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 "AMDGPUSubtarget.h" 16 #include "SIInstrInfo.h" 17 #include "MCTargetDesc/AMDGPUMCTargetDesc.h" 18 19 #include "llvm/CodeGen/MacroFusion.h" 20 21 using namespace llvm; 22 23 namespace { 24 25 /// Check if the instr pair, FirstMI and SecondMI, should be fused 26 /// together. Given SecondMI, when FirstMI is unspecified, then check if 27 /// SecondMI may be part of a fused pair at all. 28 static bool shouldScheduleAdjacent(const TargetInstrInfo &TII_, 29 const TargetSubtargetInfo &TSI, 30 const MachineInstr *FirstMI, 31 const MachineInstr &SecondMI) { 32 const SIInstrInfo &TII = static_cast<const SIInstrInfo&>(TII_); 33 34 switch (SecondMI.getOpcode()) { 35 case AMDGPU::V_ADDC_U32_e64: 36 case AMDGPU::V_SUBB_U32_e64: 37 case AMDGPU::V_SUBBREV_U32_e64: 38 case AMDGPU::V_CNDMASK_B32_e64: { 39 // Try to cluster defs of condition registers to their uses. This improves 40 // the chance VCC will be available which will allow shrinking to VOP2 41 // encodings. 42 if (!FirstMI) 43 return true; 44 45 const MachineBasicBlock &MBB = *FirstMI->getParent(); 46 const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo(); 47 const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo(); 48 const MachineOperand *Src2 = TII.getNamedOperand(SecondMI, 49 AMDGPU::OpName::src2); 50 return FirstMI->definesRegister(Src2->getReg(), TRI); 51 } 52 default: 53 return false; 54 } 55 56 return false; 57 } 58 59 } // end namespace 60 61 62 namespace llvm { 63 64 std::unique_ptr<ScheduleDAGMutation> createAMDGPUMacroFusionDAGMutation () { 65 return createMacroFusionDAGMutation(shouldScheduleAdjacent); 66 } 67 68 } // end namespace llvm 69