Subzero: Improve/refactor folding loads into the next instruction.

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 83 matching lines @@
 class TargetX8632 : public TargetLowering {
   TargetX8632() = delete;
   TargetX8632(const TargetX8632 &) = delete;
   TargetX8632 &operator=(const TargetX8632 &) = delete;
 
 public:
   static TargetX8632 *create(Cfg *Func) { return new TargetX8632(Func); }
 
   void translateOm1() override;
   void translateO2() override;
+  void doLoadOpt();
   bool doBranchOpt(Inst *I, const CfgNode *NextNode) override;
 
   SizeT getNumRegisters() const override { return RegX8632::Reg_NUM; }
   Variable *getPhysicalRegister(SizeT RegNum, Type Ty = IceType_void) override;
   IceString getRegName(SizeT RegNum, Type Ty) const override;
   llvm::SmallBitVector getRegisterSet(RegSetMask Include,
                                       RegSetMask Exclude) const override;
   const llvm::SmallBitVector &getRegisterSetForType(Type Ty) const override {
     return TypeToRegisterSet[Ty];
   }
@@ skipping 108 matching lines @@
   };
   typedef uint32_t LegalMask;
   Operand *legalize(Operand *From, LegalMask Allowed = Legal_All,
                     int32_t RegNum = Variable::NoRegister);
   Variable *legalizeToVar(Operand *From, int32_t RegNum = Variable::NoRegister);
   // Legalize the first source operand for use in the cmp instruction.
   Operand *legalizeSrc0ForCmp(Operand *Src0, Operand *Src1);
   // Turn a pointer operand into a memory operand that can be
   // used by a real load/store operation. Legalizes the operand as well.
   // This is a nop if the operand is already a legal memory operand.
-  OperandX8632Mem *formMemoryOperand(Operand *Ptr, Type Ty);
+  OperandX8632Mem *formMemoryOperand(Operand *Ptr, Type Ty,
+                                     bool DoLegalize = true);
 
   Variable *makeReg(Type Ty, int32_t RegNum = Variable::NoRegister);
   static Type stackSlotType();
 
   Variable *copyToReg(Operand *Src, int32_t RegNum = Variable::NoRegister);
 
   // Returns a vector in a register with the given constant entries.
   Variable *makeVectorOfZeros(Type Ty, int32_t RegNum = Variable::NoRegister);
   Variable *makeVectorOfOnes(Type Ty, int32_t RegNum = Variable::NoRegister);
   Variable *makeVectorOfMinusOnes(Type Ty,
@@ skipping 348 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