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[NFC][LSR] Cleanup Cost API
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Create members for Loop, ScalarEvolution, DominatorTree,
TargetTransformInfo and Formula.

Differential Revision: https://reviews.llvm.org/D58389

llvm-svn: 356131
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@sparker-arm
sparker-arm committed Mar 14, 2019
1 parent 3b2ba20 commit eb0b801
Showing 1 changed file with 54 additions and 63 deletions.
117 changes: 54 additions & 63 deletions llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
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Expand Up @@ -1015,10 +1015,17 @@ namespace {

/// This class is used to measure and compare candidate formulae.
class Cost {
const Loop *L = nullptr;
ScalarEvolution *SE = nullptr;
DominatorTree *DT = nullptr;
const TargetTransformInfo *TTI = nullptr;
TargetTransformInfo::LSRCost C;

public:
Cost() {
Cost() = delete;
Cost(const Loop *L, ScalarEvolution &SE, DominatorTree &DT,
const TargetTransformInfo &TTI) :
L(L), SE(&SE), DT(&DT), TTI(&TTI) {
C.Insns = 0;
C.NumRegs = 0;
C.AddRecCost = 0;
Expand All @@ -1029,7 +1036,7 @@ class Cost {
C.ScaleCost = 0;
}

bool isLess(Cost &Other, const TargetTransformInfo &TTI);
bool isLess(Cost &Other);

void Lose();

Expand All @@ -1048,12 +1055,9 @@ class Cost {
return C.NumRegs == ~0u;
}

void RateFormula(const TargetTransformInfo &TTI,
const Formula &F,
void RateFormula(const Formula &F,
SmallPtrSetImpl<const SCEV *> &Regs,
const DenseSet<const SCEV *> &VisitedRegs,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT,
const LSRUse &LU,
SmallPtrSetImpl<const SCEV *> *LoserRegs = nullptr);

Expand All @@ -1062,16 +1066,10 @@ class Cost {

private:
void RateRegister(const Formula &F, const SCEV *Reg,
SmallPtrSetImpl<const SCEV *> &Regs,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT,
const TargetTransformInfo &TTI);
SmallPtrSetImpl<const SCEV *> &Regs);
void RatePrimaryRegister(const Formula &F, const SCEV *Reg,
SmallPtrSetImpl<const SCEV *> &Regs,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT,
SmallPtrSetImpl<const SCEV *> *LoserRegs,
const TargetTransformInfo &TTI);
SmallPtrSetImpl<const SCEV *> *LoserRegs);
};

/// An operand value in an instruction which is to be replaced with some
Expand Down Expand Up @@ -1237,17 +1235,14 @@ static unsigned getSetupCost(const SCEV *Reg) {

/// Tally up interesting quantities from the given register.
void Cost::RateRegister(const Formula &F, const SCEV *Reg,
SmallPtrSetImpl<const SCEV *> &Regs,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT,
const TargetTransformInfo &TTI) {
SmallPtrSetImpl<const SCEV *> &Regs) {
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Reg)) {
// If this is an addrec for another loop, it should be an invariant
// with respect to L since L is the innermost loop (at least
// for now LSR only handles innermost loops).
if (AR->getLoop() != L) {
// If the AddRec exists, consider it's register free and leave it alone.
if (isExistingPhi(AR, SE))
if (isExistingPhi(AR, *SE))
return;

// It is bad to allow LSR for current loop to add induction variables
Expand All @@ -1263,23 +1258,23 @@ void Cost::RateRegister(const Formula &F, const SCEV *Reg,
}

unsigned LoopCost = 1;
if (TTI.isIndexedLoadLegal(TTI.MIM_PostInc, AR->getType()) ||
TTI.isIndexedStoreLegal(TTI.MIM_PostInc, AR->getType())) {
if (TTI->isIndexedLoadLegal(TTI->MIM_PostInc, AR->getType()) ||
TTI->isIndexedStoreLegal(TTI->MIM_PostInc, AR->getType())) {

// If the step size matches the base offset, we could use pre-indexed
// addressing.
if (TTI.shouldFavorBackedgeIndex(L)) {
if (auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)))
if (TTI->shouldFavorBackedgeIndex(L)) {
if (auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(*SE)))
if (Step->getAPInt() == F.BaseOffset)
LoopCost = 0;
}

if (TTI.shouldFavorPostInc()) {
const SCEV *LoopStep = AR->getStepRecurrence(SE);
if (TTI->shouldFavorPostInc()) {
const SCEV *LoopStep = AR->getStepRecurrence(*SE);
if (isa<SCEVConstant>(LoopStep)) {
const SCEV *LoopStart = AR->getStart();
if (!isa<SCEVConstant>(LoopStart) &&
SE.isLoopInvariant(LoopStart, L))
SE->isLoopInvariant(LoopStart, L))
LoopCost = 0;
}
}
Expand All @@ -1290,7 +1285,7 @@ void Cost::RateRegister(const Formula &F, const SCEV *Reg,
// TODO: The non-affine case isn't precisely modeled here.
if (!AR->isAffine() || !isa<SCEVConstant>(AR->getOperand(1))) {
if (!Regs.count(AR->getOperand(1))) {
RateRegister(F, AR->getOperand(1), Regs, L, SE, DT, TTI);
RateRegister(F, AR->getOperand(1), Regs);
if (isLoser())
return;
}
Expand All @@ -1303,35 +1298,29 @@ void Cost::RateRegister(const Formula &F, const SCEV *Reg,
C.SetupCost += getSetupCost(Reg);

