//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "indvars"
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Transforms/Utils/SimplifyIndVar.h"
using namespace llvm;
+#define DEBUG_TYPE "indvars"
+
STATISTIC(NumWidened , "Number of indvars widened");
STATISTIC(NumReplaced , "Number of exit values replaced");
STATISTIC(NumLFTR , "Number of loop exit tests replaced");
public:
static char ID; // Pass identification, replacement for typeid
- IndVarSimplify() : LoopPass(ID), LI(0), SE(0), DT(0), DL(0),
- Changed(false) {
+ IndVarSimplify() : LoopPass(ID), LI(nullptr), SE(nullptr), DT(nullptr),
+ DL(nullptr), Changed(false) {
initializeIndVarSimplifyPass(*PassRegistry::getPassRegistry());
}
- virtual bool runOnLoop(Loop *L, LPPassManager &LPM);
+ bool runOnLoop(Loop *L, LPPassManager &LPM) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<LoopInfo>();
AU.addRequired<ScalarEvolution>();
}
private:
- virtual void releaseMemory() {
+ void releaseMemory() override {
DeadInsts.clear();
}
if (!PHI)
return User;
- Instruction *InsertPt = 0;
+ Instruction *InsertPt = nullptr;
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i) {
if (PHI->getIncomingValue(i) != Def)
continue;
// an add or increment value can not be represented by an integer.
BinaryOperator *Incr =
dyn_cast<BinaryOperator>(PN->getIncomingValue(BackEdge));
- if (Incr == 0 || Incr->getOpcode() != Instruction::FAdd) return;
+ if (Incr == nullptr || Incr->getOpcode() != Instruction::FAdd) return;
// If this is not an add of the PHI with a constantfp, or if the constant fp
// is not an integer, bail out.
ConstantFP *IncValueVal = dyn_cast<ConstantFP>(Incr->getOperand(1));
int64_t IncValue;
- if (IncValueVal == 0 || Incr->getOperand(0) != PN ||
+ if (IncValueVal == nullptr || Incr->getOperand(0) != PN ||
!ConvertToSInt(IncValueVal->getValueAPF(), IncValue))
return;
// Check Incr uses. One user is PN and the other user is an exit condition
// used by the conditional terminator.
- Value::use_iterator IncrUse = Incr->use_begin();
+ Value::user_iterator IncrUse = Incr->user_begin();
Instruction *U1 = cast<Instruction>(*IncrUse++);
- if (IncrUse == Incr->use_end()) return;
+ if (IncrUse == Incr->user_end()) return;
Instruction *U2 = cast<Instruction>(*IncrUse++);
- if (IncrUse != Incr->use_end()) return;
+ if (IncrUse != Incr->user_end()) return;
// Find exit condition, which is an fcmp. If it doesn't exist, or if it isn't
// only used by a branch, we can't transform it.
FCmpInst *Compare = dyn_cast<FCmpInst>(U1);
if (!Compare)
Compare = dyn_cast<FCmpInst>(U2);
- if (Compare == 0 || !Compare->hasOneUse() ||
- !isa<BranchInst>(Compare->use_back()))
+ if (!Compare || !Compare->hasOneUse() ||
+ !isa<BranchInst>(Compare->user_back()))
return;
- BranchInst *TheBr = cast<BranchInst>(Compare->use_back());
+ BranchInst *TheBr = cast<BranchInst>(Compare->user_back());
// We need to verify that the branch actually controls the iteration count
// of the loop. If not, the new IV can overflow and no one will notice.
// transform it.
ConstantFP *ExitValueVal = dyn_cast<ConstantFP>(Compare->getOperand(1));
int64_t ExitValue;
- if (ExitValueVal == 0 ||
+ if (ExitValueVal == nullptr ||
!ConvertToSInt(ExitValueVal->getValueAPF(), ExitValue))
return;
unsigned NumHardInternalUses = 0;
unsigned NumSoftExternalUses = 0;
unsigned NumUses = 0;
- for (Value::use_iterator IB=Inst->use_begin(), IE=Inst->use_end();
- IB!=IE && NumUses<=6 ; ++IB) {
+ for (auto IB = Inst->user_begin(), IE = Inst->user_end();
+ IB != IE && NumUses <= 6; ++IB) {
Instruction *UseInstr = cast<Instruction>(*IB);
unsigned Opc = UseInstr->getOpcode();
NumUses++;
// Do not count the Phi as a use. LCSSA may have inserted
// plenty of trivial ones.
