// If the input value is a chrec scev, truncate the chrec's operands.
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
SmallVector<const SCEV *, 4> Operands;
- for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
- Operands.push_back(getTruncateExpr(AddRec->getOperand(i), Ty));
+ for (const SCEV *Op : AddRec->operands())
+ Operands.push_back(getTruncateExpr(Op, Ty));
return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap);
}
ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(Step, &Pred, SE);
if (OverflowLimit &&
- SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit)) {
+ SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit))
return PreStart;
- }
+
return nullptr;
}
}
// sext(C1 + (C2 * x)) --> C1 + sext(C2 * x) if C1 < C2
- if (auto SA = dyn_cast<SCEVAddExpr>(Op)) {
+ if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) {
if (SA->getNumOperands() == 2) {
- auto SC1 = dyn_cast<SCEVConstant>(SA->getOperand(0));
- auto SMul = dyn_cast<SCEVMulExpr>(SA->getOperand(1));
+ auto *SC1 = dyn_cast<SCEVConstant>(SA->getOperand(0));
+ auto *SMul = dyn_cast<SCEVMulExpr>(SA->getOperand(1));
if (SMul && SC1) {
- if (auto SC2 = dyn_cast<SCEVConstant>(SMul->getOperand(0))) {
+ if (auto *SC2 = dyn_cast<SCEVConstant>(SMul->getOperand(0))) {
const APInt &C1 = SC1->getValue()->getValue();
const APInt &C2 = SC2->getValue()->getValue();
if (C1.isStrictlyPositive() && C2.isStrictlyPositive() &&
// If Start and Step are constants, check if we can apply this
// transformation:
// sext{C1,+,C2} --> C1 + sext{0,+,C2} if C1 < C2
- auto SC1 = dyn_cast<SCEVConstant>(Start);
- auto SC2 = dyn_cast<SCEVConstant>(Step);
+ auto *SC1 = dyn_cast<SCEVConstant>(Start);
+ auto *SC2 = dyn_cast<SCEVConstant>(Step);
if (SC1 && SC2) {
const APInt &C1 = SC1->getValue()->getValue();
const APInt &C2 = SC2->getValue()->getValue();
"SCEVAddExpr operand types don't match!");
#endif
- Flags = StrengthenNoWrapFlags(this, scAddExpr, Ops, Flags);
-
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, &LI);
+ Flags = StrengthenNoWrapFlags(this, scAddExpr, Ops, Flags);
+
// If there are any constants, fold them together.
unsigned Idx = 0;
if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
break;
}
LargeMulOps.push_back(T->getOperand());
- } else if (const SCEVConstant *C =
- dyn_cast<SCEVConstant>(M->getOperand(j))) {
+ } else if (const auto *C = dyn_cast<SCEVConstant>(M->getOperand(j))) {
LargeMulOps.push_back(getAnyExtendExpr(C, SrcType));
} else {
Ok = false;
"SCEVMulExpr operand types don't match!");
#endif
- Flags = StrengthenNoWrapFlags(this, scMulExpr, Ops, Flags);
-
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, &LI);
+ Flags = StrengthenNoWrapFlags(this, scMulExpr, Ops, Flags);
+
// If there are any constants, fold them together.
unsigned Idx = 0;
if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
}
if (AnyFolded)
return getAddExpr(NewOps);
- }
- else if (const SCEVAddRecExpr *
- AddRec = dyn_cast<SCEVAddRecExpr>(Ops[1])) {
+ } else if (const auto *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(),
getZeroExtendExpr(Step, ExtTy),
AR->getLoop(), SCEV::FlagAnyWrap)) {
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(),
- SCEV::FlagNW);
+ for (const SCEV *Op : AR->operands())
+ Operands.push_back(getUDivExpr(Op, RHS));
+ return getAddRecExpr(Operands, AR->getLoop(), 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.
// (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));
+ for (const SCEV *Op : M->operands())
+ Operands.push_back(getZeroExtendExpr(Op, ExtTy));
if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands))
// Find an operand that's safely divisible.
for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
// (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded.
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));
+ for (const SCEV *Op : A->operands())
+ Operands.push_back(getZeroExtendExpr(Op, ExtTy));
if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) {
Operands.clear();
for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) {
if (const SCEVConstant *RHSCst = dyn_cast<SCEVConstant>(RHS)) {
// If the mulexpr multiplies by a constant, then that constant must be the
// first element of the mulexpr.
- if (const SCEVConstant *LHSCst =
- dyn_cast<SCEVConstant>(Mul->getOperand(0))) {
+ if (const auto *LHSCst = dyn_cast<SCEVConstant>(Mul->getOperand(0))) {
if (LHSCst == RHSCst) {
SmallVector<const SCEV *, 2> Operands;
Operands.append(Mul->op_begin() + 1, Mul->op_end());
// AddRecs require their operands be loop-invariant with respect to their
// loops. Don't perform this transformation if it would break this
// requirement.
- bool AllInvariant = true;
- for (unsigned i = 0, e = Operands.size(); i != e; ++i)
- if (!isLoopInvariant(Operands[i], L)) {
- AllInvariant = false;
- break;
- }
+ bool AllInvariant =
+ std::all_of(Operands.begin(), Operands.end(),
+ [&](const SCEV *Op) { return isLoopInvariant(Op, L); });
+
if (AllInvariant) {
// Create a recurrence for the outer loop with the same step size.