C.NumIVMuls += isa<SCEVMulExpr>(Reg) &&
SE.hasComputableLoopEvolution(Reg, L);
SE->hasComputableLoopEvolution(Reg, L);
}

/// Record this register in the set. If we haven't seen it before, rate
/// it. Optional LoserRegs provides a way to declare any formula that refers to
/// one of those regs an instant loser.
void Cost::RatePrimaryRegister(const Formula &F, const SCEV *Reg,
SmallPtrSetImpl<const SCEV *> &Regs,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT,
SmallPtrSetImpl<const SCEV *> *LoserRegs,
const TargetTransformInfo &TTI) {
SmallPtrSetImpl<const SCEV *> *LoserRegs) {
if (LoserRegs && LoserRegs->count(Reg)) {
Lose();
return;
}
if (Regs.insert(Reg).second) {
RateRegister(F, Reg, Regs, L, SE, DT, TTI);
RateRegister(F, Reg, Regs);
if (LoserRegs && isLoser())
LoserRegs->insert(Reg);
}
}

void Cost::RateFormula(const TargetTransformInfo &TTI,
const Formula &F,
void Cost::RateFormula(const Formula &F,
SmallPtrSetImpl<const SCEV *> &Regs,
const DenseSet<const SCEV *> &VisitedRegs,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT,
const LSRUse &LU,
SmallPtrSetImpl<const SCEV *> *LoserRegs) {
assert(F.isCanonical(*L) && "Cost is accurate only for canonical formula");
Expand All @@ -1344,7 +1333,7 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,
Lose();
return;
}
RatePrimaryRegister(F, ScaledReg, Regs, L, SE, DT, LoserRegs, TTI);
RatePrimaryRegister(F, ScaledReg, Regs, LoserRegs);
if (isLoser())
return;
}
Expand All @@ -1353,7 +1342,7 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,
Lose();
return;
}
RatePrimaryRegister(F, BaseReg, Regs, L, SE, DT, LoserRegs, TTI);
RatePrimaryRegister(F, BaseReg, Regs, LoserRegs);
if (isLoser())
return;
}
Expand All @@ -1364,11 +1353,11 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,
// Do not count the base and a possible second register if the target
// allows to fold 2 registers.
C.NumBaseAdds +=
NumBaseParts - (1 + (F.Scale && isAMCompletelyFolded(TTI, LU, F)));
NumBaseParts - (1 + (F.Scale && isAMCompletelyFolded(*TTI, LU, F)));
C.NumBaseAdds += (F.UnfoldedOffset != 0);

// Accumulate non-free scaling amounts.
C.ScaleCost += getScalingFactorCost(TTI, LU, F, *L);
C.ScaleCost += getScalingFactorCost(*TTI, LU, F, *L);

// Tally up the non-zero immediates.
for (const LSRFixup &Fixup : LU.Fixups) {
Expand All @@ -1383,7 +1372,7 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,
// Check with target if this offset with this instruction is
// specifically not supported.
if (LU.Kind == LSRUse::Address && Offset != 0 &&
!isAMCompletelyFolded(TTI, LSRUse::Address, LU.AccessTy, F.BaseGV,
!isAMCompletelyFolded(*TTI, LSRUse::Address, LU.AccessTy, F.BaseGV,
Offset, F.HasBaseReg, F.Scale, Fixup.UserInst))
C.NumBaseAdds++;
}
Expand All @@ -1396,7 +1385,7 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,

// Treat every new register that exceeds TTI.getNumberOfRegisters() - 1 as
// additional instruction (at least fill).
unsigned TTIRegNum = TTI.getNumberOfRegisters(false) - 1;
unsigned TTIRegNum = TTI->getNumberOfRegisters(false) - 1;
if (C.NumRegs > TTIRegNum) {
// Cost already exceeded TTIRegNum, then only newly added register can add
// new instructions.
Expand All @@ -1416,7 +1405,8 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,
//
// For {-10, +, 1}:
// i = i + 1;
if (LU.Kind == LSRUse::ICmpZero && !F.hasZeroEnd() && !TTI.canMacroFuseCmp())
if (LU.Kind == LSRUse::ICmpZero && !F.hasZeroEnd() &&
!TTI->canMacroFuseCmp())
C.Insns++;
// Each new AddRec adds 1 instruction to calculation.
C.Insns += (C.AddRecCost - PrevAddRecCost);
Expand All @@ -1440,11 +1430,11 @@ void Cost::Lose() {
}

