}
case scUnknown: {
const SCEVUnknown *U = cast<SCEVUnknown>(this);
- const Type *AllocTy;
+ Type *AllocTy;
if (U->isSizeOf(AllocTy)) {
OS << "sizeof(" << *AllocTy << ")";
return;
return;
}
- const Type *CTy;
+ Type *CTy;
Constant *FieldNo;
if (U->isOffsetOf(CTy, FieldNo)) {
OS << "offsetof(" << *CTy << ", ";
llvm_unreachable("Unknown SCEV kind!");
}
-const Type *SCEV::getType() const {
+Type *SCEV::getType() const {
switch (getSCEVType()) {
case scConstant:
return cast<SCEVConstant>(this)->getType();
}
const SCEV *
-ScalarEvolution::getConstant(const Type *Ty, uint64_t V, bool isSigned) {
- const IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
+ScalarEvolution::getConstant(Type *Ty, uint64_t V, bool isSigned) {
+ IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
return getConstant(ConstantInt::get(ITy, V, isSigned));
}
SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeIDRef ID,
- unsigned SCEVTy, const SCEV *op, const Type *ty)
+ unsigned SCEVTy, const SCEV *op, Type *ty)
: SCEV(ID, SCEVTy), Op(op), Ty(ty) {}
SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
- const SCEV *op, const Type *ty)
+ const SCEV *op, Type *ty)
: SCEVCastExpr(ID, scTruncate, op, ty) {
assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
}
SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
- const SCEV *op, const Type *ty)
+ const SCEV *op, Type *ty)
: SCEVCastExpr(ID, scZeroExtend, op, ty) {
assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
}
SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
- const SCEV *op, const Type *ty)
+ const SCEV *op, Type *ty)
: SCEVCastExpr(ID, scSignExtend, op, ty) {
assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
setValPtr(New);
}
-bool SCEVUnknown::isSizeOf(const Type *&AllocTy) const {
+bool SCEVUnknown::isSizeOf(Type *&AllocTy) const {
if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
if (VCE->getOpcode() == Instruction::PtrToInt)
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
return false;
}
-bool SCEVUnknown::isAlignOf(const Type *&AllocTy) const {
+bool SCEVUnknown::isAlignOf(Type *&AllocTy) const {
if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
if (VCE->getOpcode() == Instruction::PtrToInt)
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
if (CE->getOpcode() == Instruction::GetElementPtr &&
CE->getOperand(0)->isNullValue()) {
- const Type *Ty =
+ Type *Ty =
cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
- if (const StructType *STy = dyn_cast<StructType>(Ty))
+ if (StructType *STy = dyn_cast<StructType>(Ty))
if (!STy->isPacked() &&
CE->getNumOperands() == 3 &&
CE->getOperand(1)->isNullValue()) {
return false;
}
-bool SCEVUnknown::isOffsetOf(const Type *&CTy, Constant *&FieldNo) const {
+bool SCEVUnknown::isOffsetOf(Type *&CTy, Constant *&FieldNo) const {
if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
if (VCE->getOpcode() == Instruction::PtrToInt)
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
CE->getNumOperands() == 3 &&
CE->getOperand(0)->isNullValue() &&
CE->getOperand(1)->isNullValue()) {
- const Type *Ty =
+ Type *Ty =
cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
// Ignore vector types here so that ScalarEvolutionExpander doesn't
// emit getelementptrs that index into vectors.
/// Assume, K > 0.
static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
ScalarEvolution &SE,
- const Type* ResultTy) {
+ Type *ResultTy) {
// Handle the simplest case efficiently.
if (K == 1)
return SE.getTruncateOrZeroExtend(It, ResultTy);
MultiplyFactor = MultiplyFactor.trunc(W);
// Calculate the product, at width T+W
- const IntegerType *CalculationTy = IntegerType::get(SE.getContext(),
+ IntegerType *CalculationTy = IntegerType::get(SE.getContext(),
CalculationBits);
const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
for (unsigned i = 1; i != K; ++i) {
//===----------------------------------------------------------------------===//
const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op,
- const Type *Ty) {
+ Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) &&
"This is not a truncating conversion!");
assert(isSCEVable(Ty) &&
}
const SCEV *ScalarEvolution::getZeroExtendExpr(const SCEV *Op,
- const Type *Ty) {
+ Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
assert(isSCEVable(Ty) &&
if (AR->getNoWrapFlags(SCEV::FlagNUW))
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- // FIXME: Can use SCEV::FlagNUW
- L, SCEV::FlagAnyWrap);
+ L, AR->getNoWrapFlags());
// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
const SCEV *RecastedMaxBECount =
getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
if (MaxBECount == RecastedMaxBECount) {
- const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
+ Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
// Check whether Start+Step*MaxBECount has no unsigned overflow.
const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step);
const SCEV *Add = getAddExpr(Start, ZMul);
getAddExpr(getZeroExtendExpr(Start, WideTy),
getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
getZeroExtendExpr(Step, WideTy)));
- if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+ // Cache knowledge of AR NUW, which is propagated to this AddRec.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- // FIXME: can use FlagNUW
- L, SCEV::FlagAnyWrap);
-
+ L, AR->getNoWrapFlags());
+ }
// Similar to above, only this time treat the step value as signed.
// This covers loops that count down.
const SCEV *SMul = getMulExpr(CastedMaxBECount, Step);
getAddExpr(getZeroExtendExpr(Start, WideTy),
getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
getSignExtendExpr(Step, WideTy)));
- if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+ // Cache knowledge of AR NW, which is propagated to this AddRec.
+ // Negative step causes unsigned wrap, but it still can't self-wrap.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- // FIXME: can use FlagNW
- L, SCEV::FlagAnyWrap);
+ L, AR->getNoWrapFlags());
+ }
}
// If the backedge is guarded by a comparison with the pre-inc value
if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) ||
(isLoopEntryGuardedByCond(L, ICmpInst::ICMP_ULT, Start, N) &&
isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT,
- AR->getPostIncExpr(*this), N)))
+ AR->getPostIncExpr(*this), N))) {
+ // Cache knowledge of AR NUW, which is propagated to this AddRec.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
// Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- // FIXME: can use FlagNUW
- L, SCEV::FlagAnyWrap);
+ L, AR->getNoWrapFlags());
+ }
} else if (isKnownNegative(Step)) {
const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) -
getSignedRange(Step).getSignedMin());
if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT, AR, N) ||
(isLoopEntryGuardedByCond(L, ICmpInst::ICMP_UGT, Start, N) &&
isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT,
- AR->getPostIncExpr(*this), N)))
- // Return the expression with the addrec on the outside. The
- // negative step causes unsigned wrap, but it still can't self-wrap.
+ AR->getPostIncExpr(*this), N))) {
+ // Cache knowledge of AR NW, which is propagated to this AddRec.
+ // Negative step causes unsigned wrap, but it still can't self-wrap.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
+ // Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- // FIXME: can use FlagNW
- L, SCEV::FlagAnyWrap);
+ L, AR->getNoWrapFlags());
+ }
}
}
}
return S;
}
+// Get the limit of a recurrence such that incrementing by Step cannot cause
+// signed overflow as long as the value of the recurrence within the loop does
+// not exceed this limit before incrementing.
+static const SCEV *getOverflowLimitForStep(const SCEV *Step,
+ ICmpInst::Predicate *Pred,
+ ScalarEvolution *SE) {
+ unsigned BitWidth = SE->getTypeSizeInBits(Step->getType());
+ if (SE->isKnownPositive(Step)) {
+ *Pred = ICmpInst::ICMP_SLT;
+ return SE->getConstant(APInt::getSignedMinValue(BitWidth) -
+ SE->getSignedRange(Step).getSignedMax());
+ }
+ if (SE->isKnownNegative(Step)) {
+ *Pred = ICmpInst::ICMP_SGT;
+ return SE->getConstant(APInt::getSignedMaxValue(BitWidth) -
+ SE->getSignedRange(Step).getSignedMin());
+ }
+ return 0;
+}
+
+// The recurrence AR has been shown to have no signed wrap. Typically, if we can
+// prove NSW for AR, then we can just as easily prove NSW for its preincrement
+// or postincrement sibling. This allows normalizing a sign extended AddRec as
+// such: {sext(Step + Start),+,Step} => {(Step + sext(Start),+,Step} As a
+// result, the expression "Step + sext(PreIncAR)" is congruent with
+// "sext(PostIncAR)"
+static const SCEV *getPreStartForSignExtend(const SCEVAddRecExpr *AR,
+ Type *Ty,
+ ScalarEvolution *SE) {
+ const Loop *L = AR->getLoop();
+ const SCEV *Start = AR->getStart();
+ const SCEV *Step = AR->getStepRecurrence(*SE);
+
+ // Check for a simple looking step prior to loop entry.
+ const SCEVAddExpr *SA = dyn_cast<SCEVAddExpr>(Start);
+ if (!SA || SA->getNumOperands() != 2 || SA->getOperand(0) != Step)
+ return 0;
+
+ // This is a postinc AR. Check for overflow on the preinc recurrence using the
+ // same three conditions that getSignExtendedExpr checks.
+
+ // 1. NSW flags on the step increment.
