1 //=- MachineLoopUtils.h - Helper functions for manipulating loops -*- C++ -*-=//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 #ifndef LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H
10 #define LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H
14 class MachineBasicBlock;
15 class MachineRegisterInfo;
16 class TargetInstrInfo;
18 enum LoopPeelDirection {
19 LPD_Front, ///< Peel the first iteration of the loop.
20 LPD_Back ///< Peel the last iteration of the loop.
23 /// Peels a single block loop. Loop must have two successors, one of which
24 /// must be itself. Similarly it must have two predecessors, one of which must
27 /// The loop block is copied and inserted into the CFG such that two copies of
28 /// the loop follow on from each other. The copy is inserted either before or
29 /// after the loop based on Direction.
31 /// Phis are updated and an unconditional branch inserted at the end of the
32 /// clone so as to execute a single iteration.
34 /// The trip count of Loop is not updated.
35 MachineBasicBlock *PeelSingleBlockLoop(LoopPeelDirection Direction,
36 MachineBasicBlock *Loop,
37 MachineRegisterInfo &MRI,
38 const TargetInstrInfo *TII);
40 /// Return true if PhysReg is live outside the loop, i.e. determine if it
41 /// is live in the loop exit blocks, and false otherwise.
42 bool isRegLiveInExitBlocks(MachineLoop *Loop, int PhysReg);
46 #endif // LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H