70 lines · cpp
1//===- ARMMacroFusion.cpp - ARM Macro Fusion ----------------------===//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-exception6//7//===----------------------------------------------------------------------===//8//9/// \file This file contains the ARM implementation of the DAG scheduling10/// mutation to pair instructions back to back.11//12//===----------------------------------------------------------------------===//13 14#include "ARMMacroFusion.h"15#include "ARMSubtarget.h"16#include "llvm/CodeGen/MacroFusion.h"17#include "llvm/CodeGen/TargetInstrInfo.h"18 19namespace llvm {20 21// Fuse AES crypto encoding or decoding.22static bool isAESPair(const MachineInstr *FirstMI,23 const MachineInstr &SecondMI) {24 // Assume the 1st instr to be a wildcard if it is unspecified.25 switch(SecondMI.getOpcode()) {26 // AES encode.27 case ARM::AESMC :28 return FirstMI == nullptr || FirstMI->getOpcode() == ARM::AESE;29 // AES decode.30 case ARM::AESIMC:31 return FirstMI == nullptr || FirstMI->getOpcode() == ARM::AESD;32 }33 34 return false;35}36 37// Fuse literal generation.38static bool isLiteralsPair(const MachineInstr *FirstMI,39 const MachineInstr &SecondMI) {40 // Assume the 1st instr to be a wildcard if it is unspecified.41 if ((FirstMI == nullptr || FirstMI->getOpcode() == ARM::MOVi16) &&42 SecondMI.getOpcode() == ARM::MOVTi16)43 return true;44 45 return false;46}47 48/// Check if the instr pair, FirstMI and SecondMI, should be fused49/// together. Given SecondMI, when FirstMI is unspecified, then check if50/// SecondMI may be part of a fused pair at all.51static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,52 const TargetSubtargetInfo &TSI,53 const MachineInstr *FirstMI,54 const MachineInstr &SecondMI) {55 const ARMSubtarget &ST = static_cast<const ARMSubtarget&>(TSI);56 57 if (ST.hasFuseAES() && isAESPair(FirstMI, SecondMI))58 return true;59 if (ST.hasFuseLiterals() && isLiteralsPair(FirstMI, SecondMI))60 return true;61 62 return false;63}64 65std::unique_ptr<ScheduleDAGMutation> createARMMacroFusionDAGMutation() {66 return createMacroFusionDAGMutation(shouldScheduleAdjacent);67}68 69} // end namespace llvm70