+++ /dev/null
-//===--------------------- R600MergeVectorRegisters.cpp -------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-/// \file
-/// This pass merges inputs of swizzeable instructions into vector sharing
-/// common data and/or have enough undef subreg using swizzle abilities.
-///
-/// For instance let's consider the following pseudo code :
-/// vreg5<def> = REG_SEQ vreg1, sub0, vreg2, sub1, vreg3, sub2, undef, sub3
-/// ...
-/// vreg7<def> = REG_SEQ vreg1, sub0, vreg3, sub1, undef, sub2, vreg4, sub3
-/// (swizzable Inst) vreg7, SwizzleMask : sub0, sub1, sub2, sub3
-///
-/// is turned into :
-/// vreg5<def> = REG_SEQ vreg1, sub0, vreg2, sub1, vreg3, sub2, undef, sub3
-/// ...
-/// vreg7<def> = INSERT_SUBREG vreg4, sub3
-/// (swizzable Inst) vreg7, SwizzleMask : sub0, sub2, sub1, sub3
-///
-/// This allow regalloc to reduce register pressure for vector registers and
-/// to reduce MOV count.
-//===----------------------------------------------------------------------===//
-
-#include "AMDGPU.h"
-#include "AMDGPUSubtarget.h"
-#include "R600InstrInfo.h"
-#include "llvm/CodeGen/DFAPacketizer.h"
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-
-using namespace llvm;
-
-#define DEBUG_TYPE "vec-merger"
-
-namespace {
-
-static bool
-isImplicitlyDef(MachineRegisterInfo &MRI, unsigned Reg) {
- for (MachineRegisterInfo::def_instr_iterator It = MRI.def_instr_begin(Reg),
- E = MRI.def_instr_end(); It != E; ++It) {
- return (*It).isImplicitDef();
- }
- if (MRI.isReserved(Reg)) {
- return false;
- }
- llvm_unreachable("Reg without a def");
- return false;
-}
-
-class RegSeqInfo {
-public:
- MachineInstr *Instr;
- DenseMap<unsigned, unsigned> RegToChan;
- std::vector<unsigned> UndefReg;
- RegSeqInfo(MachineRegisterInfo &MRI, MachineInstr *MI) : Instr(MI) {
- assert(MI->getOpcode() == AMDGPU::REG_SEQUENCE);
- for (unsigned i = 1, e = Instr->getNumOperands(); i < e; i+=2) {
- MachineOperand &MO = Instr->getOperand(i);
- unsigned Chan = Instr->getOperand(i + 1).getImm();
- if (isImplicitlyDef(MRI, MO.getReg()))
- UndefReg.push_back(Chan);
- else
- RegToChan[MO.getReg()] = Chan;
- }
- }
- RegSeqInfo() {}
-
- bool operator==(const RegSeqInfo &RSI) const {
- return RSI.Instr == Instr;
- }
-};
-
-class R600VectorRegMerger : public MachineFunctionPass {
-private:
- MachineRegisterInfo *MRI;
- const R600InstrInfo *TII;
- bool canSwizzle(const MachineInstr &) const;
- bool areAllUsesSwizzeable(unsigned Reg) const;
- void SwizzleInput(MachineInstr &,
- const std::vector<std::pair<unsigned, unsigned> > &) const;
- bool tryMergeVector(const RegSeqInfo *, RegSeqInfo *,
- std::vector<std::pair<unsigned, unsigned> > &Remap) const;
- bool tryMergeUsingCommonSlot(RegSeqInfo &RSI, RegSeqInfo &CompatibleRSI,
- std::vector<std::pair<unsigned, unsigned> > &RemapChan);
- bool tryMergeUsingFreeSlot(RegSeqInfo &RSI, RegSeqInfo &CompatibleRSI,
- std::vector<std::pair<unsigned, unsigned> > &RemapChan);
