"derived loop"),
cl::init(100));
-static RegisterPass<ScalarEvolution>
-R("scalar-evolution", "Scalar Evolution Analysis", false, true);
+INITIALIZE_PASS(ScalarEvolution, "scalar-evolution",
+ "Scalar Evolution Analysis", false, true);
char ScalarEvolution::ID = 0;
//===----------------------------------------------------------------------===//
const SCEV *
ScalarEvolution::getConstant(const Type *Ty, uint64_t V, bool isSigned) {
- return getConstant(
- ConstantInt::get(cast<IntegerType>(Ty), V, isSigned));
+ const IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
+ return getConstant(ConstantInt::get(ITy, V, isSigned));
}
const Type *SCEVConstant::getType() const { return V->getType(); }
}
void SCEVCommutativeExpr::print(raw_ostream &OS) const {
- assert(NumOperands > 1 && "This plus expr shouldn't exist!");
const char *OpStr = getOperationStr();
- OS << "(" << *Operands[0];
- for (unsigned i = 1, e = NumOperands; i != e; ++i)
- OS << OpStr << *Operands[i];
+ OS << "(";
+ for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) {
+ OS << **I;
+ if (next(I) != E)
+ OS << OpStr;
+ }
OS << ")";
}
CalculationBits);
const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
for (unsigned i = 1; i != K; ++i) {
- const SCEV *S = SE.getMinusSCEV(It, SE.getIntegerSCEV(i, It->getType()));
+ const SCEV *S = SE.getMinusSCEV(It, SE.getConstant(It->getType(), i));
Dividend = SE.getMulExpr(Dividend,
SE.getTruncateOrZeroExtend(S, CalculationTy));
}
// Fold if the operand is constant.
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
return getConstant(
- cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(), Ty)));
+ cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(),
+ getEffectiveSCEVType(Ty))));
// trunc(trunc(x)) --> trunc(x)
if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op))
return getAddRecExpr(Operands, AddRec->getLoop());
}
- // The cast wasn't folded; create an explicit cast node.
- // Recompute the insert position, as it may have been invalidated.
- if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
+ // As a special case, fold trunc(undef) to undef. We don't want to
+ // know too much about SCEVUnknowns, but this special case is handy
+ // and harmless.
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Op))
+ if (isa<UndefValue>(U->getValue()))
+ return getSCEV(UndefValue::get(Ty));
+
+ // The cast wasn't folded; create an explicit cast node. We can reuse
+ // the existing insert position since if we get here, we won't have
+ // made any changes which would invalidate it.
SCEV *S = new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator),
Op, Ty);
UniqueSCEVs.InsertNode(S, IP);
Ty = getEffectiveSCEVType(Ty);
// Fold if the operand is constant.
- if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
- const Type *IntTy = getEffectiveSCEVType(Ty);
- Constant *C = ConstantExpr::getZExt(SC->getValue(), IntTy);
- if (IntTy != Ty) C = ConstantExpr::getIntToPtr(C, Ty);
- return getConstant(cast<ConstantInt>(C));
- }
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
+ return getConstant(
+ cast<ConstantInt>(ConstantExpr::getZExt(SC->getValue(),
+ getEffectiveSCEVType(Ty))));
// zext(zext(x)) --> zext(x)
if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
} 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) ||
+ 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.
Ty = getEffectiveSCEVType(Ty);
// Fold if the operand is constant.
- if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
- const Type *IntTy = getEffectiveSCEVType(Ty);
- Constant *C = ConstantExpr::getSExt(SC->getValue(), IntTy);
- if (IntTy != Ty) C = ConstantExpr::getIntToPtr(C, Ty);
- return getConstant(cast<ConstantInt>(C));
- }
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
+ return getConstant(
+ cast<ConstantInt>(ConstantExpr::getSExt(SC->getValue(),
+ getEffectiveSCEVType(Ty))));
// sext(sext(x)) --> sext(x)
if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
return getAddRecExpr(Ops, AR->getLoop());
}
+ // As a special case, fold anyext(undef) to undef. We don't want to
+ // know too much about SCEVUnknowns, but this special case is handy
+ // and harmless.
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Op))
+ if (isa<UndefValue>(U->getValue()))
+ return getSCEV(UndefValue::get(Ty));
+
// If the expression is obviously signed, use the sext cast value.
if (isa<SCEVSMaxExpr>(Op))
return SExt;
ScalarEvolution &SE) {
bool Interesting = false;
- // Iterate over the add operands.
- for (unsigned i = 0, e = NumOperands; i != e; ++i) {
+ // Iterate over the add operands. They are sorted, with constants first.
+ unsigned i = 0;
+ while (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
+ ++i;
+ // Pull a buried constant out to the outside.
+ if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero())
+ Interesting = true;
+ AccumulatedConstant += Scale * C->getValue()->getValue();
+ }
+
+ // Next comes everything else. We're especially interested in multiplies
+ // here, but they're in the middle, so just visit the rest with one loop.
+ for (; i != NumOperands; ++i) {
const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]);
if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) {
APInt NewScale =
Interesting = true;
}
}
- } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
- // Pull a buried constant out to the outside.
- if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero())
- Interesting = true;
- AccumulatedConstant += Scale * C->getValue()->getValue();
} else {
// An ordinary operand. Update the map.
std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair =
assert(!Ops.empty() && "Cannot get empty add!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
+ const Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
- assert(getEffectiveSCEVType(Ops[i]->getType()) ==
- getEffectiveSCEVType(Ops[0]->getType()) &&
+ assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
"SCEVAddExpr operand types don't match!");
#endif
if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2
// Found a match, merge the two values into a multiply, and add any
// remaining values to the result.
- const SCEV *Two = getIntegerSCEV(2, Ty);
+ const SCEV *Two = getConstant(Ty, 2);
const SCEV *Mul = getMulExpr(Ops[i], Two);
if (Ops.size() == 2)
return Mul;
}
LargeOps.push_back(T->getOperand());
} else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
- // This could be either sign or zero extension, but sign extension
- // is much more likely to be foldable here.
- LargeOps.push_back(getSignExtendExpr(C, SrcType));
+ LargeOps.push_back(getAnyExtendExpr(C, SrcType));
} else if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Ops[i])) {
SmallVector<const SCEV *, 8> LargeMulOps;
for (unsigned j = 0, f = M->getNumOperands(); j != f && Ok; ++j) {
LargeMulOps.push_back(T->getOperand());
} else if (const SCEVConstant *C =
dyn_cast<SCEVConstant>(M->getOperand(j))) {
- // This could be either sign or zero extension, but sign extension
- // is much more likely to be foldable here.
- LargeMulOps.push_back(getSignExtendExpr(C, SrcType));
+ LargeMulOps.push_back(getAnyExtendExpr(C, SrcType));
} else {
Ok = false;
break;
while (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) {
// If we have an add, expand the add operands onto the end of the operands
// list.
