//===- 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