| //=- 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_LIB_CODEGEN_MACHINELOOPUTILS_H |
| #define LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H |
| |
| namespace llvm { |
| class MachineLoop; |
| 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); |
| |
| /// Return true if PhysReg is live outside the loop, i.e. determine if it |
| /// is live in the loop exit blocks, and false otherwise. |
| bool isRegLiveInExitBlocks(MachineLoop *Loop, int PhysReg); |
| |
| } // namespace llvm |
| |
| #endif // LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H |