- Ops.insert(Ops.end(), Add->op_begin(), Add->op_end());
Ops.erase(Ops.begin()+Idx);
+ Ops.append(Add->op_begin(), Add->op_end());
DeletedAdd = true;
}
Ops.push_back(getMulExpr(getConstant(I->first),
getAddExpr(I->second)));
if (Ops.empty())
- return getIntegerSCEV(0, Ty);
+ return getConstant(Ty, 0);
if (Ops.size() == 1)
return Ops[0];
return getAddExpr(Ops);
MulOps.erase(MulOps.begin()+MulOp);
InnerMul = getMulExpr(MulOps);
}
- const SCEV *One = getIntegerSCEV(1, Ty);
+ const SCEV *One = getConstant(Ty, 1);
const SCEV *AddOne = getAddExpr(InnerMul, One);
const SCEV *OuterMul = getMulExpr(AddOne, Ops[AddOp]);
if (Ops.size() == 2) return OuterMul;
AddRec->op_end());
AddRecOps[0] = getAddExpr(LIOps);
- // It's tempting to propagate NUW/NSW flags here, but nuw/nsw addition
- // is not associative so this isn't necessarily safe.
- const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop);
+ // 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.
+ const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop,
+ HasNUW && AddRec->hasNoUnsignedWrap(),
+ HasNSW && AddRec->hasNoSignedWrap());
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
AddRec->op_end());
for (unsigned i = 0, e = OtherAddRec->getNumOperands(); i != e; ++i) {
if (i >= NewOps.size()) {
- NewOps.insert(NewOps.end(), OtherAddRec->op_begin()+i,
+ NewOps.append(OtherAddRec->op_begin()+i,
OtherAddRec->op_end());
break;
}
while (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
// If we have an mul, expand the mul operands onto the end of the operands
// list.
- Ops.insert(Ops.end(), Mul->op_begin(), Mul->op_end());
Ops.erase(Ops.begin()+Idx);
+ Ops.append(Mul->op_begin(), Mul->op_end());
DeletedMul = true;
}
// NLI * LI * {Start,+,Step} --> NLI * {LI*Start,+,LI*Step}
SmallVector<const SCEV *, 4> NewOps;
NewOps.reserve(AddRec->getNumOperands());
- if (LIOps.size() == 1) {
- const SCEV *Scale = LIOps[0];
- for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
- NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i)));
- } else {
- for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
- SmallVector<const SCEV *, 4> MulOps(LIOps.begin(), LIOps.end());
- MulOps.push_back(AddRec->getOperand(i));
- NewOps.push_back(getMulExpr(MulOps));
- }
- }
+ const SCEV *Scale = getMulExpr(LIOps);
+ for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
+ NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i)));
- // It's tempting to propagate the NSW flag here, but nsw multiplication
- // is not associative so this isn't necessarily safe.
+ // Build the new addrec. Propagate the NUW and NSW flags if both the
+ // outer mul and the inner addrec are guaranteed to have no overflow.
const SCEV *NewRec = getAddRecExpr(NewOps, AddRec->getLoop(),
HasNUW && AddRec->hasNoUnsignedWrap(),
- /*HasNSW=*/false);
+ HasNSW && AddRec->hasNoSignedWrap());
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
if (RHSC->getValue()->equalsInt(1))
return LHS; // X udiv 1 --> x
- if (RHSC->getValue()->isZero())
- return getIntegerSCEV(0, LHS->getType()); // value is undefined
-
- // 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();
- unsigned LZ = RHSC->getValue()->getValue().countLeadingZeros();
- unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ;
- // 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::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()) &&
- getZeroExtendExpr(AR, ExtTy) ==
- getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
- getZeroExtendExpr(Step, ExtTy),
- AR->getLoop())) {
- SmallVector<const SCEV *, 4> Operands;
- for (unsigned i = 0, e = AR->getNumOperands(); i != e; ++i)
- Operands.push_back(getUDivExpr(AR->getOperand(i), RHS));
- return getAddRecExpr(Operands, AR->getLoop());
- }
- // (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;
- for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i)
- Operands.push_back(getZeroExtendExpr(M->getOperand(i), ExtTy));
- if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands))
- // Find an operand that's safely divisible.
- for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
- const SCEV *Op = M->getOperand(i);
- const SCEV *Div = getUDivExpr(Op, RHSC);
- if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) {
- Operands = SmallVector<const SCEV *, 4>(M->op_begin(), M->op_end());
- Operands[i] = Div;
- return getMulExpr(Operands);
+ // If the denominator is zero, the result of the udiv is undefined. Don't
+ // try to analyze it, because the resolution chosen here may differ from
+ // the resolution chosen in other parts of the compiler.
+ if (!RHSC->getValue()->isZero()) {
+ // 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();
+ unsigned LZ = RHSC->getValue()->getValue().countLeadingZeros();
+ unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ;
+ // 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::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()) &&
+ getZeroExtendExpr(AR, ExtTy) ==
+ getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
+ getZeroExtendExpr(Step, ExtTy),
+ AR->getLoop())) {
+ SmallVector<const SCEV *, 4> Operands;
+ for (unsigned i = 0, e = AR->getNumOperands(); i != e; ++i)
+ Operands.push_back(getUDivExpr(AR->getOperand(i), RHS));
+ return getAddRecExpr(Operands, AR->getLoop());
}
+ // (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;
+ for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i)
+ Operands.push_back(getZeroExtendExpr(M->getOperand(i), ExtTy));
+ if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands))
+ // Find an operand that's safely divisible.
+ for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
+ const SCEV *Op = M->getOperand(i);
+ const SCEV *Div = getUDivExpr(Op, RHSC);
+ if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) {
+ Operands = SmallVector<const SCEV *, 4>(M->op_begin(),
+ M->op_end());
+ Operands[i] = Div;
+ return getMulExpr(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)) {
+ SmallVector<const SCEV *, 4> Operands;
+ for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i)
+ Operands.push_back(getZeroExtendExpr(A->getOperand(i), ExtTy));
+ if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) {
+ Operands.clear();
+ for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) {
+ const SCEV *Op = getUDivExpr(A->getOperand(i), RHS);
+ if (isa<SCEVUDivExpr>(Op) ||
+ getMulExpr(Op, RHS) != A->getOperand(i))
+ break;
+ Operands.push_back(Op);
+ }
+ if (Operands.size() == A->getNumOperands())
+ return getAddExpr(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)) {
- SmallVector<const SCEV *, 4> Operands;
- for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i)
- Operands.push_back(getZeroExtendExpr(A->getOperand(i), ExtTy));
- if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) {
- Operands.clear();
- for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) {
- const SCEV *Op = getUDivExpr(A->getOperand(i), RHS);
- if (isa<SCEVUDivExpr>(Op) || getMulExpr(Op, RHS) != A->getOperand(i))
- break;
- Operands.push_back(Op);
- }
- if (Operands.size() == A->getNumOperands())
- return getAddExpr(Operands);
}
- }
- // Fold if both operands are constant.
