1 //===- GCNCreateVOPD.cpp - Create VOPD Instructions ----------------------===//
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
7 //===----------------------------------------------------------------------===//
10 /// Combine VALU pairs into VOPD instructions
11 /// Only works on wave32
12 /// Has register requirements, we reject creating VOPD if the requirements are
14 /// shouldCombineVOPD mutator in postRA machine scheduler puts candidate
15 /// instructions for VOPD back-to-back
18 //===----------------------------------------------------------------------===//
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"
36 #define DEBUG_TYPE "gcn-create-vopd"
37 STATISTIC(NumVOPDCreated, "Number of VOPD Insts Created.");
43 class GCNCreateVOPD : public MachineFunctionPass {
47 const GCNSubtarget *ST = nullptr;
49 GCNCreateVOPD() : MachineFunctionPass(ID) {}
51 void getAnalysisUsage(AnalysisUsage &AU) const override {
53 MachineFunctionPass::getAnalysisUsage(AU);
56 StringRef getPassName() const override {
57 return "GCN Create VOPD Instructions";
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");
71 auto VOPDInst = BuildMI(*FirstMI->getParent(), FirstMI,
72 FirstMI->getDebugLoc(), SII->get(NewOpcode))
73 .setMIFlags(FirstMI->getFlags() | SecondMI->getFlags());
75 namespace VOPD = AMDGPU::VOPD;
76 MachineInstr *MI[] = {FirstMI, SecondMI};
78 AMDGPU::getVOPDInstInfo(FirstMI->getDesc(), SecondMI->getDesc());
80 for (auto CompIdx : VOPD::COMPONENTS) {
81 auto MCOprIdx = InstInfo[CompIdx].getIndexOfDstInMCOperands();
82 VOPDInst.add(MI[CompIdx]->getOperand(MCOprIdx));
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));
93 for (auto CompIdx : VOPD::COMPONENTS)
94 VOPDInst.copyImplicitOps(*MI[CompIdx]);
96 LLVM_DEBUG(dbgs() << "VOPD Fused: " << *VOPDInst << " from\tX: "
97 << *Pair.first << "\tY: " << *Pair.second << "\n");
99 for (auto CompIdx : VOPD::COMPONENTS)
100 MI[CompIdx]->eraseFromParent();
106 bool runOnMachineFunction(MachineFunction &MF) override {
107 if (skipFunction(MF.getFunction()))
109 ST = &MF.getSubtarget<GCNSubtarget>();
110 if (!AMDGPU::hasVOPD(*ST) || !ST->isWave32())
112 LLVM_DEBUG(dbgs() << "CreateVOPD Pass:\n");
114 const SIInstrInfo *SII = ST->getInstrInfo();
115 bool Changed = false;
117 SmallVector<std::pair<MachineInstr *, MachineInstr *>> ReplaceCandidates;
119 for (auto &MBB : MF) {
120 auto MII = MBB.begin(), E = MBB.end();
122 auto *FirstMI = &*MII;
123 MII = next_nodbg(MII, MBB.end());
124 if (MII == MBB.end())
126 if (FirstMI->isDebugInstr())
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;
135 if (FirstCanBeVOPD.X && SecondCanBeVOPD.Y)
136 Pair = {FirstMI, SecondMI};
137 else if (FirstCanBeVOPD.Y && SecondCanBeVOPD.X)
138 Pair = {SecondMI, FirstMI};
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);
149 for (auto &Pair : ReplaceCandidates) {
150 Changed |= doReplace(SII, Pair);
159 char GCNCreateVOPD::ID = 0;
161 char &llvm::GCNCreateVOPDID = GCNCreateVOPD::ID;
163 INITIALIZE_PASS(GCNCreateVOPD, DEBUG_TYPE, "GCN Create VOPD Instructions",