diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 16 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/saturating-add-sub.ll | 16 |
2 files changed, 20 insertions, 12 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) { diff --git a/llvm/test/Transforms/InstCombine/saturating-add-sub.ll b/llvm/test/Transforms/InstCombine/saturating-add-sub.ll index 96848629438..17c0d958838 100644 --- a/llvm/test/Transforms/InstCombine/saturating-add-sub.ll +++ b/llvm/test/Transforms/InstCombine/saturating-add-sub.ll @@ -672,11 +672,10 @@ define i32 @uadd_sat_commute_add(i32 %xp, i32 %y) { define i32 @uadd_sat_ugt(i32 %x, i32 %yp) { ; CHECK-LABEL: @uadd_sat_ugt( ; CHECK-NEXT: [[Y:%.*]] = sdiv i32 [[YP:%.*]], 2442 -; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1 -; CHECK-NEXT: [[A:%.*]] = add i32 [[Y]], [[X]] -; CHECK-NEXT: [[C:%.*]] = icmp ugt i32 [[Y]], [[NOTX]] -; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 -1, i32 [[A]] -; CHECK-NEXT: ret i32 [[R]] +; CHECK-NEXT: [[A:%.*]] = add i32 [[Y]], [[X:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]] +; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]] +; CHECK-NEXT: ret i32 [[TMP2]] ; %y = sdiv i32 %yp, 2442 ; thwart complexity-based-canonicalization %notx = xor i32 %x, -1 @@ -690,11 +689,10 @@ define i32 @uadd_sat_ugt_commute_add(i32 %xp, i32 %yp) { ; CHECK-LABEL: @uadd_sat_ugt_commute_add( ; CHECK-NEXT: [[Y:%.*]] = sdiv i32 [[YP:%.*]], 2442 ; CHECK-NEXT: [[X:%.*]] = srem i32 42, [[XP:%.*]] -; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X]], -1 ; CHECK-NEXT: [[A:%.*]] = add i32 [[X]], [[Y]] -; CHECK-NEXT: [[C:%.*]] = icmp ugt i32 [[Y]], [[NOTX]] -; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 -1, i32 [[A]] -; CHECK-NEXT: ret i32 [[R]] +; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]] +; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]] +; CHECK-NEXT: ret i32 [[TMP2]] ; %y = sdiv i32 %yp, 2442 ; thwart complexity-based-canonicalization %x = srem i32 42, %xp ; thwart complexity-based-canonicalization |