+ const SCEV *PreStart = SA->getOperand(1);
+ const SCEVAddRecExpr *PreAR = dyn_cast<SCEVAddRecExpr>(
+ SE->getAddRecExpr(PreStart, Step, L, SCEV::FlagAnyWrap));
+
+ if (PreAR && PreAR->getNoWrapFlags(SCEV::FlagNSW))
+ return PreStart;
+
+ // 2. Direct overflow check on the step operation's expression.
+ unsigned BitWidth = SE->getTypeSizeInBits(AR->getType());
+ Type *WideTy = IntegerType::get(SE->getContext(), BitWidth * 2);
+ const SCEV *OperandExtendedStart =
+ SE->getAddExpr(SE->getSignExtendExpr(PreStart, WideTy),
+ SE->getSignExtendExpr(Step, WideTy));
+ if (SE->getSignExtendExpr(Start, WideTy) == OperandExtendedStart) {
+ // Cache knowledge of PreAR NSW.
+ if (PreAR)
+ const_cast<SCEVAddRecExpr *>(PreAR)->setNoWrapFlags(SCEV::FlagNSW);
+ // FIXME: this optimization needs a unit test
+ DEBUG(dbgs() << "SCEV: untested prestart overflow check\n");
+ return PreStart;
+ }
+
+ // 3. Loop precondition.
+ ICmpInst::Predicate Pred;
+ const SCEV *OverflowLimit = getOverflowLimitForStep(Step, &Pred, SE);
+
+ if (OverflowLimit &&
+ SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit)) {
+ return PreStart;
+ }
+ return 0;
+}
+
+// Get the normalized sign-extended expression for this AddRec's Start.
+static const SCEV *getSignExtendAddRecStart(const SCEVAddRecExpr *AR,
+ Type *Ty,
+ ScalarEvolution *SE) {
+ const SCEV *PreStart = getPreStartForSignExtend(AR, Ty, SE);
+ if (!PreStart)
+ return SE->getSignExtendExpr(AR->getStart(), Ty);
+
+ return SE->getAddExpr(SE->getSignExtendExpr(AR->getStepRecurrence(*SE), Ty),
+ SE->getSignExtendExpr(PreStart, Ty));
+}
+
const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
- const Type *Ty) {
+ Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
assert(isSCEVable(Ty) &&
// If we have special knowledge that this addrec won't overflow,
// we don't need to do any further analysis.
if (AR->getNoWrapFlags(SCEV::FlagNSW))
- return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ return getAddRecExpr(getSignExtendAddRecStart(AR, Ty, this),
getSignExtendExpr(Step, Ty),
- // FIXME: can use SCEV::FlagNSW
- L, SCEV::FlagAnyWrap);
+ L, SCEV::FlagNSW);
// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
const SCEV *RecastedMaxBECount =
getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
if (MaxBECount == RecastedMaxBECount) {
- const Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
+ Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
// Check whether Start+Step*MaxBECount has no signed overflow.
const SCEV *SMul = getMulExpr(CastedMaxBECount, Step);
const SCEV *Add = getAddExpr(Start, SMul);
getAddExpr(getSignExtendExpr(Start, WideTy),
getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
getSignExtendExpr(Step, WideTy)));
- if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+ // Cache knowledge of AR NSW, which is propagated to this AddRec.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
// Return the expression with the addrec on the outside.
- return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ return getAddRecExpr(getSignExtendAddRecStart(AR, Ty, this),
getSignExtendExpr(Step, Ty),
- // FIXME: can use SCEV::FlagNSW
- L, SCEV::FlagAnyWrap);
-
+ L, AR->getNoWrapFlags());
+ }
// Similar to above, only this time treat the step value as unsigned.
// This covers loops that count up with an unsigned step.
const SCEV *UMul = getMulExpr(CastedMaxBECount, Step);
getAddExpr(getSignExtendExpr(Start, WideTy),
getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
getZeroExtendExpr(Step, WideTy)));
- if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+ // Cache knowledge of AR NSW, which is propagated to this AddRec.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
// Return the expression with the addrec on the outside.
- return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ return getAddRecExpr(getSignExtendAddRecStart(AR, Ty, this),
getZeroExtendExpr(Step, Ty),
- // FIXME: can use SCEV::FlagNSW
- L, SCEV::FlagAnyWrap);
+ L, AR->getNoWrapFlags());
+ }
}
// If the backedge is guarded by a comparison with the pre-inc value
// the addrec is safe. Also, if the entry is guarded by a comparison
// with the start value and the backedge is guarded by a comparison
// with the post-inc value, the addrec is safe.
- if (isKnownPositive(Step)) {
- const SCEV *N = getConstant(APInt::getSignedMinValue(BitWidth) -
- getSignedRange(Step).getSignedMax());
- if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SLT, AR, N) ||
- (isLoopEntryGuardedByCond(L, ICmpInst::ICMP_SLT, Start, N) &&
- isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SLT,
- AR->getPostIncExpr(*this), N)))
- // Return the expression with the addrec on the outside.
- return getAddRecExpr(getSignExtendExpr(Start, Ty),
- getSignExtendExpr(Step, Ty),
- // FIXME: can use SCEV::FlagNSW
- L, SCEV::FlagAnyWrap);
- } else if (isKnownNegative(Step)) {
- const SCEV *N = getConstant(APInt::getSignedMaxValue(BitWidth) -
- getSignedRange(Step).getSignedMin());
- if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SGT, AR, N) ||
- (isLoopEntryGuardedByCond(L, ICmpInst::ICMP_SGT, Start, N) &&
- isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_SGT,
- AR->getPostIncExpr(*this), N)))
- // Return the expression with the addrec on the outside.
- return getAddRecExpr(getSignExtendExpr(Start, Ty),
- getSignExtendExpr(Step, Ty),
- // FIXME: can use SCEV::FlagNSW
- L, SCEV::FlagAnyWrap);
+ ICmpInst::Predicate Pred;
+ const SCEV *OverflowLimit = getOverflowLimitForStep(Step, &Pred, this);
+ if (OverflowLimit &&
+ (isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) ||
+ (isLoopEntryGuardedByCond(L, Pred, Start, OverflowLimit) &&
+ isLoopBackedgeGuardedByCond(L, Pred, AR->getPostIncExpr(*this),
+ OverflowLimit)))) {
+ // Cache knowledge of AR NSW, then propagate NSW to the wide AddRec.
+ const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
+ return getAddRecExpr(getSignExtendAddRecStart(AR, Ty, this),
+ getSignExtendExpr(Step, Ty),
+ L, AR->getNoWrapFlags());
}
}
}
/// unspecified bits out to the given type.
///
const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
- const Type *Ty) {
+ Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
"This is not an extending conversion!");
assert(isSCEVable(Ty) &&
for (SCEVAddRecExpr::op_iterator I = AR->op_begin(), E = AR->op_end();
I != E; ++I)
Ops.push_back(getAnyExtendExpr(*I, Ty));
- // FIXME: can use AR->getNoWrapFlags(SCEV::FlagNW)
- return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagAnyWrap);
+ return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagNW);
}
// As a special case, fold anyext(undef) to undef. We don't want to
assert(!Ops.empty() && "Cannot get empty add!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
- const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
+ Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVAddExpr operand types don't match!");
#endif
// If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
- if (!(Flags & SCEV::FlagNUW) && (Flags & SCEV::FlagNSW)) {
+ // And vice-versa.
+ int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW;
+ SCEV::NoWrapFlags SignOrUnsignWrap = maskFlags(Flags, SignOrUnsignMask);
+ if (SignOrUnsignWrap && (SignOrUnsignWrap != SignOrUnsignMask)) {
bool All = true;
for (SmallVectorImpl<const SCEV *>::const_iterator I = Ops.begin(),
E = Ops.end(); I != E; ++I)
All = false;
break;
}
- if (All) Flags = setFlags(Flags, SCEV::FlagNUW);
+ if (All) Flags = setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask);
}
// Sort by complexity, this groups all similar expression types together.
// Okay, check to see if the same value occurs in the operand list more than
// once. If so, merge them together into an multiply expression. Since we
// sorted the list, these values are required to be adjacent.
- const Type *Ty = Ops[0]->getType();
+ Type *Ty = Ops[0]->getType();
bool FoundMatch = false;
for (unsigned i = 0, e = Ops.size(); i != e-1; ++i)
if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2
// if the contents of the resulting outer trunc fold to something simple.
for (; Idx < Ops.size() && isa<SCEVTruncateExpr>(Ops[Idx]); ++Idx) {
const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(Ops[Idx]);
- const Type *DstType = Trunc->getType();
- const Type *SrcType = Trunc->getOperand()->getType();
+ Type *DstType = Trunc->getType();
+ Type *SrcType = Trunc->getOperand()->getType();
SmallVector<const SCEV *, 8> LargeOps;
bool Ok = true;
// Check all the operands to see if they can be represented in the
// Build the new addrec. Propagate the NUW and NSW flags if both the
// outer add and the inner addrec are guaranteed to have no overflow.
- // FIXME: Always propagate NW
- // AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW))
- Flags = AddRec->getNoWrapFlags(Flags);
+ // Always propagate NW.
+ Flags = AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW));
const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags);
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
- // Otherwise, add the folded AddRec by the non-liv parts.
