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[SCEV] Extract out a getRangeForAffineAR; NFC 

Pure code-motion change.  Will be used later in making getRange more clever.

llvm-svn: 262437
This commit is contained in:
Sanjoy Das 2016-03-02 00:57:39 +00:00
parent ca5e90f83c
commit b765b633cb
2 changed files with 77 additions and 57 deletions
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6
llvm/include/llvm/Analysis/ScalarEvolution.h
View File

@ -666,6 +666,12 @@ namespace llvm {
/// Determine the range for a particular SCEV.
ConstantRange getRange(const SCEV *S, RangeSignHint Hint);
/// Determines the range for the affine SCEVAddRecExpr {\p Start,+,\p Stop}.
/// Helper for \c getRange.
ConstantRange getRangeForAffineAR(const SCEV *Start, const SCEV *Stop,
const SCEV *MaxBECount,
unsigned BitWidth);
/// We know that there is no SCEV for the specified value. Analyze the
/// expression.
const SCEV *createSCEV(Value *V);

128
llvm/lib/Analysis/ScalarEvolution.cpp
View File

@ -4391,66 +4391,15 @@ ScalarEvolution::getRange(const SCEV *S,
// TODO: non-affine addrec
if (AddRec->isAffine()) {
Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
// Check for overflow. This must be done with ConstantRange arithmetic
// because we could be called from within the ScalarEvolution overflow
// checking code.
MaxBECount = getNoopOrZeroExtend(MaxBECount, Ty);
ConstantRange MaxBECountRange = getUnsignedRange(MaxBECount);
ConstantRange ZExtMaxBECountRange =
MaxBECountRange.zextOrTrunc(BitWidth * 2 + 1);
const SCEV *Start = AddRec->getStart();
const SCEV *Step = AddRec->getStepRecurrence(*this);
ConstantRange StepSRange = getSignedRange(Step);
ConstantRange SExtStepSRange = StepSRange.sextOrTrunc(BitWidth * 2 + 1);
ConstantRange StartURange = getUnsignedRange(Start);
ConstantRange EndURange =
StartURange.add(MaxBECountRange.multiply(StepSRange));
// Check for unsigned overflow.
ConstantRange ZExtStartURange =
StartURange.zextOrTrunc(BitWidth * 2 + 1);
ConstantRange ZExtEndURange = EndURange.zextOrTrunc(BitWidth * 2 + 1);
if (ZExtStartURange.add(ZExtMaxBECountRange.multiply(SExtStepSRange)) ==
ZExtEndURange) {
APInt Min = APIntOps::umin(StartURange.getUnsignedMin(),
EndURange.getUnsignedMin());
APInt Max = APIntOps::umax(StartURange.getUnsignedMax(),
EndURange.getUnsignedMax());
bool IsFullRange = Min.isMinValue() && Max.isMaxValue();
if (!IsFullRange)
ConservativeResult =
ConservativeResult.intersectWith(ConstantRange(Min, Max + 1));
}
ConstantRange StartSRange = getSignedRange(Start);
ConstantRange EndSRange =
StartSRange.add(MaxBECountRange.multiply(StepSRange));
// Check for signed overflow. This must be done with ConstantRange
// arithmetic because we could be called from within the ScalarEvolution
// overflow checking code.
ConstantRange SExtStartSRange =
StartSRange.sextOrTrunc(BitWidth * 2 + 1);
ConstantRange SExtEndSRange = EndSRange.sextOrTrunc(BitWidth * 2 + 1);
if (SExtStartSRange.add(ZExtMaxBECountRange.multiply(SExtStepSRange)) ==
SExtEndSRange) {
APInt Min = APIntOps::smin(StartSRange.getSignedMin(),
EndSRange.getSignedMin());
APInt Max = APIntOps::smax(StartSRange.getSignedMax(),
