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-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp907
1 files changed, 383 insertions, 524 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 65e60498ff95..ad96a5f475f1 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -22,6 +22,7 @@
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
+#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
@@ -49,13 +50,6 @@ using namespace llvm;
using namespace PatternMatch;
-static Value *createMinMax(InstCombiner::BuilderTy &Builder,
- SelectPatternFlavor SPF, Value *A, Value *B) {
- CmpInst::Predicate Pred = getMinMaxPred(SPF);
- assert(CmpInst::isIntPredicate(Pred) && "Expected integer predicate");
- return Builder.CreateSelect(Builder.CreateICmp(Pred, A, B), A, B);
-}
-
/// Replace a select operand based on an equality comparison with the identity
/// constant of a binop.
static Instruction *foldSelectBinOpIdentity(SelectInst &Sel,
@@ -370,6 +364,7 @@ Instruction *InstCombinerImpl::foldSelectOpOp(SelectInst &SI, Instruction *TI,
// one-use constraint, but that needs be examined carefully since it may not
// reduce the total number of instructions.
if (TI->getNumOperands() != 2 || FI->getNumOperands() != 2 ||
+ !TI->isSameOperationAs(FI) ||
(!isa<BinaryOperator>(TI) && !isa<GetElementPtrInst>(TI)) ||
!TI->hasOneUse() || !FI->hasOneUse())
return nullptr;
@@ -444,69 +439,56 @@ Instruction *InstCombinerImpl::foldSelectIntoOp(SelectInst &SI, Value *TrueVal,
Value *FalseVal) {
// See the comment above GetSelectFoldableOperands for a description of the
// transformation we are doing here.
- if (auto *TVI = dyn_cast<BinaryOperator>(TrueVal)) {
- if (TVI->hasOneUse() && !isa<Constant>(FalseVal)) {
- if (unsigned SFO = getSelectFoldableOperands(TVI)) {
- unsigned OpToFold = 0;
- if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
- OpToFold = 1;
- } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
- OpToFold = 2;
- }
+ auto TryFoldSelectIntoOp = [&](SelectInst &SI, Value *TrueVal,
+ Value *FalseVal,
+ bool Swapped) -> Instruction * {
+ if (auto *TVI = dyn_cast<BinaryOperator>(TrueVal)) {
+ if (TVI->hasOneUse() && !isa<Constant>(FalseVal)) {
+ if (unsigned SFO = getSelectFoldableOperands(TVI)) {
+ unsigned OpToFold = 0;
+ if ((SFO & 1) && FalseVal == TVI->getOperand(0))
+ OpToFold = 1;
+ else if ((SFO & 2) && FalseVal == TVI->getOperand(1))
+ OpToFold = 2;
- if (OpToFold) {
- Constant *C = ConstantExpr::getBinOpIdentity(TVI->getOpcode(),
- TVI->getType(), true);
- Value *OOp = TVI->getOperand(2-OpToFold);
- // Avoid creating select between 2 constants unless it's selecting
- // between 0, 1 and -1.
- const APInt *OOpC;
- bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
- if (!isa<Constant>(OOp) ||
- (OOpIsAPInt && isSelect01(C->getUniqueInteger(), *OOpC))) {
- Value *NewSel = Builder.CreateSelect(SI.getCondition(), OOp, C);
- NewSel->takeName(TVI);
- BinaryOperator *BO = BinaryOperator::Create(TVI->getOpcode(),
- FalseVal, NewSel);
- BO->copyIRFlags(TVI);
- return BO;
+ if (OpToFold) {
+ FastMathFlags FMF;
+ // TODO: We probably ought to revisit cases where the select and FP
+ // instructions have different flags and add tests to ensure the
+ // behaviour is correct.
+ if (isa<FPMathOperator>(&SI))
+ FMF = SI.getFastMathFlags();
+ Constant *C = ConstantExpr::getBinOpIdentity(
+ TVI->getOpcode(), TVI->getType(), true, FMF.noSignedZeros());
+ Value *OOp = TVI->getOperand(2 - OpToFold);
+ // Avoid creating select between 2 constants unless it's selecting
+ // between 0, 1 and -1.
+ const APInt *OOpC;
+ bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
+ if (!isa<Constant>(OOp) ||
+ (OOpIsAPInt && isSelect01(C->getUniqueInteger(), *OOpC))) {
+ Value *NewSel = Builder.CreateSelect(
+ SI.getCondition(), Swapped ? C : OOp, Swapped ? OOp : C);
+ if (isa<FPMathOperator>(&SI))
+ cast<Instruction>(NewSel)->setFastMathFlags(FMF);
+ NewSel->takeName(TVI);
+ BinaryOperator *BO =
+ BinaryOperator::Create(TVI->getOpcode(), FalseVal, NewSel);
+ BO->copyIRFlags(TVI);
+ return BO;
+ }
}
}
}
}
- }
+ return nullptr;
+ };
- if (auto *FVI = dyn_cast<BinaryOperator>(FalseVal)) {
- if (FVI->hasOneUse() && !isa<Constant>(TrueVal)) {
- if (unsigned SFO = getSelectFoldableOperands(FVI)) {
- unsigned OpToFold = 0;
- if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
- OpToFold = 1;
- } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
- OpToFold = 2;
- }
+ if (Instruction *R = TryFoldSelectIntoOp(SI, TrueVal, FalseVal, false))
+ return R;
- if (OpToFold) {
- Constant *C = ConstantExpr::getBinOpIdentity(FVI->getOpcode(),
- FVI->getType(), true);
- Value *OOp = FVI->getOperand(2-OpToFold);
- // Avoid creating select between 2 constants unless it's selecting
- // between 0, 1 and -1.
- const APInt *OOpC;
- bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
- if (!isa<Constant>(OOp) ||
- (OOpIsAPInt && isSelect01(C->getUniqueInteger(), *OOpC))) {
- Value *NewSel = Builder.CreateSelect(SI.getCondition(), C, OOp);
- NewSel->takeName(FVI);
- BinaryOperator *BO = BinaryOperator::Create(FVI->getOpcode(),
- TrueVal, NewSel);
- BO->copyIRFlags(FVI);
- return BO;
- }
- }
- }
- }
- }
+ if (Instruction *R = TryFoldSelectIntoOp(SI, FalseVal, TrueVal, true))
+ return R;
return nullptr;
}
@@ -535,6 +517,16 @@ static Instruction *foldSelectICmpAndAnd(Type *SelType, const ICmpInst *Cmp,
// Where %B may be optionally shifted: lshr %X, %Z.
Value *X, *Z;
const bool HasShift = match(B, m_OneUse(m_LShr(m_Value(X), m_Value(Z))));
+
+ // The shift must be valid.
