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Use ScaledThreshold to calculate Unroll count #162247

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Use ScaledThreshold to calculate Unroll count #162247

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3 changes: 3 additions & 0 deletions llvm/include/llvm/Analysis/TargetTransformInfo.h
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Original file line number Diff line number Diff line change
Expand Up @@ -574,6 +574,9 @@ class TargetTransformInfo {
/// The cost threshold for the unrolled loop, like Threshold, but used
/// for partial/runtime unrolling (set to UINT_MAX to disable).
unsigned PartialThreshold;
/// The cost threshold for the unrolled loop, like Threshold, but used
/// for calculating unroll count for loop.
unsigned ScaledThreshold;
/// The cost threshold for the unrolled loop when optimizing for size, like
/// OptSizeThreshold, but used for partial/runtime unrolling (set to
/// UINT_MAX to disable).
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5 changes: 3 additions & 2 deletions llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
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Expand Up @@ -201,6 +201,7 @@ TargetTransformInfo::UnrollingPreferences llvm::gatherUnrollingPreferences(
UP.MaxPercentThresholdBoost = 400;
UP.OptSizeThreshold = UnrollOptSizeThreshold;
UP.PartialThreshold = 150;
UP.ScaledThreshold = 100;
UP.PartialOptSizeThreshold = UnrollOptSizeThreshold;
UP.Count = 0;
UP.DefaultUnrollRuntimeCount = 8;
Expand Down Expand Up @@ -884,8 +885,8 @@ shouldPartialUnroll(const unsigned LoopSize, const unsigned TripCount,
if (UP.PartialThreshold != NoThreshold) {
// Reduce unroll count to be modulo of TripCount for partial unrolling.
if (UCE.getUnrolledLoopSize(UP, count) > UP.PartialThreshold)
count = (std::max(UP.PartialThreshold, UP.BEInsns + 1) - UP.BEInsns) /
(LoopSize - UP.BEInsns);
count = (std::max(UP.ScaledThreshold, UP.BEInsns + 1) - UP.BEInsns) /
(LoopSize - UP.BEInsns);
if (count > UP.MaxCount)
count = UP.MaxCount;
while (count != 0 && TripCount % count != 0)
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