- MachineInstr *RebuildVector(RegSeqInfo *MI,
- const RegSeqInfo *BaseVec,
- const std::vector<std::pair<unsigned, unsigned> > &RemapChan) const;
- void RemoveMI(MachineInstr *);
- void trackRSI(const RegSeqInfo &RSI);
-
- typedef DenseMap<unsigned, std::vector<MachineInstr *> > InstructionSetMap;
- DenseMap<MachineInstr *, RegSeqInfo> PreviousRegSeq;
- InstructionSetMap PreviousRegSeqByReg;
- InstructionSetMap PreviousRegSeqByUndefCount;
-public:
- static char ID;
- R600VectorRegMerger(TargetMachine &tm) : MachineFunctionPass(ID),
- TII(nullptr) { }
-
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.setPreservesCFG();
- AU.addRequired<MachineDominatorTree>();
- AU.addPreserved<MachineDominatorTree>();
- AU.addRequired<MachineLoopInfo>();
- AU.addPreserved<MachineLoopInfo>();
- MachineFunctionPass::getAnalysisUsage(AU);
- }
-
- const char *getPassName() const override {
- return "R600 Vector Registers Merge Pass";
- }
-
- bool runOnMachineFunction(MachineFunction &Fn) override;
-};
-
-char R600VectorRegMerger::ID = 0;
-
-bool R600VectorRegMerger::canSwizzle(const MachineInstr &MI)
- const {
- if (TII->get(MI.getOpcode()).TSFlags & R600_InstFlag::TEX_INST)
- return true;
- switch (MI.getOpcode()) {
- case AMDGPU::R600_ExportSwz:
- case AMDGPU::EG_ExportSwz:
- return true;
- default:
- return false;
- }
-}
-
-bool R600VectorRegMerger::tryMergeVector(const RegSeqInfo *Untouched,
- RegSeqInfo *ToMerge, std::vector< std::pair<unsigned, unsigned> > &Remap)
- const {
- unsigned CurrentUndexIdx = 0;
- for (DenseMap<unsigned, unsigned>::iterator It = ToMerge->RegToChan.begin(),
- E = ToMerge->RegToChan.end(); It != E; ++It) {
- DenseMap<unsigned, unsigned>::const_iterator PosInUntouched =
- Untouched->RegToChan.find((*It).first);
- if (PosInUntouched != Untouched->RegToChan.end()) {
- Remap.push_back(std::pair<unsigned, unsigned>
- ((*It).second, (*PosInUntouched).second));
- continue;
- }
- if (CurrentUndexIdx >= Untouched->UndefReg.size())
- return false;
- Remap.push_back(std::pair<unsigned, unsigned>
- ((*It).second, Untouched->UndefReg[CurrentUndexIdx++]));
- }
-
- return true;
-}
-
-static
-unsigned getReassignedChan(
- const std::vector<std::pair<unsigned, unsigned> > &RemapChan,
- unsigned Chan) {
- for (unsigned j = 0, je = RemapChan.size(); j < je; j++) {
- if (RemapChan[j].first == Chan)
- return RemapChan[j].second;
- }
- llvm_unreachable("Chan wasn't reassigned");
-}
-
-MachineInstr *R600VectorRegMerger::RebuildVector(
- RegSeqInfo *RSI, const RegSeqInfo *BaseRSI,
- const std::vector<std::pair<unsigned, unsigned> > &RemapChan) const {
- unsigned Reg = RSI->Instr->getOperand(0).getReg();
- MachineBasicBlock::iterator Pos = RSI->Instr;
- MachineBasicBlock &MBB = *Pos->getParent();
- DebugLoc DL = Pos->getDebugLoc();
-
- unsigned SrcVec = BaseRSI->Instr->getOperand(0).getReg();
- DenseMap<unsigned, unsigned> UpdatedRegToChan = BaseRSI->RegToChan;
