScratchRegs;
   llvm::SmallBitVector RegsUsed;
   std::array<VarList, IceType_NUM> PhysicalRegisters;
   // GotVar is a Variable that holds the GlobalOffsetTable address for Non-SFI
   // mode.
   Variable *GotVar = nullptr;
 
   /// Randomize a given immediate operand
   Operand *randomizeOrPoolImmediate(Constant *Immediate,
                                     int32_t RegNum = Variable::NoRegister);
   X86OperandMem *
@@ skipping 80 matching lines @@
 
   static FixupKind PcRelFixup;
   static FixupKind AbsFixup;
 };
 } // end of namespace X86NAMESPACE
 } // end of namespace Ice
 
 #include "IceTargetLoweringX86BaseImpl.h"
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASE_H