Subzero: Remove unneeded ScratchRegs.

src/IceTargetLoweringMIPS32.h

 //===- subzero/src/IceTargetLoweringMIPS32.h - MIPS32 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 246 matching lines @@
                          RandomNumberGenerator &RNG) override;
   void
   makeRandomRegisterPermutation(llvm::SmallVectorImpl<int32_t> &Permutation,
                                 const llvm::SmallBitVector &ExcludeRegisters,
                                 uint64_t Salt) const override;
 
   bool UsesFramePointer = false;
   bool NeedsStackAlignment = false;
   static llvm::SmallBitVector TypeToRegisterSet[RCMIPS32_NUM];
   static llvm::SmallBitVector RegisterAliases[RegMIPS32::Reg_NUM];
-  static llvm::SmallBitVector ScratchRegs;
   llvm::SmallBitVector RegsUsed;
   VarList PhysicalRegisters[IceType_NUM];
 
 private:
   ENABLE_MAKE_UNIQUE;
 };
 
 class TargetDataMIPS32 final : public TargetDataLowering {
   TargetDataMIPS32() = delete;
   TargetDataMIPS32(const TargetDataMIPS32 &) = delete;
@@ skipping 33 matching lines @@
   explicit TargetHeaderMIPS32(GlobalContext *Ctx);
 
 private:
   ~TargetHeaderMIPS32() = default;
 };
 
 } // end of namespace MIPS32
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGMIPS32_H