Skip to content

[LoopPeel] Address followup comments on #121104 #155221

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Aug 25, 2025
Merged

[LoopPeel] Address followup comments on #121104 #155221

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 9 additions & 11 deletions llvm/lib/Transforms/Utils/LoopPeel.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -225,9 +225,9 @@ class PhiAnalyzer {

// Auxiliary function to calculate the number of iterations for a comparison
// instruction or a binary operator.
PeelCounter mergeTwoCounter(const Instruction &CmpOrBinaryOp,
const PeelCounterValue &LHS,
const PeelCounterValue &RHS) const;
PeelCounter mergeTwoCounters(const Instruction &CmpOrBinaryOp,
const PeelCounterValue &LHS,
const PeelCounterValue &RHS) const;

// Returns true if the \p Phi is an induction in the target loop. This is a
// lightweight check and possible to detect an IV in some cases.
Expand Down Expand Up @@ -269,15 +269,13 @@ bool PhiAnalyzer::isInductionPHI(const PHINode *Phi) const {
break;

// Avoid infinite loop.
if (Visited.contains(Cur))
if (!Visited.insert(Cur).second)
return false;

auto *I = dyn_cast<Instruction>(Cur);
if (!I || !L.contains(I))
return false;

Visited.insert(Cur);

if (auto *Cast = dyn_cast<CastInst>(I)) {
Cur = Cast->getOperand(0);
} else if (auto *BinOp = dyn_cast<BinaryOperator>(I)) {
Expand All @@ -300,14 +298,14 @@ bool PhiAnalyzer::isInductionPHI(const PHINode *Phi) const {

/// When either \p LHS or \p RHS is an IV, the result of \p CmpOrBinaryOp is
/// considered an IV only if it is an addition or a subtraction. Otherwise the
/// result can be a value that is neither an loop-invariant nor an IV.
/// result can be a value that is neither a loop-invariant nor an IV.
///
/// If both \p LHS and \p RHS are loop-invariants, then the result of
/// \CmpOrBinaryOp is also a loop-invariant.
PhiAnalyzer::PeelCounter
PhiAnalyzer::mergeTwoCounter(const Instruction &CmpOrBinaryOp,
const PeelCounterValue &LHS,
const PeelCounterValue &RHS) const {
PhiAnalyzer::mergeTwoCounters(const Instruction &CmpOrBinaryOp,
const PeelCounterValue &LHS,
const PeelCounterValue &RHS) const {
auto &[LVal, LTy] = LHS;
auto &[RVal, RTy] = RHS;
unsigned NewVal = std::max(LVal, RVal);
Expand Down Expand Up @@ -380,7 +378,7 @@ PhiAnalyzer::PeelCounter PhiAnalyzer::calculate(const Value &V) {
if (RHS == Unknown)
return Unknown;
return (IterationsToInvarianceOrInduction[I] =
mergeTwoCounter(*I, *LHS, *RHS));
mergeTwoCounters(*I, *LHS, *RHS));
}
if (I->isCast())
// Cast instructions get the value of the operand.
Expand Down
Loading