llvm/llvm/lib/Target/ARM/MVETailPredUtils.h

//===-- MVETailPredUtils.h - Tail predication utility functions -*- 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
//
//===----------------------------------------------------------------------===//
//
// This file contains utility functions for low overhead and tail predicated
// loops, shared between the ARMLowOverheadLoops pass and anywhere else that
// needs them.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_ARM_MVETAILPREDUTILS_H
#define LLVM_LIB_TARGET_ARM_MVETAILPREDUTILS_H

#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/TargetInstrInfo.h"

namespace llvm {

static inline unsigned VCTPOpcodeToLSTP(unsigned Opcode, bool IsDoLoop) { … }

static inline unsigned getTailPredVectorWidth(unsigned Opcode) { … }

static inline bool isVCTP(const MachineInstr *MI) { … }

static inline bool isDoLoopStart(const MachineInstr &MI) { … }

static inline bool isWhileLoopStart(const MachineInstr &MI) { … }

static inline bool isLoopStart(const MachineInstr &MI) { … }

// Return the TargetBB stored in a t2WhileLoopStartLR/t2WhileLoopStartTP.
inline MachineBasicBlock *getWhileLoopStartTargetBB(const MachineInstr &MI) { … }

// WhileLoopStart holds the exit block, so produce a subs Op0, Op1, 0 and then a
// beq that branches to the exit branch.
// If UseCmp is true, this will create a t2CMP instead of a t2SUBri, meaning the
// value of LR into the loop will not be setup. This is used if the LR setup is
// done via another means (via a t2DoLoopStart, for example).
inline void RevertWhileLoopStartLR(MachineInstr *MI, const TargetInstrInfo *TII,
                                   unsigned BrOpc = ARM::t2Bcc,
                                   bool UseCmp = false) { … }

inline void RevertDoLoopStart(MachineInstr *MI, const TargetInstrInfo *TII) { … }

inline void RevertLoopDec(MachineInstr *MI, const TargetInstrInfo *TII,
                          bool SetFlags = false) { … }

// Generate a subs, or sub and cmp, and a branch instead of an LE.
inline void RevertLoopEnd(MachineInstr *MI, const TargetInstrInfo *TII,
                          unsigned BrOpc = ARM::t2Bcc, bool SkipCmp = false) { … }

} // end namespace llvm

#endif // LLVM_LIB_TARGET_ARM_MVETAILPREDUTILS_H