- if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
- Constant *LHSCV = LHSC->getValue();
- Constant *RHSCV = RHSC->getValue();
- return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV,
- RHSCV)));
+ // Fold if both operands are constant.
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
+ Constant *LHSCV = LHSC->getValue();
+ Constant *RHSCV = RHSC->getValue();
+ return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV,
+ RHSCV)));
+ }
}
}
Operands.push_back(Start);
if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
if (StepChrec->getLoop() == L) {
- Operands.insert(Operands.end(), StepChrec->op_begin(),
- StepChrec->op_end());
+ Operands.append(StepChrec->op_begin(), StepChrec->op_end());
return getAddRecExpr(Operands, L);
}
if (Idx < Ops.size()) {
bool DeletedSMax = false;
while (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(Ops[Idx])) {
- Ops.insert(Ops.end(), SMax->op_begin(), SMax->op_end());
Ops.erase(Ops.begin()+Idx);
+ Ops.append(SMax->op_begin(), SMax->op_end());
DeletedSMax = true;
}
// so, delete one. Since we sorted the list, these values are required to
// be adjacent.
for (unsigned i = 0, e = Ops.size()-1; i != e; ++i)
- if (Ops[i] == Ops[i+1]) { // X smax Y smax Y --> X smax Y
+ // X smax Y smax Y --> X smax Y
+ // X smax Y --> X, if X is always greater than Y
+ if (Ops[i] == Ops[i+1] ||
+ isKnownPredicate(ICmpInst::ICMP_SGE, Ops[i], Ops[i+1])) {
+ Ops.erase(Ops.begin()+i+1, Ops.begin()+i+2);
+ --i; --e;
+ } else if (isKnownPredicate(ICmpInst::ICMP_SLE, Ops[i], Ops[i+1])) {
Ops.erase(Ops.begin()+i, Ops.begin()+i+1);
--i; --e;
}
if (Idx < Ops.size()) {
bool DeletedUMax = false;
while (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(Ops[Idx])) {
- Ops.insert(Ops.end(), UMax->op_begin(), UMax->op_end());
Ops.erase(Ops.begin()+Idx);
+ Ops.append(UMax->op_begin(), UMax->op_end());
DeletedUMax = true;
}
// so, delete one. Since we sorted the list, these values are required to
// be adjacent.
for (unsigned i = 0, e = Ops.size()-1; i != e; ++i)
- if (Ops[i] == Ops[i+1]) { // X umax Y umax Y --> X umax Y
+ // X umax Y umax Y --> X umax Y
+ // X umax Y --> X, if X is always greater than Y
+ if (Ops[i] == Ops[i+1] ||
+ isKnownPredicate(ICmpInst::ICMP_UGE, Ops[i], Ops[i+1])) {
+ Ops.erase(Ops.begin()+i+1, Ops.begin()+i+2);
+ --i; --e;
+ } else if (isKnownPredicate(ICmpInst::ICMP_ULE, Ops[i], Ops[i+1])) {
Ops.erase(Ops.begin()+i, Ops.begin()+i+1);
--i; --e;
}
Constant *C = ConstantExpr::getSizeOf(AllocTy);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- C = ConstantFoldConstantExpression(CE, TD);
+ if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
+ C = Folded;
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
const SCEV *ScalarEvolution::getAlignOfExpr(const Type *AllocTy) {
Constant *C = ConstantExpr::getAlignOf(AllocTy);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- C = ConstantFoldConstantExpression(CE, TD);
+ if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
+ C = Folded;
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
Constant *C = ConstantExpr::getOffsetOf(STy, FieldNo);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- C = ConstantFoldConstantExpression(CE, TD);
+ if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
+ C = Folded;
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
Constant *FieldNo) {
Constant *C = ConstantExpr::getOffsetOf(CTy, FieldNo);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- C = ConstantFoldConstantExpression(CE, TD);
+ if (Constant *Folded = ConstantFoldConstantExpression(CE, TD))
+ C = Folded;
const Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(CTy));
return getTruncateOrZeroExtend(getSCEV(C), Ty);
}
return S;
}
-/// getIntegerSCEV - Given a SCEVable type, create a constant for the
-/// specified signed integer value and return a SCEV for the constant.
-const SCEV *ScalarEvolution::getIntegerSCEV(int64_t Val, const Type *Ty) {
- const IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
- return getConstant(ConstantInt::get(ITy, Val));
-}
-
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V) {
///
const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS,
const SCEV *RHS) {
+ // Fast path: X - X --> 0.
+ if (LHS == RHS)
+ return getConstant(LHS->getType(), 0);
+
// X - Y --> X + -Y
return getAddExpr(LHS, getNegativeSCEV(RHS));
}
///
const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
- bool InBounds = GEP->isInBounds();
+ // Don't blindly transfer the inbounds flag from the GEP instruction to the
+ // Add expression, because the Instruction may be guarded by control flow
+ // and the no-overflow bits may not be valid for the expression in any
+ // context.
+
const 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())
return getUnknown(GEP);
- const SCEV *TotalOffset = getIntegerSCEV(0, IntPtrTy);
+ const SCEV *TotalOffset = getConstant(IntPtrTy, 0);
gep_type_iterator GTI = gep_type_begin(GEP);
for (GetElementPtrInst::op_iterator I = next(GEP->op_begin()),
E = GEP->op_end();
if (const StructType *STy = dyn_cast<StructType>(*GTI++)) {
// For a struct, add the member offset.
unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
- TotalOffset = getAddExpr(TotalOffset,
- getOffsetOfExpr(STy, FieldNo),
- /*HasNUW=*/false, /*HasNSW=*/InBounds);
+ const SCEV *FieldOffset = getOffsetOfExpr(STy, FieldNo);
+
+ // Add the field offset to the running total offset.
+ TotalOffset = getAddExpr(TotalOffset, FieldOffset);
} else {
// For an array, add the element offset, explicitly scaled.
- const SCEV *LocalOffset = getSCEV(Index);
+ const SCEV *ElementSize = getSizeOfExpr(*GTI);
+ const SCEV *IndexS = getSCEV(Index);
// Getelementptr indices are signed.
- LocalOffset = getTruncateOrSignExtend(LocalOffset, IntPtrTy);
- // Lower "inbounds" GEPs to NSW arithmetic.
- LocalOffset = getMulExpr(LocalOffset, getSizeOfExpr(*GTI),
- /*HasNUW=*/false, /*HasNSW=*/InBounds);
- TotalOffset = getAddExpr(TotalOffset, LocalOffset,
- /*HasNUW=*/false, /*HasNSW=*/InBounds);
+ IndexS = getTruncateOrSignExtend(IndexS, IntPtrTy);
+
+ // Multiply the index by the element size to compute the element offset.
+ const SCEV *LocalOffset = getMulExpr(IndexS, ElementSize);
+
+ // Add the element offset to the running total offset.
