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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 /// \file This file contains the ARM implementation of the DAG scheduling 10 /// 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 19 namespace llvm { 20 21 // Fuse AES crypto encoding or decoding. 22 static 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. 38 static 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 fused 49 /// together. Given SecondMI, when FirstMI is unspecified, then check if 50 /// SecondMI may be part of a fused pair at all. 51 static 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 65 std::unique_ptr<ScheduleDAGMutation> createARMMacroFusionDAGMutation () { 66 return createMacroFusionDAGMutation(shouldScheduleAdjacent); 67 } 68 69 } // end namespace llvm 70