llvm::UnrollRuntimeLoopRemainder

Synopsis

Declared in <llvm/Transforms/Utils/UnrollLoop.h>

bool
UnrollRuntimeLoopRemainder(
    Loop* L,
    unsigned int Count,
    bool AllowExpensiveTripCount,
    bool UseEpilogRemainder,
    bool UnrollRemainder,
    bool ForgetAllSCEV,
    LoopInfo* LI,
    ScalarEvolution* SE,
    DominatorTree* DT,
    AssumptionCache* AC,
    TargetTransformInfo const* TTI,
    bool PreserveLCSSA,
    unsigned int SCEVExpansionBudget,
    bool RuntimeUnrollMultiExit,
    Loop** ResultLoop = nullptr,
    std::optional<unsigned int> OriginalTripCount = std::nullopt,
    BranchProbability OriginalLoopProb = BranchProbability::getUnknown());

Description

Ensures the latch trip count is a multiple of Count when the trip count is not known statically. May create and optionally unroll a remainder loop.

Return Value

True if the remainder transformation succeeded.

Parameters

Name	Description
L	Loop to prepare for runtime unrolling.
Count	Unroll factor that the remainder logic must satisfy.
AllowExpensiveTripCount	Allow costly run-time trip-count computation.
UseEpilogRemainder	Prefer an epilog remainder over a prolog.
UnrollRemainder	Unroll the generated remainder loop when profitable.
ForgetAllSCEV	Forget all SCEV expressions for the loop after rewrite.
LI	LoopInfo to keep consistent.
SE	ScalarEvolution used to compute the trip count.
DT	Dominator tree to update.
AC	Assumption cache used by subsequent simplifications.
TTI	Target transform info for cost checks.
PreserveLCSSA	Whether to preserve LCSSA form.
SCEVExpansionBudget	Budget for expanding the trip-count SCEV.
RuntimeUnrollMultiExit	Allow runtime unrolling with multiple exits.
ResultLoop	If non-null, receives the remainder loop when created.
OriginalTripCount	Optional original trip count used for probabilities.
OriginalLoopProb	Optional original loop-latch branch probability.