/// The cost threshold for the unrolled loop when optimizing for size (set
/// to UINT_MAX to disable).
unsigned OptSizeThreshold;
+ /// 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 when optimizing for size, like
+ /// OptSizeThreshold, but used for partial/runtime unrolling (set to UINT_MAX
+ /// to disable).
+ unsigned PartialOptSizeThreshold;
/// A forced unrolling factor (the number of concatenated bodies of the
/// original loop in the unrolled loop body). When set to 0, the unrolling
/// transformation will select an unrolling factor based on the current cost
/// threshold and other factors.
unsigned Count;
+ // Set the maximum unrolling factor. The unrolling factor may be selected
+ // using the appropriate cost threshold, but may not exceed this number
+ // (set to UINT_MAX to disable). This does not apply in cases where the
+ // loop is being fully unrolled.
+ unsigned MaxCount;
/// Allow partial unrolling (unrolling of loops to expand the size of the
/// loop body, not only to eliminate small constant-trip-count loops).
bool Partial;
TargetTransformInfo::UnrollingPreferences UP;
UP.Threshold = CurrentThreshold;
UP.OptSizeThreshold = OptSizeUnrollThreshold;
+ UP.PartialThreshold = CurrentThreshold;
+ UP.PartialOptSizeThreshold = OptSizeUnrollThreshold;
UP.Count = CurrentCount;
+ UP.MaxCount = UINT_MAX;
UP.Partial = CurrentAllowPartial;
UP.Runtime = CurrentRuntime;
TTI.getUnrollingPreferences(L, UP);
// function is marked as optimize-for-size, and the unroll threshold was
// not user specified.
unsigned Threshold = UserThreshold ? CurrentThreshold : UP.Threshold;
+ unsigned PartialThreshold =
+ UserThreshold ? CurrentThreshold : UP.PartialThreshold;
if (!UserThreshold &&
Header->getParent()->getAttributes().
hasAttribute(AttributeSet::FunctionIndex,
- Attribute::OptimizeForSize))
+ Attribute::OptimizeForSize)) {
Threshold = UP.OptSizeThreshold;
+ PartialThreshold = UP.PartialOptSizeThreshold;
+ }
// Find trip count and trip multiple if count is not available
unsigned TripCount = 0;
}
// Enforce the threshold.
- if (Threshold != NoThreshold) {
+ if (Threshold != NoThreshold && PartialThreshold != NoThreshold) {
unsigned NumInlineCandidates;
bool notDuplicatable;
unsigned LoopSize = ApproximateLoopSize(L, NumInlineCandidates,
}
if (TripCount) {
// Reduce unroll count to be modulo of TripCount for partial unrolling
- Count = Threshold / LoopSize;
+ Count = PartialThreshold / LoopSize;
while (Count != 0 && TripCount%Count != 0)
Count--;
}
else if (Runtime) {
// Reduce unroll count to be a lower power-of-two value
- while (Count != 0 && Size > Threshold) {
+ while (Count != 0 && Size > PartialThreshold) {
Count >>= 1;
Size = LoopSize*Count;
}
}
+ if (Count > UP.MaxCount)
+ Count = UP.MaxCount;
if (Count < 2) {
DEBUG(dbgs() << " could not unroll partially\n");
return false;