Subzero: Strength-reduce mul by certain constants.

src/IceTargetLoweringX8632.h

 //===- subzero/src/IceTargetLoweringX8632.h - x86-32 lowering ---*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the TargetLoweringX8632 class, which
@@ skipping 542 matching lines @@
     _set_dest_nonkillable();
     Context.insert(InstFakeUse::create(Func, Src));
   }
   void _xor(Variable *Dest, Operand *Src0) {
     Context.insert(InstX8632Xor::create(Func, Dest, Src0));
   }
   void _set_dest_nonkillable() {
     Context.getLastInserted()->setDestNonKillable();
   }
 
+  bool optimizeScalarMul(Variable *Dest, Operand *Src0, int32_t Src1);
+
   const X86InstructionSet InstructionSet;
   bool IsEbpBasedFrame;
   bool NeedsStackAlignment;
   size_t SpillAreaSizeBytes;
   llvm::SmallBitVector TypeToRegisterSet[IceType_NUM];
   llvm::SmallBitVector ScratchRegs;
   llvm::SmallBitVector RegsUsed;
   VarList PhysicalRegisters[IceType_NUM];
   static IceString RegNames[];
 
@@ skipping 20 matching lines @@
 
 private:
   void lowerGlobal(const VariableDeclaration &Var) const;
   ~TargetDataX8632() override {}
   template <typename T> static void emitConstantPool(GlobalContext *Ctx);
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX8632_H