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[SCEV] Remove extra APInt copies from getRangeForAffineARHelper. 

This changes one parameter to be a const APInt& since we only read from it. Use std::move on local APInts once they are no longer needed so we can reuse their allocations. Lastly, use operator+=(uint64_t) instead of adding 1 to an APInt twice creating a new APInt each time.

llvm-svn: 302335
This commit is contained in:
Craig Topper 2017-05-06 06:03:07 +00:00
parent 69f1af29fb
commit 6c5e22a4b8
1 changed files with 10 additions and 13 deletions
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23
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -4843,7 +4843,7 @@ ScalarEvolution::getRange(const SCEV *S,
// argument defines if we treat Step as signed or unsigned. // argument defines if we treat Step as signed or unsigned.
static ConstantRange getRangeForAffineARHelper(APInt Step, static ConstantRange getRangeForAffineARHelper(APInt Step,
ConstantRange StartRange, ConstantRange StartRange,
APInt MaxBECount, const APInt &MaxBECount,
unsigned BitWidth, bool Signed) { unsigned BitWidth, bool Signed) {
// If either Step or MaxBECount is 0, then the expression won't change, and we // If either Step or MaxBECount is 0, then the expression won't change, and we
// just need to return the initial range. // just need to return the initial range.
@ -4882,8 +4882,8 @@ static ConstantRange getRangeForAffineARHelper(APInt Step,
// if the expression is decreasing and will be increased by Offset otherwise. // if the expression is decreasing and will be increased by Offset otherwise.
APInt StartLower = StartRange.getLower(); APInt StartLower = StartRange.getLower();
APInt StartUpper = StartRange.getUpper() - 1; APInt StartUpper = StartRange.getUpper() - 1;
APInt MovedBoundary = APInt MovedBoundary = Descending ? (StartLower - std::move(Offset))
Descending ? (StartLower - Offset) : (StartUpper + Offset); : (StartUpper + std::move(Offset));
// It's possible that the new minimum/maximum value will fall into the initial // It's possible that the new minimum/maximum value will fall into the initial
// range (due to wrap around). This means that the expression can take any // range (due to wrap around). This means that the expression can take any
@ -4891,21 +4891,18 @@ static ConstantRange getRangeForAffineARHelper(APInt Step,
if (StartRange.contains(MovedBoundary)) if (StartRange.contains(MovedBoundary))
return ConstantRange(BitWidth, /* isFullSet = */ true); return ConstantRange(BitWidth, /* isFullSet = */ true);
APInt NewLower, NewUpper; APInt NewLower =
if (Descending) { Descending ? std::move(MovedBoundary) : std::move(StartLower);
NewLower = MovedBoundary; APInt NewUpper =
NewUpper = StartUpper; Descending ? std::move(StartUpper) : std::move(MovedBoundary);
} else { NewUpper += 1;
NewLower = StartLower;
NewUpper = MovedBoundary;
}
// If we end up with full range, return a proper full range. // If we end up with full range, return a proper full range.
if (NewLower == NewUpper + 1) if (NewLower == NewUpper)
return ConstantRange(BitWidth, /* isFullSet = */ true); return ConstantRange(BitWidth, /* isFullSet = */ true);
// No overflow detected, return [StartLower, StartUpper + Offset + 1) range. // No overflow detected, return [StartLower, StartUpper + Offset + 1) range.
return ConstantRange(NewLower, NewUpper + 1); return ConstantRange(std::move(NewLower), std::move(NewUpper));
} }
ConstantRange ScalarEvolution::getRangeForAffineAR(const SCEV *Start, ConstantRange ScalarEvolution::getRangeForAffineAR(const SCEV *Start,