+ // Otherwise, add the folded AddRec by the non-invariant parts.
for (unsigned i = 0;; ++i)
if (Ops[i] == AddRec) {
Ops[i] = NewRec;
assert(!Ops.empty() && "Cannot get empty mul!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
- const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
+ Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVMulExpr operand types don't match!");
#endif
// If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
- if (!(Flags & SCEV::FlagNUW) && (Flags & SCEV::FlagNSW)) {
+ // And vice-versa.
+ int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW;
+ SCEV::NoWrapFlags SignOrUnsignWrap = maskFlags(Flags, SignOrUnsignMask);
+ if (SignOrUnsignWrap && (SignOrUnsignWrap != SignOrUnsignMask)) {
bool All = true;
for (SmallVectorImpl<const SCEV *>::const_iterator I = Ops.begin(),
E = Ops.end(); I != E; ++I)
All = false;
break;
}
- if (All) Flags = setFlags(Flags, SCEV::FlagNUW);
+ if (All) Flags = setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask);
}
// Sort by complexity, this groups all similar expression types together.
if (AnyFolded)
return getAddExpr(NewOps);
}
+ else if (const SCEVAddRecExpr *
+ AddRec = dyn_cast<SCEVAddRecExpr>(Ops[1])) {
+ // Negation preserves a recurrence's no self-wrap property.
+ SmallVector<const SCEV *, 4> Operands;
+ for (SCEVAddRecExpr::op_iterator I = AddRec->op_begin(),
+ E = AddRec->op_end(); I != E; ++I) {
+ Operands.push_back(getMulExpr(Ops[0], *I));
+ }
+ return getAddRecExpr(Operands, AddRec->getLoop(),
+ AddRec->getNoWrapFlags(SCEV::FlagNW));
+ }
}
}
// outer mul and the inner addrec are guaranteed to have no overflow.
//
// No self-wrap cannot be guaranteed after changing the step size, but
- // will be infered if either NUW or NSW is true.
+ // will be inferred if either NUW or NSW is true.
Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW));
const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags);
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
- // Otherwise, multiply the folded AddRec by the non-liv parts.
+ // Otherwise, multiply the folded AddRec by the non-invariant parts.
for (unsigned i = 0;; ++i)
if (Ops[i] == AddRec) {
Ops[i] = NewRec;
// multiplied together. If so, we can fold them.
for (unsigned OtherIdx = Idx+1;
OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
- ++OtherIdx)
+ ++OtherIdx) {
+ bool Retry = false;
if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) {
- // F * G, where F = {A,+,B}<L> and G = {C,+,D}<L> -->
- // {A*C,+,F*D + G*B + B*D}<L>
+ // {A,+,B}<L> * {C,+,D}<L> --> {A*C,+,A*D + B*C + B*D,+,2*B*D}<L>
+ //
+ // {A,+,B} * {C,+,D} = A+It*B * C+It*D = A*C + (A*D + B*C)*It + B*D*It^2
+ // Given an equation of the form x + y*It + z*It^2 (above), we want to
+ // express it in terms of {X,+,Y,+,Z}.
+ // {X,+,Y,+,Z} = X + Y*It + Z*(It^2 - It)/2.
+ // Rearranging, X = x, Y = y+z, Z = 2z.
+ //
+ // x = A*C, y = (A*D + B*C), z = B*D.
+ // Therefore X = A*C, Y = A*D + B*C + B*D and Z = 2*B*D.
for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
++OtherIdx)
if (const SCEVAddRecExpr *OtherAddRec =
dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]))
if (OtherAddRec->getLoop() == AddRecLoop) {
- const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
- const SCEV *NewStart = getMulExpr(F->getStart(), G->getStart());
- const SCEV *B = F->getStepRecurrence(*this);
- const SCEV *D = G->getStepRecurrence(*this);
- const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
- getMulExpr(G, B),
- getMulExpr(B, D));
- const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
- F->getLoop(),
- SCEV::FlagAnyWrap);
- if (Ops.size() == 2) return NewAddRec;
- Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
- Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
+ const SCEV *A = AddRec->getStart();
+ const SCEV *B = AddRec->getStepRecurrence(*this);
+ const SCEV *C = OtherAddRec->getStart();
+ const SCEV *D = OtherAddRec->getStepRecurrence(*this);
+ const SCEV *NewStart = getMulExpr(A, C);
+ const SCEV *BD = getMulExpr(B, D);
+ const SCEV *NewStep = getAddExpr(getMulExpr(A, D),
+ getMulExpr(B, C), BD);
+ const SCEV *NewSecondOrderStep =
+ getMulExpr(BD, getConstant(BD->getType(), 2));
+
+ // This can happen when AddRec or OtherAddRec have >3 operands.
+ // TODO: support these add-recs.
+ if (isLoopInvariant(NewStart, AddRecLoop) &&
+ isLoopInvariant(NewStep, AddRecLoop) &&
+ isLoopInvariant(NewSecondOrderStep, AddRecLoop)) {
+ SmallVector<const SCEV *, 3> AddRecOps;
+ AddRecOps.push_back(NewStart);
+ AddRecOps.push_back(NewStep);
+ AddRecOps.push_back(NewSecondOrderStep);
+ const SCEV *NewAddRec = getAddRecExpr(AddRecOps,
+ AddRec->getLoop(),
+ SCEV::FlagAnyWrap);
+ if (Ops.size() == 2) return NewAddRec;
+ Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
+ Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
+ Retry = true;
+ }
}
- return getMulExpr(Ops);
+ if (Retry)
+ return getMulExpr(Ops);
}
+ }
// Otherwise couldn't fold anything into this recurrence. Move onto the
// next one.
// Determine if the division can be folded into the operands of
// its operands.
// TODO: Generalize this to non-constants by using known-bits information.
- const Type *Ty = LHS->getType();
+ Type *Ty = LHS->getType();
unsigned LZ = RHSC->getValue()->getValue().countLeadingZeros();
unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ - 1;
// For non-power-of-two values, effectively round the value up to the
// nearest power of two.
if (!RHSC->getValue()->getValue().isPowerOf2())
++MaxShiftAmt;
- const IntegerType *ExtTy =
+ IntegerType *ExtTy =
IntegerType::get(getContext(), getTypeSizeInBits(Ty) + MaxShiftAmt);
- // {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS))
if (const SCEVConstant *Step =
- dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this)))
- if (!Step->getValue()->getValue()
- .urem(RHSC->getValue()->getValue()) &&
+ dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this))) {
+ // {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded.
+ const APInt &StepInt = Step->getValue()->getValue();
+ const APInt &DivInt = RHSC->getValue()->getValue();
+ if (!StepInt.urem(DivInt) &&
getZeroExtendExpr(AR, ExtTy) ==
getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
getZeroExtendExpr(Step, ExtTy),
for (unsigned i = 0, e = AR->getNumOperands(); i != e; ++i)
Operands.push_back(getUDivExpr(AR->getOperand(i), RHS));
return getAddRecExpr(Operands, AR->getLoop(),
- // FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
- SCEV::FlagAnyWrap);
+ SCEV::FlagNW);
+ }
+ /// Get a canonical UDivExpr for a recurrence.
+ /// {X,+,N}/C => {Y,+,N}/C where Y=X-(X%N). Safe when C%N=0.
+ // We can currently only fold X%N if X is constant.
+ const SCEVConstant *StartC = dyn_cast<SCEVConstant>(AR->getStart());
+ if (StartC && !DivInt.urem(StepInt) &&
+ getZeroExtendExpr(AR, ExtTy) ==
+ getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
+ getZeroExtendExpr(Step, ExtTy),
+ AR->getLoop(), SCEV::FlagAnyWrap)) {
+ const APInt &StartInt = StartC->getValue()->getValue();
+ const APInt &StartRem = StartInt.urem(StepInt);
+ if (StartRem != 0)
+ LHS = getAddRecExpr(getConstant(StartInt - StartRem), Step,
+ AR->getLoop(), SCEV::FlagNW);
}
+ }
// (A*B)/C --> A*(B/C) if safe and B/C can be folded.
if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) {
SmallVector<const SCEV *, 4> Operands;
}
}
// (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded.
- if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(LHS)) {
+ if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(LHS)) {
SmallVector<const SCEV *, 4> Operands;
for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i)
Operands.push_back(getZeroExtendExpr(A->getOperand(i), ExtTy));
if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
if (StepChrec->getLoop() == L) {
Operands.append(StepChrec->op_begin(), StepChrec->op_end());
- // FIXME: can use maskFlags(Flags, SCEV::FlagNW)
- return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap);
+ return getAddRecExpr(Operands, L, maskFlags(Flags, SCEV::FlagNW));
}
Operands.push_back(Step);
const Loop *L, SCEV::NoWrapFlags Flags) {
if (Operands.size() == 1) return Operands[0];
#ifndef NDEBUG
- const Type *ETy = getEffectiveSCEVType(Operands[0]->getType());
+ Type *ETy = getEffectiveSCEVType(Operands[0]->getType());
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&
"SCEVAddRecExpr operand types don't match!");
// with a SCEVCouldNotCompute as the cached BE count).
// If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
- if (!(Flags & SCEV::FlagNUW) && (Flags & SCEV::FlagNSW)) {
+ // And vice-versa.