//
maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags());
NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags);
- AllInvariant = true;
- for (unsigned i = 0, e = NestedOperands.size(); i != e; ++i)
- if (!isLoopInvariant(NestedOperands[i], NestedLoop)) {
- AllInvariant = false;
- break;
- }
+ AllInvariant = std::all_of(
+ NestedOperands.begin(), NestedOperands.end(),
+ [&](const SCEV *Op) { return isLoopInvariant(Op, NestedLoop); });
+
if (AllInvariant) {
// Ok, both add recurrences are valid after the transformation.
//
Type *ScalarEvolution::getEffectiveSCEVType(Type *Ty) const {
assert(isSCEVable(Ty) && "Type is not SCEVable!");
- if (Ty->isIntegerTy()) {
+ if (Ty->isIntegerTy())
return Ty;
- }
// The only other support type is pointer.
assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!");
if (const SCEVCastExpr *Cast = dyn_cast<SCEVCastExpr>(V)) {
return getPointerBase(Cast->getOperand());
- }
- else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) {
+ } else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) {
const SCEV *PtrOp = nullptr;
for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
I != E; ++I) {
if (!Visited.insert(I).second)
continue;
- ValueExprMapType::iterator It =
- ValueExprMap.find_as(static_cast<Value *>(I));
+ auto It = ValueExprMap.find_as(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
const SCEV *Old = It->second;
return PHISCEV;
}
}
- } else if (const SCEVAddRecExpr *AddRec =
- dyn_cast<SCEVAddRecExpr>(BEValue)) {
+ } else if (const auto *AddRec = dyn_cast<SCEVAddRecExpr>(BEValue)) {
// Otherwise, this could be a loop like this:
// i = 0; for (j = 1; ..; ++j) { .... i = j; }
// In this case, j = {1,+,1} and BEValue is j.
return nullptr;
}
-const SCEV *ScalarEvolution::createNodeFromSelectLikePHI(PHINode *PN) {
- const Loop *L = LI.getLoopFor(PN->getParent());
+// Checks if the SCEV S is available at BB. S is considered available at BB
+// if S can be materialized at BB without introducing a fault.
+static bool IsAvailableOnEntry(const Loop *L, DominatorTree &DT, const SCEV *S,
+ BasicBlock *BB) {
+ struct CheckAvailable {
+ bool TraversalDone = false;
+ bool Available = true;
- // Try to match a control flow sequence that branches out at BI and merges
- // back at Merge into a "C ? LHS : RHS" select pattern. Return true on a
- // successful match.
- auto BrPHIToSelect = [&](BranchInst *BI, PHINode *Merge, Value *&C,
- Value *&LHS, Value *&RHS) {
- C = BI->getCondition();
+ const Loop *L = nullptr; // The loop BB is in (can be nullptr)
+ BasicBlock *BB = nullptr;
+ DominatorTree &DT;
- BasicBlockEdge LeftEdge(BI->getParent(), BI->getSuccessor(0));
- BasicBlockEdge RightEdge(BI->getParent(), BI->getSuccessor(1));
+ CheckAvailable(const Loop *L, BasicBlock *BB, DominatorTree &DT)
+ : L(L), BB(BB), DT(DT) {}
- if (!LeftEdge.isSingleEdge())
+ bool setUnavailable() {
+ TraversalDone = true;
+ Available = false;
return false;
-
- assert(RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()");
-
- Use &LeftUse = Merge->getOperandUse(0);
- Use &RightUse = Merge->getOperandUse(1);
-
- if (DT.dominates(LeftEdge, LeftUse) && DT.dominates(RightEdge, RightUse)) {
- LHS = LeftUse;
- RHS = RightUse;
- return true;
}
- if (DT.dominates(LeftEdge, RightUse) && DT.dominates(RightEdge, LeftUse)) {
- LHS = RightUse;
- RHS = LeftUse;
+ bool follow(const SCEV *S) {
+ switch (S->getSCEVType()) {
+ case scConstant: case scTruncate: case scZeroExtend: case scSignExtend:
+ case scAddExpr: case scMulExpr: case scUMaxExpr: case scSMaxExpr:
+ // These expressions are available if their operand(s) is/are.
return true;
- }
- return false;
- };
+ case scAddRecExpr: {
+ // We allow add recurrences that are on the loop BB is in, or some
+ // outer loop. This guarantees availability because the value of the
+ // add recurrence at BB is simply the "current" value of the induction
+ // variable. We can relax this in the future; for instance an add
+ // recurrence on a sibling dominating loop is also available at BB.
+ const auto *ARLoop = cast<SCEVAddRecExpr>(S)->getLoop();
+ if (L && (ARLoop == L || ARLoop->contains(L)))
+ return true;
+
+ return setUnavailable();
+ }
- // Checks if the SCEV S is available at BB. S is considered available at BB
- // if S can be materialized at BB without introducing a fault.
