LoopPeel.h

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//===- llvm/Transforms/Utils/LoopPeel.h ----- Peeling 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 peeling utilities. It does not define any
// actual pass or policy.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_TRANSFORMS_UTILS_LOOPPEEL_H
#define LLVM_TRANSFORMS_UTILS_LOOPPEEL_H
 
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
 
namespace llvm {
 
LLVM_ABI bool canPeel(const Loop *L);
 
/// Returns true if the last iteration of \p L can be peeled off. It makes sure
/// the loop exit condition can be adjusted when peeling and that the loop
/// executes at least 2 iterations.
LLVM_ABI bool canPeelLastIteration(const Loop &L, ScalarEvolution &SE);
 
/// VMap is the value-map that maps instructions from the original loop to
/// instructions in the last peeled-off iteration. If \p PeelLast is true, peel
/// off the last \p PeelCount iterations from \p L (canPeelLastIteration must be
/// true for \p L), otherwise peel off the first \p PeelCount iterations.
LLVM_ABI void peelLoop(Loop *L, unsigned PeelCount, bool PeelLast, LoopInfo *LI,
                       ScalarEvolution *SE, DominatorTree &DT,
                       AssumptionCache *AC, bool PreserveLCSSA,
                       ValueToValueMapTy &VMap);
 
LLVM_ABI TargetTransformInfo::PeelingPreferences
gatherPeelingPreferences(Loop *L, ScalarEvolution &SE,
                         const TargetTransformInfo &TTI,
                         std::optional<bool> UserAllowPeeling,
                         std::optional<bool> UserAllowProfileBasedPeeling,
                         bool UnrollingSpecficValues = false);
 
LLVM_ABI void computePeelCount(Loop *L, unsigned LoopSize,
                               TargetTransformInfo::PeelingPreferences &PP,
                               unsigned TripCount, DominatorTree &DT,
                               ScalarEvolution &SE,
                               const TargetTransformInfo &TTI,
                               AssumptionCache *AC = nullptr,
                               unsigned Threshold = UINT_MAX);
 
} // end namespace llvm
 
#endif // LLVM_TRANSFORMS_UTILS_LOOPPEEL_H