NumUses--;
- for (Value::use_iterator PB=UseInstr->use_begin(),
- PE=UseInstr->use_end();
- PB!=PE && NumUses<=6 ; ++PB, ++NumUses) {
+ for (auto PB = UseInstr->user_begin(),
+ PE = UseInstr->user_end();
+ PB != PE && NumUses <= 6; ++PB, ++NumUses) {
unsigned PhiOpc = cast<Instruction>(*PB)->getOpcode();
if (PhiOpc != Instruction::Call && PhiOpc != Instruction::Ret)
NumSoftExternalUses++;
Type *WidestNativeType; // Widest integer type created [sz]ext
bool IsSigned; // Was an sext user seen before a zext?
- WideIVInfo() : NarrowIV(0), WidestNativeType(0), IsSigned(false) {}
+ WideIVInfo() : NarrowIV(nullptr), WidestNativeType(nullptr),
+ IsSigned(false) {}
};
}
Instruction *NarrowUse;
Instruction *WideDef;
- NarrowIVDefUse(): NarrowDef(0), NarrowUse(0), WideDef(0) {}
+ NarrowIVDefUse(): NarrowDef(nullptr), NarrowUse(nullptr), WideDef(nullptr) {}
NarrowIVDefUse(Instruction *ND, Instruction *NU, Instruction *WD):
NarrowDef(ND), NarrowUse(NU), WideDef(WD) {}
L(LI->getLoopFor(OrigPhi->getParent())),
SE(SEv),
DT(DTree),
- WidePhi(0),
- WideInc(0),
- WideIncExpr(0),
+ WidePhi(nullptr),
+ WideInc(nullptr),
+ WideIncExpr(nullptr),
DeadInsts(DI) {
assert(L->getHeader() == OrigPhi->getParent() && "Phi must be an IV");
}
unsigned Opcode = DU.NarrowUse->getOpcode();
switch (Opcode) {
default:
- return 0;
+ return nullptr;
case Instruction::Add:
case Instruction::Mul:
case Instruction::UDiv:
const SCEVAddRecExpr* WidenIV::GetExtendedOperandRecurrence(NarrowIVDefUse DU) {
// Handle the common case of add<nsw/nuw>
if (DU.NarrowUse->getOpcode() != Instruction::Add)
- return 0;
+ return nullptr;
// One operand (NarrowDef) has already been extended to WideDef. Now determine
// if extending the other will lead to a recurrence.
unsigned ExtendOperIdx = DU.NarrowUse->getOperand(0) == DU.NarrowDef ? 1 : 0;
assert(DU.NarrowUse->getOperand(1-ExtendOperIdx) == DU.NarrowDef && "bad DU");
- const SCEV *ExtendOperExpr = 0;
+ const SCEV *ExtendOperExpr = nullptr;
const OverflowingBinaryOperator *OBO =
cast<OverflowingBinaryOperator>(DU.NarrowUse);
if (IsSigned && OBO->hasNoSignedWrap())
ExtendOperExpr = SE->getZeroExtendExpr(
SE->getSCEV(DU.NarrowUse->getOperand(ExtendOperIdx)), WideType);
else
- return 0;
+ return nullptr;
// When creating this AddExpr, don't apply the current operations NSW or NUW
// flags. This instruction may be guarded by control flow that the no-wrap
SE->getAddExpr(SE->getSCEV(DU.WideDef), ExtendOperExpr));
if (!AddRec || AddRec->getLoop() != L)
- return 0;
+ return nullptr;
return AddRec;
}
/// recurrence. Otherwise return NULL.
const SCEVAddRecExpr *WidenIV::GetWideRecurrence(Instruction *NarrowUse) {
if (!SE->isSCEVable(NarrowUse->getType()))
- return 0;
+ return nullptr;
const SCEV *NarrowExpr = SE->getSCEV(NarrowUse);
if (SE->getTypeSizeInBits(NarrowExpr->getType())
>= SE->getTypeSizeInBits(WideType)) {
// NarrowUse implicitly widens its operand. e.g. a gep with a narrow
// index. So don't follow this use.