- auto IsAvailableOnEntry = [&](const SCEV *S, BasicBlock *BB) {
- struct CheckAvailable {
- bool TraversalDone = false;
- bool Available = true;
+ case scUnknown: {
+ // For SCEVUnknown, we check for simple dominance.
+ const auto *SU = cast<SCEVUnknown>(S);
+ Value *V = SU->getValue();
- const Loop *L = nullptr; // The loop BB is in (can be nullptr)
- BasicBlock *BB = nullptr;
- DominatorTree &DT;
+ if (isa<Argument>(V))
+ return false;
- CheckAvailable(const Loop *L, BasicBlock *BB, DominatorTree &DT)
- : L(L), BB(BB), DT(DT) {}
+ if (isa<Instruction>(V) && DT.dominates(cast<Instruction>(V), BB))
+ return false;
- bool setUnavailable() {
- TraversalDone = true;
- Available = false;
- return false;
+ return setUnavailable();
}
- bool follow(const SCEV *S) {
- switch (S->getSCEVType()) {
- case scConstant: case scTruncate: case scZeroExtend: case scSignExtend:
- case scAddExpr: case scMulExpr: case scUMaxExpr: case scSMaxExpr:
- // These expressions are available if their operand(s) is/are.
- return true;
+ case scUDivExpr:
+ case scCouldNotCompute:
+ // We do not try to smart about these at all.
+ return setUnavailable();
+ }
+ llvm_unreachable("switch should be fully covered!");
+ }
- case scAddRecExpr: {
- // We allow add recurrences that are on the loop BB is in, or some
- // outer loop. This guarantees availability because the value of the
- // add recurrence at BB is simply the "current" value of the induction
- // variable. We can relax this in the future; for instance an add
- // recurrence on a sibling dominating loop is also available at BB.
- const auto *ARLoop = cast<SCEVAddRecExpr>(S)->getLoop();
- if (L && (ARLoop == L || ARLoop->contains(L)))
- return true;
+ bool isDone() { return TraversalDone; }
+ };
- return setUnavailable();
- }
+ CheckAvailable CA(L, BB, DT);
+ SCEVTraversal<CheckAvailable> ST(CA);
- case scUnknown: {
- // For SCEVUnknown, we check for simple dominance.
- const auto *SU = cast<SCEVUnknown>(S);
- Value *V = SU->getValue();
+ ST.visitAll(S);
+ return CA.Available;
+}
- if (isa<Argument>(V))
- return false;
+// Try to match a control flow sequence that branches out at BI and merges back
+// at Merge into a "C ? LHS : RHS" select pattern. Return true on a successful
+// match.
+static bool BrPHIToSelect(DominatorTree &DT, BranchInst *BI, PHINode *Merge,
+ Value *&C, Value *&LHS, Value *&RHS) {
+ C = BI->getCondition();
- if (isa<Instruction>(V) && DT.dominates(cast<Instruction>(V), BB))
- return false;
+ BasicBlockEdge LeftEdge(BI->getParent(), BI->getSuccessor(0));
+ BasicBlockEdge RightEdge(BI->getParent(), BI->getSuccessor(1));
- return setUnavailable();
- }
+ if (!LeftEdge.isSingleEdge())
+ return false;
- case scUDivExpr:
- case scCouldNotCompute:
- // We do not try to smart about these at all.
- return setUnavailable();
- }
- llvm_unreachable("switch should be fully covered!");
- }
+ assert(RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()");
- bool isDone() { return TraversalDone; }
- };
+ Use &LeftUse = Merge->getOperandUse(0);
+ Use &RightUse = Merge->getOperandUse(1);
- CheckAvailable CA(L, BB, DT);
- SCEVTraversal<CheckAvailable> ST(CA);
+ if (DT.dominates(LeftEdge, LeftUse) && DT.dominates(RightEdge, RightUse)) {
+ LHS = LeftUse;
+ RHS = RightUse;
+ return true;
+ }
- ST.visitAll(S);
- return CA.Available;
- };
+ if (DT.dominates(LeftEdge, RightUse) && DT.dominates(RightEdge, LeftUse)) {
+ LHS = RightUse;
+ RHS = LeftUse;
+ return true;
+ }
+
+ return false;
+}
+const SCEV *ScalarEvolution::createNodeFromSelectLikePHI(PHINode *PN) {
if (PN->getNumIncomingValues() == 2) {
+ const Loop *L = LI.getLoopFor(PN->getParent());
+
// Try to match
//
// br %cond, label %left, label %right
auto *BI = dyn_cast<BranchInst>(IDom->getTerminator());
Value *Cond = nullptr, *LHS = nullptr, *RHS = nullptr;
- if (BI && BI->isConditional() && BrPHIToSelect(BI, PN, Cond, LHS, RHS) &&
- IsAvailableOnEntry(getSCEV(LHS), PN->getParent()) &&
- IsAvailableOnEntry(getSCEV(RHS), PN->getParent()))
+ if (BI && BI->isConditional() &&
+ BrPHIToSelect(DT, BI, PN, Cond, LHS, RHS) &&
+ IsAvailableOnEntry(L, DT, getSCEV(LHS), PN->getParent()) &&
+ IsAvailableOnEntry(L, DT, getSCEV(RHS), PN->getParent()))
return createNodeForSelectOrPHI(PN, Cond, LHS, RHS);
}
Value *Cond,
Value *TrueVal,
Value *FalseVal) {
+ // Handle "constant" branch or select. This can occur for instance when a
+ // loop pass transforms an inner loop and moves on to process the outer loop.