+ TotalOffset = getAddExpr(TotalOffset, LocalOffset);
}
}
- return getAddExpr(getSCEV(Base), TotalOffset,
- /*HasNUW=*/false, /*HasNSW=*/InBounds);
+
+ // Get the SCEV for the GEP base.
+ const SCEV *BaseS = getSCEV(Base);
+
+ // Add the total offset from all the GEP indices to the base.
+ return getAddExpr(BaseS, TotalOffset);
}
/// GetMinTrailingZeros - Determine the minimum number of zero bits that S is
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
if (!C->getValue()->isZero())
ConservativeResult =
- ConstantRange(C->getValue()->getValue(), APInt(BitWidth, 0));
+ ConservativeResult.intersectWith(
+ ConstantRange(C->getValue()->getValue(), APInt(BitWidth, 0)));
// TODO: non-affine addrec
if (AddRec->isAffine()) {
else if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return getConstant(CI);
else if (isa<ConstantPointerNull>(V))
- return getIntegerSCEV(0, V->getType());
+ return getConstant(V->getType(), 0);
else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
return GA->mayBeOverridden() ? getUnknown(V) : getSCEV(GA->getAliasee());
else
Operator *U = cast<Operator>(V);
switch (Opcode) {
case Instruction::Add:
- // Don't transfer the NSW and NUW bits from the Add instruction to the
- // Add expression, because the Instruction may be guarded by control
- // flow and the no-overflow bits may not be valid for the expression in
- // any context.
return getAddExpr(getSCEV(U->getOperand(0)),
getSCEV(U->getOperand(1)));
case Instruction::Mul:
- // Don't transfer the NSW and NUW bits from the Mul instruction to the
- // Mul expression, as with Add.
return getMulExpr(getSCEV(U->getOperand(0)),
getSCEV(U->getOperand(1)));
case Instruction::UDiv:
// Turn shift left of a constant amount into a multiply.
if (ConstantInt *SA = dyn_cast<ConstantInt>(U->getOperand(1))) {
uint32_t BitWidth = cast<IntegerType>(U->getType())->getBitWidth();
+
+ // If the shift count is not less than the bitwidth, the result of
+ // the shift is undefined. Don't try to analyze it, because the
+ // resolution chosen here may differ from the resolution chosen in
+ // other parts of the compiler.
+ if (SA->getValue().uge(BitWidth))
+ break;
+
Constant *X = ConstantInt::get(getContext(),
- APInt(BitWidth, 1).shl(SA->getLimitedValue(BitWidth)));
+ APInt(BitWidth, 1).shl(SA->getZExtValue()));
return getMulExpr(getSCEV(U->getOperand(0)), getSCEV(X));
}
break;
// Turn logical shift right of a constant into a unsigned divide.
if (ConstantInt *SA = dyn_cast<ConstantInt>(U->getOperand(1))) {
uint32_t BitWidth = cast<IntegerType>(U->getType())->getBitWidth();
+
+ // If the shift count is not less than the bitwidth, the result of
+ // the shift is undefined. Don't try to analyze it, because the
+ // resolution chosen here may differ from the resolution chosen in
+ // other parts of the compiler.
+ if (SA->getValue().uge(BitWidth))
+ break;
+
Constant *X = ConstantInt::get(getContext(),
- APInt(BitWidth, 1).shl(SA->getLimitedValue(BitWidth)));
+ APInt(BitWidth, 1).shl(SA->getZExtValue()));
return getUDivExpr(getSCEV(U->getOperand(0)), getSCEV(X));
}
break;
case Instruction::AShr:
// For a two-shift sext-inreg, use sext(trunc(x)) as the SCEV expression.
if (ConstantInt *CI = dyn_cast<ConstantInt>(U->getOperand(1)))
- if (Instruction *L = dyn_cast<Instruction>(U->getOperand(0)))
+ if (Operator *L = dyn_cast<Operator>(U->getOperand(0)))
if (L->getOpcode() == Instruction::Shl &&
L->getOperand(1) == U->getOperand(1)) {
- unsigned BitWidth = getTypeSizeInBits(U->getType());
+ uint64_t BitWidth = getTypeSizeInBits(U->getType());
+
+ // If the shift count is not less than the bitwidth, the result of
+ // the shift is undefined. Don't try to analyze it, because the
+ // resolution chosen here may differ from the resolution chosen in
+ // other parts of the compiler.
+ if (CI->getValue().uge(BitWidth))
+ break;
+
uint64_t Amt = BitWidth - CI->getZExtValue();
if (Amt == BitWidth)
return getSCEV(L->getOperand(0)); // shift by zero --> noop
- if (Amt > BitWidth)
- return getIntegerSCEV(0, U->getType()); // value is undefined
return
getSignExtendExpr(getTruncateExpr(getSCEV(L->getOperand(0)),
- IntegerType::get(getContext(), Amt)),
- U->getType());
+ IntegerType::get(getContext(),
+ Amt)),
+ U->getType());
}
break;
// fall through
case ICmpInst::ICMP_SGT:
case ICmpInst::ICMP_SGE:
- if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
- return getSMaxExpr(getSCEV(LHS), getSCEV(RHS));
- else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
- return getSMinExpr(getSCEV(LHS), getSCEV(RHS));
+ // a >s b ? a+x : b+x -> smax(a, b)+x
+ // a >s b ? b+x : a+x -> smin(a, b)+x
+ if (LHS->getType() == U->getType()) {
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *RS = getSCEV(RHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, LS);
+ const SCEV *RDiff = getMinusSCEV(RA, RS);
+ if (LDiff == RDiff)
+ return getAddExpr(getSMaxExpr(LS, RS), LDiff);
+ LDiff = getMinusSCEV(LA, RS);
+ RDiff = getMinusSCEV(RA, LS);
+ if (LDiff == RDiff)
+ return getAddExpr(getSMinExpr(LS, RS), LDiff);
+ }
break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
// fall through
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE:
- if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
- return getUMaxExpr(getSCEV(LHS), getSCEV(RHS));
- else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
- return getUMinExpr(getSCEV(LHS), getSCEV(RHS));
+ // a >u b ? a+x : b+x -> umax(a, b)+x
+ // a >u b ? b+x : a+x -> umin(a, b)+x
+ if (LHS->getType() == U->getType()) {
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *RS = getSCEV(RHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, LS);
+ const SCEV *RDiff = getMinusSCEV(RA, RS);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMaxExpr(LS, RS), LDiff);
+ LDiff = getMinusSCEV(LA, RS);
+ RDiff = getMinusSCEV(RA, LS);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMinExpr(LS, RS), LDiff);
+ }
break;
case ICmpInst::ICMP_NE:
- // n != 0 ? n : 1 -> umax(n, 1)
- if (LHS == U->getOperand(1) &&
- isa<ConstantInt>(U->getOperand(2)) &&
- cast<ConstantInt>(U->getOperand(2))->isOne() &&
+ // n != 0 ? n+x : 1+x -> umax(n, 1)+x
+ if (LHS->getType() == U->getType() &&
isa<ConstantInt>(RHS) &&
- cast<ConstantInt>(RHS)->isZero())
- return getUMaxExpr(getSCEV(LHS), getSCEV(U->getOperand(2)));
+ cast<ConstantInt>(RHS)->isZero()) {
+ const SCEV *One = getConstant(LHS->getType(), 1);
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, LS);
+ const SCEV *RDiff = getMinusSCEV(RA, One);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMaxExpr(LS, One), LDiff);
+ }
break;
case ICmpInst::ICMP_EQ:
- // n == 0 ? 1 : n -> umax(n, 1)
- if (LHS == U->getOperand(2) &&
- isa<ConstantInt>(U->getOperand(1)) &&
- cast<ConstantInt>(U->getOperand(1))->isOne() &&
+ // n == 0 ? 1+x : n+x -> umax(n, 1)+x
+ if (LHS->getType() == U->getType() &&
isa<ConstantInt>(RHS) &&
- cast<ConstantInt>(RHS)->isZero())
- return getUMaxExpr(getSCEV(LHS), getSCEV(U->getOperand(1)));
+ cast<ConstantInt>(RHS)->isZero()) {
+ const SCEV *One = getConstant(LHS->getType(), 1);
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, One);
+ const SCEV *RDiff = getMinusSCEV(RA, LS);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMaxExpr(LS, One), LDiff);
+ }
break;
default:
break;
ConstantEvolutionLoopExitValue.erase(PN);
}
+ // If there's a SCEVUnknown tying this value into the SCEV
+ // space, remove it from the folding set map. The SCEVUnknown
+ // object and any other SCEV objects which reference it
+ // (transitively) remain allocated, effectively leaked until
+ // the underlying BumpPtrAllocator is freed.