+ int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW;
+ SCEV::NoWrapFlags SignOrUnsignWrap = maskFlags(Flags, SignOrUnsignMask);
+ if (SignOrUnsignWrap && (SignOrUnsignWrap != SignOrUnsignMask)) {
bool All = true;
for (SmallVectorImpl<const SCEV *>::const_iterator I = Operands.begin(),
E = Operands.end(); I != E; ++I)
All = false;
break;
}
- if (All) Flags = setFlags(Flags, SCEV::FlagNUW);
+ if (All) Flags = setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask);
}
// Canonicalize nested AddRecs in by nesting them in order of loop depth.
if (AllInvariant) {
// Create a recurrence for the outer loop with the same step size.
//
- // FIXME:
// The outer recurrence keeps its NW flag but only keeps NUW/NSW if the
// inner recurrence has the same property.
- // maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags());
- SCEV::NoWrapFlags OuterFlags = SCEV::FlagAnyWrap;
+ SCEV::NoWrapFlags OuterFlags =
+ maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags());
NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags);
AllInvariant = true;
if (AllInvariant) {
// Ok, both add recurrences are valid after the transformation.
//
- // FIXME:
// The inner recurrence keeps its NW flag but only keeps NUW/NSW if
// the outer recurrence has the same property.
- // maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags);
- SCEV::NoWrapFlags InnerFlags = SCEV::FlagAnyWrap;
+ SCEV::NoWrapFlags InnerFlags =
+ maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags);
return getAddRecExpr(NestedOperands, NestedLoop, InnerFlags);
}
}
assert(!Ops.empty() && "Cannot get empty smax!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
- const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
+ Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVSMaxExpr operand types don't match!");
assert(!Ops.empty() && "Cannot get empty umax!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
- const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
+ Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVUMaxExpr operand types don't match!");
return getNotSCEV(getUMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
}
-const SCEV *ScalarEvolution::getSizeOfExpr(const Type *AllocTy) {
+const SCEV *ScalarEvolution::getSizeOfExpr(Type *AllocTy) {
// If we have TargetData, we can bypass creating a target-independent
// constant expression and then folding it back into a ConstantInt.
// This is just a compile-time optimization.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
C = Folded;
- const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
+ Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
-const SCEV *ScalarEvolution::getAlignOfExpr(const Type *AllocTy) {
+const SCEV *ScalarEvolution::getAlignOfExpr(Type *AllocTy) {
Constant *C = ConstantExpr::getAlignOf(AllocTy);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
C = Folded;
- const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
+ Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
-const SCEV *ScalarEvolution::getOffsetOfExpr(const StructType *STy,
+const SCEV *ScalarEvolution::getOffsetOfExpr(StructType *STy,
unsigned FieldNo) {
// If we have TargetData, we can bypass creating a target-independent
// constant expression and then folding it back into a ConstantInt.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
C = Folded;
- const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
+ Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
-const SCEV *ScalarEvolution::getOffsetOfExpr(const Type *CTy,
+const SCEV *ScalarEvolution::getOffsetOfExpr(Type *CTy,
Constant *FieldNo) {
Constant *C = ConstantExpr::getOffsetOf(CTy, FieldNo);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
C = Folded;
- const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(CTy));
+ Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(CTy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
/// the SCEV framework. This primarily includes integer types, and it
/// can optionally include pointer types if the ScalarEvolution class
/// has access to target-specific information.
-bool ScalarEvolution::isSCEVable(const Type *Ty) const {
+bool ScalarEvolution::isSCEVable(Type *Ty) const {
// Integers and pointers are always SCEVable.
return Ty->isIntegerTy() || Ty->isPointerTy();
}
/// getTypeSizeInBits - Return the size in bits of the specified type,
/// for which isSCEVable must return true.
-uint64_t ScalarEvolution::getTypeSizeInBits(const Type *Ty) const {
+uint64_t ScalarEvolution::getTypeSizeInBits(Type *Ty) const {
assert(isSCEVable(Ty) && "Type is not SCEVable!");
// If we have a TargetData, use it!
/// the given type and which represents how SCEV will treat the given
/// type, for which isSCEVable must return true. For pointer types,
/// this is the pointer-sized integer type.
-const Type *ScalarEvolution::getEffectiveSCEVType(const Type *Ty) const {
+Type *ScalarEvolution::getEffectiveSCEVType(Type *Ty) const {
assert(isSCEVable(Ty) && "Type is not SCEVable!");
if (Ty->isIntegerTy())
return getConstant(
cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue())));
- const Type *Ty = V->getType();
+ Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
return getMulExpr(V,
getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))));
return getConstant(
cast<ConstantInt>(ConstantExpr::getNot(VC->getValue())));
- const Type *Ty = V->getType();
+ Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
const SCEV *AllOnes =
getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty)));
}
/// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1.
-///
-/// FIXME: prohibit FlagNUW here, as soon as getMinusSCEVForExitTest goes.
const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
SCEV::NoWrapFlags Flags) {
+ assert(!maskFlags(Flags, SCEV::FlagNUW) && "subtraction does not have NUW");
+
// Fast path: X - X --> 0.
if (LHS == RHS)
return getConstant(LHS->getType(), 0);
/// input value to the specified type. If the type must be extended, it is zero
/// extended.
const SCEV *
-ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, const Type *Ty) {
- const Type *SrcTy = V->getType();
+ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, Type *Ty) {
+ Type *SrcTy = V->getType();
assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate or zero extend with non-integer arguments!");
/// extended.
const SCEV *
ScalarEvolution::getTruncateOrSignExtend(const SCEV *V,
- const Type *Ty) {
- const Type *SrcTy = V->getType();
+ Type *Ty) {
+ Type *SrcTy = V->getType();
assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate or zero extend with non-integer arguments!");
/// input value to the specified type. If the type must be extended, it is zero
/// extended. The conversion must not be narrowing.
const SCEV *
-ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, const Type *Ty) {
- const Type *SrcTy = V->getType();
+ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, Type *Ty) {
+ Type *SrcTy = V->getType();
assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot noop or zero extend with non-integer arguments!");
/// input value to the specified type. If the type must be extended, it is sign
/// extended. The conversion must not be narrowing.
const SCEV *
-ScalarEvolution::getNoopOrSignExtend(const SCEV *V, const Type *Ty) {
- const Type *SrcTy = V->getType();
+ScalarEvolution::getNoopOrSignExtend(const SCEV *V, Type *Ty) {
+ Type *SrcTy = V->getType();
assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot noop or sign extend with non-integer arguments!");
/// it is extended with unspecified bits. The conversion must not be
/// narrowing.
const SCEV *
-ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, const Type *Ty) {
- const Type *SrcTy = V->getType();
+ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, Type *Ty) {
+ Type *SrcTy = V->getType();
assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot noop or any extend with non-integer arguments!");
/// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
/// input value to the specified type. The conversion must not be widening.
const SCEV *
-ScalarEvolution::getTruncateOrNoop(const SCEV *V, const Type *Ty) {
- const Type *SrcTy = V->getType();
+ScalarEvolution::getTruncateOrNoop(const SCEV *V, Type *Ty) {
+ Type *SrcTy = V->getType();
assert((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
(Ty->isIntegerTy() || Ty->isPointerTy()) &&
"Cannot truncate or noop with non-integer arguments!");
return getUMinExpr(PromotedLHS, PromotedRHS);
}
+/// getPointerBase - Transitively follow the chain of pointer-type operands
+/// until reaching a SCEV that does not have a single pointer operand. This
+/// returns a SCEVUnknown pointer for well-formed pointer-type expressions,
+/// but corner cases do exist.
+const SCEV *ScalarEvolution::getPointerBase(const SCEV *V) {
+ // A pointer operand may evaluate to a nonpointer expression, such as null.
+ if (!V->getType()->isPointerTy())
+ return V;
+
+ if (const SCEVCastExpr *Cast = dyn_cast<SCEVCastExpr>(V)) {
+ return getPointerBase(Cast->getOperand());
+ }
+ else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) {
+ const SCEV *PtrOp = 0;
+ for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
+ I != E; ++I) {
+ if ((*I)->getType()->isPointerTy()) {
+ // Cannot find the base of an expression with multiple pointer operands.
+ if (PtrOp)
+ return V;
+ PtrOp = *I;
+ }
+ }
+ if (!PtrOp)
+ return V;
+ return getPointerBase(PtrOp);
+ }
+ return V;
+}
+
/// PushDefUseChildren - Push users of the given Instruction
/// onto the given Worklist.
static void
// unsigned but we may have a negative index from the base
// pointer.
if (GEP->isInBounds())
- // FIXME: should be SCEV::FlagNW
- Flags = setFlags(Flags, SCEV::FlagNSW);
+ Flags = setFlags(Flags, SCEV::FlagNW);
}
const SCEV *StartVal = getSCEV(StartValueV);
// context.
bool isInBounds = GEP->isInBounds();
- const Type *IntPtrTy = getEffectiveSCEVType(GEP->getType());
+ Type *IntPtrTy = getEffectiveSCEVType(GEP->getType());
Value *Base = GEP->getOperand(0);
// Don't attempt to analyze GEPs over unsized objects.
if (!cast<PointerType>(Base->getType())->getElementType()->isSized())
I != E; ++I) {
Value *Index = *I;
// Compute the (potentially symbolic) offset in bytes for this index.