+ // TODO: This restricts the fold to constant shift amounts. Is there a way to
+ // handle variable shifts safely? PR47012
+ if (HasShift &&
+ !match(Z, m_SpecificInt_ICMP(CmpInst::ICMP_ULT,
+ APInt(SelType->getScalarSizeInBits(),
+ SelType->getScalarSizeInBits()))))
+ return nullptr;
+
if (!HasShift)
X = B;
@@ -1096,74 +1088,55 @@ static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
return true;
}
-/// If this is an integer min/max (icmp + select) with a constant operand,
-/// create the canonical icmp for the min/max operation and canonicalize the
-/// constant to the 'false' operand of the select:
-/// select (icmp Pred X, C1), C2, X --> select (icmp Pred' X, C2), X, C2
-/// Note: if C1 != C2, this will change the icmp constant to the existing
-/// constant operand of the select.
-static Instruction *canonicalizeMinMaxWithConstant(SelectInst &Sel,
- ICmpInst &Cmp,
- InstCombinerImpl &IC) {
- if (!Cmp.hasOneUse() || !isa<Constant>(Cmp.getOperand(1)))
- return nullptr;
-
- // Canonicalize the compare predicate based on whether we have min or max.
+static Instruction *canonicalizeSPF(SelectInst &Sel, ICmpInst &Cmp,
+ InstCombinerImpl &IC) {
Value *LHS, *RHS;
- SelectPatternResult SPR = matchSelectPattern(&Sel, LHS, RHS);
- if (!SelectPatternResult::isMinOrMax(SPR.Flavor))
- return nullptr;
-
- // Is this already canonical?
- ICmpInst::Predicate CanonicalPred = getMinMaxPred(SPR.Flavor);
- if (Cmp.getOperand(0) == LHS && Cmp.getOperand(1) == RHS &&
- Cmp.getPredicate() == CanonicalPred)
- return nullptr;
-
- // Bail out on unsimplified X-0 operand (due to some worklist management bug),
- // as this may cause an infinite combine loop. Let the sub be folded first.
- if (match(LHS, m_Sub(m_Value(), m_Zero())) ||
- match(RHS, m_Sub(m_Value(), m_Zero())))
+ // TODO: What to do with pointer min/max patterns?
+ if (!Sel.getType()->isIntOrIntVectorTy())
return nullptr;
- // Create the canonical compare and plug it into the select.
- IC.replaceOperand(Sel, 0, IC.Builder.CreateICmp(CanonicalPred, LHS, RHS));
-
- // If the select operands did not change, we're done.
- if (Sel.getTrueValue() == LHS && Sel.getFalseValue() == RHS)
- return &Sel;
-
- // If we are swapping the select operands, swap the metadata too.
- assert(Sel.getTrueValue() == RHS && Sel.getFalseValue() == LHS &&
- "Unexpected results from matchSelectPattern");
- Sel.swapValues();
- Sel.swapProfMetadata();
- return &Sel;
-}
-
-static Instruction *canonicalizeAbsNabs(SelectInst &Sel, ICmpInst &Cmp,
- InstCombinerImpl &IC) {
- if (!Cmp.hasOneUse() || !isa<Constant>(Cmp.getOperand(1)))
- return nullptr;
-
- Value *LHS, *RHS;
SelectPatternFlavor SPF = matchSelectPattern(&Sel, LHS, RHS).Flavor;
- if (SPF != SelectPatternFlavor::SPF_ABS &&
- SPF != SelectPatternFlavor::SPF_NABS)
- return nullptr;
+ if (SPF == SelectPatternFlavor::SPF_ABS ||
+ SPF == SelectPatternFlavor::SPF_NABS) {
+ if (!Cmp.hasOneUse() && !RHS->hasOneUse())
+ return nullptr; // TODO: Relax this restriction.
+
+ // Note that NSW flag can only be propagated for normal, non-negated abs!
+ bool IntMinIsPoison = SPF == SelectPatternFlavor::SPF_ABS &&
+ match(RHS, m_NSWNeg(m_Specific(LHS)));
+ Constant *IntMinIsPoisonC =
+ ConstantInt::get(Type::getInt1Ty(Sel.getContext()), IntMinIsPoison);
+ Instruction *Abs =
+ IC.Builder.CreateBinaryIntrinsic(Intrinsic::abs, LHS, IntMinIsPoisonC);
- // Note that NSW flag can only be propagated for normal, non-negated abs!
- bool IntMinIsPoison = SPF == SelectPatternFlavor::SPF_ABS &&
- match(RHS, m_NSWNeg(m_Specific(LHS)));
- Constant *IntMinIsPoisonC =
- ConstantInt::get(Type::getInt1Ty(Sel.getContext()), IntMinIsPoison);
- Instruction *Abs =
- IC.Builder.CreateBinaryIntrinsic(Intrinsic::abs, LHS, IntMinIsPoisonC);
+ if (SPF == SelectPatternFlavor::SPF_NABS)
+ return BinaryOperator::CreateNeg(Abs); // Always without NSW flag!
+ return IC.replaceInstUsesWith(Sel, Abs);
+ }
- if (SPF == SelectPatternFlavor::SPF_NABS)
- return BinaryOperator::CreateNeg(Abs); // Always without NSW flag!
+ if (SelectPatternResult::isMinOrMax(SPF)) {
+ Intrinsic::ID IntrinsicID;
+ switch (SPF) {
+ case SelectPatternFlavor::SPF_UMIN:
+ IntrinsicID = Intrinsic::umin;
+ break;
+ case SelectPatternFlavor::SPF_UMAX:
+ IntrinsicID = Intrinsic::umax;
+ break;
+ case SelectPatternFlavor::SPF_SMIN:
+ IntrinsicID = Intrinsic::smin;
+ break;
+ case SelectPatternFlavor::SPF_SMAX:
+ IntrinsicID = Intrinsic::smax;
+ break;
+ default:
+ llvm_unreachable("Unexpected SPF");
+ }
+ return IC.replaceInstUsesWith(
+ Sel, IC.Builder.CreateBinaryIntrinsic(IntrinsicID, LHS, RHS));
+ }
- return IC.replaceInstUsesWith(Sel, Abs);
+ return nullptr;
}
/// If we have a select with an equality comparison, then we know the value in
@@ -1336,6 +1309,7 @@ static Value *canonicalizeClampLike(SelectInst &Sel0, ICmpInst &Cmp0,
ICmpInst::Predicate::ICMP_NE,
APInt::getAllOnes(C0->getType()->getScalarSizeInBits()))))
return nullptr; // Can't do, have all-ones element[s].
+ Pred0 = ICmpInst::getFlippedStrictnessPredicate(Pred0);
C0 = InstCombiner::AddOne(C0);
break;
default:
@@ -1401,15 +1375,22 @@ static Value *canonicalizeClampLike(SelectInst &Sel0, ICmpInst &Cmp0,
case ICmpInst::Predicate::ICMP_SGE:
// Also non-canonical, but here we don't need to change C2,
// so we don't have any restrictions on C2, so we can just handle it.
+ Pred1 = ICmpInst::Predicate::ICMP_SLT;
std::swap(ReplacementLow, ReplacementHigh);
break;
default:
return nullptr; // Unknown predicate.