+ //
+ // This permits SCEV pointers to be used as keys in maps
+ // such as the ValuesAtScopes map.
+ FoldingSetNodeID ID;
+ ID.AddInteger(scUnknown);
+ ID.AddPointer(I);
+ void *IP;
+ if (SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) {
+ UniqueSCEVs.RemoveNode(S);
+
+ // This isn't necessary, but we might as well remove the
+ // value from the ValuesAtScopes map too.
+ ValuesAtScopes.erase(S);
+ }
+
PushDefUseChildren(I, Worklist);
}
}
return getCouldNotCompute();
else
// The backedge is never taken.
- return getIntegerSCEV(0, CI->getType());
+ return getConstant(CI->getType(), 0);
}
// If it's not an integer or pointer comparison then compute it the hard way.
Cond = ICmpInst::getSwappedPredicate(Cond);
}
+ // Simplify the operands before analyzing them.
+ (void)SimplifyICmpOperands(Cond, LHS, RHS);
+
// If we have a comparison of a chrec against a constant, try to use value
// ranges to answer this query.
if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS))
// constant or derived from a PHI node themselves.
PHINode *PHI = 0;
for (unsigned Op = 0, e = I->getNumOperands(); Op != e; ++Op)
- if (!(isa<Constant>(I->getOperand(Op)) ||
- isa<GlobalValue>(I->getOperand(Op)))) {
+ if (!isa<Constant>(I->getOperand(Op))) {
PHINode *P = getConstantEvolvingPHI(I->getOperand(Op), L);
if (P == 0) return 0; // Not evolving from PHI
if (PHI == 0)
const TargetData *TD) {
if (isa<PHINode>(V)) return PHIVal;
if (Constant *C = dyn_cast<Constant>(V)) return C;
- if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) return GV;
Instruction *I = cast<Instruction>(V);
- std::vector<Constant*> Operands;
- Operands.resize(I->getNumOperands());
+ std::vector<Constant*> Operands(I->getNumOperands());
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
Operands[i] = EvaluateExpression(I->getOperand(i), PHIVal, TD);
return RetVal = 0; // Must be a constant.
Value *BEValue = PN->getIncomingValue(SecondIsBackedge);
- PHINode *PN2 = getConstantEvolvingPHI(BEValue, L);
- if (PN2 != PN)
+ if (getConstantEvolvingPHI(BEValue, L) != PN &&
+ !isa<Constant>(BEValue))
return RetVal = 0; // Not derived from same PHI.
// Execute the loop symbolically to determine the exit value.
PHINode *PN = getConstantEvolvingPHI(Cond, L);
if (PN == 0) return getCouldNotCompute();
- // Since the loop is canonicalized, the PHI node must have two entries. One
- // entry must be a constant (coming in from outside of the loop), and the
+ // If the loop is canonicalized, the PHI will have exactly two entries.
+ // That's the only form we support here.
+ if (PN->getNumIncomingValues() != 2) return getCouldNotCompute();
+
+ // One entry must be a constant (coming in from outside of the loop), and the
// second must be derived from the same PHI.
bool SecondIsBackedge = L->contains(PN->getIncomingBlock(1));
Constant *StartCST =
if (StartCST == 0) return getCouldNotCompute(); // Must be a constant.
Value *BEValue = PN->getIncomingValue(SecondIsBackedge);
- PHINode *PN2 = getConstantEvolvingPHI(BEValue, L);
- if (PN2 != PN) return getCouldNotCompute(); // Not derived from same PHI.
+ if (getConstantEvolvingPHI(BEValue, L) != PN &&
+ !isa<Constant>(BEValue))
+ return getCouldNotCompute(); // Not derived from same PHI.
// Okay, we find a PHI node that defines the trip count of this loop. Execute
// the loop symbolically to determine when the condition gets a value of
// the arguments into constants, and if so, try to constant propagate the
// result. This is particularly useful for computing loop exit values.
if (CanConstantFold(I)) {
- std::vector<Constant*> Operands;
- Operands.reserve(I->getNumOperands());
+ SmallVector<Constant *, 4> Operands;
+ bool MadeImprovement = false;
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
Value *Op = I->getOperand(i);
if (Constant *C = dyn_cast<Constant>(Op)) {
Operands.push_back(C);
- } else {
- // If any of the operands is non-constant and if they are
- // non-integer and non-pointer, don't even try to analyze them
- // with scev techniques.
- if (!isSCEVable(Op->getType()))
- return V;
-
- const SCEV *OpV = getSCEVAtScope(Op, L);
- if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(OpV)) {
- Constant *C = SC->getValue();
- if (C->getType() != Op->getType())
- C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
- Op->getType(),
- false),
- C, Op->getType());
- Operands.push_back(C);
- } else if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(OpV)) {
- if (Constant *C = dyn_cast<Constant>(SU->getValue())) {
- if (C->getType() != Op->getType())
- C =
- ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
- Op->getType(),
- false),
- C, Op->getType());
- Operands.push_back(C);
- } else
- return V;
- } else {
- return V;
- }
+ continue;
}
+
+ // If any of the operands is non-constant and if they are
+ // non-integer and non-pointer, don't even try to analyze them
+ // with scev techniques.
