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| 14 | pmbaty | 1 | //=- MachineLoopUtils.h - Helper functions for manipulating loops -*- C++ -*-=// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |||
| 9 | #ifndef LLVM_CODEGEN_MACHINELOOPUTILS_H |
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| 10 | #define LLVM_CODEGEN_MACHINELOOPUTILS_H |
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| 11 | |||
| 12 | namespace llvm { |
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| 13 | class MachineBasicBlock; |
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| 14 | class MachineRegisterInfo; |
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| 15 | class TargetInstrInfo; |
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| 16 | |||
| 17 | enum LoopPeelDirection { |
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| 18 | LPD_Front, ///< Peel the first iteration of the loop. |
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| 19 | LPD_Back ///< Peel the last iteration of the loop. |
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| 20 | }; |
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| 21 | |||
| 22 | /// Peels a single block loop. Loop must have two successors, one of which |
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| 23 | /// must be itself. Similarly it must have two predecessors, one of which must |
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| 24 | /// be itself. |
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| 25 | /// |
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| 26 | /// The loop block is copied and inserted into the CFG such that two copies of |
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| 27 | /// the loop follow on from each other. The copy is inserted either before or |
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| 28 | /// after the loop based on Direction. |
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| 29 | /// |
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| 30 | /// Phis are updated and an unconditional branch inserted at the end of the |
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| 31 | /// clone so as to execute a single iteration. |
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| 32 | /// |
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| 33 | /// The trip count of Loop is not updated. |
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| 34 | MachineBasicBlock *PeelSingleBlockLoop(LoopPeelDirection Direction, |
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| 35 | MachineBasicBlock *Loop, |
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| 36 | MachineRegisterInfo &MRI, |
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| 37 | const TargetInstrInfo *TII); |
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| 38 | |||
| 39 | } // namespace llvm |
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| 40 | |||
| 41 | #endif // LLVM_CODEGEN_MACHINELOOPUTILS_H |