}
+ assert(Pred1 == ICmpInst::Predicate::ICMP_SLT &&
+ "Unexpected predicate type.");
// The thresholds of this clamp-like pattern.
auto *ThresholdLowIncl = ConstantExpr::getNeg(C1);
auto *ThresholdHighExcl = ConstantExpr::getSub(C0, C1);
+
+ assert((Pred0 == ICmpInst::Predicate::ICMP_ULT ||
+ Pred0 == ICmpInst::Predicate::ICMP_UGE) &&
+ "Unexpected predicate type.");
if (Pred0 == ICmpInst::Predicate::ICMP_UGE)
std::swap(ThresholdLowIncl, ThresholdHighExcl);
@@ -1530,17 +1511,71 @@ tryToReuseConstantFromSelectInComparison(SelectInst &Sel, ICmpInst &Cmp,
return &Sel;
}
+static Instruction *foldSelectZeroOrOnes(ICmpInst *Cmp, Value *TVal,
+ Value *FVal,
+ InstCombiner::BuilderTy &Builder) {
+ if (!Cmp->hasOneUse())
+ return nullptr;
+
+ const APInt *CmpC;
+ if (!match(Cmp->getOperand(1), m_APIntAllowUndef(CmpC)))
+ return nullptr;
+
+ // (X u< 2) ? -X : -1 --> sext (X != 0)
+ Value *X = Cmp->getOperand(0);
+ if (Cmp->getPredicate() == ICmpInst::ICMP_ULT && *CmpC == 2 &&
+ match(TVal, m_Neg(m_Specific(X))) && match(FVal, m_AllOnes()))
+ return new SExtInst(Builder.CreateIsNotNull(X), TVal->getType());
+
+ // (X u> 1) ? -1 : -X --> sext (X != 0)
+ if (Cmp->getPredicate() == ICmpInst::ICMP_UGT && *CmpC == 1 &&
+ match(FVal, m_Neg(m_Specific(X))) && match(TVal, m_AllOnes()))
+ return new SExtInst(Builder.CreateIsNotNull(X), TVal->getType());
+
+ return nullptr;
+}
+
+static Value *foldSelectInstWithICmpConst(SelectInst &SI, ICmpInst *ICI) {
+ const APInt *CmpC;
+ Value *V;
+ CmpInst::Predicate Pred;
+ if (!match(ICI, m_ICmp(Pred, m_Value(V), m_APInt(CmpC))))
+ return nullptr;
+
+ BinaryOperator *BO;
+ const APInt *C;
+ CmpInst::Predicate CPred;
+ if (match(&SI, m_Select(m_Specific(ICI), m_APInt(C), m_BinOp(BO))))
+ CPred = ICI->getPredicate();
+ else if (match(&SI, m_Select(m_Specific(ICI), m_BinOp(BO), m_APInt(C))))
+ CPred = ICI->getInversePredicate();
+ else
+ return nullptr;
+
+ const APInt *BinOpC;
+ if (!match(BO, m_BinOp(m_Specific(V), m_APInt(BinOpC))))
+ return nullptr;
+
+ ConstantRange R = ConstantRange::makeExactICmpRegion(CPred, *CmpC)
+ .binaryOp(BO->getOpcode(), *BinOpC);
+ if (R == *C) {
+ BO->dropPoisonGeneratingFlags();
+ return BO;
+ }
+ return nullptr;
+}
+
/// Visit a SelectInst that has an ICmpInst as its first operand.
Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
ICmpInst *ICI) {
if (Instruction *NewSel = foldSelectValueEquivalence(SI, *ICI))
return NewSel;
- if (Instruction *NewSel = canonicalizeMinMaxWithConstant(SI, *ICI, *this))
- return NewSel;
+ if (Instruction *NewSPF = canonicalizeSPF(SI, *ICI, *this))
+ return NewSPF;
- if (Instruction *NewAbs = canonicalizeAbsNabs(SI, *ICI, *this))
- return NewAbs;
+ if (Value *V = foldSelectInstWithICmpConst(SI, ICI))
+ return replaceInstUsesWith(SI, V);
if (Value *V = canonicalizeClampLike(SI, *ICI, Builder))
return replaceInstUsesWith(SI, V);
@@ -1572,6 +1607,22 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
}
}
+ // Canonicalize a signbit condition to use zero constant by swapping:
+ // (CmpLHS > -1) ? TV : FV --> (CmpLHS < 0) ? FV : TV
+ // To avoid conflicts (infinite loops) with other canonicalizations, this is
+ // not applied with any constant select arm.
+ if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_AllOnes()) &&
+ !match(TrueVal, m_Constant()) && !match(FalseVal, m_Constant()) &&
+ ICI->hasOneUse()) {
+ InstCombiner::BuilderTy::InsertPointGuard Guard(Builder);
+ Builder.SetInsertPoint(&SI);
+ Value *IsNeg = Builder.CreateIsNeg(CmpLHS, ICI->getName());
+ replaceOperand(SI, 0, IsNeg);
+ SI.swapValues();
+ SI.swapProfMetadata();
+ return &SI;
+ }
+
// FIXME: This code is nearly duplicated in InstSimplify. Using/refactoring
// decomposeBitTestICmp() might help.
{
@@ -1629,6 +1680,9 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
if (Instruction *V = foldSelectCtlzToCttz(ICI, TrueVal, FalseVal, Builder))
return V;
+ if (Instruction *V = foldSelectZeroOrOnes(ICI, TrueVal, FalseVal, Builder))
+ return V;
+
if (Value *V = foldSelectICmpAndOr(ICI, TrueVal, FalseVal, Builder))
return replaceInstUsesWith(SI, V);
@@ -1698,114 +1752,6 @@ Instruction *InstCombinerImpl::foldSPFofSPF(Instruction *Inner,
// TODO: This could be done in instsimplify.
if (SPF1 == SPF2 && SelectPatternResult::isMinOrMax(SPF1))
return replaceInstUsesWith(Outer, Inner);
-
- // MAX(MIN(a, b), a) -> a
- // MIN(MAX(a, b), a) -> a
- // TODO: This could be done in instsimplify.
- if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) ||
- (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) ||
- (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) ||
- (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN))
- return replaceInstUsesWith(Outer, C);
- }
-
- if (SPF1 == SPF2) {
- const APInt *CB, *CC;
- if (match(B, m_APInt(CB)) && match(C, m_APInt(CC))) {
- // MIN(MIN(A, 23), 97) -> MIN(A, 23)
- // MAX(MAX(A, 97), 23) -> MAX(A, 97)
- // TODO: This could be done in instsimplify.
