1 //===- MacroFusion.h - Macro Fusion -----------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 /// \file This file contains the definition of the DAG scheduling mutation to 10 /// pair instructions back to back. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_CODEGEN_MACROFUSION_H 15 #define LLVM_CODEGEN_MACROFUSION_H 16 17 #include "llvm/ADT/ArrayRef.h" 18 #include <memory> 19 20 namespace llvm { 21 22 class MachineInstr; 23 class ScheduleDAGMutation; 24 class TargetInstrInfo; 25 class TargetSubtargetInfo; 26 class ScheduleDAGInstrs; 27 class SUnit; 28 29 /// Check if the instr pair, FirstMI and SecondMI, should be fused 30 /// together. Given SecondMI, when FirstMI is unspecified, then check if 31 /// SecondMI may be part of a fused pair at all. 32 using MacroFusionPredTy = bool (*)(const TargetInstrInfo &TII, 33 const TargetSubtargetInfo &STI, 34 const MachineInstr *FirstMI, 35 const MachineInstr &SecondMI); 36 37 /// Checks if the number of cluster edges between SU and its predecessors is 38 /// less than FuseLimit 39 bool hasLessThanNumFused(const SUnit &SU, unsigned FuseLimit); 40 41 /// Create an artificial edge between FirstSU and SecondSU. 42 /// Make data dependencies from the FirstSU also dependent on the SecondSU to 43 /// prevent them from being scheduled between the FirstSU and the SecondSU 44 /// and vice-versa. 45 /// Fusing more than 2 instructions is not currently supported. 46 bool fuseInstructionPair(ScheduleDAGInstrs &DAG, SUnit &FirstSU, 47 SUnit &SecondSU); 48 49 /// Create a DAG scheduling mutation to pair instructions back to back 50 /// for instructions that benefit according to the target-specific 51 /// predicate functions. shouldScheduleAdjacent will be true if any of the 52 /// provided predicates are true. 53 /// If BranchOnly is true, only branch instructions with one of their 54 /// predecessors will be fused. 55 std::unique_ptr<ScheduleDAGMutation> 56 createMacroFusionDAGMutation(ArrayRef<MacroFusionPredTy> Predicates, 57 bool BranchOnly = false); 58 59 } // end namespace llvm 60 61 #endif // LLVM_CODEGEN_MACROFUSION_H 62