- if (const StructType *STy = dyn_cast<StructType>(*GTI++)) {
+ if (StructType *STy = dyn_cast<StructType>(*GTI++)) {
// For a struct, add the member offset.
unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
const SCEV *FieldOffset = getOffsetOfExpr(STy, FieldNo);
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
// If there's no unsigned wrap, the value will never be less than its
// initial value.
- // FIXME: can broaden to FlagNW?
if (AddRec->getNoWrapFlags(SCEV::FlagNUW))
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
if (!C->getValue()->isZero())
// TODO: non-affine addrec
if (AddRec->isAffine()) {
- const Type *Ty = AddRec->getType();
+ Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
// TODO: non-affine addrec
if (AddRec->isAffine()) {
- const Type *Ty = AddRec->getType();
+ Type *Ty = AddRec->getType();
const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
AddOps.push_back(Op1);
}
AddOps.push_back(getSCEV(U->getOperand(0)));
- return getAddExpr(AddOps);
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
+ OverflowingBinaryOperator *OBO = cast<OverflowingBinaryOperator>(V);
+ if (OBO->hasNoSignedWrap())
+ setFlags(Flags, SCEV::FlagNSW);
+ if (OBO->hasNoUnsignedWrap())
+ setFlags(Flags, SCEV::FlagNUW);
+ return getAddExpr(AddOps, Flags);
}
case Instruction::Mul: {
// See the Add code above.
LCI->getValue() == CI->getValue())
if (const SCEVZeroExtendExpr *Z =
dyn_cast<SCEVZeroExtendExpr>(getSCEV(U->getOperand(0)))) {
- const Type *UTy = U->getType();
+ Type *UTy = U->getType();
const SCEV *Z0 = Z->getOperand();
- const Type *Z0Ty = Z0->getType();
+ Type *Z0Ty = Z0->getType();
unsigned Z0TySize = getTypeSizeInBits(Z0Ty);
// If C is a low-bits mask, the zero extend is serving to
// Iteration Count Computation Code
//
+/// getSmallConstantTripCount - Returns the maximum trip count of this loop as a
+/// normal unsigned value, if possible. Returns 0 if the trip count is unknown
+/// or not constant. Will also return 0 if the maximum trip count is very large
+/// (>= 2^32)
+unsigned ScalarEvolution::getSmallConstantTripCount(Loop *L,
+ BasicBlock *ExitBlock) {
+ const SCEVConstant *ExitCount =
+ dyn_cast<SCEVConstant>(getExitCount(L, ExitBlock));
+ if (!ExitCount)
+ return 0;
+
+ ConstantInt *ExitConst = ExitCount->getValue();
+
+ // Guard against huge trip counts.
+ if (ExitConst->getValue().getActiveBits() > 32)
+ return 0;
+
+ // In case of integer overflow, this returns 0, which is correct.
+ return ((unsigned)ExitConst->getZExtValue()) + 1;
+}
+
+/// getSmallConstantTripMultiple - Returns the largest constant divisor of the
+/// trip count of this loop as a normal unsigned value, if possible. This
+/// means that the actual trip count is always a multiple of the returned
+/// value (don't forget the trip count could very well be zero as well!).
+///
+/// Returns 1 if the trip count is unknown or not guaranteed to be the
+/// multiple of a constant (which is also the case if the trip count is simply
+/// constant, use getSmallConstantTripCount for that case), Will also return 1
+/// if the trip count is very large (>= 2^32).
+unsigned ScalarEvolution::getSmallConstantTripMultiple(Loop *L,
+ BasicBlock *ExitBlock) {
+ const SCEV *ExitCount = getExitCount(L, ExitBlock);
+ if (ExitCount == getCouldNotCompute())
+ return 1;
+
+ // Get the trip count from the BE count by adding 1.
+ const SCEV *TCMul = getAddExpr(ExitCount,
+ getConstant(ExitCount->getType(), 1));
+ // FIXME: SCEV distributes multiplication as V1*C1 + V2*C1. We could attempt
+ // to factor simple cases.
+ if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(TCMul))
+ TCMul = Mul->getOperand(0);
+
+ const SCEVConstant *MulC = dyn_cast<SCEVConstant>(TCMul);
+ if (!MulC)
+ return 1;
+
+ ConstantInt *Result = MulC->getValue();
+
+ // Guard against huge trip counts.
+ if (!Result || Result->getValue().getActiveBits() > 32)
+ return 1;
+
+ return (unsigned)Result->getZExtValue();
+}
+
+// getExitCount - Get the expression for the number of loop iterations for which
+// this loop is guaranteed not to exit via ExitintBlock. Otherwise return
+// SCEVCouldNotCompute.
+const SCEV *ScalarEvolution::getExitCount(Loop *L, BasicBlock *ExitingBlock) {
+ return getBackedgeTakenInfo(L).getExact(ExitingBlock, this);
+}
+
/// getBackedgeTakenCount - If the specified loop has a predictable
/// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute
/// object. The backedge-taken count is the number of times the loop header
/// hasLoopInvariantBackedgeTakenCount).
///
const SCEV *ScalarEvolution::getBackedgeTakenCount(const Loop *L) {
- return getBackedgeTakenInfo(L).Exact;
+ return getBackedgeTakenInfo(L).getExact(this);
}
/// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except
/// return the least SCEV value that is known never to be less than the
/// actual backedge taken count.
const SCEV *ScalarEvolution::getMaxBackedgeTakenCount(const Loop *L) {
- return getBackedgeTakenInfo(L).Max;
+ return getBackedgeTakenInfo(L).getMax(this);
}
/// PushLoopPHIs - Push PHI nodes in the header of the given loop
const ScalarEvolution::BackedgeTakenInfo &
ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
- // Initially insert a CouldNotCompute for this loop. If the insertion
+ // Initially insert an invalid entry for this loop. If the insertion
// succeeds, proceed to actually compute a backedge-taken count and
// update the value. The temporary CouldNotCompute value tells SCEV
// code elsewhere that it shouldn't attempt to request a new
// backedge-taken count, which could result in infinite recursion.
- std::pair<std::map<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
- BackedgeTakenCounts.insert(std::make_pair(L, getCouldNotCompute()));
+ std::pair<DenseMap<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
+ BackedgeTakenCounts.insert(std::make_pair(L, BackedgeTakenInfo()));
if (!Pair.second)
return Pair.first->second;
- BackedgeTakenInfo BECount = ComputeBackedgeTakenCount(L);
- if (BECount.Exact != getCouldNotCompute()) {
- assert(isLoopInvariant(BECount.Exact, L) &&
- isLoopInvariant(BECount.Max, L) &&
+ // ComputeBackedgeTakenCount may allocate memory for its result. Inserting it
+ // into the BackedgeTakenCounts map transfers ownership. Otherwise, the result
+ // must be cleared in this scope.
+ BackedgeTakenInfo Result = ComputeBackedgeTakenCount(L);
+
+ if (Result.getExact(this) != getCouldNotCompute()) {
+ assert(isLoopInvariant(Result.getExact(this), L) &&
+ isLoopInvariant(Result.getMax(this), L) &&
"Computed backedge-taken count isn't loop invariant for loop!");
++NumTripCountsComputed;
-
- // Update the value in the map.
- Pair.first->second = BECount;
- } else {
- if (BECount.Max != getCouldNotCompute())
- // Update the value in the map.
- Pair.first->second = BECount;
- if (isa<PHINode>(L->getHeader()->begin()))
- // Only count loops that have phi nodes as not being computable.
- ++NumTripCountsNotComputed;
+ }
+ else if (Result.getMax(this) == getCouldNotCompute() &&
+ isa<PHINode>(L->getHeader()->begin())) {
+ // Only count loops that have phi nodes as not being computable.
+ ++NumTripCountsNotComputed;
}
// Now that we know more about the trip count for this loop, forget any
// conservative estimates made without the benefit of trip count
// information. This is similar to the code in forgetLoop, except that
// it handles SCEVUnknown PHI nodes specially.
- if (BECount.hasAnyInfo()) {
+ if (Result.hasAnyInfo()) {
SmallVector<Instruction *, 16> Worklist;
PushLoopPHIs(L, Worklist);
PushDefUseChildren(I, Worklist);
}
}
- return Pair.first->second;
+
+ // Re-lookup the insert position, since the call to
+ // ComputeBackedgeTakenCount above could result in a
+ // recusive call to getBackedgeTakenInfo (on a different
+ // loop), which would invalidate the iterator computed
+ // earlier.
+ return BackedgeTakenCounts.find(L)->second = Result;
}
/// forgetLoop - This method should be called by the client when it has
/// compute a trip count, or if the loop is deleted.
void ScalarEvolution::forgetLoop(const Loop *L) {
// Drop any stored trip count value.
- BackedgeTakenCounts.erase(L);
+ DenseMap<const Loop*, BackedgeTakenInfo>::iterator BTCPos =
+ BackedgeTakenCounts.find(L);
+ if (BTCPos != BackedgeTakenCounts.end()) {
+ BTCPos->second.clear();
+ BackedgeTakenCounts.erase(BTCPos);
+ }
// Drop information about expressions based on loop-header PHIs.
SmallVector<Instruction *, 16> Worklist;
}
}
+/// getExact - Get the exact loop backedge taken count considering all loop
+/// exits. If all exits are computable, this is the minimum computed count.