- if ((SPF1 == SPF_UMIN && CB->ule(*CC)) ||
- (SPF1 == SPF_SMIN && CB->sle(*CC)) ||
- (SPF1 == SPF_UMAX && CB->uge(*CC)) ||
- (SPF1 == SPF_SMAX && CB->sge(*CC)))
- return replaceInstUsesWith(Outer, Inner);
-
- // MIN(MIN(A, 97), 23) -> MIN(A, 23)
- // MAX(MAX(A, 23), 97) -> MAX(A, 97)
- if ((SPF1 == SPF_UMIN && CB->ugt(*CC)) ||
- (SPF1 == SPF_SMIN && CB->sgt(*CC)) ||
- (SPF1 == SPF_UMAX && CB->ult(*CC)) ||
- (SPF1 == SPF_SMAX && CB->slt(*CC))) {
- Outer.replaceUsesOfWith(Inner, A);
- return &Outer;
- }
- }
- }
-
- // max(max(A, B), min(A, B)) --> max(A, B)
- // min(min(A, B), max(A, B)) --> min(A, B)
- // TODO: This could be done in instsimplify.
- if (SPF1 == SPF2 &&
- ((SPF1 == SPF_UMIN && match(C, m_c_UMax(m_Specific(A), m_Specific(B)))) ||
- (SPF1 == SPF_SMIN && match(C, m_c_SMax(m_Specific(A), m_Specific(B)))) ||
- (SPF1 == SPF_UMAX && match(C, m_c_UMin(m_Specific(A), m_Specific(B)))) ||
- (SPF1 == SPF_SMAX && match(C, m_c_SMin(m_Specific(A), m_Specific(B))))))
- return replaceInstUsesWith(Outer, Inner);
-
- // ABS(ABS(X)) -> ABS(X)
- // NABS(NABS(X)) -> NABS(X)
- // TODO: This could be done in instsimplify.
- if (SPF1 == SPF2 && (SPF1 == SPF_ABS || SPF1 == SPF_NABS)) {
- return replaceInstUsesWith(Outer, Inner);
- }
-
- // ABS(NABS(X)) -> ABS(X)
- // NABS(ABS(X)) -> NABS(X)
- if ((SPF1 == SPF_ABS && SPF2 == SPF_NABS) ||
- (SPF1 == SPF_NABS && SPF2 == SPF_ABS)) {
- SelectInst *SI = cast<SelectInst>(Inner);
- Value *NewSI =
- Builder.CreateSelect(SI->getCondition(), SI->getFalseValue(),
- SI->getTrueValue(), SI->getName(), SI);
- return replaceInstUsesWith(Outer, NewSI);
- }
-
- auto IsFreeOrProfitableToInvert =
- [&](Value *V, Value *&NotV, bool &ElidesXor) {
- if (match(V, m_Not(m_Value(NotV)))) {
- // If V has at most 2 uses then we can get rid of the xor operation
- // entirely.
- ElidesXor |= !V->hasNUsesOrMore(3);
- return true;
- }
-
- if (isFreeToInvert(V, !V->hasNUsesOrMore(3))) {
- NotV = nullptr;
- return true;
- }
-
- return false;
- };
-
- Value *NotA, *NotB, *NotC;
- bool ElidesXor = false;
-
- // MIN(MIN(~A, ~B), ~C) == ~MAX(MAX(A, B), C)
- // MIN(MAX(~A, ~B), ~C) == ~MAX(MIN(A, B), C)
- // MAX(MIN(~A, ~B), ~C) == ~MIN(MAX(A, B), C)
- // MAX(MAX(~A, ~B), ~C) == ~MIN(MIN(A, B), C)
- //
- // This transform is performance neutral if we can elide at least one xor from
- // the set of three operands, since we'll be tacking on an xor at the very
- // end.
- if (SelectPatternResult::isMinOrMax(SPF1) &&
- SelectPatternResult::isMinOrMax(SPF2) &&
- IsFreeOrProfitableToInvert(A, NotA, ElidesXor) &&
- IsFreeOrProfitableToInvert(B, NotB, ElidesXor) &&
- IsFreeOrProfitableToInvert(C, NotC, ElidesXor) && ElidesXor) {
- if (!NotA)
- NotA = Builder.CreateNot(A);
- if (!NotB)
- NotB = Builder.CreateNot(B);
- if (!NotC)
- NotC = Builder.CreateNot(C);
-
- Value *NewInner = createMinMax(Builder, getInverseMinMaxFlavor(SPF1), NotA,
- NotB);
- Value *NewOuter = Builder.CreateNot(
- createMinMax(Builder, getInverseMinMaxFlavor(SPF2), NewInner, NotC));
- return replaceInstUsesWith(Outer, NewOuter);
}
return nullptr;
@@ -2238,163 +2184,6 @@ static Value *foldSelectCmpXchg(SelectInst &SI) {
return nullptr;
}
-static Instruction *moveAddAfterMinMax(SelectPatternFlavor SPF, Value *X,
- Value *Y,
- InstCombiner::BuilderTy &Builder) {
- assert(SelectPatternResult::isMinOrMax(SPF) && "Expected min/max pattern");
- bool IsUnsigned = SPF == SelectPatternFlavor::SPF_UMIN ||
- SPF == SelectPatternFlavor::SPF_UMAX;
- // TODO: If InstSimplify could fold all cases where C2 <= C1, we could change
- // the constant value check to an assert.
- Value *A;
- const APInt *C1, *C2;
- if (IsUnsigned && match(X, m_NUWAdd(m_Value(A), m_APInt(C1))) &&
- match(Y, m_APInt(C2)) && C2->uge(*C1) && X->hasNUses(2)) {
- // umin (add nuw A, C1), C2 --> add nuw (umin A, C2 - C1), C1
- // umax (add nuw A, C1), C2 --> add nuw (umax A, C2 - C1), C1
- Value *NewMinMax = createMinMax(Builder, SPF, A,
- ConstantInt::get(X->getType(), *C2 - *C1));
- return BinaryOperator::CreateNUW(BinaryOperator::Add, NewMinMax,
- ConstantInt::get(X->getType(), *C1));
- }
-
- if (!IsUnsigned && match(X, m_NSWAdd(m_Value(A), m_APInt(C1))) &&
- match(Y, m_APInt(C2)) && X->hasNUses(2)) {
- bool Overflow;
- APInt Diff = C2->ssub_ov(*C1, Overflow);
- if (!Overflow) {
- // smin (add nsw A, C1), C2 --> add nsw (smin A, C2 - C1), C1
- // smax (add nsw A, C1), C2 --> add nsw (smax A, C2 - C1), C1
- Value *NewMinMax = createMinMax(Builder, SPF, A,
- ConstantInt::get(X->getType(), Diff));
- return BinaryOperator::CreateNSW(BinaryOperator::Add, NewMinMax,
- ConstantInt::get(X->getType(), *C1));
- }
- }
-
- return nullptr;
-}
-
-/// Match a sadd_sat or ssub_sat which is using min/max to clamp the value.
-Instruction *InstCombinerImpl::matchSAddSubSat(Instruction &MinMax1) {
- Type *Ty = MinMax1.getType();
-
- // We are looking for a tree of:
- // max(INT_MIN, min(INT_MAX, add(sext(A), sext(B))))
- // Where the min and max could be reversed
- Instruction *MinMax2;
- BinaryOperator *AddSub;
- const APInt *MinValue, *MaxValue;
- if (match(&MinMax1, m_SMin(m_Instruction(MinMax2), m_APInt(MaxValue)))) {
- if (!match(MinMax2, m_SMax(m_BinOp(AddSub), m_APInt(MinValue))))
- return nullptr;
- } else if (match(&MinMax1,
- m_SMax(m_Instruction(MinMax2), m_APInt(MinValue)))) {
- if (!match(MinMax2, m_SMin(m_BinOp(AddSub), m_APInt(MaxValue))))
- return nullptr;
- } else
- return nullptr;
-
- // Check that the constants clamp a saturate, and that the new type would be
- // sensible to convert to.
