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//===- llvm/Transforms/Utils/UnrollLoop.h - Unrolling utilities -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines some loop unrolling utilities. It does not define any
// actual pass or policy, but provides a single function to perform loop
// unrolling.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_UNROLLLOOP_H
#define LLVM_TRANSFORMS_UTILS_UNROLLLOOP_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
namespace llvm {
class AssumptionCache;
class BasicBlock;
class BlockFrequencyInfo;
class DependenceInfo;
class DominatorTree;
class Loop;
class LoopInfo;
class MDNode;
class ProfileSummaryInfo;
class OptimizationRemarkEmitter;
class ScalarEvolution;
using NewLoopsMap = SmallDenseMap<const Loop *, Loop *, 4>;
/// @{
/// Metadata attribute names
const char *const LLVMLoopUnrollFollowupAll = "llvm.loop.unroll.followup_all";
const char *const LLVMLoopUnrollFollowupUnrolled =
"llvm.loop.unroll.followup_unrolled";
const char *const LLVMLoopUnrollFollowupRemainder =
"llvm.loop.unroll.followup_remainder";
/// @}
const Loop* addClonedBlockToLoopInfo(BasicBlock *OriginalBB,
BasicBlock *ClonedBB, LoopInfo *LI,
NewLoopsMap &NewLoops);
/// Represents the result of a \c UnrollLoop invocation.
enum class LoopUnrollResult {
/// The loop was not modified.
Unmodified,
/// The loop was partially unrolled -- we still have a loop, but with a
/// smaller trip count. We may also have emitted epilogue loop if the loop
/// had a non-constant trip count.
PartiallyUnrolled,
/// The loop was fully unrolled into straight-line code. We no longer have
/// any back-edges.
FullyUnrolled
};
struct UnrollLoopOptions {
unsigned Count;
unsigned TripCount;
bool Force;
bool AllowRuntime;
bool AllowExpensiveTripCount;
bool PreserveCondBr;
bool PreserveOnlyFirst;
unsigned TripMultiple;
unsigned PeelCount;
bool UnrollRemainder;
bool ForgetAllSCEV;
};
LoopUnrollResult UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
ScalarEvolution *SE, DominatorTree *DT,
AssumptionCache *AC, OptimizationRemarkEmitter *ORE,
bool PreserveLCSSA, Loop **RemainderLoop = nullptr);
bool UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
bool AllowExpensiveTripCount,
bool UseEpilogRemainder, bool UnrollRemainder,
bool ForgetAllSCEV, LoopInfo *LI,
ScalarEvolution *SE, DominatorTree *DT,
AssumptionCache *AC, bool PreserveLCSSA,
Loop **ResultLoop = nullptr);
void computePeelCount(Loop *L, unsigned LoopSize,
TargetTransformInfo::UnrollingPreferences &UP,
unsigned &TripCount, ScalarEvolution &SE);
bool canPeel(Loop *L);
bool peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI, ScalarEvolution *SE,
DominatorTree *DT, AssumptionCache *AC, bool PreserveLCSSA);
LoopUnrollResult UnrollAndJamLoop(Loop *L, unsigned Count, unsigned TripCount,
unsigned TripMultiple, bool UnrollRemainder,
LoopInfo *LI, ScalarEvolution *SE,
DominatorTree *DT, AssumptionCache *AC,
OptimizationRemarkEmitter *ORE,
Loop **EpilogueLoop = nullptr);
bool isSafeToUnrollAndJam(Loop *L, ScalarEvolution &SE, DominatorTree &DT,
DependenceInfo &DI);
bool computeUnrollCount(Loop *L, const TargetTransformInfo &TTI,
DominatorTree &DT, LoopInfo *LI, ScalarEvolution &SE,
const SmallPtrSetImpl<const Value *> &EphValues,
OptimizationRemarkEmitter *ORE, unsigned &TripCount,
unsigned MaxTripCount, unsigned &TripMultiple,
unsigned LoopSize,
TargetTransformInfo::UnrollingPreferences &UP,
bool &UseUpperBound);
void remapInstruction(Instruction *I, ValueToValueMapTy &VMap);
void simplifyLoopAfterUnroll(Loop *L, bool SimplifyIVs, LoopInfo *LI,
ScalarEvolution *SE, DominatorTree *DT,
AssumptionCache *AC);
MDNode *GetUnrollMetadata(MDNode *LoopID, StringRef Name);
TargetTransformInfo::UnrollingPreferences gatherUnrollingPreferences(
Loop *L, ScalarEvolution &SE, const TargetTransformInfo &TTI,
BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI, int OptLevel,
Optional<unsigned> UserThreshold, Optional<unsigned> UserCount,
Optional<bool> UserAllowPartial, Optional<bool> UserRuntime,
Optional<bool> UserUpperBound, Optional<bool> UserAllowPeeling);
unsigned ApproximateLoopSize(const Loop *L, unsigned &NumCalls,
bool &NotDuplicatable, bool &Convergent,
const TargetTransformInfo &TTI,
const SmallPtrSetImpl<const Value *> &EphValues,
unsigned BEInsns);
} // end namespace llvm
#endif // LLVM_TRANSFORMS_UTILS_UNROLLLOOP_H
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