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[unroll] Use early return in shouldFullUnroll [nfc]

This commit is contained in:
Philip Reames 2021-11-23 09:01:23 -08:00
parent d75ed9864a
commit 5c77aa2b91
1 changed files with 18 additions and 20 deletions
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38
llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
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@ -807,27 +807,25 @@ static Optional<unsigned> shouldFullUnroll(
const unsigned FullUnrollTripCount, const UnrollCostEstimator UCE,
const TargetTransformInfo::UnrollingPreferences &UP) {
if (FullUnrollTripCount && FullUnrollTripCount <= UP.FullUnrollMaxCount) {
// When computing the unrolled size, note that BEInsns are not replicated
// like the rest of the loop body.
if (UCE.getUnrolledLoopSize(UP) < UP.Threshold) {
return FullUnrollTripCount;
if (!FullUnrollTripCount || FullUnrollTripCount >= UP.FullUnrollMaxCount)
return None;
} else {
// The loop isn't that small, but we still can fully unroll it if that
// helps to remove a significant number of instructions.
// To check that, run additional analysis on the loop.
if (Optional<EstimatedUnrollCost> Cost = analyzeLoopUnrollCost(
L, FullUnrollTripCount, DT, SE, EphValues, TTI,
UP.Threshold * UP.MaxPercentThresholdBoost / 100,
UP.MaxIterationsCountToAnalyze)) {
unsigned Boost =
getFullUnrollBoostingFactor(*Cost, UP.MaxPercentThresholdBoost);
if (Cost->UnrolledCost < UP.Threshold * Boost / 100) {
return FullUnrollTripCount;
}
}
}
// When computing the unrolled size, note that BEInsns are not replicated
// like the rest of the loop body.
if (UCE.getUnrolledLoopSize(UP) < UP.Threshold)
return FullUnrollTripCount;
// The loop isn't that small, but we still can fully unroll it if that
// helps to remove a significant number of instructions.
// To check that, run additional analysis on the loop.
if (Optional<EstimatedUnrollCost> Cost = analyzeLoopUnrollCost(
L, FullUnrollTripCount, DT, SE, EphValues, TTI,
UP.Threshold * UP.MaxPercentThresholdBoost / 100,
UP.MaxIterationsCountToAnalyze)) {
unsigned Boost =
getFullUnrollBoostingFactor(*Cost, UP.MaxPercentThresholdBoost);
if (Cost->UnrolledCost < UP.Threshold * Boost / 100)
return FullUnrollTripCount;
}
return None;
}