- if (!(*MaxValue + 1).isPowerOf2() || -*MinValue != *MaxValue + 1)
- return nullptr;
- // In what bitwidth can this be treated as saturating arithmetics?
- unsigned NewBitWidth = (*MaxValue + 1).logBase2() + 1;
- // FIXME: This isn't quite right for vectors, but using the scalar type is a
- // good first approximation for what should be done there.
- if (!shouldChangeType(Ty->getScalarType()->getIntegerBitWidth(), NewBitWidth))
- return nullptr;
-
- // Also make sure that the number of uses is as expected. The 3 is for the
- // the two items of the compare and the select, or 2 from a min/max.
- unsigned ExpUses = isa<IntrinsicInst>(MinMax1) ? 2 : 3;
- if (MinMax2->hasNUsesOrMore(ExpUses) || AddSub->hasNUsesOrMore(ExpUses))
- return nullptr;
-
- // Create the new type (which can be a vector type)
- Type *NewTy = Ty->getWithNewBitWidth(NewBitWidth);
-
- Intrinsic::ID IntrinsicID;
- if (AddSub->getOpcode() == Instruction::Add)
- IntrinsicID = Intrinsic::sadd_sat;
- else if (AddSub->getOpcode() == Instruction::Sub)
- IntrinsicID = Intrinsic::ssub_sat;
- else
- return nullptr;
-
- // The two operands of the add/sub must be nsw-truncatable to the NewTy. This
- // is usually achieved via a sext from a smaller type.
- if (ComputeMaxSignificantBits(AddSub->getOperand(0), 0, AddSub) >
- NewBitWidth ||
- ComputeMaxSignificantBits(AddSub->getOperand(1), 0, AddSub) > NewBitWidth)
- return nullptr;
-
- // Finally create and return the sat intrinsic, truncated to the new type
- Function *F = Intrinsic::getDeclaration(MinMax1.getModule(), IntrinsicID, NewTy);
- Value *AT = Builder.CreateTrunc(AddSub->getOperand(0), NewTy);
- Value *BT = Builder.CreateTrunc(AddSub->getOperand(1), NewTy);
- Value *Sat = Builder.CreateCall(F, {AT, BT});
- return CastInst::Create(Instruction::SExt, Sat, Ty);
-}
-
-/// Reduce a sequence of min/max with a common operand.
-static Instruction *factorizeMinMaxTree(SelectPatternFlavor SPF, Value *LHS,
- Value *RHS,
- InstCombiner::BuilderTy &Builder) {
- assert(SelectPatternResult::isMinOrMax(SPF) && "Expected a min/max");
- // TODO: Allow FP min/max with nnan/nsz.
- if (!LHS->getType()->isIntOrIntVectorTy())
- return nullptr;
-
- // Match 3 of the same min/max ops. Example: umin(umin(), umin()).
- Value *A, *B, *C, *D;
- SelectPatternResult L = matchSelectPattern(LHS, A, B);
- SelectPatternResult R = matchSelectPattern(RHS, C, D);
- if (SPF != L.Flavor || L.Flavor != R.Flavor)
- return nullptr;
-
- // Look for a common operand. The use checks are different than usual because
- // a min/max pattern typically has 2 uses of each op: 1 by the cmp and 1 by
- // the select.
- Value *MinMaxOp = nullptr;
- Value *ThirdOp = nullptr;
- if (!LHS->hasNUsesOrMore(3) && RHS->hasNUsesOrMore(3)) {
- // If the LHS is only used in this chain and the RHS is used outside of it,
- // reuse the RHS min/max because that will eliminate the LHS.
- if (D == A || C == A) {
- // min(min(a, b), min(c, a)) --> min(min(c, a), b)
- // min(min(a, b), min(a, d)) --> min(min(a, d), b)
- MinMaxOp = RHS;
- ThirdOp = B;
- } else if (D == B || C == B) {
- // min(min(a, b), min(c, b)) --> min(min(c, b), a)
- // min(min(a, b), min(b, d)) --> min(min(b, d), a)
- MinMaxOp = RHS;
- ThirdOp = A;
- }
- } else if (!RHS->hasNUsesOrMore(3)) {
- // Reuse the LHS. This will eliminate the RHS.
- if (D == A || D == B) {
- // min(min(a, b), min(c, a)) --> min(min(a, b), c)
- // min(min(a, b), min(c, b)) --> min(min(a, b), c)
- MinMaxOp = LHS;
- ThirdOp = C;
- } else if (C == A || C == B) {
- // min(min(a, b), min(b, d)) --> min(min(a, b), d)
- // min(min(a, b), min(c, b)) --> min(min(a, b), d)
- MinMaxOp = LHS;
- ThirdOp = D;
- }
- }
- if (!MinMaxOp || !ThirdOp)
- return nullptr;
-
- CmpInst::Predicate P = getMinMaxPred(SPF);
- Value *CmpABC = Builder.CreateICmp(P, MinMaxOp, ThirdOp);
- return SelectInst::Create(CmpABC, MinMaxOp, ThirdOp);
-}
-
/// Try to reduce a funnel/rotate pattern that includes a compare and select
/// into a funnel shift intrinsic. Example:
/// rotl32(a, b) --> (b == 0 ? a : ((a >> (32 - b)) | (a << b)))
@@ -2484,7 +2273,8 @@ static Instruction *foldSelectToCopysign(SelectInst &Sel,
// Match select ?, TC, FC where the constants are equal but negated.
// TODO: Generalize to handle a negated variable operand?
const APFloat *TC, *FC;
- if (!match(TVal, m_APFloat(TC)) || !match(FVal, m_APFloat(FC)) ||
+ if (!match(TVal, m_APFloatAllowUndef(TC)) ||
+ !match(FVal, m_APFloatAllowUndef(FC)) ||
!abs(*TC).bitwiseIsEqual(abs(*FC)))
return nullptr;
@@ -2504,17 +2294,16 @@ static Instruction *foldSelectToCopysign(SelectInst &Sel,
// (bitcast X) < 0 ? TC : -TC --> copysign(TC, -X)
// (bitcast X) >= 0 ? -TC : TC --> copysign(TC, -X)
// (bitcast X) >= 0 ? TC : -TC --> copysign(TC, X)
+ // Note: FMF from the select can not be propagated to the new instructions.
if (IsTrueIfSignSet ^ TC->isNegative())
- X = Builder.CreateFNegFMF(X, &Sel);
+ X = Builder.CreateFNeg(X);
// Canonicalize the magnitude argument as the positive constant since we do
// not care about its sign.
