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 19using namespace llvm; 20 21namespace { 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. 26static 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 60namespace llvm { 61 62std::unique_ptr<ScheduleDAGMutation> createAMDGPUMacroFusionDAGMutation() { 63 return createMacroFusionDAGMutation(shouldScheduleAdjacent); 64} 65 66} // end namespace llvm 67