1 //===--- AMDGPUMacroFusion.cpp - AMDGPU 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 AMDGPU implementation of the DAG scheduling 10 /// mutation to pair instructions back to back. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "AMDGPUMacroFusion.h" 15 #include "MCTargetDesc/AMDGPUMCTargetDesc.h" 16 #include "SIInstrInfo.h" 17 #include "llvm/CodeGen/MacroFusion.h" 18 19 using namespace llvm; 20 21 namespace { 22 23 /// Check if the instr pair, FirstMI and SecondMI, should be fused 24 /// together. Given SecondMI, when FirstMI is unspecified, then check if 25 /// SecondMI may be part of a fused pair at all. 26 static bool shouldScheduleAdjacent(const TargetInstrInfo &TII_, 27 const TargetSubtargetInfo &TSI, 28 const MachineInstr *FirstMI, 29 const MachineInstr &SecondMI) { 30 const SIInstrInfo &TII = static_cast<const SIInstrInfo&>(TII_); 31 32 switch (SecondMI.getOpcode()) { 33 case AMDGPU::V_ADDC_U32_e64: 34 case AMDGPU::V_SUBB_U32_e64: 35 case AMDGPU::V_SUBBREV_U32_e64: 36 case AMDGPU::V_CNDMASK_B32_e64: { 37 // Try to cluster defs of condition registers to their uses. This improves 38 // the chance VCC will be available which will allow shrinking to VOP2 39 // encodings. 40 if (!FirstMI) 41 return true; 42 43 const MachineBasicBlock &MBB = *FirstMI->getParent(); 44 const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo(); 45 const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo(); 46 const MachineOperand *Src2 = TII.getNamedOperand(SecondMI, 47 AMDGPU::OpName::src2); 48 return FirstMI->definesRegister(Src2->getReg(), TRI); 49 } 50 default: 51 return false; 52 } 53 54 return false; 55 } 56 57 } // end namespace 58 59 60 namespace llvm { 61 62 std::unique_ptr<ScheduleDAGMutation> createAMDGPUMacroFusionDAGMutation () { 63 return createMacroFusionDAGMutation(shouldScheduleAdjacent); 64 } 65 66 } // end namespace llvm 67