- Value *MagArg = TC->isNegative() ? FVal : TVal;
+ Value *MagArg = ConstantFP::get(SelType, abs(*TC));
Function *F = Intrinsic::getDeclaration(Sel.getModule(), Intrinsic::copysign,
Sel.getType());
- Instruction *CopySign = CallInst::Create(F, { MagArg, X });
- CopySign->setFastMathFlags(Sel.getFastMathFlags());
- return CopySign;
+ return CallInst::Create(F, { MagArg, X });
}
Instruction *InstCombinerImpl::foldVectorSelect(SelectInst &Sel) {
@@ -2715,29 +2504,144 @@ Instruction *InstCombinerImpl::foldAndOrOfSelectUsingImpliedCond(Value *Op,
}
}
-Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
+// Canonicalize select with fcmp to fabs(). -0.0 makes this tricky. We need
+// fast-math-flags (nsz) or fsub with +0.0 (not fneg) for this to work.
+static Instruction *foldSelectWithFCmpToFabs(SelectInst &SI,
+ InstCombinerImpl &IC) {
Value *CondVal = SI.getCondition();
- Value *TrueVal = SI.getTrueValue();
- Value *FalseVal = SI.getFalseValue();
- Type *SelType = SI.getType();
- // FIXME: Remove this workaround when freeze related patches are done.
- // For select with undef operand which feeds into an equality comparison,
- // don't simplify it so loop unswitch can know the equality comparison
- // may have an undef operand. This is a workaround for PR31652 caused by
- // descrepancy about branch on undef between LoopUnswitch and GVN.
- if (match(TrueVal, m_Undef()) || match(FalseVal, m_Undef())) {
- if (llvm::any_of(SI.users(), [&](User *U) {
- ICmpInst *CI = dyn_cast<ICmpInst>(U);
- if (CI && CI->isEquality())
- return true;
- return false;
- })) {
+ for (bool Swap : {false, true}) {
+ Value *TrueVal = SI.getTrueValue();
+ Value *X = SI.getFalseValue();
+ CmpInst::Predicate Pred;
+
+ if (Swap)
+ std::swap(TrueVal, X);
+
+ if (!match(CondVal, m_FCmp(Pred, m_Specific(X), m_AnyZeroFP())))
+ continue;
+
+ // fold (X <= +/-0.0) ? (0.0 - X) : X to fabs(X), when 'Swap' is false
+ // fold (X > +/-0.0) ? X : (0.0 - X) to fabs(X), when 'Swap' is true
+ if (match(TrueVal, m_FSub(m_PosZeroFP(), m_Specific(X)))) {
+ if (!Swap && (Pred == FCmpInst::FCMP_OLE || Pred == FCmpInst::FCMP_ULE)) {
+ Value *Fabs = IC.Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, &SI);
+ return IC.replaceInstUsesWith(SI, Fabs);
+ }
+ if (Swap && (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_UGT)) {
+ Value *Fabs = IC.Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, &SI);
+ return IC.replaceInstUsesWith(SI, Fabs);
+ }
+ }
+
+ // With nsz, when 'Swap' is false:
+ // fold (X < +/-0.0) ? -X : X or (X <= +/-0.0) ? -X : X to fabs(X)
+ // fold (X > +/-0.0) ? -X : X or (X >= +/-0.0) ? -X : X to -fabs(x)
+ // when 'Swap' is true:
+ // fold (X > +/-0.0) ? X : -X or (X >= +/-0.0) ? X : -X to fabs(X)
+ // fold (X < +/-0.0) ? X : -X or (X <= +/-0.0) ? X : -X to -fabs(X)
+ if (!match(TrueVal, m_FNeg(m_Specific(X))) || !SI.hasNoSignedZeros())
return nullptr;
+
+ if (Swap)
+ Pred = FCmpInst::getSwappedPredicate(Pred);
+
+ bool IsLTOrLE = Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_OLE ||
+ Pred == FCmpInst::FCMP_ULT || Pred == FCmpInst::FCMP_ULE;
+ bool IsGTOrGE = Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_OGE ||
+ Pred == FCmpInst::FCMP_UGT || Pred == FCmpInst::FCMP_UGE;
+
+ if (IsLTOrLE) {
+ Value *Fabs = IC.Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, &SI);
+ return IC.replaceInstUsesWith(SI, Fabs);
+ }
+ if (IsGTOrGE) {
+ Value *Fabs = IC.Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, &SI);
+ Instruction *NewFNeg = UnaryOperator::CreateFNeg(Fabs);
+ NewFNeg->setFastMathFlags(SI.getFastMathFlags());
+ return NewFNeg;
}
}
- if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal,
+ return nullptr;
+}
+
+// Match the following IR pattern:
+// %x.lowbits = and i8 %x, %lowbitmask
+// %x.lowbits.are.zero = icmp eq i8 %x.lowbits, 0
+// %x.biased = add i8 %x, %bias
+// %x.biased.highbits = and i8 %x.biased, %highbitmask
+// %x.roundedup = select i1 %x.lowbits.are.zero, i8 %x, i8 %x.biased.highbits
+// Define:
+// %alignment = add i8 %lowbitmask, 1
+// Iff 1. an %alignment is a power-of-two (aka, %lowbitmask is a low bit mask)
+// and 2. %bias is equal to either %lowbitmask or %alignment,
+// and 3. %highbitmask is equal to ~%lowbitmask (aka, to -%alignment)
+// then this pattern can be transformed into:
+// %x.offset = add i8 %x, %lowbitmask
+// %x.roundedup = and i8 %x.offset, %highbitmask
+static Value *
+foldRoundUpIntegerWithPow2Alignment(SelectInst &SI,
+ InstCombiner::BuilderTy &Builder) {
+ Value *Cond = SI.getCondition();
+ Value *X = SI.getTrueValue();
+ Value *XBiasedHighBits = SI.getFalseValue();
+
+ ICmpInst::Predicate Pred;
+ Value *XLowBits;
+ if (!match(Cond, m_ICmp(Pred, m_Value(XLowBits), m_ZeroInt())) ||
+ !ICmpInst::isEquality(Pred))
+ return nullptr;
+
+ if (Pred == ICmpInst::Predicate::ICMP_NE)
+ std::swap(X, XBiasedHighBits);
+
+ // FIXME: we could support non non-splats here.
+
+ const APInt *LowBitMaskCst;
+ if (!match(XLowBits, m_And(m_Specific(X), m_APIntAllowUndef(LowBitMaskCst))))
+ return nullptr;
+
+ const APInt *BiasCst, *HighBitMaskCst;
+ if (!match(XBiasedHighBits,
+ m_And(m_Add(m_Specific(X), m_APIntAllowUndef(BiasCst)),
+ m_APIntAllowUndef(HighBitMaskCst))))
+ return nullptr;
+
+ if (!LowBitMaskCst->isMask())
+ return nullptr;
+
+ APInt InvertedLowBitMaskCst = ~*LowBitMaskCst;
+ if (InvertedLowBitMaskCst != *HighBitMaskCst)
+ return nullptr;
+
+ APInt AlignmentCst = *LowBitMaskCst + 1;
+
+ if (*BiasCst != AlignmentCst && *BiasCst != *LowBitMaskCst)
+ return nullptr;
+
+ if (!XBiasedHighBits->hasOneUse()) {
+ if (*BiasCst == *LowBitMaskCst)
+ return XBiasedHighBits;
+ return nullptr;
+ }
+
+ // FIXME: could we preserve undef's here?