+ if (auto *CI = dyn_cast<ConstantInt>(Cond))
+ return getSCEV(CI->isOne() ? TrueVal : FalseVal);
+
// Try to match some simple smax or umax patterns.
auto *ICI = dyn_cast<ICmpInst>(Cond);
if (!ICI)
if (!Pair.second)
return Pair.first->second;
- // ComputeBackedgeTakenCount may allocate memory for its result. Inserting it
+ // 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);
+ BackedgeTakenInfo Result = computeBackedgeTakenCount(L);
if (Result.getExact(this) != getCouldNotCompute()) {
assert(isLoopInvariant(Result.getExact(this), L) &&
}
// Re-lookup the insert position, since the call to
- // ComputeBackedgeTakenCount above could result in a
+ // computeBackedgeTakenCount above could result in a
// recusive call to getBackedgeTakenInfo (on a different
// loop), which would invalidate the iterator computed
// earlier.
delete[] ExitNotTaken.getNextExit();
}
-/// ComputeBackedgeTakenCount - Compute the number of times the backedge
+/// computeBackedgeTakenCount - Compute the number of times the backedge
/// of the specified loop will execute.
ScalarEvolution::BackedgeTakenInfo
-ScalarEvolution::ComputeBackedgeTakenCount(const Loop *L) {
+ScalarEvolution::computeBackedgeTakenCount(const Loop *L) {
SmallVector<BasicBlock *, 8> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);
// and compute maxBECount.
for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
BasicBlock *ExitBB = ExitingBlocks[i];
- ExitLimit EL = ComputeExitLimit(L, ExitBB);
+ ExitLimit EL = computeExitLimit(L, ExitBB);
// 1. For each exit that can be computed, add an entry to ExitCounts.
// CouldComputeBECount is true only if all exits can be computed.
return BackedgeTakenInfo(ExitCounts, CouldComputeBECount, MaxBECount);
}
-/// 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) {
+ScalarEvolution::computeExitLimit(const Loop *L, BasicBlock *ExitingBlock) {
- // Okay, we've chosen an exiting block. See what condition causes us to
- // exit at this block and remember the exit block and whether all other targets
+ // Okay, we've chosen an exiting block. See what condition causes us to exit
+ // at this block and remember the exit block and whether all other targets
// lead to the loop header.
bool MustExecuteLoopHeader = true;
BasicBlock *Exit = nullptr;
if (BranchInst *BI = dyn_cast<BranchInst>(Term)) {
assert(BI->isConditional() && "If unconditional, it can't be in loop!");
// Proceed to the next level to examine the exit condition expression.
- return ComputeExitLimitFromCond(L, BI->getCondition(), BI->getSuccessor(0),
+ return computeExitLimitFromCond(L, BI->getCondition(), BI->getSuccessor(0),
BI->getSuccessor(1),
/*ControlsExit=*/IsOnlyExit);
}
if (SwitchInst *SI = dyn_cast<SwitchInst>(Term))
- return ComputeExitLimitFromSingleExitSwitch(L, SI, Exit,
+ return computeExitLimitFromSingleExitSwitch(L, SI, Exit,
/*ControlsExit=*/IsOnlyExit);
return getCouldNotCompute();
}
-/// ComputeExitLimitFromCond - 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.
///
/// condition is true and can infer that failing to meet the condition prior to
/// integer wraparound results in undefined behavior.
ScalarEvolution::ExitLimit
-ScalarEvolution::ComputeExitLimitFromCond(const Loop *L,
+ScalarEvolution::computeExitLimitFromCond(const Loop *L,
Value *ExitCond,
BasicBlock *TBB,
BasicBlock *FBB,
if (BO->getOpcode() == Instruction::And) {
// Recurse on the operands of the and.
bool EitherMayExit = L->contains(TBB);
- ExitLimit EL0 = ComputeExitLimitFromCond(L, BO->getOperand(0), TBB, FBB,
+ ExitLimit EL0 = computeExitLimitFromCond(L, BO->getOperand(0), TBB, FBB,
ControlsExit && !EitherMayExit);
- ExitLimit EL1 = ComputeExitLimitFromCond(L, BO->getOperand(1), TBB, FBB,
+ ExitLimit EL1 = computeExitLimitFromCond(L, BO->getOperand(1), TBB, FBB,
ControlsExit && !EitherMayExit);
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
if (BO->getOpcode() == Instruction::Or) {
// Recurse on the operands of the or.
