Skip to content

[LV][VPlan] Remove any-of reduction from precomputeCost. NFC #117109

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Nov 22, 2024
Merged
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 2 additions & 22 deletions llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -7278,34 +7278,14 @@ LoopVectorizationPlanner::precomputeCosts(VPlan &Plan, ElementCount VF,

// The legacy cost model has special logic to compute the cost of in-loop
// reductions, which may be smaller than the sum of all instructions involved
// in the reduction. For AnyOf reductions, VPlan codegen may remove the select
// which the legacy cost model uses to assign cost. Pre-compute their costs
// for now.
// in the reduction.
// TODO: Switch to costing based on VPlan once the logic has been ported.
for (const auto &[RedPhi, RdxDesc] : Legal->getReductionVars()) {
if (ForceTargetInstructionCost.getNumOccurrences())
continue;

if (!CM.isInLoopReduction(RedPhi) &&
!RecurrenceDescriptor::isAnyOfRecurrenceKind(
RdxDesc.getRecurrenceKind()))
continue;

// AnyOf reduction codegen may remove the select. To match the legacy cost
// model, pre-compute the cost for AnyOf reductions here.
if (RecurrenceDescriptor::isAnyOfRecurrenceKind(
RdxDesc.getRecurrenceKind())) {
auto *Select = cast<SelectInst>(*find_if(
RedPhi->users(), [](User *U) { return isa<SelectInst>(U); }));
assert(!CostCtx.SkipCostComputation.contains(Select) &&
"reduction op visited multiple times");
CostCtx.SkipCostComputation.insert(Select);
auto ReductionCost = CostCtx.getLegacyCost(Select, VF);
LLVM_DEBUG(dbgs() << "Cost of " << ReductionCost << " for VF " << VF
<< ":\n any-of reduction " << *Select << "\n");
Cost += ReductionCost;
if (!CM.isInLoopReduction(RedPhi))
continue;
}

const auto &ChainOps = RdxDesc.getReductionOpChain(RedPhi, OrigLoop);
SetVector<Instruction *> ChainOpsAndOperands(ChainOps.begin(),
Expand Down
Loading