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[SCEV] Improve code in isKnownPredicateViaConstantRanges (NFC) #147335

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Merged
artagnon merged 1 commit into from
Jul 7, 2025
Merged

[SCEV] Improve code in isKnownPredicateViaConstantRanges (NFC) #147335

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26 changes: 5 additions & 21 deletions llvm/lib/Analysis/ScalarEvolution.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -11376,11 +11376,9 @@ bool ScalarEvolution::isKnownPredicateViaConstantRanges(CmpPredicate Pred,
if (HasSameValue(LHS, RHS))
return ICmpInst::isTrueWhenEqual(Pred);

// This code is split out from isKnownPredicate because it is called from
// within isLoopEntryGuardedByCond.

auto CheckRanges = [&](const ConstantRange &RangeLHS,
const ConstantRange &RangeRHS) {
auto CheckRange = [&](bool IsSigned) {
auto RangeLHS = IsSigned ? getSignedRange(LHS) : getUnsignedRange(LHS);
auto RangeRHS = IsSigned ? getSignedRange(RHS) : getUnsignedRange(RHS);
return RangeLHS.icmp(Pred, RangeRHS);
};

Expand All @@ -11390,27 +11388,13 @@ bool ScalarEvolution::isKnownPredicateViaConstantRanges(CmpPredicate Pred,
return false;

if (Pred == CmpInst::ICMP_NE) {
auto SL = getSignedRange(LHS);
auto SR = getSignedRange(RHS);
if (CheckRanges(SL, SR))
return true;
auto UL = getUnsignedRange(LHS);
auto UR = getUnsignedRange(RHS);
if (CheckRanges(UL, UR))
if (CheckRange(true) || CheckRange(false))
return true;
auto *Diff = getMinusSCEV(LHS, RHS);
return !isa<SCEVCouldNotCompute>(Diff) && isKnownNonZero(Diff);
}

if (CmpInst::isSigned(Pred)) {
auto SL = getSignedRange(LHS);
auto SR = getSignedRange(RHS);
return CheckRanges(SL, SR);
}

auto UL = getUnsignedRange(LHS);
auto UR = getUnsignedRange(RHS);
return CheckRanges(UL, UR);
return CheckRange(CmpInst::isSigned(Pred));
}

bool ScalarEvolution::isKnownPredicateViaNoOverflow(CmpPredicate Pred,
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