bool EitherMayExit = L->contains(FBB);
- ExitLimit EL0 = ComputeExitLimitFromCond(L, BO->getOperand(0), TBB, FBB,
+ ExitLimit EL0 = computeExitLimitFromCond(L, BO->getOperand(0), TBB, FBB,
ControlsExit && !EitherMayExit);
- ExitLimit EL1 = ComputeExitLimitFromCond(L, BO->getOperand(1), TBB, FBB,
+ ExitLimit EL1 = computeExitLimitFromCond(L, BO->getOperand(1), TBB, FBB,
ControlsExit && !EitherMayExit);
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
// 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 ComputeExitLimitFromICmp(L, ExitCondICmp, TBB, FBB, ControlsExit);
+ return computeExitLimitFromICmp(L, ExitCondICmp, TBB, FBB, ControlsExit);
// 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 ComputeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
+ return computeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
}
-/// 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::ExitLimit
-ScalarEvolution::ComputeExitLimitFromICmp(const Loop *L,
+ScalarEvolution::computeExitLimitFromICmp(const Loop *L,
ICmpInst *ExitCond,
BasicBlock *TBB,
BasicBlock *FBB,
if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0)))
if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) {
ExitLimit ItCnt =
- ComputeLoadConstantCompareExitLimit(LI, RHS, L, Cond);
+ computeLoadConstantCompareExitLimit(LI, RHS, L, Cond);
if (ItCnt.hasAnyInfo())
return ItCnt;
}
}
default:
#if 0
- dbgs() << "ComputeBackedgeTakenCount ";
+ dbgs() << "computeBackedgeTakenCount ";
if (ExitCond->getOperand(0)->getType()->isUnsigned())
dbgs() << "[unsigned] ";
dbgs() << *LHS << " "
#endif
break;
}
- return ComputeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
+ return computeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
}
ScalarEvolution::ExitLimit
-ScalarEvolution::ComputeExitLimitFromSingleExitSwitch(const Loop *L,
+ScalarEvolution::computeExitLimitFromSingleExitSwitch(const Loop *L,
SwitchInst *Switch,
BasicBlock *ExitingBlock,
bool ControlsExit) {
return cast<SCEVConstant>(Val)->getValue();
}
-/// ComputeLoadConstantCompareExitLimit - 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::ExitLimit
-ScalarEvolution::ComputeLoadConstantCompareExitLimit(
+ScalarEvolution::computeLoadConstantCompareExitLimit(
LoadInst *LI,
Constant *RHS,
const Loop *L,
Instruction *I = dyn_cast<Instruction>(V);
if (!I || !canConstantEvolve(I, L)) return nullptr;
- if (PHINode *PN = dyn_cast<PHINode>(I)) {
+ if (PHINode *PN = dyn_cast<PHINode>(I))
return PN;
- }
// Record non-constant instructions contained by the loop.
DenseMap<Instruction *, PHINode *> PHIMap;
ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
const APInt &BEs,
const Loop *L) {
- DenseMap<PHINode*, Constant*>::const_iterator I =
- ConstantEvolutionLoopExitValue.find(PN);
+ auto I = ConstantEvolutionLoopExitValue.find(PN);
if (I != ConstantEvolutionLoopExitValue.end())
return I->second;
BasicBlock *Header = L->getHeader();
assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!");
- // Since the loop is canonicalized, the PHI node must have two entries. One
+ BasicBlock *Latch = L->getLoopLatch();
+ if (!Latch)
+ return nullptr;
+
+ // Since the loop has one latch, the PHI node must have two entries. 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));
- PHINode *PHI = nullptr;
- for (BasicBlock::iterator I = Header->begin();
- (PHI = dyn_cast<PHINode>(I)); ++I) {
- Constant *StartCST =
- dyn_cast<Constant>(PHI->getIncomingValue(!SecondIsBackedge));
+
+ BasicBlock *NonLatch = Latch == PN->getIncomingBlock(0)
+ ? PN->getIncomingBlock(1)
+ : PN->getIncomingBlock(0);
+
+ assert(PN->getNumIncomingValues() == 2 && "Follows from having one latch!");
+
+ // Note: not all PHI nodes in the same block have to have their incoming
+ // values in the same order, so we use the basic block to look up the incoming
+ // value, not an index.
+
+ for (auto &I : *Header) {
+ PHINode *PHI = dyn_cast<PHINode>(&I);
+ if (!PHI) break;
+ auto *StartCST =
+ dyn_cast<Constant>(PHI->getIncomingValueForBlock(NonLatch));
if (!StartCST) continue;
CurrentIterVals[PHI] = StartCST;
}
if (!CurrentIterVals.count(PN))
return RetVal = nullptr;
- Value *BEValue = PN->getIncomingValue(SecondIsBackedge);
+ Value *BEValue = PN->getIncomingValueForBlock(Latch);
// Execute the loop symbolically to determine the exit value.
if (BEs.getActiveBits() >= 32)
// cease to be able to evaluate one of them or if they stop evolving,
// because that doesn't necessarily prevent us from computing PN.
SmallVector<std::pair<PHINode *, Constant *>, 8> PHIsToCompute;
- for (DenseMap<Instruction *, Constant *>::const_iterator
- I = CurrentIterVals.begin(), E = CurrentIterVals.end(); I != E; ++I){
- PHINode *PHI = dyn_cast<PHINode>(I->first);
+ for (const auto &I : CurrentIterVals) {
+ PHINode *PHI = dyn_cast<PHINode>(I.first);
if (!PHI || PHI == PN || PHI->getParent() != Header) continue;
- PHIsToCompute.push_back(std::make_pair(PHI, I->second));
+ PHIsToCompute.emplace_back(PHI, I.second);
}
// We use two distinct loops because EvaluateExpression may invalidate any
// iterators into CurrentIterVals.
