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Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp')
-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp81
1 files changed, 43 insertions, 38 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 3d251d6..1eca177 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1225,8 +1225,12 @@ static Value *foldSelectCttzCtlz(ICmpInst *ICI, Value *TrueVal, Value *FalseVal,
// zext/trunc) have one use (ending at the select), the cttz/ctlz result will
// not be used if the input is zero. Relax to 'zero is poison' for that case.
if (II->hasOneUse() && SelectArg->hasOneUse() &&
- !match(II->getArgOperand(1), m_One()))
+ !match(II->getArgOperand(1), m_One())) {
II->setArgOperand(1, ConstantInt::getTrue(II->getContext()));
+ // noundef attribute on the intrinsic may no longer be valid.
+ II->dropUBImplyingAttrsAndMetadata();
+ IC.addToWorklist(II);
+ }
return nullptr;
}
@@ -1685,8 +1689,7 @@ tryToReuseConstantFromSelectInComparison(SelectInst &Sel, ICmpInst &Cmp,
return nullptr;
// Check the constant we'd have with flipped-strictness predicate.
- auto FlippedStrictness =
- InstCombiner::getFlippedStrictnessPredicateAndConstant(Pred, C0);
+ auto FlippedStrictness = getFlippedStrictnessPredicateAndConstant(Pred, C0);
if (!FlippedStrictness)
return nullptr;
@@ -1966,8 +1969,7 @@ static Value *foldSelectWithConstOpToBinOp(ICmpInst *Cmp, Value *TrueVal,
Value *RHS;
SelectPatternFlavor SPF;
const DataLayout &DL = BOp->getDataLayout();
- auto Flipped =
- InstCombiner::getFlippedStrictnessPredicateAndConstant(Predicate, C1);
+ auto Flipped = getFlippedStrictnessPredicateAndConstant(Predicate, C1);
if (C3 == ConstantFoldBinaryOpOperands(Opcode, C1, C2, DL)) {
SPF = getSelectPattern(Predicate).Flavor;
@@ -2819,9 +2821,9 @@ static Instruction *foldSelectWithSRem(SelectInst &SI, InstCombinerImpl &IC,
// %cnd = icmp slt i32 %rem, 0
// %add = add i32 %rem, %n
// %sel = select i1 %cnd, i32 %add, i32 %rem
- if (match(TrueVal, m_Add(m_Specific(RemRes), m_Value(Remainder))) &&
+ if (match(TrueVal, m_c_Add(m_Specific(RemRes), m_Value(Remainder))) &&
match(RemRes, m_SRem(m_Value(Op), m_Specific(Remainder))) &&
- IC.isKnownToBeAPowerOfTwo(Remainder, /*OrZero*/ true) &&
+ IC.isKnownToBeAPowerOfTwo(Remainder, /*OrZero=*/true) &&
FalseVal == RemRes)
return FoldToBitwiseAnd(Remainder);
@@ -3769,22 +3771,9 @@ static Value *foldSelectIntoAddConstant(SelectInst &SI,
if (!SIFOp || !SIFOp->hasNoSignedZeros() || !SIFOp->hasNoNaNs())
return nullptr;
- // select((fcmp Pred, X, 0), (fadd X, C), C)
- // => fadd((select (fcmp Pred, X, 0), X, 0), C)
- //
- // Pred := OGT, OGE, OLT, OLE, UGT, UGE, ULT, and ULE
- Instruction *FAdd;
- Constant *C;
- Value *X, *Z;
- CmpPredicate Pred;
-
- // Note: OneUse check for `Cmp` is necessary because it makes sure that other
- // InstCombine folds don't undo this transformation and cause an infinite
- // loop. Furthermore, it could also increase the operation count.
- if (match(&SI, m_Select(m_OneUse(m_FCmp(Pred, m_Value(X), m_Value(Z))),
- m_OneUse(m_Instruction(FAdd)), m_Constant(C))) ||
- match(&SI, m_Select(m_OneUse(m_FCmp(Pred, m_Value(X), m_Value(Z))),
- m_Constant(C), m_OneUse(m_Instruction(FAdd))))) {
+ auto TryFoldIntoAddConstant =
+ [&Builder, &SI](CmpInst::Predicate Pred, Value *X, Value *Z,
+ Instruction *FAdd, Constant *C, bool Swapped) -> Value * {
// Only these relational predicates can be transformed into maxnum/minnum
// intrinsic.
