1 //===- GCNCreateVOPD.cpp - Create VOPD Instructions ----------------------===// 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 10 /// Combine VALU pairs into VOPD instructions 11 /// Only works on wave32 12 /// Has register requirements, we reject creating VOPD if the requirements are 13 /// not met. 14 /// shouldCombineVOPD mutator in postRA machine scheduler puts candidate 15 /// instructions for VOPD back-to-back 16 /// 17 // 18 //===----------------------------------------------------------------------===// 19 20 #include "AMDGPU.h" 21 #include "GCNSubtarget.h" 22 #include "GCNVOPDUtils.h" 23 #include "MCTargetDesc/AMDGPUMCTargetDesc.h" 24 #include "SIInstrInfo.h" 25 #include "Utils/AMDGPUBaseInfo.h" 26 #include "llvm/ADT/SmallVector.h" 27 #include "llvm/ADT/Statistic.h" 28 #include "llvm/ADT/StringMap.h" 29 #include "llvm/CodeGen/MachineBasicBlock.h" 30 #include "llvm/CodeGen/MachineInstr.h" 31 #include "llvm/CodeGen/MachineOperand.h" 32 #include "llvm/Support/Casting.h" 33 #include "llvm/Support/Debug.h" 34 #include <utility> 35 36 #define DEBUG_TYPE "gcn-create-vopd" 37 STATISTIC(NumVOPDCreated, "Number of VOPD Insts Created."); 38 39 using namespace llvm; 40 41 namespace { 42 43 class GCNCreateVOPD : public MachineFunctionPass { 44 private: 45 public: 46 static char ID; 47 const GCNSubtarget *ST = nullptr; 48 49 GCNCreateVOPD() : MachineFunctionPass(ID) {} 50 51 void getAnalysisUsage(AnalysisUsage &AU) const override { 52 AU.setPreservesCFG(); 53 MachineFunctionPass::getAnalysisUsage(AU); 54 } 55 56 StringRef getPassName() const override { 57 return "GCN Create VOPD Instructions"; 58 } 59 60 bool doReplace(const SIInstrInfo *SII, 61 std::pair<MachineInstr *, MachineInstr *> &Pair) { 62 auto *FirstMI = Pair.first; 63 auto *SecondMI = Pair.second; 64 unsigned Opc1 = FirstMI->getOpcode(); 65 unsigned Opc2 = SecondMI->getOpcode(); 66 int NewOpcode = AMDGPU::getVOPDFull(AMDGPU::getVOPDOpcode(Opc1), 67 AMDGPU::getVOPDOpcode(Opc2)); 68 assert(NewOpcode != -1 && 69 "Should have previously determined this as a possible VOPD\n"); 70 71 auto VOPDInst = BuildMI(*FirstMI->getParent(), FirstMI, 72 FirstMI->getDebugLoc(), SII->get(NewOpcode)) 73 .setMIFlags(FirstMI->getFlags() | SecondMI->getFlags()); 74 75 namespace VOPD = AMDGPU::VOPD; 76 MachineInstr *MI[] = {FirstMI, SecondMI}; 77 auto InstInfo = 78 AMDGPU::getVOPDInstInfo(FirstMI->getDesc(), SecondMI->getDesc()); 79 80 for (auto CompIdx : VOPD::COMPONENTS) { 81 auto MCOprIdx = InstInfo[CompIdx].getIndexOfDstInMCOperands(); 82 VOPDInst.add(MI[CompIdx]->getOperand(MCOprIdx)); 83 } 84 85 for (auto CompIdx : VOPD::COMPONENTS) { 86 auto CompSrcOprNum = InstInfo[CompIdx].getCompSrcOperandsNum(); 87 for (unsigned CompSrcIdx = 0; CompSrcIdx < CompSrcOprNum; ++CompSrcIdx) { 88 auto MCOprIdx = InstInfo[CompIdx].getIndexOfSrcInMCOperands(CompSrcIdx); 89 VOPDInst.add(MI[CompIdx]->getOperand(MCOprIdx)); 90 } 91 } 92 93 for (auto CompIdx : VOPD::COMPONENTS) 94 VOPDInst.copyImplicitOps(*MI[CompIdx]); 95 96 LLVM_DEBUG(dbgs() << "VOPD Fused: " << *VOPDInst << " from\tX: " 97 << *Pair.first << "\tY: " << *Pair.second << "\n"); 98 99 for (auto CompIdx : VOPD::COMPONENTS) 100 MI[CompIdx]->eraseFromParent(); 101 102 ++NumVOPDCreated; 103 return true; 104 } 105 106 bool runOnMachineFunction(MachineFunction &MF) override { 107 if (skipFunction(MF.getFunction())) 108 return false; 109 ST = &MF.getSubtarget<GCNSubtarget>(); 110 if (!AMDGPU::hasVOPD(*ST) || !ST->isWave32()) 111 return false; 112 LLVM_DEBUG(dbgs() << "CreateVOPD Pass:\n"); 113 114 const SIInstrInfo *SII = ST->getInstrInfo(); 115 bool Changed = false; 116 117 SmallVector<std::pair<MachineInstr *, MachineInstr *>> ReplaceCandidates; 118 119 for (auto &MBB : MF) { 120 auto MII = MBB.begin(), E = MBB.end(); 121 while (MII != E) { 122 auto *FirstMI = &*MII; 123 MII = next_nodbg(MII, MBB.end()); 124 if (MII == MBB.end()) 125 break; 126 if (FirstMI->isDebugInstr()) 127 continue; 128 auto *SecondMI = &*MII; 129 unsigned Opc = FirstMI->getOpcode(); 130 unsigned Opc2 = SecondMI->getOpcode(); 131 llvm::AMDGPU::CanBeVOPD FirstCanBeVOPD = AMDGPU::getCanBeVOPD(Opc); 132 llvm::AMDGPU::CanBeVOPD SecondCanBeVOPD = AMDGPU::getCanBeVOPD(Opc2); 133 std::pair<MachineInstr *, MachineInstr *> Pair; 134 135 if (FirstCanBeVOPD.X && SecondCanBeVOPD.Y) 136 Pair = {FirstMI, SecondMI}; 137 else if (FirstCanBeVOPD.Y && SecondCanBeVOPD.X) 138 Pair = {SecondMI, FirstMI}; 139 else 140 continue; 141 // checkVOPDRegConstraints cares about program order, but doReplace 142 // cares about X-Y order in the constituted VOPD 143 if (llvm::checkVOPDRegConstraints(*SII, *FirstMI, *SecondMI)) { 144 ReplaceCandidates.push_back(Pair); 145 ++MII; 146 } 147 } 148 } 149 for (auto &Pair : ReplaceCandidates) { 150 Changed |= doReplace(SII, Pair); 151 } 152 153 return Changed; 154 } 155 }; 156 157 } // namespace 158 159 char GCNCreateVOPD::ID = 0; 160 161 char &llvm::GCNCreateVOPDID = GCNCreateVOPD::ID; 162 163 INITIALIZE_PASS(GCNCreateVOPD, DEBUG_TYPE, "GCN Create VOPD Instructions", 164 false, false) 165