+const SCEV *
+ScalarEvolution::BackedgeTakenInfo::getExact(ScalarEvolution *SE) const {
+ // If any exits were not computable, the loop is not computable.
+ if (!ExitNotTaken.isCompleteList()) return SE->getCouldNotCompute();
+
+ // We need at least one computable exit.
+ if (!ExitNotTaken.ExitingBlock) return SE->getCouldNotCompute();
+ assert(ExitNotTaken.ExactNotTaken && "uninitialized not-taken info");
+
+ const SCEV *BECount = 0;
+ for (const ExitNotTakenInfo *ENT = &ExitNotTaken;
+ ENT != 0; ENT = ENT->getNextExit()) {
+
+ assert(ENT->ExactNotTaken != SE->getCouldNotCompute() && "bad exit SCEV");
+
+ if (!BECount)
+ BECount = ENT->ExactNotTaken;
+ else
+ BECount = SE->getUMinFromMismatchedTypes(BECount, ENT->ExactNotTaken);
+ }
+ assert(BECount && "Invalid not taken count for loop exit");
+ return BECount;
+}
+
+/// getExact - Get the exact not taken count for this loop exit.
+const SCEV *
+ScalarEvolution::BackedgeTakenInfo::getExact(BasicBlock *ExitingBlock,
+ ScalarEvolution *SE) const {
+ for (const ExitNotTakenInfo *ENT = &ExitNotTaken;
+ ENT != 0; ENT = ENT->getNextExit()) {
+
+ if (ENT->ExitingBlock == ExitingBlock)
+ return ENT->ExactNotTaken;
+ }
+ return SE->getCouldNotCompute();
+}
+
+/// getMax - Get the max backedge taken count for the loop.
+const SCEV *
+ScalarEvolution::BackedgeTakenInfo::getMax(ScalarEvolution *SE) const {
+ return Max ? Max : SE->getCouldNotCompute();
+}
+
+/// Allocate memory for BackedgeTakenInfo and copy the not-taken count of each
+/// computable exit into a persistent ExitNotTakenInfo array.
+ScalarEvolution::BackedgeTakenInfo::BackedgeTakenInfo(
+ SmallVectorImpl< std::pair<BasicBlock *, const SCEV *> > &ExitCounts,
+ bool Complete, const SCEV *MaxCount) : Max(MaxCount) {
+
+ if (!Complete)
+ ExitNotTaken.setIncomplete();
+
+ unsigned NumExits = ExitCounts.size();
+ if (NumExits == 0) return;
+
+ ExitNotTaken.ExitingBlock = ExitCounts[0].first;
+ ExitNotTaken.ExactNotTaken = ExitCounts[0].second;
+ if (NumExits == 1) return;
+
+ // Handle the rare case of multiple computable exits.
+ ExitNotTakenInfo *ENT = new ExitNotTakenInfo[NumExits-1];
+
+ ExitNotTakenInfo *PrevENT = &ExitNotTaken;
+ for (unsigned i = 1; i < NumExits; ++i, PrevENT = ENT, ++ENT) {
+ PrevENT->setNextExit(ENT);
+ ENT->ExitingBlock = ExitCounts[i].first;
+ ENT->ExactNotTaken = ExitCounts[i].second;
+ }
+}
+
+/// clear - Invalidate this result and free the ExitNotTakenInfo array.
+void ScalarEvolution::BackedgeTakenInfo::clear() {
+ ExitNotTaken.ExitingBlock = 0;
+ ExitNotTaken.ExactNotTaken = 0;
+ delete[] ExitNotTaken.getNextExit();
+}
+
/// ComputeBackedgeTakenCount - Compute the number of times the backedge
/// of the specified loop will execute.
ScalarEvolution::BackedgeTakenInfo
L->getExitingBlocks(ExitingBlocks);
// Examine all exits and pick the most conservative values.
- const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
- bool CouldNotComputeBECount = false;
+ bool CouldComputeBECount = true;
+ SmallVector<std::pair<BasicBlock *, const SCEV *>, 4> ExitCounts;
for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
- BackedgeTakenInfo NewBTI =
- ComputeBackedgeTakenCountFromExit(L, ExitingBlocks[i]);
-
- if (NewBTI.Exact == getCouldNotCompute()) {
+ ExitLimit EL = ComputeExitLimit(L, ExitingBlocks[i]);
+ if (EL.Exact == getCouldNotCompute())
// We couldn't compute an exact value for this exit, so
// we won't be able to compute an exact value for the loop.
- CouldNotComputeBECount = true;
- BECount = getCouldNotCompute();
- } else if (!CouldNotComputeBECount) {
- if (BECount == getCouldNotCompute())
- BECount = NewBTI.Exact;
- else
- BECount = getUMinFromMismatchedTypes(BECount, NewBTI.Exact);
- }
+ CouldComputeBECount = false;
+ else
+ ExitCounts.push_back(std::make_pair(ExitingBlocks[i], EL.Exact));
+
if (MaxBECount == getCouldNotCompute())
- MaxBECount = NewBTI.Max;
- else if (NewBTI.Max != getCouldNotCompute())
- MaxBECount = getUMinFromMismatchedTypes(MaxBECount, NewBTI.Max);
+ MaxBECount = EL.Max;
+ else if (EL.Max != getCouldNotCompute())
+ MaxBECount = getUMinFromMismatchedTypes(MaxBECount, EL.Max);
}
- return BackedgeTakenInfo(BECount, MaxBECount);
+ return BackedgeTakenInfo(ExitCounts, CouldComputeBECount, MaxBECount);
}
-/// ComputeBackedgeTakenCountFromExit - Compute the number of times the backedge
-/// of the specified loop will execute if it exits via the specified block.
-ScalarEvolution::BackedgeTakenInfo
-ScalarEvolution::ComputeBackedgeTakenCountFromExit(const Loop *L,
- BasicBlock *ExitingBlock) {
+/// ComputeExitLimit - Compute the number of times the backedge of the specified
+/// loop will execute if it exits via the specified block.
+ScalarEvolution::ExitLimit
+ScalarEvolution::ComputeExitLimit(const Loop *L, BasicBlock *ExitingBlock) {
// Okay, we've chosen an exiting block. See what condition causes us to
// exit at this block.
}
// Proceed to the next level to examine the exit condition expression.
- return ComputeBackedgeTakenCountFromExitCond(L, ExitBr->getCondition(),
- ExitBr->getSuccessor(0),
- ExitBr->getSuccessor(1));
+ return ComputeExitLimitFromCond(L, ExitBr->getCondition(),
+ ExitBr->getSuccessor(0),
+ ExitBr->getSuccessor(1));
}
-/// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the
+/// ComputeExitLimitFromCond - Compute the number of times the
/// backedge of the specified loop will execute if its exit condition
/// were a conditional branch of ExitCond, TBB, and FBB.
-ScalarEvolution::BackedgeTakenInfo
-ScalarEvolution::ComputeBackedgeTakenCountFromExitCond(const Loop *L,
- Value *ExitCond,
- BasicBlock *TBB,
- BasicBlock *FBB) {
+ScalarEvolution::ExitLimit
+ScalarEvolution::ComputeExitLimitFromCond(const Loop *L,
+ Value *ExitCond,
+ BasicBlock *TBB,
+ BasicBlock *FBB) {
// Check if the controlling expression for this loop is an And or Or.
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(ExitCond)) {
if (BO->getOpcode() == Instruction::And) {
// Recurse on the operands of the and.
- BackedgeTakenInfo BTI0 =
- ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(0), TBB, FBB);
- BackedgeTakenInfo BTI1 =
- ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(1), TBB, FBB);
+ ExitLimit EL0 = ComputeExitLimitFromCond(L, BO->getOperand(0), TBB, FBB);
+ ExitLimit EL1 = ComputeExitLimitFromCond(L, BO->getOperand(1), TBB, FBB);
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
if (L->contains(TBB)) {
// Both conditions must be true for the loop to continue executing.
// Choose the less conservative count.
- if (BTI0.Exact == getCouldNotCompute() ||
- BTI1.Exact == getCouldNotCompute())
+ if (EL0.Exact == getCouldNotCompute() ||
+ EL1.Exact == getCouldNotCompute())
BECount = getCouldNotCompute();
else
- BECount = getUMinFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
- if (BTI0.Max == getCouldNotCompute())
- MaxBECount = BTI1.Max;
- else if (BTI1.Max == getCouldNotCompute())
- MaxBECount = BTI0.Max;
+ BECount = getUMinFromMismatchedTypes(EL0.Exact, EL1.Exact);
+ if (EL0.Max == getCouldNotCompute())
+ MaxBECount = EL1.Max;
+ else if (EL1.Max == getCouldNotCompute())
+ MaxBECount = EL0.Max;
else
- MaxBECount = getUMinFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ MaxBECount = getUMinFromMismatchedTypes(EL0.Max, EL1.Max);
} else {
// Both conditions must be true at the same time for the loop to exit.