if (!CmpInst::isRelational(Pred) || !match(Z, m_AnyZeroFP()))
@@ -3793,7 +3782,8 @@ static Value *foldSelectIntoAddConstant(SelectInst &SI,
if (!match(FAdd, m_FAdd(m_Specific(X), m_Specific(C))))
return nullptr;
- Value *NewSelect = Builder.CreateSelect(SI.getCondition(), X, Z, "", &SI);
+ Value *NewSelect = Builder.CreateSelect(SI.getCondition(), Swapped ? Z : X,
+ Swapped ? X : Z, "", &SI);
NewSelect->takeName(&SI);
Value *NewFAdd = Builder.CreateFAdd(NewSelect, C);
@@ -3808,7 +3798,27 @@ static Value *foldSelectIntoAddConstant(SelectInst &SI,
cast<Instruction>(NewSelect)->setFastMathFlags(NewFMF);
return NewFAdd;
- }
+ };
+
+ // select((fcmp Pred, X, 0), (fadd X, C), C)
+ // => fadd((select (fcmp Pred, X, 0), X, 0), C)
+ //
+ // Pred := OGT, OGE, OLT, OLE, UGT, UGE, ULT, and ULE
+ Instruction *FAdd;
+ Constant *C;
+ Value *X, *Z;
+ CmpPredicate Pred;
+
+ // Note: OneUse check for `Cmp` is necessary because it makes sure that other
+ // InstCombine folds don't undo this transformation and cause an infinite
+ // loop. Furthermore, it could also increase the operation count.
+ if (match(&SI, m_Select(m_OneUse(m_FCmp(Pred, m_Value(X), m_Value(Z))),
+ m_OneUse(m_Instruction(FAdd)), m_Constant(C))))
+ return TryFoldIntoAddConstant(Pred, X, Z, FAdd, C, /*Swapped=*/false);
+
+ if (match(&SI, m_Select(m_OneUse(m_FCmp(Pred, m_Value(X), m_Value(Z))),
+ m_Constant(C), m_OneUse(m_Instruction(FAdd)))))
+ return TryFoldIntoAddConstant(Pred, X, Z, FAdd, C, /*Swapped=*/true);
return nullptr;
}
@@ -3902,12 +3912,11 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
// (X ugt Y) ? X : Y -> (X ole Y) ? Y : X
if (FCmp->hasOneUse() && FCmpInst::isUnordered(Pred)) {
FCmpInst::Predicate InvPred = FCmp->getInversePredicate();
- IRBuilder<>::FastMathFlagGuard FMFG(Builder);
// FIXME: The FMF should propagate from the select, not the fcmp.
- Builder.setFastMathFlags(FCmp->getFastMathFlags());
- Value *NewCond = Builder.CreateFCmp(InvPred, Cmp0, Cmp1,
- FCmp->getName() + ".inv");
- Value *NewSel = Builder.CreateSelect(NewCond, FalseVal, TrueVal);
+ Value *NewCond = Builder.CreateFCmpFMF(InvPred, Cmp0, Cmp1, FCmp,
+ FCmp->getName() + ".inv");
+ Value *NewSel =
+ Builder.CreateSelectFMF(NewCond, FalseVal, TrueVal, FCmp);
return replaceInstUsesWith(SI, NewSel);
}
}
@@ -4072,15 +4081,11 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
CmpInst::Predicate MinMaxPred = getMinMaxPred(SPF, SPR.Ordered);
Value *Cmp;
- if (CmpInst::isIntPredicate(MinMaxPred)) {
+ if (CmpInst::isIntPredicate(MinMaxPred))
Cmp = Builder.CreateICmp(MinMaxPred, LHS, RHS);
- } else {
- IRBuilder<>::FastMathFlagGuard FMFG(Builder);
- auto FMF =
- cast<FPMathOperator>(SI.getCondition())->getFastMathFlags();
- Builder.setFastMathFlags(FMF);
- Cmp = Builder.CreateFCmp(MinMaxPred, LHS, RHS);
- }
+ else
+ Cmp = Builder.CreateFCmpFMF(MinMaxPred, LHS, RHS,
+ cast<Instruction>(SI.getCondition()));
Value *NewSI = Builder.CreateSelect(Cmp, LHS, RHS, SI.getName(), &SI);
if (!IsCastNeeded)
generated by cgit v1.1 at 2025-09-27 15:59:42 +0000