EndSRange.getSignedMax());
bool IsFullRange = Min.isMinSignedValue() && Max.isMaxSignedValue();
if (!IsFullRange)
ConservativeResult =
ConservativeResult.intersectWith(ConstantRange(Min, Max + 1));
}
auto RangeFromAffine = getRangeForAffineAR(
AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount,
BitWidth);
if (!RangeFromAffine.isFullSet())
ConservativeResult =
ConservativeResult.intersectWith(RangeFromAffine);
}
}
@ -4490,6 +4439,71 @@ ScalarEvolution::getRange(const SCEV *S,
return setRange(S, SignHint, ConservativeResult);
}
ConstantRange ScalarEvolution::getRangeForAffineAR(const SCEV *Start,
const SCEV *Step,
const SCEV *MaxBECount,
unsigned BitWidth) {
assert(!isa<SCEVCouldNotCompute>(MaxBECount) &&
getTypeSizeInBits(MaxBECount->getType()) <= BitWidth &&
"Precondition!");
ConstantRange Result(BitWidth, /* isFullSet = */ true);
// Check for overflow. This must be done with ConstantRange arithmetic
// because we could be called from within the ScalarEvolution overflow
// checking code.
MaxBECount = getNoopOrZeroExtend(MaxBECount, Start->getType());
ConstantRange MaxBECountRange = getUnsignedRange(MaxBECount);
ConstantRange ZExtMaxBECountRange =
MaxBECountRange.zextOrTrunc(BitWidth * 2 + 1);
ConstantRange StepSRange = getSignedRange(Step);
ConstantRange SExtStepSRange = StepSRange.sextOrTrunc(BitWidth * 2 + 1);
ConstantRange StartURange = getUnsignedRange(Start);
ConstantRange EndURange =
StartURange.add(MaxBECountRange.multiply(StepSRange));
// Check for unsigned overflow.
ConstantRange ZExtStartURange = StartURange.zextOrTrunc(BitWidth * 2 + 1);
ConstantRange ZExtEndURange = EndURange.zextOrTrunc(BitWidth * 2 + 1);
if (ZExtStartURange.add(ZExtMaxBECountRange.multiply(SExtStepSRange)) ==
ZExtEndURange) {
APInt Min = APIntOps::umin(StartURange.getUnsignedMin(),
EndURange.getUnsignedMin());
APInt Max = APIntOps::umax(StartURange.getUnsignedMax(),
EndURange.getUnsignedMax());
bool IsFullRange = Min.isMinValue() && Max.isMaxValue();
if (!IsFullRange)
Result =
Result.intersectWith(ConstantRange(Min, Max + 1));
}
ConstantRange StartSRange = getSignedRange(Start);
ConstantRange EndSRange =
StartSRange.add(MaxBECountRange.multiply(StepSRange));
// Check for signed overflow. This must be done with ConstantRange
// arithmetic because we could be called from within the ScalarEvolution
// overflow checking code.
ConstantRange SExtStartSRange = StartSRange.sextOrTrunc(BitWidth * 2 + 1);
ConstantRange SExtEndSRange = EndSRange.sextOrTrunc(BitWidth * 2 + 1);
if (SExtStartSRange.add(ZExtMaxBECountRange.multiply(SExtStepSRange)) ==
SExtEndSRange) {
APInt Min =
APIntOps::smin(StartSRange.getSignedMin(), EndSRange.getSignedMin());
APInt Max =
APIntOps::smax(StartSRange.getSignedMax(), EndSRange.getSignedMax());
bool IsFullRange = Min.isMinSignedValue() && Max.isMaxSignedValue();
if (!IsFullRange)
Result =
Result.intersectWith(ConstantRange(Min, Max + 1));
}
return Result;
}
SCEV::NoWrapFlags ScalarEvolution::getNoWrapFlagsFromUB(const Value *V) {
if (isa<ConstantExpr>(V)) return SCEV::FlagAnyWrap;
const BinaryOperator *BinOp = cast<BinaryOperator>(V);