// For now, be conservative.
assert(L->contains(FBB) && "Loop block has no successor in loop!");
- if (BTI0.Max == BTI1.Max)
- MaxBECount = BTI0.Max;
- if (BTI0.Exact == BTI1.Exact)
- BECount = BTI0.Exact;
+ if (EL0.Max == EL1.Max)
+ MaxBECount = EL0.Max;
+ if (EL0.Exact == EL1.Exact)
+ BECount = EL0.Exact;
}
- return BackedgeTakenInfo(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount);
}
if (BO->getOpcode() == Instruction::Or) {
// Recurse on the operands of the or.
- BackedgeTakenInfo BTI0 =
- ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(0), TBB, FBB);
- BackedgeTakenInfo BTI1 =
- ComputeBackedgeTakenCountFromExitCond(L, BO->getOperand(1), TBB, FBB);
+ ExitLimit EL0 = ComputeExitLimitFromCond(L, BO->getOperand(0), TBB, FBB);
+ ExitLimit EL1 = ComputeExitLimitFromCond(L, BO->getOperand(1), TBB, FBB);
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
if (L->contains(FBB)) {
// Both conditions must be false for the loop to continue executing.
// Choose the less conservative count.
- if (BTI0.Exact == getCouldNotCompute() ||
- BTI1.Exact == getCouldNotCompute())
+ if (EL0.Exact == getCouldNotCompute() ||
+ EL1.Exact == getCouldNotCompute())
BECount = getCouldNotCompute();
else
- BECount = getUMinFromMismatchedTypes(BTI0.Exact, BTI1.Exact);
- if (BTI0.Max == getCouldNotCompute())
- MaxBECount = BTI1.Max;
- else if (BTI1.Max == getCouldNotCompute())
- MaxBECount = BTI0.Max;
+ BECount = getUMinFromMismatchedTypes(EL0.Exact, EL1.Exact);
+ if (EL0.Max == getCouldNotCompute())
+ MaxBECount = EL1.Max;
+ else if (EL1.Max == getCouldNotCompute())
+ MaxBECount = EL0.Max;
else
- MaxBECount = getUMinFromMismatchedTypes(BTI0.Max, BTI1.Max);
+ MaxBECount = getUMinFromMismatchedTypes(EL0.Max, EL1.Max);
} else {
// Both conditions must be false at the same time for the loop to exit.
// For now, be conservative.
assert(L->contains(TBB) && "Loop block has no successor in loop!");
- if (BTI0.Max == BTI1.Max)
- MaxBECount = BTI0.Max;
- if (BTI0.Exact == BTI1.Exact)
- BECount = BTI0.Exact;
+ if (EL0.Max == EL1.Max)
+ MaxBECount = EL0.Max;
+ if (EL0.Exact == EL1.Exact)
+ BECount = EL0.Exact;
}
- return BackedgeTakenInfo(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount);
}
}
// With an icmp, it may be feasible to compute an exact backedge-taken count.
// Proceed to the next level to examine the icmp.
if (ICmpInst *ExitCondICmp = dyn_cast<ICmpInst>(ExitCond))
- return ComputeBackedgeTakenCountFromExitCondICmp(L, ExitCondICmp, TBB, FBB);
+ return ComputeExitLimitFromICmp(L, ExitCondICmp, TBB, FBB);
// Check for a constant condition. These are normally stripped out by
// SimplifyCFG, but ScalarEvolution may be used by a pass which wishes to
}
// If it's not an integer or pointer comparison then compute it the hard way.
- return ComputeBackedgeTakenCountExhaustively(L, ExitCond, !L->contains(TBB));
+ return ComputeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
}
-static const SCEVAddRecExpr *
-isSimpleUnwrappingAddRec(const SCEV *S, const Loop *L) {
- const SCEVAddRecExpr *SA = dyn_cast<SCEVAddRecExpr>(S);
-
- // The SCEV must be an addrec of this loop.
- if (!SA || SA->getLoop() != L || !SA->isAffine())
- return 0;
-
- // The SCEV must be known to not wrap in some way to be interesting.
- if (!SA->getNoWrapFlags(SCEV::FlagNW))
- return 0;
-
- // The stride must be a constant so that we know if it is striding up or down.
- if (!isa<SCEVConstant>(SA->getOperand(1)))
- return 0;
- return SA;
-}
-
-/// getMinusSCEVForExitTest - When considering an exit test for a loop with a
-/// "x != y" exit test, we turn this into a computation that evaluates x-y != 0,
-/// and this function returns the expression to use for x-y. We know and take
-/// advantage of the fact that this subtraction is only being used in a
-/// comparison by zero context.
-///
-/// FIXME: this can be completely removed once AddRec FlagNWs are propagated.
-static const SCEV *getMinusSCEVForExitTest(const SCEV *LHS, const SCEV *RHS,
- const Loop *L, ScalarEvolution &SE) {
- // If either LHS or RHS is an AddRec SCEV (of this loop) that is known to not
- // self-wrap, then we know that the value will either become the other one
- // (and thus the loop terminates), that the loop will terminate through some
- // other exit condition first, or that the loop has undefined behavior. This
- // information is useful when the addrec has a stride that is != 1 or -1,
- // because it means we can't "miss" the exit value.
- //
- // In any of these three cases, it is safe to turn the exit condition into a
- // "counting down" AddRec (to zero) by subtracting the two inputs as normal,
- // but since we know that the "end cannot be missed" we can force the
- // resulting AddRec to be a NUW addrec. Since it is counting down, this means
- // that the AddRec *cannot* pass zero.
-
- // See if LHS and RHS are addrec's we can handle.
- const SCEVAddRecExpr *LHSA = isSimpleUnwrappingAddRec(LHS, L);
- const SCEVAddRecExpr *RHSA = isSimpleUnwrappingAddRec(RHS, L);
-
- // If neither addrec is interesting, just return a minus.
- if (RHSA == 0 && LHSA == 0)
- return SE.getMinusSCEV(LHS, RHS);
-
- // If only one of LHS and RHS are an AddRec of this loop, make sure it is LHS.
- if (RHSA && LHSA == 0) {
- // Safe because a-b === b-a for comparisons against zero.
- std::swap(LHS, RHS);
- std::swap(LHSA, RHSA);
- }
-
- // Handle the case when only one is advancing in a non-overflowing way.
- if (RHSA == 0) {
- // If RHS is loop varying, then we can't predict when LHS will cross it.
- if (!SE.isLoopInvariant(RHS, L))
- return SE.getMinusSCEV(LHS, RHS);
-
- // If LHS has a positive stride, then we compute RHS-LHS, because the loop
- // is counting up until it crosses RHS (which must be larger than LHS). If
- // it is negative, we compute LHS-RHS because we're counting down to RHS.
- const ConstantInt *Stride =
- cast<SCEVConstant>(LHSA->getOperand(1))->getValue();
- if (Stride->getValue().isNegative())
- std::swap(LHS, RHS);
-
- return SE.getMinusSCEV(RHS, LHS, SCEV::FlagNUW);
- }
-
- // If both LHS and RHS are interesting, we have something like:
- // a+i*4 != b+i*8.
- const ConstantInt *LHSStride =
- cast<SCEVConstant>(LHSA->getOperand(1))->getValue();
- const ConstantInt *RHSStride =
- cast<SCEVConstant>(RHSA->getOperand(1))->getValue();
-
- // If the strides are equal, then this is just a (complex) loop invariant
- // comparison of a and b.
- if (LHSStride == RHSStride)
- return SE.getMinusSCEV(LHSA->getStart(), RHSA->getStart());
-
- // If the signs of the strides differ, then the negative stride is counting
- // down to the positive stride.
- if (LHSStride->getValue().isNegative() != RHSStride->getValue().isNegative()){
- if (RHSStride->getValue().isNegative())
- std::swap(LHS, RHS);
- } else {
- // If LHS's stride is smaller than RHS's stride, then "b" must be less than
- // "a" and "b" is RHS is counting up (catching up) to LHS. This is true
- // whether the strides are positive or negative.
- if (RHSStride->getValue().slt(LHSStride->getValue()))
- std::swap(LHS, RHS);
- }
-
- return SE.getMinusSCEV(LHS, RHS, SCEV::FlagNUW);
-}
-
-/// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of times the
+/// ComputeExitLimitFromICmp - Compute the number of times the
/// backedge of the specified loop will execute if its exit condition
/// were a conditional branch of the ICmpInst ExitCond, TBB, and FBB.
