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[VPlan] Handle scalar-VF in transforms (NFC) #161365

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Merged
merged 1 commit into from
Sep 30, 2025
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Merged

[VPlan] Handle scalar-VF in transforms (NFC) #161365

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8 changes: 3 additions & 5 deletions llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8164,14 +8164,12 @@ void LoopVectorizationPlanner::buildVPlansWithVPRecipes(ElementCount MinVF,
VFRange SubRange = {VF, MaxVFTimes2};
if (auto Plan = tryToBuildVPlanWithVPRecipes(
std::unique_ptr<VPlan>(VPlan0->duplicate()), SubRange, &LVer)) {
bool HasScalarVF = Plan->hasScalarVFOnly();
// Now optimize the initial VPlan.
if (!HasScalarVF)
VPlanTransforms::runPass(VPlanTransforms::truncateToMinimalBitwidths,
*Plan, CM.getMinimalBitwidths());
VPlanTransforms::runPass(VPlanTransforms::truncateToMinimalBitwidths,
*Plan, CM.getMinimalBitwidths());
VPlanTransforms::runPass(VPlanTransforms::optimize, *Plan);
// TODO: try to put it close to addActiveLaneMask().
if (CM.foldTailWithEVL() && !HasScalarVF)
if (CM.foldTailWithEVL())
VPlanTransforms::runPass(VPlanTransforms::addExplicitVectorLength,
*Plan, CM.getMaxSafeElements());
assert(verifyVPlanIsValid(*Plan) && "VPlan is invalid");
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4 changes: 4 additions & 0 deletions llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
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Expand Up @@ -2124,6 +2124,8 @@ static void licm(VPlan &Plan) {

void VPlanTransforms::truncateToMinimalBitwidths(
VPlan &Plan, const MapVector<Instruction *, uint64_t> &MinBWs) {
if (Plan.hasScalarVFOnly())
return;
// Keep track of created truncates, so they can be re-used. Note that we
// cannot use RAUW after creating a new truncate, as this would could make
// other uses have different types for their operands, making them invalidly
Expand Down Expand Up @@ -2704,6 +2706,8 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
///
void VPlanTransforms::addExplicitVectorLength(
VPlan &Plan, const std::optional<unsigned> &MaxSafeElements) {
if (Plan.hasScalarVFOnly())
return;
VPBasicBlock *Header = Plan.getVectorLoopRegion()->getEntryBasicBlock();

auto *CanonicalIVPHI = Plan.getCanonicalIV();
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