43 lines
1.5 KiB
C
43 lines
1.5 KiB
C
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//=- MachineLoopUtils.h - Helper functions for manipulating loops -*- C++ -*-=//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H
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#define LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H
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namespace llvm {
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class MachineLoop;
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class MachineBasicBlock;
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class MachineRegisterInfo;
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class TargetInstrInfo;
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enum LoopPeelDirection {
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LPD_Front, ///< Peel the first iteration of the loop.
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LPD_Back ///< Peel the last iteration of the loop.
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};
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/// Peels a single block loop. Loop must have two successors, one of which
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/// must be itself. Similarly it must have two predecessors, one of which must
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/// be itself.
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///
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/// The loop block is copied and inserted into the CFG such that two copies of
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/// the loop follow on from each other. The copy is inserted either before or
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/// after the loop based on Direction.
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///
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/// Phis are updated and an unconditional branch inserted at the end of the
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/// clone so as to execute a single iteration.
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///
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/// The trip count of Loop is not updated.
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MachineBasicBlock *PeelSingleBlockLoop(LoopPeelDirection Direction,
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MachineBasicBlock *Loop,
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MachineRegisterInfo &MRI,
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const TargetInstrInfo *TII);
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} // namespace llvm
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#endif // LLVM_LIB_CODEGEN_MACHINELOOPUTILS_H
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