diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp | 31 |
1 files changed, 14 insertions, 17 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp index 5209dad31b5..078c938ff9a 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp @@ -774,34 +774,31 @@ Instruction *InstCombiner::visitLShr(BinaryOperator &I) { if (Instruction *R = commonShiftTransforms(I)) return R; - if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) { - unsigned ShAmt = Op1C->getZExtValue(); - - if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op0)) { - unsigned BitWidth = Op0->getType()->getScalarSizeInBits(); + const APInt *ShAmtAPInt; + if (match(Op1, m_APInt(ShAmtAPInt))) { + unsigned ShAmt = ShAmtAPInt->getZExtValue(); + unsigned BitWidth = Op0->getType()->getScalarSizeInBits(); + auto *II = dyn_cast<IntrinsicInst>(Op0); + if (II && isPowerOf2_32(BitWidth) && Log2_32(BitWidth) == ShAmt && + (II->getIntrinsicID() == Intrinsic::ctlz || + II->getIntrinsicID() == Intrinsic::cttz || + II->getIntrinsicID() == Intrinsic::ctpop)) { // ctlz.i32(x)>>5 --> zext(x == 0) // cttz.i32(x)>>5 --> zext(x == 0) // ctpop.i32(x)>>5 --> zext(x == -1) - if ((II->getIntrinsicID() == Intrinsic::ctlz || - II->getIntrinsicID() == Intrinsic::cttz || - II->getIntrinsicID() == Intrinsic::ctpop) && - isPowerOf2_32(BitWidth) && Log2_32(BitWidth) == ShAmt) { - bool isCtPop = II->getIntrinsicID() == Intrinsic::ctpop; - Constant *RHS = ConstantInt::getSigned(Op0->getType(), isCtPop ? -1:0); - Value *Cmp = Builder->CreateICmpEQ(II->getArgOperand(0), RHS); - return new ZExtInst(Cmp, II->getType()); - } + bool IsPop = II->getIntrinsicID() == Intrinsic::ctpop; + Constant *RHS = ConstantInt::getSigned(Op0->getType(), IsPop ? -1 : 0); + Value *Cmp = Builder->CreateICmpEQ(II->getArgOperand(0), RHS); + return new ZExtInst(Cmp, II->getType()); } // If the shifted-out value is known-zero, then this is an exact shift. if (!I.isExact() && - MaskedValueIsZero(Op0, APInt::getLowBitsSet(Op1C->getBitWidth(), ShAmt), - 0, &I)){ + MaskedValueIsZero(Op0, APInt::getLowBitsSet(BitWidth, ShAmt), 0, &I)) { I.setIsExact(); return &I; } } - return nullptr; } |