+ if (!isSCEVable(Op->getType()))
+ return V;
+
+ const SCEV *OrigV = getSCEV(Op);
+ const SCEV *OpV = getSCEVAtScope(OrigV, L);
+ MadeImprovement |= OrigV != OpV;
+
+ Constant *C = 0;
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(OpV))
+ C = SC->getValue();
+ if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(OpV))
+ C = dyn_cast<Constant>(SU->getValue());
+ if (!C) return V;
+ if (C->getType() != Op->getType())
+ C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
+ Op->getType(),
+ false),
+ C, Op->getType());
+ Operands.push_back(C);
}
- Constant *C = 0;
- if (const CmpInst *CI = dyn_cast<CmpInst>(I))
- C = ConstantFoldCompareInstOperands(CI->getPredicate(),
- Operands[0], Operands[1], TD);
- else
- C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- &Operands[0], Operands.size(), TD);
- if (C)
+ // Check to see if getSCEVAtScope actually made an improvement.
+ if (MadeImprovement) {
+ Constant *C = 0;
+ if (const CmpInst *CI = dyn_cast<CmpInst>(I))
+ C = ConstantFoldCompareInstOperands(CI->getPredicate(),
+ Operands[0], Operands[1], TD);
+ else
+ C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
+ &Operands[0], Operands.size(), TD);
+ if (!C) return V;
return getSCEV(C);
+ }
}
}
// If this is a loop recurrence for a loop that does not contain L, then we
// are dealing with the final value computed by the loop.
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
- if (!L || !AddRec->getLoop()->contains(L)) {
+ // First, attempt to evaluate each operand.
+ // Avoid performing the look-up in the common case where the specified
+ // expression has no loop-variant portions.
+ for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
+ const SCEV *OpAtScope = getSCEVAtScope(AddRec->getOperand(i), L);
+ if (OpAtScope == AddRec->getOperand(i))
+ continue;
+
+ // Okay, at least one of these operands is loop variant but might be
+ // foldable. Build a new instance of the folded commutative expression.
+ SmallVector<const SCEV *, 8> NewOps(AddRec->op_begin(),
+ AddRec->op_begin()+i);
+ NewOps.push_back(OpAtScope);
+ for (++i; i != e; ++i)
+ NewOps.push_back(getSCEVAtScope(AddRec->getOperand(i), L));
+
+ AddRec = cast<SCEVAddRecExpr>(getAddRecExpr(NewOps, AddRec->getLoop()));
+ break;
+ }
+
+ // If the scope is outside the addrec's loop, evaluate it by using the
+ // loop exit value of the addrec.
+ if (!AddRec->getLoop()->contains(L)) {
// To evaluate this recurrence, we need to know how many times the AddRec
// loop iterates. Compute this now.
const SCEV *BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop());
// Then, evaluate the AddRec.
return AddRec->evaluateAtIteration(BackedgeTakenCount, *this);
}
+
return AddRec;
}
// already. If so, the backedge will execute zero times.
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
if (!C->getValue()->isNullValue())
- return getIntegerSCEV(0, C->getType());
+ return getConstant(C->getType(), 0);
return getCouldNotCompute(); // Otherwise it will loop infinitely.
}
return getCouldNotCompute();
}
-/// getLoopPredecessor - If the given loop's header has exactly one unique
-/// predecessor outside the loop, return it. Otherwise return null.
-///
-BasicBlock *ScalarEvolution::getLoopPredecessor(const Loop *L) {
- BasicBlock *Header = L->getHeader();
- BasicBlock *Pred = 0;
- for (pred_iterator PI = pred_begin(Header), E = pred_end(Header);
- PI != E; ++PI)
- if (!L->contains(*PI)) {
- if (Pred && Pred != *PI) return 0; // Multiple predecessors.
- Pred = *PI;
- }
- return Pred;
-}
-
/// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
/// (which may not be an immediate predecessor) which has exactly one
/// successor from which BB is reachable, or null if no such block is
/// found.
///
-BasicBlock *
+std::pair<BasicBlock *, BasicBlock *>
ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) {
// If the block has a unique predecessor, then there is no path from the
// predecessor to the block that does not go through the direct edge
// from the predecessor to the block.
if (BasicBlock *Pred = BB->getSinglePredecessor())
- return Pred;
+ return std::make_pair(Pred, BB);
// A loop's header is defined to be a block that dominates the loop.
// If the header has a unique predecessor outside the loop, it must be
// a block that has exactly one successor that can reach the loop.
if (Loop *L = LI->getLoopFor(BB))
- return getLoopPredecessor(L);
+ return std::make_pair(L->getLoopPredecessor(), L->getHeader());
- return 0;
+ return std::pair<BasicBlock *, BasicBlock *>();
}
/// HasSameValue - SCEV structural equivalence is usually sufficient for
return false;
}
+/// SimplifyICmpOperands - Simplify LHS and RHS in a comparison with
+/// predicate Pred. Return true iff any changes were made.
+///
+bool ScalarEvolution::SimplifyICmpOperands(ICmpInst::Predicate &Pred,
+ const SCEV *&LHS, const SCEV *&RHS) {
+ bool Changed = false;
+
+ // Canonicalize a constant to the right side.
+ if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
+ // Check for both operands constant.
+ if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
+ if (ConstantExpr::getICmp(Pred,
+ LHSC->getValue(),
+ RHSC->getValue())->isNullValue())
+ goto trivially_false;
+ else
+ goto trivially_true;
+ }
+ // Otherwise swap the operands to put the constant on the right.
+ std::swap(LHS, RHS);
+ Pred = ICmpInst::getSwappedPredicate(Pred);
+ Changed = true;
+ }
+
+ // If we're comparing an addrec with a value which is loop-invariant in the
+ // addrec's loop, put the addrec on the left. Also make a dominance check,
+ // as both operands could be addrecs loop-invariant in each other's loop.
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS)) {
+ const Loop *L = AR->getLoop();
+ if (LHS->isLoopInvariant(L) && LHS->properlyDominates(L->getHeader(), DT)) {
+ std::swap(LHS, RHS);
+ Pred = ICmpInst::getSwappedPredicate(Pred);
+ Changed = true;
+ }
+ }
+
+ // If there's a constant operand, canonicalize comparisons with boundary
+ // cases, and canonicalize *-or-equal comparisons to regular comparisons.
