diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index 8b5dd7923c4..3ee418feb0e 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -677,13 +677,23 @@ static Value *canonicalizeSaturatedSubtract(const ICmpInst *ICI, static Value *canonicalizeSaturatedAdd(ICmpInst *Cmp, Value *TVal, Value *FVal, InstCombiner::BuilderTy &Builder) { - if (!Cmp->hasOneUse() || Cmp->getPredicate() != ICmpInst::ICMP_ULT) + if (!Cmp->hasOneUse()) return nullptr; - // Match unsigned saturated add of 2 variables with an unnecessary 'not'. - // TODO: There are more variations of this pattern. + // Canonicalize to 'ULT' to simplify matching below. Value *Cmp0 = Cmp->getOperand(0); Value *Cmp1 = Cmp->getOperand(1); + ICmpInst::Predicate Pred = Cmp->getPredicate(); + if (Pred == ICmpInst::ICMP_UGT) { + Pred = ICmpInst::ICMP_ULT; + std::swap(Cmp0, Cmp1); + } + + if (Pred != ICmpInst::ICMP_ULT) + return nullptr; + + // Match unsigned saturated add of 2 variables with an unnecessary 'not'. + // TODO: There are more variations of this pattern. Value *X, *Y; if (match(TVal, m_AllOnes()) && match(Cmp0, m_Not(m_Value(X))) && match(FVal, m_c_Add(m_Specific(X), m_Value(Y))) && Y == Cmp1) { |