- for (SmallVectorImpl<std::pair<PHINode *, Constant*> >::const_iterator
- I = PHIsToCompute.begin(), E = PHIsToCompute.end(); I != E; ++I) {
- PHINode *PHI = I->first;
+ for (const auto &I : PHIsToCompute) {
+ PHINode *PHI = I.first;
Constant *&NextPHI = NextIterVals[PHI];
if (!NextPHI) { // Not already computed.
- Value *BEValue = PHI->getIncomingValue(SecondIsBackedge);
+ Value *BEValue = PHI->getIncomingValueForBlock(Latch);
NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
}
- if (NextPHI != I->second)
+ if (NextPHI != I.second)
StoppedEvolving = false;
}
}
}
-/// 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::ComputeExitCountExhaustively(const Loop *L,
+const SCEV *ScalarEvolution::computeExitCountExhaustively(const Loop *L,
Value *Cond,
bool ExitWhen) {
PHINode *PN = getConstantEvolvingPHI(Cond, L);
BasicBlock *Header = L->getHeader();
assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!");
- // 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));
- PHINode *PHI = nullptr;
- for (BasicBlock::iterator I = Header->begin();
- (PHI = dyn_cast<PHINode>(I)); ++I) {
- Constant *StartCST =
- dyn_cast<Constant>(PHI->getIncomingValue(!SecondIsBackedge));
+ BasicBlock *Latch = L->getLoopLatch();
+ assert(Latch && "Should follow from NumIncomingValues == 2!");
+
+ // NonLatch is the preheader, or something equivalent.
+ BasicBlock *NonLatch = Latch == PN->getIncomingBlock(0)
+ ? PN->getIncomingBlock(1)
+ : PN->getIncomingBlock(0);
+
+ // Note: not all PHI nodes in the same block have to have their incoming
+ // values in the same order, so we use the basic block to look up the incoming
+ // value, not an index.
+
+ for (auto &I : *Header) {
+ PHINode *PHI = dyn_cast<PHINode>(&I);
+ if (!PHI)
+ break;
+ auto *StartCST =
+ dyn_cast<Constant>(PHI->getIncomingValueForBlock(NonLatch));
if (!StartCST) continue;
CurrentIterVals[PHI] = StartCST;
}
unsigned MaxIterations = MaxBruteForceIterations; // Limit analysis.
const DataLayout &DL = F.getParent()->getDataLayout();
for (unsigned IterationNum = 0; IterationNum != MaxIterations;++IterationNum){
- ConstantInt *CondVal = dyn_cast_or_null<ConstantInt>(
+ auto *CondVal = dyn_cast_or_null<ConstantInt>(
EvaluateExpression(Cond, L, CurrentIterVals, DL, &TLI));
// Couldn't symbolically evaluate.
// calling EvaluateExpression on them because that may invalidate iterators
// into CurrentIterVals.
SmallVector<PHINode *, 8> PHIsToCompute;
- for (DenseMap<Instruction *, Constant *>::const_iterator
- I = CurrentIterVals.begin(), E = CurrentIterVals.end(); I != E; ++I){
- PHINode *PHI = dyn_cast<PHINode>(I->first);
+ for (const auto &I : CurrentIterVals) {
+ PHINode *PHI = dyn_cast<PHINode>(I.first);
if (!PHI || PHI->getParent() != Header) continue;
PHIsToCompute.push_back(PHI);
}
- for (SmallVectorImpl<PHINode *>::const_iterator I = PHIsToCompute.begin(),
- E = PHIsToCompute.end(); I != E; ++I) {
- PHINode *PHI = *I;
+ for (PHINode *PHI : PHIsToCompute) {
Constant *&NextPHI = NextIterVals[PHI];
if (NextPHI) continue; // Already computed!
- Value *BEValue = PHI->getIncomingValue(SecondIsBackedge);
+ Value *BEValue = PHI->getIncomingValueForBlock(Latch);
NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
}
CurrentIterVals.swap(NextIterVals);
if (CanConstantFold(I)) {
SmallVector<Constant *, 4> Operands;
bool MadeImprovement = false;
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
- Value *Op = I->getOperand(i);
+ for (Value *Op : I->operands()) {
if (Constant *C = dyn_cast<Constant>(Op)) {
Operands.push_back(C);
continue;
bool ScalarEvolution::isKnownPredicateViaSplitting(ICmpInst::Predicate Pred,
const SCEV *LHS,
const SCEV *RHS) {
- if (ProvingSplitPredicate)
+ if (Pred != ICmpInst::ICMP_ULT || ProvingSplitPredicate)
return false;
// Allowing arbitrary number of activations of isKnownPredicateViaSplitting on
// expensive; and using isKnownNonNegative(RHS) is sufficient for most of the
// interesting cases seen in practice. We can consider "upgrading" L >= 0 to
// use isKnownPredicate later if needed.
- if (Pred == ICmpInst::ICMP_ULT && isKnownNonNegative(RHS) &&
+ if (isKnownNonNegative(RHS) &&
isKnownPredicate(CmpInst::ICMP_SGE, LHS, getZero(LHS->getType())) &&
isKnownPredicate(CmpInst::ICMP_SLT, LHS, RHS))
return true;
return false;
}
-// Return true if More == (Less + C), where C is a constant.
