Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- MacroFusion.h - Macro Fusion -----------------------------*- 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

//

//===----------------------------------------------------------------------===//

//

/// \file This file contains the definition of the DAG scheduling mutation to

/// pair instructions back to back.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_MACROFUSION_H

#define LLVM_CODEGEN_MACROFUSION_H

#include <functional>

#include <memory>

namespace llvm {

class MachineInstr;

class ScheduleDAGMutation;

class TargetInstrInfo;

class TargetSubtargetInfo;

class ScheduleDAGInstrs;

class SUnit;

/// Check if the instr pair, FirstMI and SecondMI, should be fused

/// together. Given SecondMI, when FirstMI is unspecified, then check if

/// SecondMI may be part of a fused pair at all.

using ShouldSchedulePredTy = std::function<bool(const TargetInstrInfo &TII,

                                                const TargetSubtargetInfo &TSI,

                                                const MachineInstr *FirstMI,

                                                const MachineInstr &SecondMI)>;

/// Checks if the number of cluster edges between SU and its predecessors is

/// less than FuseLimit

bool hasLessThanNumFused(const SUnit &SU, unsigned FuseLimit);

/// Create an artificial edge between FirstSU and SecondSU.

/// Make data dependencies from the FirstSU also dependent on the SecondSU to

/// prevent them from being scheduled between the FirstSU and the SecondSU

/// and vice-versa.

/// Fusing more than 2 instructions is not currently supported.

bool fuseInstructionPair(ScheduleDAGInstrs &DAG, SUnit &FirstSU,

                         SUnit &SecondSU);

/// Create a DAG scheduling mutation to pair instructions back to back

/// for instructions that benefit according to the target-specific

/// shouldScheduleAdjacent predicate function.

std::unique_ptr<ScheduleDAGMutation>

createMacroFusionDAGMutation(ShouldSchedulePredTy shouldScheduleAdjacent);

/// Create a DAG scheduling mutation to pair branch instructions with one

/// of their predecessors back to back for instructions that benefit according

/// to the target-specific shouldScheduleAdjacent predicate function.

std::unique_ptr<ScheduleDAGMutation>

createBranchMacroFusionDAGMutation(ShouldSchedulePredTy shouldScheduleAdjacent);

} // end namespace llvm

#endif // LLVM_CODEGEN_MACROFUSION_H