+ if (const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS)) {
+ const APInt &RA = RC->getValue()->getValue();
+ switch (Pred) {
+ default: llvm_unreachable("Unexpected ICmpInst::Predicate value!");
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_NE:
+ break;
+ case ICmpInst::ICMP_UGE:
+ if ((RA - 1).isMinValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA - 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMaxValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ Changed = true;
+ break;
+ }
+ if (RA.isMinValue()) goto trivially_true;
+
+ Pred = ICmpInst::ICMP_UGT;
+ RHS = getConstant(RA - 1);
+ Changed = true;
+ break;
+ case ICmpInst::ICMP_ULE:
+ if ((RA + 1).isMaxValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA + 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMinValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ Changed = true;
+ break;
+ }
+ if (RA.isMaxValue()) goto trivially_true;
+
+ Pred = ICmpInst::ICMP_ULT;
+ RHS = getConstant(RA + 1);
+ Changed = true;
+ break;
+ case ICmpInst::ICMP_SGE:
+ if ((RA - 1).isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA - 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ Changed = true;
+ break;
+ }
+ if (RA.isMinSignedValue()) goto trivially_true;
+
+ Pred = ICmpInst::ICMP_SGT;
+ RHS = getConstant(RA - 1);
+ Changed = true;
+ break;
+ case ICmpInst::ICMP_SLE:
+ if ((RA + 1).isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ RHS = getConstant(RA + 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ Changed = true;
+ break;
+ }
+ if (RA.isMaxSignedValue()) goto trivially_true;
+
+ Pred = ICmpInst::ICMP_SLT;
+ RHS = getConstant(RA + 1);
+ Changed = true;
+ break;
+ case ICmpInst::ICMP_UGT:
+ if (RA.isMinValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ Changed = true;
+ break;
+ }
+ if ((RA + 1).isMaxValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA + 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMaxValue()) goto trivially_false;
+ break;
+ case ICmpInst::ICMP_ULT:
+ if (RA.isMaxValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ Changed = true;
+ break;
+ }
+ if ((RA - 1).isMinValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA - 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMinValue()) goto trivially_false;
+ break;
+ case ICmpInst::ICMP_SGT:
+ if (RA.isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ Changed = true;
+ break;
+ }
+ if ((RA + 1).isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA + 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMaxSignedValue()) goto trivially_false;
+ break;
+ case ICmpInst::ICMP_SLT:
+ if (RA.isMaxSignedValue()) {
+ Pred = ICmpInst::ICMP_NE;
+ Changed = true;
+ break;
+ }
+ if ((RA - 1).isMinSignedValue()) {
+ Pred = ICmpInst::ICMP_EQ;
+ RHS = getConstant(RA - 1);
+ Changed = true;
+ break;
+ }
+ if (RA.isMinSignedValue()) goto trivially_false;
+ break;
+ }
+ }
+
+ // Check for obvious equality.
+ if (HasSameValue(LHS, RHS)) {
+ if (ICmpInst::isTrueWhenEqual(Pred))
+ goto trivially_true;
+ if (ICmpInst::isFalseWhenEqual(Pred))
+ goto trivially_false;
+ }
+
+ // If possible, canonicalize GE/LE comparisons to GT/LT comparisons, by
+ // adding or subtracting 1 from one of the operands.
+ switch (Pred) {
+ case ICmpInst::ICMP_SLE:
+ if (!getSignedRange(RHS).getSignedMax().isMaxSignedValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Pred = ICmpInst::ICMP_SLT;
+ Changed = true;
+ } else if (!getSignedRange(LHS).getSignedMin().isMinSignedValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Pred = ICmpInst::ICMP_SLT;
+ Changed = true;
+ }
+ break;
+ case ICmpInst::ICMP_SGE:
+ if (!getSignedRange(RHS).getSignedMin().isMinSignedValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Pred = ICmpInst::ICMP_SGT;
+ Changed = true;
+ } else if (!getSignedRange(LHS).getSignedMax().isMaxSignedValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Pred = ICmpInst::ICMP_SGT;
+ Changed = true;
+ }
+ break;
+ case ICmpInst::ICMP_ULE:
+ if (!getUnsignedRange(RHS).getUnsignedMax().isMaxValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Pred = ICmpInst::ICMP_ULT;
+ Changed = true;
+ } else if (!getUnsignedRange(LHS).getUnsignedMin().isMinValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Pred = ICmpInst::ICMP_ULT;
+ Changed = true;
+ }
+ break;
+ case ICmpInst::ICMP_UGE:
+ if (!getUnsignedRange(RHS).getUnsignedMin().isMinValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Pred = ICmpInst::ICMP_UGT;
+ Changed = true;
+ } else if (!getUnsignedRange(LHS).getUnsignedMax().isMaxValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Pred = ICmpInst::ICMP_UGT;
+ Changed = true;
+ }
+ break;
+ default:
+ break;
+ }
+
+ // TODO: More simplifications are possible here.
+
+ return Changed;
+
+trivially_true:
+ // Return 0 == 0.
+ LHS = RHS = getConstant(Type::getInt1Ty(getContext()), 0);
+ Pred = ICmpInst::ICMP_EQ;
+ return true;
+
+trivially_false:
+ // Return 0 != 0.
+ LHS = RHS = getConstant(Type::getInt1Ty(getContext()), 0);
+ Pred = ICmpInst::ICMP_NE;
+ return true;
+}
+
bool ScalarEvolution::isKnownNegative(const SCEV *S) {
return getSignedRange(S).getSignedMax().isNegative();
}
bool ScalarEvolution::isKnownPredicate(ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS) {
+ // Canonicalize the inputs first.
+ (void)SimplifyICmpOperands(Pred, LHS, RHS);
+
// If LHS or RHS is an addrec, check to see if the condition is true in
// every iteration of the loop.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS))
if (isLoopEntryGuardedByCond(
AR->getLoop(), Pred, AR->getStart(), RHS) &&
isLoopBackedgeGuardedByCond(
- AR->getLoop(), Pred,
- getAddExpr(AR, AR->getStepRecurrence(*this)), RHS))
+ AR->getLoop(), Pred, AR->getPostIncExpr(*this), RHS))
return true;
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS))
if (isLoopEntryGuardedByCond(
AR->getLoop(), Pred, LHS, AR->getStart()) &&
isLoopBackedgeGuardedByCond(
- AR->getLoop(), Pred,
- LHS, getAddExpr(AR, AR->getStepRecurrence(*this))))
+ AR->getLoop(), Pred, LHS, AR->getPostIncExpr(*this)))
return true;
// Otherwise see what can be done with known constant ranges.
// (interprocedural conditions notwithstanding).
if (!L) return false;
- BasicBlock *Predecessor = getLoopPredecessor(L);
- BasicBlock *PredecessorDest = L->getHeader();
-
// Starting at the loop predecessor, climb up the predecessor chain, as long
// as there are predecessors that can be found that have unique successors
// leading to the original header.
- for (; Predecessor;
- PredecessorDest = Predecessor,
- Predecessor = getPredecessorWithUniqueSuccessorForBB(Predecessor)) {
+ for (std::pair<BasicBlock *, BasicBlock *>
+ Pair(L->getLoopPredecessor(), L->getHeader());
+ Pair.first;
+ Pair = getPredecessorWithUniqueSuccessorForBB(Pair.first)) {
BranchInst *LoopEntryPredicate =
- dyn_cast<BranchInst>(Predecessor->getTerminator());
+ dyn_cast<BranchInst>(Pair.first->getTerminator());
if (!LoopEntryPredicate ||
LoopEntryPredicate->isUnconditional())
continue;
if (isImpliedCond(LoopEntryPredicate->getCondition(), Pred, LHS, RHS,
- LoopEntryPredicate->getSuccessor(0) != PredecessorDest))
+ LoopEntryPredicate->getSuccessor(0) != Pair.second))
return true;
}
// Canonicalize the query to match the way instcombine will have
// canonicalized the comparison.