+ Type *Ty = X->getType();
+ Value *XOffset = Builder.CreateAdd(X, ConstantInt::get(Ty, *LowBitMaskCst),
+ X->getName() + ".biased");
+ Value *R = Builder.CreateAnd(XOffset, ConstantInt::get(Ty, *HighBitMaskCst));
+ R->takeName(&SI);
+ return R;
+}
+
+Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
+ Value *CondVal = SI.getCondition();
+ Value *TrueVal = SI.getTrueValue();
+ Value *FalseVal = SI.getFalseValue();
+ Type *SelType = SI.getType();
+
+ if (Value *V = simplifySelectInst(CondVal, TrueVal, FalseVal,
SQ.getWithInstruction(&SI)))
return replaceInstUsesWith(SI, V);
@@ -2747,8 +2651,6 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
if (Instruction *I = canonicalizeScalarSelectOfVecs(SI, *this))
return I;
- CmpInst::Predicate Pred;
-
// Avoid potential infinite loops by checking for non-constant condition.
// TODO: Can we assert instead by improving canonicalizeSelectToShuffle()?
// Scalar select must have simplified?
@@ -2757,13 +2659,29 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
// Folding select to and/or i1 isn't poison safe in general. impliesPoison
// checks whether folding it does not convert a well-defined value into
// poison.
- if (match(TrueVal, m_One()) && impliesPoison(FalseVal, CondVal)) {
- // Change: A = select B, true, C --> A = or B, C
- return BinaryOperator::CreateOr(CondVal, FalseVal);
+ if (match(TrueVal, m_One())) {
+ if (impliesPoison(FalseVal, CondVal)) {
+ // Change: A = select B, true, C --> A = or B, C
+ return BinaryOperator::CreateOr(CondVal, FalseVal);
+ }
+
+ if (auto *LHS = dyn_cast<FCmpInst>(CondVal))
+ if (auto *RHS = dyn_cast<FCmpInst>(FalseVal))
+ if (Value *V = foldLogicOfFCmps(LHS, RHS, /*IsAnd*/ false,
+ /*IsSelectLogical*/ true))
+ return replaceInstUsesWith(SI, V);
}
- if (match(FalseVal, m_Zero()) && impliesPoison(TrueVal, CondVal)) {
- // Change: A = select B, C, false --> A = and B, C
- return BinaryOperator::CreateAnd(CondVal, TrueVal);
+ if (match(FalseVal, m_Zero())) {
+ if (impliesPoison(TrueVal, CondVal)) {
+ // Change: A = select B, C, false --> A = and B, C
+ return BinaryOperator::CreateAnd(CondVal, TrueVal);
+ }
+
+ if (auto *LHS = dyn_cast<FCmpInst>(CondVal))
+ if (auto *RHS = dyn_cast<FCmpInst>(TrueVal))
+ if (Value *V = foldLogicOfFCmps(LHS, RHS, /*IsAnd*/ true,
+ /*IsSelectLogical*/ true))
+ return replaceInstUsesWith(SI, V);
}
auto *One = ConstantInt::getTrue(SelType);
@@ -2821,6 +2739,20 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
match(TrueVal, m_Specific(B)) && match(FalseVal, m_Zero()))
return replaceOperand(SI, 0, A);
+ Value *C;
+ // select (~a | c), a, b -> and a, (or c, freeze(b))
+ if (match(CondVal, m_c_Or(m_Not(m_Specific(TrueVal)), m_Value(C))) &&
+ CondVal->hasOneUse()) {
+ FalseVal = Builder.CreateFreeze(FalseVal);
+ return BinaryOperator::CreateAnd(TrueVal, Builder.CreateOr(C, FalseVal));
+ }
+ // select (~c & b), a, b -> and b, (or freeze(a), c)
+ if (match(CondVal, m_c_And(m_Not(m_Value(C)), m_Specific(FalseVal))) &&
+ CondVal->hasOneUse()) {
+ TrueVal = Builder.CreateFreeze(TrueVal);
+ return BinaryOperator::CreateAnd(FalseVal, Builder.CreateOr(C, TrueVal));
+ }
+
if (!SelType->isVectorTy()) {
if (Value *S = simplifyWithOpReplaced(TrueVal, CondVal, One, SQ,
/* AllowRefinement */ true))
@@ -2846,16 +2778,11 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
/* IsAnd */ IsAnd))
return I;
- if (auto *ICmp0 = dyn_cast<ICmpInst>(CondVal)) {
- if (auto *ICmp1 = dyn_cast<ICmpInst>(Op1)) {
- if (auto *V = foldAndOrOfICmpsOfAndWithPow2(ICmp0, ICmp1, &SI, IsAnd,
- /* IsLogical */ true))
- return replaceInstUsesWith(SI, V);
-
- if (auto *V = foldEqOfParts(ICmp0, ICmp1, IsAnd))
+ if (auto *ICmp0 = dyn_cast<ICmpInst>(CondVal))
+ if (auto *ICmp1 = dyn_cast<ICmpInst>(Op1))
+ if (auto *V = foldAndOrOfICmps(ICmp0, ICmp1, SI, IsAnd,
+ /* IsLogical */ true))
return replaceInstUsesWith(SI, V);
- }
- }
}
// select (select a, true, b), c, false -> select a, c, false
@@ -2959,42 +2886,9 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
}
}
- // Canonicalize select with fcmp to fabs(). -0.0 makes this tricky. We need
- // fast-math-flags (nsz) or fsub with +0.0 (not fneg) for this to work.
- // (X <= +/-0.0) ? (0.0 - X) : X --> fabs(X)
- if (match(CondVal, m_FCmp(Pred, m_Specific(FalseVal), m_AnyZeroFP())) &&
- match(TrueVal, m_FSub(m_PosZeroFP(), m_Specific(FalseVal))) &&
- (Pred == FCmpInst::FCMP_OLE || Pred == FCmpInst::FCMP_ULE)) {
- Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, FalseVal, &SI);
- return replaceInstUsesWith(SI, Fabs);
- }
- // (X > +/-0.0) ? X : (0.0 - X) --> fabs(X)
- if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
- match(FalseVal, m_FSub(m_PosZeroFP(), m_Specific(TrueVal))) &&
- (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_UGT)) {
- Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
- return replaceInstUsesWith(SI, Fabs);
- }
- // With nnan and nsz:
- // (X < +/-0.0) ? -X : X --> fabs(X)
- // (X <= +/-0.0) ? -X : X --> fabs(X)
- if (match(CondVal, m_FCmp(Pred, m_Specific(FalseVal), m_AnyZeroFP())) &&
- match(TrueVal, m_FNeg(m_Specific(FalseVal))) && SI.hasNoSignedZeros() &&
- (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_OLE ||
- Pred == FCmpInst::FCMP_ULT || Pred == FCmpInst::FCMP_ULE)) {
- Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, FalseVal, &SI);
- return replaceInstUsesWith(SI, Fabs);
- }
- // With nnan and nsz:
- // (X > +/-0.0) ? X : -X --> fabs(X)
- // (X >= +/-0.0) ? X : -X --> fabs(X)
- if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
- match(FalseVal, m_FNeg(m_Specific(TrueVal))) && SI.hasNoSignedZeros() &&
- (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_OGE ||
- Pred == FCmpInst::FCMP_UGT || Pred == FCmpInst::FCMP_UGE)) {
- Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
- return replaceInstUsesWith(SI, Fabs);
- }
+ // Fold selecting to fabs.
