Commit cad91074 authored by Nikita Popov's avatar Nikita Popov
Browse files

[InstCombine] Create new insts in foldICmpEqIntrinsicWithConstant; NFCI 

In line with current conventions, create new instructions rather
than modify two operands in place and performing manual worklist
management.

This should be NFC apart from possible worklist order changes.
parent 01943a59

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

+15 −27
Original line number Diff line number Diff line
@@ -3025,20 +3025,16 @@ Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp, 
  unsigned BitWidth = C.getBitWidth();

  switch (II->getIntrinsicID()) {

  case Intrinsic::bswap:

    Worklist.Add(II);

    Cmp.setOperand(0, II->getArgOperand(0));

    Cmp.setOperand(1, ConstantInt::get(Ty, C.byteSwap()));

    return &Cmp;

    // bswap(A) == C  ->  A == bswap(C)

    return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),

                        ConstantInt::get(Ty, C.byteSwap()));



  case Intrinsic::ctlz:

  case Intrinsic::cttz: {

    // ctz(A) == bitwidth(A)  ->  A == 0 and likewise for !=

    if (C == BitWidth) {

      Worklist.Add(II);

      Cmp.setOperand(0, II->getArgOperand(0));

      Cmp.setOperand(1, ConstantInt::getNullValue(Ty));

      return &Cmp;

    }

    if (C == BitWidth)

      return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),

                          ConstantInt::getNullValue(Ty));



    // ctz(A) == C -> A & Mask1 == Mask2, where Mask2 only has bit C set

    // and Mask1 has bits 0..C+1 set. Similar for ctl, but for high bits.
@@ -3051,10 +3047,9 @@ Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp, 
      APInt Mask2 = IsTrailing

        ? APInt::getOneBitSet(BitWidth, Num)

        : APInt::getOneBitSet(BitWidth, BitWidth - Num - 1);

      Cmp.setOperand(0, Builder.CreateAnd(II->getArgOperand(0), Mask1));

      Cmp.setOperand(1, ConstantInt::get(Ty, Mask2));

      Worklist.Add(II);

      return &Cmp;

      return new ICmpInst(Cmp.getPredicate(),

          Builder.CreateAnd(II->getArgOperand(0), Mask1),

          ConstantInt::get(Ty, Mask2));

    }

    break;

  }
@@ -3063,14 +3058,10 @@ Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp, 
    // popcount(A) == 0  ->  A == 0 and likewise for !=

    // popcount(A) == bitwidth(A)  ->  A == -1 and likewise for !=

    bool IsZero = C.isNullValue();

    if (IsZero || C == BitWidth) {

      Worklist.Add(II);

      Cmp.setOperand(0, II->getArgOperand(0));

      auto *NewOp =

          IsZero ? Constant::getNullValue(Ty) : Constant::getAllOnesValue(Ty);

      Cmp.setOperand(1, NewOp);

      return &Cmp;

    }

    if (IsZero || C == BitWidth)

      return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),

          IsZero ? Constant::getNullValue(Ty) : Constant::getAllOnesValue(Ty));



    break;

  }
@@ -3078,9 +3069,7 @@ Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp, 
    // uadd.sat(a, b) == 0  ->  (a | b) == 0

    if (C.isNullValue()) {

      Value *Or = Builder.CreateOr(II->getArgOperand(0), II->getArgOperand(1));

      return replaceInstUsesWith(Cmp, Builder.CreateICmp(

          Cmp.getPredicate(), Or, Constant::getNullValue(Ty)));



      return new ICmpInst(Cmp.getPredicate(), Or, Constant::getNullValue(Ty));

    }

    break;

  }
@@ -3090,8 +3079,7 @@ Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp, 
    if (C.isNullValue()) {

      ICmpInst::Predicate NewPred = Cmp.getPredicate() == ICmpInst::ICMP_EQ

          ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_UGT;

      return ICmpInst::Create(Instruction::ICmp, NewPred,

                              II->getArgOperand(0), II->getArgOperand(1));

      return new ICmpInst(NewPred, II->getArgOperand(0), II->getArgOperand(1));

    }

    break;

  }