-static bool IsConstDiff(ScalarEvolution &SE, const SCEV *Less, const SCEV *More,
- APInt &C) {
- // We avoid subtracting expressions here because this function is usually
- // fairly deep in the call stack (i.e. is called many times).
+bool ScalarEvolution::splitBinaryAdd(const SCEV *Expr,
+ const SCEV *&L, const SCEV *&R,
+ SCEV::NoWrapFlags &Flags) {
+ const auto *AE = dyn_cast<SCEVAddExpr>(Expr);
+ if (!AE || AE->getNumOperands() != 2)
+ return false;
- auto SplitBinaryAdd = [](const SCEV *Expr, const SCEV *&L, const SCEV *&R) {
- const auto *AE = dyn_cast<SCEVAddExpr>(Expr);
- if (!AE || AE->getNumOperands() != 2)
- return false;
+ L = AE->getOperand(0);
+ R = AE->getOperand(1);
+ Flags = AE->getNoWrapFlags();
+ return true;
+}
- L = AE->getOperand(0);
- R = AE->getOperand(1);
- return true;
- };
+bool ScalarEvolution::computeConstantDifference(const SCEV *Less,
+ const SCEV *More,
+ APInt &C) {
+ // We avoid subtracting expressions here because this function is usually
+ // fairly deep in the call stack (i.e. is called many times).
if (isa<SCEVAddRecExpr>(Less) && isa<SCEVAddRecExpr>(More)) {
const auto *LAR = cast<SCEVAddRecExpr>(Less);
if (!LAR->isAffine() || !MAR->isAffine())
return false;
- if (LAR->getStepRecurrence(SE) != MAR->getStepRecurrence(SE))
+ if (LAR->getStepRecurrence(*this) != MAR->getStepRecurrence(*this))
return false;
Less = LAR->getStart();
}
const SCEV *L, *R;
- if (SplitBinaryAdd(Less, L, R))
+ SCEV::NoWrapFlags Flags;
+ if (splitBinaryAdd(Less, L, R, Flags))
if (const auto *LC = dyn_cast<SCEVConstant>(L))
if (R == More) {
C = -(LC->getValue()->getValue());
return true;
}
- if (SplitBinaryAdd(More, L, R))
+ if (splitBinaryAdd(More, L, R, Flags))
if (const auto *LC = dyn_cast<SCEVConstant>(L))
if (R == Less) {
C = LC->getValue()->getValue();
// C)".
APInt LDiff, RDiff;
- if (!IsConstDiff(*this, FoundLHS, LHS, LDiff) ||
- !IsConstDiff(*this, FoundRHS, RHS, RDiff) ||
+ if (!computeConstantDifference(FoundLHS, LHS, LDiff) ||
+ !computeConstantDifference(FoundRHS, RHS, RDiff) ||
LDiff != RDiff)
return false;
/// If Expr computes ~A, return A else return nullptr
static const SCEV *MatchNotExpr(const SCEV *Expr) {
const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Expr);
- if (!Add || Add->getNumOperands() != 2) return nullptr;
-
- const SCEVConstant *AddLHS = dyn_cast<SCEVConstant>(Add->getOperand(0));
- if (!(AddLHS && AddLHS->getValue()->getValue().isAllOnesValue()))
+ if (!Add || Add->getNumOperands() != 2 ||
+ !Add->getOperand(0)->isAllOnesValue())
return nullptr;
const SCEVMulExpr *AddRHS = dyn_cast<SCEVMulExpr>(Add->getOperand(1));
- if (!AddRHS || AddRHS->getNumOperands() != 2) return nullptr;
-
- const SCEVConstant *MulLHS = dyn_cast<SCEVConstant>(AddRHS->getOperand(0));
- if (!(MulLHS && MulLHS->getValue()->getValue().isAllOnesValue()))
+ if (!AddRHS || AddRHS->getNumOperands() != 2 ||
+ !AddRHS->getOperand(0)->isAllOnesValue())
return nullptr;
return AddRHS->getOperand(1);
Operands[0] = SE.getZero(SC->getType());
const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop(),
getNoWrapFlags(FlagNW));
- if (const SCEVAddRecExpr *ShiftedAddRec =
- dyn_cast<SCEVAddRecExpr>(Shifted))
+ if (const auto *ShiftedAddRec = dyn_cast<SCEVAddRecExpr>(Shifted))
return ShiftedAddRec->getNumIterationsInRange(
Range.subtract(SC->getValue()->getValue()), SE);
// This is strange and shouldn't happen.
// The only time we can solve this is when we have all constant indices.
// Otherwise, we cannot determine the overflow conditions.
- for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
- if (!isa<SCEVConstant>(getOperand(i)))
- return SE.getCouldNotCompute();
-
+ if (std::any_of(op_begin(), op_end(),
+ [](const SCEV *Op) { return !isa<SCEVConstant>(Op);}))
+ return SE.getCouldNotCompute();
// Okay at this point we know that all elements of the chrec are constants and
// that the start element is zero.
}
bool isDone() const { return false; }
};
+
+// Check if a SCEV contains an AddRecExpr.
