llvm/llvm/include/llvm/ADT/GenericCycleInfo.h

//===- GenericCycleInfo.h - Info for Cycles in any IR ------*- 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Find all cycles in a control-flow graph, including irreducible loops.
///
/// See docs/CycleTerminology.rst for a formal definition of cycles.
///
/// Briefly:
/// - A cycle is a generalization of a loop which can represent
///   irreducible control flow.
/// - Cycles identified in a program are implementation defined,
///   depending on the DFS traversal chosen.
/// - Cycles are well-nested, and form a forest with a parent-child
///   relationship.
/// - In any choice of DFS, every natural loop L is represented by a
///   unique cycle C which is a superset of L.
/// - In the absence of irreducible control flow, the cycles are
///   exactly the natural loops in the program.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_GENERICCYCLEINFO_H
#define LLVM_ADT_GENERICCYCLEINFO_H

#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/GenericSSAContext.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

namespace llvm {

template <typename ContextT> class GenericCycleInfo;
template <typename ContextT> class GenericCycleInfoCompute;

/// A possibly irreducible generalization of a \ref Loop.
template <typename ContextT> class GenericCycle { … };

/// \brief Cycle information for a function.
template <typename ContextT> class GenericCycleInfo { … };

/// \brief GraphTraits for iterating over a sub-tree of the CycleT tree.
template <typename CycleRefT, typename ChildIteratorT> struct CycleGraphTraits { … };

GraphTraits<const GenericCycle<BlockT> *>;
GraphTraits<GenericCycle<BlockT> *>;

} // namespace llvm

#endif // LLVM_ADT_GENERICCYCLEINFO_H