- return 0;
+ return nullptr;
}
const SCEV *WideExpr = IsSigned ?
SE->getZeroExtendExpr(NarrowExpr, WideType);
const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(WideExpr);
if (!AddRec || AddRec->getLoop() != L)
- return 0;
+ return nullptr;
return AddRec;
}
DEBUG(dbgs() << "INDVARS: Widen lcssa phi " << *UsePhi
<< " to " << *WidePhi << "\n");
}
- return 0;
+ return nullptr;
}
}
// Our raison d'etre! Eliminate sign and zero extension.
// push the uses of WideDef here.
// No further widening is needed. The deceased [sz]ext had done it for us.
- return 0;
+ return nullptr;
}
// Does this user itself evaluate to a recurrence after widening?
// follow it. Instead insert a Trunc to kill off the original use,
// eventually isolating the original narrow IV so it can be removed.
truncateIVUse(DU, DT);
- return 0;
+ return nullptr;
}
// Assume block terminators cannot evaluate to a recurrence. We can't to
// insert a Trunc after a terminator if there happens to be a critical edge.
// Reuse the IV increment that SCEVExpander created as long as it dominates
// NarrowUse.
- Instruction *WideUse = 0;
+ Instruction *WideUse = nullptr;
if (WideAddRec == WideIncExpr
&& Rewriter.hoistIVInc(WideInc, DU.NarrowUse))
WideUse = WideInc;
else {
WideUse = CloneIVUser(DU);
if (!WideUse)
- return 0;
+ return nullptr;
}
// Evaluation of WideAddRec ensured that the narrow expression could be
// extended outside the loop without overflow. This suggests that the wide use
DEBUG(dbgs() << "Wide use expression mismatch: " << *WideUse
<< ": " << *SE->getSCEV(WideUse) << " != " << *WideAddRec << "\n");
DeadInsts.push_back(WideUse);
- return 0;
+ return nullptr;
}
// Returning WideUse pushes it on the worklist.
/// pushNarrowIVUsers - Add eligible users of NarrowDef to NarrowIVUsers.
///
void WidenIV::pushNarrowIVUsers(Instruction *NarrowDef, Instruction *WideDef) {
- for (Value::use_iterator UI = NarrowDef->use_begin(),
- UE = NarrowDef->use_end(); UI != UE; ++UI) {
- Instruction *NarrowUse = cast<Instruction>(*UI);
+ for (User *U : NarrowDef->users()) {
+ Instruction *NarrowUser = cast<Instruction>(U);
// Handle data flow merges and bizarre phi cycles.
- if (!Widened.insert(NarrowUse))
+ if (!Widened.insert(NarrowUser))
continue;
- NarrowIVUsers.push_back(NarrowIVDefUse(NarrowDef, NarrowUse, WideDef));
+ NarrowIVUsers.push_back(NarrowIVDefUse(NarrowDef, NarrowUser, WideDef));
}
}
// Is this phi an induction variable?
const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(OrigPhi));
if (!AddRec)
- return NULL;
+ return nullptr;
// Widen the induction variable expression.
const SCEV *WideIVExpr = IsSigned ?
// Can the IV be extended outside the loop without overflow?
AddRec = dyn_cast<SCEVAddRecExpr>(WideIVExpr);
if (!AddRec || AddRec->getLoop() != L)
- return NULL;
+ return nullptr;
// An AddRec must have loop-invariant operands. Since this AddRec is
// materialized by a loop header phi, the expression cannot have any post-loop
}
// Implement the interface used by simplifyUsersOfIV.