- // First, put a constant operand on the right.
- if (isa<SCEVConstant>(LHS)) {
- std::swap(LHS, RHS);
- Pred = ICmpInst::getSwappedPredicate(Pred);
- }
- // Then, canonicalize comparisons with boundary cases.
- if (const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS)) {
- const APInt &RA = RC->getValue()->getValue();
- switch (Pred) {
- default: llvm_unreachable("Unexpected ICmpInst::Predicate value!");
- case ICmpInst::ICMP_EQ:
- case ICmpInst::ICMP_NE:
- break;
- case ICmpInst::ICMP_UGE:
- if ((RA - 1).isMinValue()) {
- Pred = ICmpInst::ICMP_NE;
- RHS = getConstant(RA - 1);
- break;
- }
- if (RA.isMaxValue()) {
- Pred = ICmpInst::ICMP_EQ;
- break;
- }
- if (RA.isMinValue()) return true;
- break;
- case ICmpInst::ICMP_ULE:
- if ((RA + 1).isMaxValue()) {
- Pred = ICmpInst::ICMP_NE;
- RHS = getConstant(RA + 1);
- break;
- }
- if (RA.isMinValue()) {
- Pred = ICmpInst::ICMP_EQ;
- break;
- }
- if (RA.isMaxValue()) return true;
- break;
- case ICmpInst::ICMP_SGE:
- if ((RA - 1).isMinSignedValue()) {
- Pred = ICmpInst::ICMP_NE;
- RHS = getConstant(RA - 1);
- break;
- }
- if (RA.isMaxSignedValue()) {
- Pred = ICmpInst::ICMP_EQ;
- break;
- }
- if (RA.isMinSignedValue()) return true;
- break;
- case ICmpInst::ICMP_SLE:
- if ((RA + 1).isMaxSignedValue()) {
- Pred = ICmpInst::ICMP_NE;
- RHS = getConstant(RA + 1);
- break;
- }
- if (RA.isMinSignedValue()) {
- Pred = ICmpInst::ICMP_EQ;
- break;
- }
- if (RA.isMaxSignedValue()) return true;
- break;
- case ICmpInst::ICMP_UGT:
- if (RA.isMinValue()) {
- Pred = ICmpInst::ICMP_NE;
- break;
- }
- if ((RA + 1).isMaxValue()) {
- Pred = ICmpInst::ICMP_EQ;
- RHS = getConstant(RA + 1);
- break;
- }
- if (RA.isMaxValue()) return false;
- break;
- case ICmpInst::ICMP_ULT:
- if (RA.isMaxValue()) {
- Pred = ICmpInst::ICMP_NE;
- break;
- }
- if ((RA - 1).isMinValue()) {
- Pred = ICmpInst::ICMP_EQ;
- RHS = getConstant(RA - 1);
- break;
- }
- if (RA.isMinValue()) return false;
- break;
- case ICmpInst::ICMP_SGT:
- if (RA.isMinSignedValue()) {
- Pred = ICmpInst::ICMP_NE;
- break;
- }
- if ((RA + 1).isMaxSignedValue()) {
- Pred = ICmpInst::ICMP_EQ;
- RHS = getConstant(RA + 1);
- break;
- }
- if (RA.isMaxSignedValue()) return false;
- break;
- case ICmpInst::ICMP_SLT:
- if (RA.isMaxSignedValue()) {
- Pred = ICmpInst::ICMP_NE;
- break;
- }
- if ((RA - 1).isMinSignedValue()) {
- Pred = ICmpInst::ICMP_EQ;
- RHS = getConstant(RA - 1);
- break;
- }
- if (RA.isMinSignedValue()) return false;
- break;
- }
- }
+ if (SimplifyICmpOperands(Pred, LHS, RHS))
+ if (LHS == RHS)
+ return CmpInst::isTrueWhenEqual(Pred);
+ if (SimplifyICmpOperands(FoundPred, FoundLHS, FoundRHS))
+ if (FoundLHS == FoundRHS)
+ return CmpInst::isFalseWhenEqual(Pred);
// Check to see if we can make the LHS or RHS match.
if (LHS == FoundRHS || RHS == FoundLHS) {
"This code doesn't handle negative strides yet!");
const Type *Ty = Start->getType();
- const SCEV *NegOne = getIntegerSCEV(-1, Ty);
+ const SCEV *NegOne = getConstant(Ty, (uint64_t)-1);
const SCEV *Diff = getMinusSCEV(End, Start);
const SCEV *RoundUp = getAddExpr(Step, NegOne);
// behavior, so if wrap does occur, the loop could either terminate or
// loop infinitely, but in either case, the loop is guaranteed to
// iterate at least until the iteration where the wrapping occurs.
- const SCEV *One = getIntegerSCEV(1, Step->getType());
+ const SCEV *One = getConstant(Step->getType(), 1);
if (isSigned) {
APInt Max = APInt::getSignedMaxValue(BitWidth);
if ((Max - getSignedRange(getMinusSCEV(Step, One)).getSignedMax())
// This allows the subsequent ceiling division of (N+(step-1))/step to
// compute the correct value.
const SCEV *StepMinusOne = getMinusSCEV(Step,
- getIntegerSCEV(1, Step->getType()));
+ getConstant(Step->getType(), 1));
MaxEnd = isSigned ?
getSMinExpr(MaxEnd,
getMinusSCEV(getConstant(APInt::getSignedMaxValue(BitWidth)),
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart()))
if (!SC->getValue()->isZero()) {
SmallVector<const SCEV *, 4> Operands(op_begin(), op_end());
- Operands[0] = SE.getIntegerSCEV(0, SC->getType());
+ Operands[0] = SE.getConstant(SC->getType(), 0);
const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop());
if (const SCEVAddRecExpr *ShiftedAddRec =
dyn_cast<SCEVAddRecExpr>(Shifted))
// iteration exits.
unsigned BitWidth = SE.getTypeSizeInBits(getType());
if (!Range.contains(APInt(BitWidth, 0)))
- return SE.getIntegerSCEV(0, getType());
+ return SE.getConstant(getType(), 0);
if (isAffine()) {
// If this is an affine expression then we have this situation:
WriteAsOperand(OS, F, /*PrintType=*/false);
OS << "\n";
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
- if (isSCEVable(I->getType())) {
+ if (isSCEVable(I->getType()) && !isa<CmpInst>(*I)) {
OS << *I << '\n';
OS << " --> ";
const SCEV *SV = SE.getSCEV(&*I);
projects / oota-llvm.git / blobdiff