-ScalarEvolution::BackedgeTakenInfo
-ScalarEvolution::ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
- ICmpInst *ExitCond,
- BasicBlock *TBB,
- BasicBlock *FBB) {
+ScalarEvolution::ExitLimit
+ScalarEvolution::ComputeExitLimitFromICmp(const Loop *L,
+ ICmpInst *ExitCond,
+ BasicBlock *TBB,
+ BasicBlock *FBB) {
// If the condition was exit on true, convert the condition to exit on false
ICmpInst::Predicate Cond;
// Handle common loops like: for (X = "string"; *X; ++X)
if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0)))
if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) {
- BackedgeTakenInfo ItCnt =
- ComputeLoadConstantCompareBackedgeTakenCount(LI, RHS, L, Cond);
+ ExitLimit ItCnt =
+ ComputeLoadConstantCompareExitLimit(LI, RHS, L, Cond);
if (ItCnt.hasAnyInfo())
return ItCnt;
}
switch (Cond) {
case ICmpInst::ICMP_NE: { // while (X != Y)
// Convert to: while (X-Y != 0)
- // FIXME: Once AddRec FlagNW are propagated, should be:
- // BackedgeTakenInfo BTI = HowFarToZero(getMinusSCEV(LHS, RHS), L);
- BackedgeTakenInfo BTI = HowFarToZero(getMinusSCEVForExitTest(LHS, RHS, L,
- *this), L);
- if (BTI.hasAnyInfo()) return BTI;
+ ExitLimit EL = HowFarToZero(getMinusSCEV(LHS, RHS), L);
+ if (EL.hasAnyInfo()) return EL;
break;
}
case ICmpInst::ICMP_EQ: { // while (X == Y)
// Convert to: while (X-Y == 0)
- BackedgeTakenInfo BTI = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
- if (BTI.hasAnyInfo()) return BTI;
+ ExitLimit EL = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
+ if (EL.hasAnyInfo()) return EL;
break;
}
case ICmpInst::ICMP_SLT: {
- BackedgeTakenInfo BTI = HowManyLessThans(LHS, RHS, L, true);
- if (BTI.hasAnyInfo()) return BTI;
+ ExitLimit EL = HowManyLessThans(LHS, RHS, L, true);
+ if (EL.hasAnyInfo()) return EL;
break;
}
case ICmpInst::ICMP_SGT: {
- BackedgeTakenInfo BTI = HowManyLessThans(getNotSCEV(LHS),
+ ExitLimit EL = HowManyLessThans(getNotSCEV(LHS),
getNotSCEV(RHS), L, true);
- if (BTI.hasAnyInfo()) return BTI;
+ if (EL.hasAnyInfo()) return EL;
break;
}
case ICmpInst::ICMP_ULT: {
- BackedgeTakenInfo BTI = HowManyLessThans(LHS, RHS, L, false);
- if (BTI.hasAnyInfo()) return BTI;
+ ExitLimit EL = HowManyLessThans(LHS, RHS, L, false);
+ if (EL.hasAnyInfo()) return EL;
break;
}
case ICmpInst::ICMP_UGT: {
- BackedgeTakenInfo BTI = HowManyLessThans(getNotSCEV(LHS),
+ ExitLimit EL = HowManyLessThans(getNotSCEV(LHS),
getNotSCEV(RHS), L, false);
- if (BTI.hasAnyInfo()) return BTI;
+ if (EL.hasAnyInfo()) return EL;
break;
}
default:
#endif
break;
}
- return
- ComputeBackedgeTakenCountExhaustively(L, ExitCond, !L->contains(TBB));
+ return ComputeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
}
static ConstantInt *
if (Idx >= CA->getNumOperands()) return 0; // Bogus program
Init = cast<Constant>(CA->getOperand(Idx));
} else if (isa<ConstantAggregateZero>(Init)) {
- if (const StructType *STy = dyn_cast<StructType>(Init->getType())) {
+ if (StructType *STy = dyn_cast<StructType>(Init->getType())) {
assert(Idx < STy->getNumElements() && "Bad struct index!");
Init = Constant::getNullValue(STy->getElementType(Idx));
- } else if (
const ArrayType *ATy = dyn_cast<ArrayType>(Init->getType())) {
+ } else if (ArrayType *ATy = dyn_cast<ArrayType>(Init->getType())) {
if (Idx >= ATy->getNumElements()) return 0; // Bogus program
Init = Constant::getNullValue(ATy->getElementType());
} else {
return Init;
}
-/// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition of
+/// ComputeLoadConstantCompareExitLimit - Given an exit condition of
/// 'icmp op load X, cst', try to see if we can compute the backedge
/// execution count.
-ScalarEvolution::BackedgeTakenInfo
-ScalarEvolution::ComputeLoadConstantCompareBackedgeTakenCount(
- LoadInst *LI,
- Constant *RHS,
- const Loop *L,
- ICmpInst::Predicate predicate) {
+ScalarEvolution::ExitLimit
+ScalarEvolution::ComputeLoadConstantCompareExitLimit(
+ LoadInst *LI,
+ Constant *RHS,
+ const Loop *L,
+ ICmpInst::Predicate predicate) {
+
if (LI->isVolatile()) return getCouldNotCompute();
// Check to see if the loaded pointer is a getelementptr of a global.
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
Operands[1], TD);
- return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size(), TD);
+ return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Operands, TD);
}
/// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
const APInt &BEs,
const Loop *L) {
-
std::map<PHINode*, Constant*>::const_iterator I =
+
DenseMap<PHINode*, Constant*>::const_iterator I =
ConstantEvolutionLoopExitValue.find(PN);
if (I != ConstantEvolutionLoopExitValue.end())
return I->second;
}
}
-/// ComputeBackedgeTakenCountExhaustively - If the loop is known to execute a
+/// ComputeExitCountExhaustively - If the loop is known to execute a
/// constant number of times (the condition evolves only from constants),
/// try to evaluate a few iterations of the loop until we get the exit
/// condition gets a value of ExitWhen (true or false). If we cannot
/// evaluate the trip count of the loop, return getCouldNotCompute().
-const SCEV *
-ScalarEvolution::ComputeBackedgeTakenCountExhaustively(const Loop *L,
- Value *Cond,
- bool ExitWhen) {
+const SCEV * ScalarEvolution::ComputeExitCountExhaustively(const Loop *L,
+ Value *Cond,
+ bool ExitWhen) {
PHINode *PN = getConstantEvolvingPHI(Cond, L);
if (PN == 0) return getCouldNotCompute();
Operands[0], Operands[1], TD);
else
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size(), TD);
+ Operands, TD);
if (!C) return V;
return getSCEV(C);
}
for (++i; i != e; ++i)
NewOps.push_back(getSCEVAtScope(AddRec->getOperand(i), L));
- AddRec = cast<SCEVAddRecExpr>(
+ const SCEV *FoldedRec =
getAddRecExpr(NewOps, AddRec->getLoop(),
- // FIXME: AddRec->getNoWrapFlags(SCEV::FlagNW)
- SCEV::FlagAnyWrap));
+ AddRec->getNoWrapFlags(SCEV::FlagNW));
+ AddRec = dyn_cast<SCEVAddRecExpr>(FoldedRec);
+ // The addrec may be folded to a nonrecurrence, for example, if the
+ // induction variable is multiplied by zero after constant folding. Go
+ // ahead and return the folded value.
+ if (!AddRec)
+ return FoldedRec;
break;
}
/// now expressed as a single expression, V = x-y. So the exit test is
/// effectively V != 0. We know and take advantage of the fact that this
/// expression only being used in a comparison by zero context.
-ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ExitLimit
ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
// If the value is a constant
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
/// HowFarToNonZero - Return the number of times a backedge checking the
/// specified value for nonzero will execute. If not computable, return
/// CouldNotCompute
-ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ExitLimit
ScalarEvolution::HowFarToNonZero(const SCEV *V, const Loop *L) {
// Loops that look like: while (X == 0) are very strange indeed. We don't
// handle them yet except for the trivial case. This could be expanded in the
assert(!isKnownNegative(Step) &&
"This code doesn't handle negative strides yet!");
- const Type *Ty = Start->getType();
+ Type *Ty = Start->getType();
// When Start == End, we have an exact BECount == 0. Short-circuit this case
// here because SCEV may not be able to determine that the unsigned division
if (!NoWrap) {
// Check Add for unsigned overflow.
// TODO: More sophisticated things could be done here.
- const Type *WideTy = IntegerType::get(getContext(),
+ Type *WideTy = IntegerType::get(getContext(),
getTypeSizeInBits(Ty) + 1);
const SCEV *EDiff = getZeroExtendExpr(Diff, WideTy);
const SCEV *ERoundUp = getZeroExtendExpr(RoundUp, WideTy);
/// HowManyLessThans - Return the number of times a backedge containing the
/// specified less-than comparison will execute. If not computable, return
/// CouldNotCompute.
-ScalarEvolution::BackedgeTakenInfo
+ScalarEvolution::ExitLimit
ScalarEvolution::HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
const Loop *L, bool isSigned) {
// Only handle: "ADDREC < LoopInvariant".
if (isa<SCEVCouldNotCompute>(MaxBECount))
MaxBECount = BECount;
- return BackedgeTakenInfo(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount);
}
return getCouldNotCompute();
SmallVector<const SCEV *, 4> Operands(op_begin(), op_end());
Operands[0] = SE.getConstant(SC->getType(), 0);
const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop(),
- // FIXME: getNoWrapFlags(FlagNW)
- FlagAnyWrap);
+ getNoWrapFlags(FlagNW));
if (const SCEVAddRecExpr *ShiftedAddRec =
dyn_cast<SCEVAddRecExpr>(Shifted))
return ShiftedAddRec->getNumIterationsInRange(
FirstUnknown = 0;
ValueExprMap.clear();
+
+ // Free any extra memory created for ExitNotTakenInfo in the unlikely event
+ // that a loop had multiple computable exits.
+ for (DenseMap<const Loop*, BackedgeTakenInfo>::iterator I =
+ BackedgeTakenCounts.begin(), E = BackedgeTakenCounts.end();
+ I != E; ++I) {
+ I->second.clear();
+ }
+
BackedgeTakenCounts.clear();
ConstantEvolutionLoopExitValue.clear();
ValuesAtScopes.clear();
projects / oota-llvm.git / blobdiff