67 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9/// \file This file contains the AMDGPU implementation of the DAG scheduling10/// 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 fused24/// together. Given SecondMI, when FirstMI is unspecified, then check if25/// 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 improves38 // the chance VCC will be available which will allow shrinking to VOP239 // 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 namespace58 59 60namespace llvm {61 62std::unique_ptr<ScheduleDAGMutation> createAMDGPUMacroFusionDAGMutation() {63 return createMacroFusionDAGMutation(shouldScheduleAdjacent);64}65 66} // end namespace llvm67