+ if (Instruction *Fabs = foldSelectWithFCmpToFabs(SI, *this))
+ return Fabs;
// See if we are selecting two values based on a comparison of the two values.
if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
@@ -3066,8 +2960,6 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
if (Instruction *R = foldSPFofSPF(cast<Instruction>(RHS), SPF2, LHS2,
RHS2, SI, SPF, LHS))
return R;
- // TODO.
- // ABS(-X) -> ABS(X)
}
if (SelectPatternResult::isMinOrMax(SPF)) {
@@ -3102,46 +2994,6 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
Value *NewCast = Builder.CreateCast(CastOp, NewSI, SelType);
return replaceInstUsesWith(SI, NewCast);
}
-
- // MAX(~a, ~b) -> ~MIN(a, b)
- // MAX(~a, C) -> ~MIN(a, ~C)
- // MIN(~a, ~b) -> ~MAX(a, b)
- // MIN(~a, C) -> ~MAX(a, ~C)
- auto moveNotAfterMinMax = [&](Value *X, Value *Y) -> Instruction * {
- Value *A;
- if (match(X, m_Not(m_Value(A))) && !X->hasNUsesOrMore(3) &&
- !isFreeToInvert(A, A->hasOneUse()) &&
- // Passing false to only consider m_Not and constants.
- isFreeToInvert(Y, false)) {
- Value *B = Builder.CreateNot(Y);
- Value *NewMinMax = createMinMax(Builder, getInverseMinMaxFlavor(SPF),
- A, B);
- // Copy the profile metadata.
- if (MDNode *MD = SI.getMetadata(LLVMContext::MD_prof)) {
- cast<SelectInst>(NewMinMax)->setMetadata(LLVMContext::MD_prof, MD);
- // Swap the metadata if the operands are swapped.
- if (X == SI.getFalseValue() && Y == SI.getTrueValue())
- cast<SelectInst>(NewMinMax)->swapProfMetadata();
- }
-
- return BinaryOperator::CreateNot(NewMinMax);
- }
-
- return nullptr;
- };
-
- if (Instruction *I = moveNotAfterMinMax(LHS, RHS))
- return I;
- if (Instruction *I = moveNotAfterMinMax(RHS, LHS))
- return I;
-
- if (Instruction *I = moveAddAfterMinMax(SPF, LHS, RHS, Builder))
- return I;
-
- if (Instruction *I = factorizeMinMaxTree(SPF, LHS, RHS, Builder))
- return I;
- if (Instruction *I = matchSAddSubSat(SI))
- return I;
}
}
@@ -3307,35 +3159,42 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
if (Value *Fr = foldSelectWithFrozenICmp(SI, Builder))
return replaceInstUsesWith(SI, Fr);
+ if (Value *V = foldRoundUpIntegerWithPow2Alignment(SI, Builder))
+ return replaceInstUsesWith(SI, V);
+
// select(mask, mload(,,mask,0), 0) -> mload(,,mask,0)
// Load inst is intentionally not checked for hasOneUse()
if (match(FalseVal, m_Zero()) &&
- match(TrueVal, m_MaskedLoad(m_Value(), m_Value(), m_Specific(CondVal),
- m_CombineOr(m_Undef(), m_Zero())))) {
- auto *MaskedLoad = cast<IntrinsicInst>(TrueVal);
- if (isa<UndefValue>(MaskedLoad->getArgOperand(3)))
- MaskedLoad->setArgOperand(3, FalseVal /* Zero */);
- return replaceInstUsesWith(SI, MaskedLoad);
+ (match(TrueVal, m_MaskedLoad(m_Value(), m_Value(), m_Specific(CondVal),
+ m_CombineOr(m_Undef(), m_Zero()))) ||
+ match(TrueVal, m_MaskedGather(m_Value(), m_Value(), m_Specific(CondVal),
+ m_CombineOr(m_Undef(), m_Zero()))))) {
+ auto *MaskedInst = cast<IntrinsicInst>(TrueVal);
+ if (isa<UndefValue>(MaskedInst->getArgOperand(3)))
+ MaskedInst->setArgOperand(3, FalseVal /* Zero */);
+ return replaceInstUsesWith(SI, MaskedInst);
}
Value *Mask;
if (match(TrueVal, m_Zero()) &&
- match(FalseVal, m_MaskedLoad(m_Value(), m_Value(), m_Value(Mask),
- m_CombineOr(m_Undef(), m_Zero()))) &&
+ (match(FalseVal, m_MaskedLoad(m_Value(), m_Value(), m_Value(Mask),
+ m_CombineOr(m_Undef(), m_Zero()))) ||
+ match(FalseVal, m_MaskedGather(m_Value(), m_Value(), m_Value(Mask),
+ m_CombineOr(m_Undef(), m_Zero())))) &&
(CondVal->getType() == Mask->getType())) {
// We can remove the select by ensuring the load zeros all lanes the
// select would have. We determine this by proving there is no overlap
// between the load and select masks.
// (i.e (load_mask & select_mask) == 0 == no overlap)
bool CanMergeSelectIntoLoad = false;
- if (Value *V = SimplifyAndInst(CondVal, Mask, SQ.getWithInstruction(&SI)))
+ if (Value *V = simplifyAndInst(CondVal, Mask, SQ.getWithInstruction(&SI)))
CanMergeSelectIntoLoad = match(V, m_Zero());
if (CanMergeSelectIntoLoad) {
- auto *MaskedLoad = cast<IntrinsicInst>(FalseVal);
- if (isa<UndefValue>(MaskedLoad->getArgOperand(3)))
- MaskedLoad->setArgOperand(3, TrueVal /* Zero */);
- return replaceInstUsesWith(SI, MaskedLoad);
+ auto *MaskedInst = cast<IntrinsicInst>(FalseVal);
+ if (isa<UndefValue>(MaskedInst->getArgOperand(3)))
+ MaskedInst->setArgOperand(3, TrueVal /* Zero */);
+ return replaceInstUsesWith(SI, MaskedInst);
}
}
generated by cgit v1.3 (git 2.53.0) at 2026-03-10 17:09:48 +0000