Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//=- MachineLoopUtils.h - Helper functions for manipulating loops -*- 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

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_MACHINELOOPUTILS_H

#define LLVM_CODEGEN_MACHINELOOPUTILS_H

namespace llvm {

class MachineBasicBlock;

class MachineRegisterInfo;

class TargetInstrInfo;

enum LoopPeelDirection {

  LPD_Front, ///< Peel the first iteration of the loop.

  LPD_Back   ///< Peel the last iteration of the loop.

};

/// Peels a single block loop. Loop must have two successors, one of which

/// must be itself. Similarly it must have two predecessors, one of which must

/// be itself.

///

/// The loop block is copied and inserted into the CFG such that two copies of

/// the loop follow on from each other. The copy is inserted either before or

/// after the loop based on Direction.

///

/// Phis are updated and an unconditional branch inserted at the end of the

/// clone so as to execute a single iteration.

///

/// The trip count of Loop is not updated.

MachineBasicBlock *PeelSingleBlockLoop(LoopPeelDirection Direction,

                                       MachineBasicBlock *Loop,

                                       MachineRegisterInfo &MRI,

                                       const TargetInstrInfo *TII);

} // namespace llvm

#endif // LLVM_CODEGEN_MACHINELOOPUTILS_H