/// Choose the lower cost.
bool Cost::isLess(Cost &Other, const TargetTransformInfo &TTI) {
bool Cost::isLess(Cost &Other) {
if (InsnsCost.getNumOccurrences() > 0 && InsnsCost &&
C.Insns != Other.C.Insns)
return C.Insns < Other.C.Insns;
return TTI.isLSRCostLess(C, Other.C);
return TTI->isLSRCostLess(C, Other.C);
}

#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
Expand Down Expand Up @@ -4327,9 +4317,9 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
// avoids the need to recompute this information across formulae using the
// same bad AddRec. Passing LoserRegs is also essential unless we remove
// the corresponding bad register from the Regs set.
Cost CostF;
Cost CostF(L, SE, DT, TTI);
Regs.clear();
CostF.RateFormula(TTI, F, Regs, VisitedRegs, L, SE, DT, LU, &LoserRegs);
CostF.RateFormula(F, Regs, VisitedRegs, LU, &LoserRegs);
if (CostF.isLoser()) {
// During initial formula generation, undesirable formulae are generated
// by uses within other loops that have some non-trivial address mode or
Expand Down Expand Up @@ -4360,10 +4350,10 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {

Formula &Best = LU.Formulae[P.first->second];

Cost CostBest;
Cost CostBest(L, SE, DT, TTI);
Regs.clear();
CostBest.RateFormula(TTI, Best, Regs, VisitedRegs, L, SE, DT, LU);
if (CostF.isLess(CostBest, TTI))
CostBest.RateFormula(Best, Regs, VisitedRegs, LU);
if (CostF.isLess(CostBest))
std::swap(F, Best);
LLVM_DEBUG(dbgs() << " Filtering out formula "; F.print(dbgs());
dbgs() << "\n"
Expand Down Expand Up @@ -4611,12 +4601,13 @@ void LSRInstance::NarrowSearchSpaceByFilterFormulaWithSameScaledReg() {

// If the new register numbers are the same, choose the Formula with
// less Cost.
Cost CostFA, CostFB;
Cost CostFA(L, SE, DT, TTI);
Cost CostFB(L, SE, DT, TTI);
Regs.clear();
CostFA.RateFormula(TTI, FA, Regs, VisitedRegs, L, SE, DT, LU);
CostFA.RateFormula(FA, Regs, VisitedRegs, LU);
Regs.clear();
CostFB.RateFormula(TTI, FB, Regs, VisitedRegs, L, SE, DT, LU);
return CostFA.isLess(CostFB, TTI);
CostFB.RateFormula(FB, Regs, VisitedRegs, LU);
return CostFA.isLess(CostFB);
};

bool Any = false;
Expand Down Expand Up @@ -4902,7 +4893,7 @@ void LSRInstance::SolveRecurse(SmallVectorImpl<const Formula *> &Solution,
ReqRegs.insert(S);

SmallPtrSet<const SCEV *, 16> NewRegs;
Cost NewCost;
Cost NewCost(L, SE, DT, TTI);
for (const Formula &F : LU.Formulae) {
// Ignore formulae which may not be ideal in terms of register reuse of
// ReqRegs. The formula should use all required registers before
Expand All @@ -4926,8 +4917,8 @@ void LSRInstance::SolveRecurse(SmallVectorImpl<const Formula *> &Solution,
// the current best, prune the search at that point.
NewCost = CurCost;
NewRegs = CurRegs;
NewCost.RateFormula(TTI, F, NewRegs, VisitedRegs, L, SE, DT, LU);
if (NewCost.isLess(SolutionCost, TTI)) {
NewCost.RateFormula(F, NewRegs, VisitedRegs, LU);
if (NewCost.isLess(SolutionCost)) {
Workspace.push_back(&F);
if (Workspace.size() != Uses.size()) {
SolveRecurse(Solution, SolutionCost, Workspace, NewCost,
Expand All @@ -4936,9 +4927,9 @@ void LSRInstance::SolveRecurse(SmallVectorImpl<const Formula *> &Solution,
VisitedRegs.insert(F.ScaledReg ? F.ScaledReg : F.BaseRegs[0]);
} else {
LLVM_DEBUG(dbgs() << "New best at "; NewCost.print(dbgs());
dbgs() << ".\n Regs:"; for (const SCEV *S
: NewRegs) dbgs()
<< ' ' << *S;
dbgs() << ".\nRegs:\n";
for (const SCEV *S : NewRegs) dbgs()
<< "- " << *S << "\n";
dbgs() << '\n');

SolutionCost = NewCost;
Expand All @@ -4953,9 +4944,9 @@ void LSRInstance::SolveRecurse(SmallVectorImpl<const Formula *> &Solution,
/// vector.
void LSRInstance::Solve(SmallVectorImpl<const Formula *> &Solution) const {
SmallVector<const Formula *, 8> Workspace;
Cost SolutionCost;
Cost SolutionCost(L, SE, DT, TTI);
SolutionCost.Lose();
Cost CurCost;
Cost CurCost(L, SE, DT, TTI);
SmallPtrSet<const SCEV *, 16> CurRegs;
DenseSet<const SCEV *> VisitedRegs;
Workspace.reserve(Uses.size());
Expand Down

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