diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index ee51bc03312..601295339ad 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1358,19 +1358,28 @@ Instruction *InstCombiner::foldIRemByPowerOfTwoToBitTest(ICmpInst &I) { /// Fold equality-comparison between zero and any (maybe truncated) right-shift /// by one-less-than-bitwidth into a sign test on the original value. -Instruction *foldSignBitTest(ICmpInst &I) { +Instruction *InstCombiner::foldSignBitTest(ICmpInst &I) { + Instruction *Val; ICmpInst::Predicate Pred; - Value *X; - Constant *C; - if (!I.isEquality() || - !match(&I, m_ICmp(Pred, m_TruncOrSelf(m_Shr(m_Value(X), m_Constant(C))), - m_Zero()))) + if (!I.isEquality() || !match(&I, m_ICmp(Pred, m_Instruction(Val), m_Zero()))) return nullptr; - Type *XTy = X->getType(); - unsigned XBitWidth = XTy->getScalarSizeInBits(); - if (!match(C, m_SpecificInt_ICMP(ICmpInst::Predicate::ICMP_EQ, - APInt(XBitWidth, XBitWidth - 1)))) + Value *X; + Type *XTy; + + Constant *C; + if (match(Val, m_TruncOrSelf(m_Shr(m_Value(X), m_Constant(C))))) { + XTy = X->getType(); + unsigned XBitWidth = XTy->getScalarSizeInBits(); + if (!match(C, m_SpecificInt_ICMP(ICmpInst::Predicate::ICMP_EQ, + APInt(XBitWidth, XBitWidth - 1)))) + return nullptr; + } else if (isa<BinaryOperator>(Val) && + (X = reassociateShiftAmtsOfTwoSameDirectionShifts( + cast<BinaryOperator>(Val), SQ.getWithInstruction(Val), + /*AnalyzeForSignBitExtraction=*/true))) { + XTy = X->getType(); + } else return nullptr; return ICmpInst::Create(Instruction::ICmp, |