+struct SCEVHasAddRec {
+ bool &ContainsAddRec;
+
+ SCEVHasAddRec(bool &ContainsAddRec) : ContainsAddRec(ContainsAddRec) {
+ ContainsAddRec = false;
+ }
+
+ bool follow(const SCEV *S) {
+ if (isa<SCEVAddRecExpr>(S)) {
+ ContainsAddRec = true;
+
+ // Stop recursion: once we collected a term, do not walk its operands.
+ return false;
+ }
+
+ // Keep looking.
+ return true;
+ }
+ bool isDone() const { return false; }
+};
+
+// Find factors that are multiplied with an expression that (possibly as a
+// subexpression) contains an AddRecExpr. In the expression:
+//
+// 8 * (100 + %p * %q * (%a + {0, +, 1}_loop))
+//
+// "%p * %q" are factors multiplied by the expression "(%a + {0, +, 1}_loop)"
+// that contains the AddRec {0, +, 1}_loop. %p * %q are likely to be array size
+// parameters as they form a product with an induction variable.
+//
+// This collector expects all array size parameters to be in the same MulExpr.
+// It might be necessary to later add support for collecting parameters that are
+// spread over different nested MulExpr.
+struct SCEVCollectAddRecMultiplies {
+ SmallVectorImpl<const SCEV *> &Terms;
+ ScalarEvolution &SE;
+
+ SCEVCollectAddRecMultiplies(SmallVectorImpl<const SCEV *> &T, ScalarEvolution &SE)
+ : Terms(T), SE(SE) {}
+
+ bool follow(const SCEV *S) {
+ if (auto *Mul = dyn_cast<SCEVMulExpr>(S)) {
+ bool HasAddRec = false;
+ SmallVector<const SCEV *, 0> Operands;
+ for (auto Op : Mul->operands()) {
+ if (isa<SCEVUnknown>(Op)) {
+ Operands.push_back(Op);
+ } else {
+ bool ContainsAddRec;
+ SCEVHasAddRec ContiansAddRec(ContainsAddRec);
+ visitAll(Op, ContiansAddRec);
+ HasAddRec |= ContainsAddRec;
+ }
+ }
+ if (Operands.size() == 0)
+ return true;
+
+ if (!HasAddRec)
+ return false;
+
+ Terms.push_back(SE.getMulExpr(Operands));
+ // Stop recursion: once we collected a term, do not walk its operands.
+ return false;
+ }
+
+ // Keep looking.
+ return true;
+ }
+ bool isDone() const { return false; }
+};
}
-/// Find parametric terms in this SCEVAddRecExpr.
+/// Find parametric terms in this SCEVAddRecExpr. We first for parameters in
+/// two places:
+/// 1) The strides of AddRec expressions.
+/// 2) Unknowns that are multiplied with AddRec expressions.
void ScalarEvolution::collectParametricTerms(const SCEV *Expr,
SmallVectorImpl<const SCEV *> &Terms) {
SmallVector<const SCEV *, 4> Strides;
for (const SCEV *T : Terms)
dbgs() << *T << "\n";
});
+
+ SCEVCollectAddRecMultiplies MulCollector(Terms, *this);
+ visitAll(Expr, MulCollector);
}
static bool findArrayDimensionsRec(ScalarEvolution &SE,
ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this);
- // Divide all terms by the element size.
+ // Try to divide all terms by the element size. If term is not divisible by
+ // element size, proceed with the original term.
for (const SCEV *&Term : Terms) {
const SCEV *Q, *R;
SCEVDivision::divide(SE, Term, ElementSize, &Q, &R);
- Term = Q;
+ if (!Q->isZero())
+ Term = Q;
}
SmallVector<const SCEV *, 4> NewTerms;
if (Sizes.empty())
return;
- if (auto AR = dyn_cast<SCEVAddRecExpr>(Expr))
+ if (auto *AR = dyn_cast<SCEVAddRecExpr>(Expr))
if (!AR->isAffine())
return;
// 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();
- }
+ for (auto &BTCI : BackedgeTakenCounts)
+ BTCI.second.clear();
assert(PendingLoopPredicates.empty() && "isImpliedCond garbage");
assert(!WalkingBEDominatingConds && "isLoopBackedgeGuardedByCond garbage!");
OS << "Classifying expressions for: ";
F.printAsOperand(OS, /*PrintType=*/false);
OS << "\n";
- for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
- if (isSCEVable(I->getType()) && !isa<CmpInst>(*I)) {
- OS << *I << '\n';
+ for (Instruction &I : instructions(F))
+ if (isSCEVable(I.getType()) && !isa<CmpInst>(I)) {
+ OS << I << '\n';
OS << " --> ";
- const SCEV *SV = SE.getSCEV(&*I);
+ const SCEV *SV = SE.getSCEV(&I);
SV->print(OS);
if (!isa<SCEVCouldNotCompute>(SV)) {
OS << " U: ";
SE.getSignedRange(SV).print(OS);
}
- const Loop *L = LI.getLoopFor((*I).getParent());
+ const Loop *L = LI.getLoopFor(I.getParent());
const SCEV *AtUse = SE.getSCEVAtScope(SV, L);
if (AtUse != SV) {
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