- virtual void visitCast(CastInst *Cast) { visitIVCast(Cast, WI, SE, DL); }
+ void visitCast(CastInst *Cast) override { visitIVCast(Cast, WI, SE, DL); }
};
}
static PHINode *getLoopPhiForCounter(Value *IncV, Loop *L, DominatorTree *DT) {
Instruction *IncI = dyn_cast<Instruction>(IncV);
if (!IncI)
- return 0;
+ return nullptr;
switch (IncI->getOpcode()) {
case Instruction::Add:
if (IncI->getNumOperands() == 2)
break;
default:
- return 0;
+ return nullptr;
}
PHINode *Phi = dyn_cast<PHINode>(IncI->getOperand(0));
if (Phi && Phi->getParent() == L->getHeader()) {
if (isLoopInvariant(IncI->getOperand(1), L, DT))
return Phi;
- return 0;
+ return nullptr;
}
if (IncI->getOpcode() == Instruction::GetElementPtr)
- return 0;
+ return nullptr;
// Allow add/sub to be commuted.
Phi = dyn_cast<PHINode>(IncI->getOperand(1));
if (isLoopInvariant(IncI->getOperand(0), L, DT))
return Phi;
}
- return 0;
+ return nullptr;
}
/// Return the compare guarding the loop latch, or NULL for unrecognized tests.
BasicBlock *LatchBlock = L->getLoopLatch();
// Don't bother with LFTR if the loop is not properly simplified.
if (!LatchBlock)
- return 0;
+ return nullptr;
BranchInst *BI = dyn_cast<BranchInst>(L->getExitingBlock()->getTerminator());
assert(BI && "expected exit branch");
int LatchIdx = Phi->getBasicBlockIndex(LatchBlock);
Value *IncV = Phi->getIncomingValue(LatchIdx);
- for (Value::use_iterator UI = Phi->use_begin(), UE = Phi->use_end();
- UI != UE; ++UI) {
- if (*UI != Cond && *UI != IncV) return false;
- }
+ for (User *U : Phi->users())
+ if (U != Cond && U != IncV) return false;
- for (Value::use_iterator UI = IncV->use_begin(), UE = IncV->use_end();
- UI != UE; ++UI) {
- if (*UI != Cond && *UI != Phi) return false;
- }
+ for (User *U : IncV->users())
+ if (U != Cond && U != Phi) return false;
return true;
}
cast<BranchInst>(L->getExitingBlock()->getTerminator())->getCondition();
// Loop over all of the PHI nodes, looking for a simple counter.
- PHINode *BestPhi = 0;
- const SCEV *BestInit = 0;
+ PHINode *BestPhi = nullptr;
+ const SCEV *BestInit = nullptr;
BasicBlock *LatchBlock = L->getLoopLatch();
assert(LatchBlock && "needsLFTR should guarantee a loop latch");
// IVInit integer and IVCount pointer would only occur if a canonical IV
// were generated on top of case #2, which is not expected.
- const SCEV *IVLimit = 0;
+ const SCEV *IVLimit = nullptr;
// For unit stride, IVCount = Start + BECount with 2's complement overflow.
// For non-zero Start, compute IVCount here.
if (AR->getStart()->isZero())
// Determine if there is a use in or before the loop (direct or
// otherwise).
bool UsedInLoop = false;
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
- UI != UE; ++UI) {
- User *U = *UI;
- BasicBlock *UseBB = cast<Instruction>(U)->getParent();
- if (PHINode *P = dyn_cast<PHINode>(U)) {
+ for (Use &U : I->uses()) {
+ Instruction *User = cast<Instruction>(U.getUser());
+ BasicBlock *UseBB = User->getParent();
+ if (PHINode *P = dyn_cast<PHINode>(User)) {
unsigned i =
- PHINode::getIncomingValueNumForOperand(UI.getOperandNo());
+ PHINode::getIncomingValueNumForOperand(U.getOperandNo());
UseBB = P->getIncomingBlock(i);
}
if (UseBB == Preheader || L->contains(UseBB)) {
SE = &getAnalysis<ScalarEvolution>();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- DL = DLP ? &DLP->getDataLayout() : 0;
+ DL = DLP ? &DLP->getDataLayout() : nullptr;
TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
DeadInsts.clear();
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