- std::vector<unsigned> UpdatedUndef = BaseRSI->UndefReg;
- for (DenseMap<unsigned, unsigned>::iterator It = RSI->RegToChan.begin(),
- E = RSI->RegToChan.end(); It != E; ++It) {
- unsigned DstReg = MRI->createVirtualRegister(&AMDGPU::R600_Reg128RegClass);
- unsigned SubReg = (*It).first;
- unsigned Swizzle = (*It).second;
- unsigned Chan = getReassignedChan(RemapChan, Swizzle);
-
- MachineInstr *Tmp = BuildMI(MBB, Pos, DL, TII->get(AMDGPU::INSERT_SUBREG),
- DstReg)
- .addReg(SrcVec)
- .addReg(SubReg)
- .addImm(Chan);
- UpdatedRegToChan[SubReg] = Chan;
- std::vector<unsigned>::iterator ChanPos =
- std::find(UpdatedUndef.begin(), UpdatedUndef.end(), Chan);
- if (ChanPos != UpdatedUndef.end())
- UpdatedUndef.erase(ChanPos);
- assert(std::find(UpdatedUndef.begin(), UpdatedUndef.end(), Chan) ==
- UpdatedUndef.end() &&
- "UpdatedUndef shouldn't contain Chan more than once!");
- DEBUG(dbgs() << " ->"; Tmp->dump(););
- (void)Tmp;
- SrcVec = DstReg;
- }
- Pos = BuildMI(MBB, Pos, DL, TII->get(AMDGPU::COPY), Reg)
- .addReg(SrcVec);
- DEBUG(dbgs() << " ->"; Pos->dump(););
-
- DEBUG(dbgs() << " Updating Swizzle:\n");
- for (MachineRegisterInfo::use_instr_iterator It = MRI->use_instr_begin(Reg),
- E = MRI->use_instr_end(); It != E; ++It) {
- DEBUG(dbgs() << " ";(*It).dump(); dbgs() << " ->");
- SwizzleInput(*It, RemapChan);
- DEBUG((*It).dump());
- }
- RSI->Instr->eraseFromParent();
-
- // Update RSI
- RSI->Instr = Pos;
- RSI->RegToChan = UpdatedRegToChan;
- RSI->UndefReg = UpdatedUndef;
-
- return Pos;
-}
-
-void R600VectorRegMerger::RemoveMI(MachineInstr *MI) {
- for (InstructionSetMap::iterator It = PreviousRegSeqByReg.begin(),
- E = PreviousRegSeqByReg.end(); It != E; ++It) {
- std::vector<MachineInstr *> &MIs = (*It).second;
- MIs.erase(std::find(MIs.begin(), MIs.end(), MI), MIs.end());
- }
- for (InstructionSetMap::iterator It = PreviousRegSeqByUndefCount.begin(),
- E = PreviousRegSeqByUndefCount.end(); It != E; ++It) {
- std::vector<MachineInstr *> &MIs = (*It).second;
- MIs.erase(std::find(MIs.begin(), MIs.end(), MI), MIs.end());
- }
-}
-
-void R600VectorRegMerger::SwizzleInput(MachineInstr &MI,
- const std::vector<std::pair<unsigned, unsigned> > &RemapChan) const {
- unsigned Offset;
- if (TII->get(MI.getOpcode()).TSFlags & R600_InstFlag::TEX_INST)
- Offset = 2;
- else
- Offset = 3;
- for (unsigned i = 0; i < 4; i++) {
- unsigned Swizzle = MI.getOperand(i + Offset).getImm() + 1;
- for (unsigned j = 0, e = RemapChan.size(); j < e; j++) {
- if (RemapChan[j].first == Swizzle) {
- MI.getOperand(i + Offset).setImm(RemapChan[j].second - 1);
- break;
- }
- }
- }
-}
-
-bool R600VectorRegMerger::areAllUsesSwizzeable(unsigned Reg) const {
- for (MachineRegisterInfo::use_instr_iterator It = MRI->use_instr_begin(Reg),
- E = MRI->use_instr_end(); It != E; ++It) {
- if (!canSwizzle(*It))
- return false;
- }
- return true;
-}
-
-bool R600VectorRegMerger::tryMergeUsingCommonSlot(RegSeqInfo &RSI,
- RegSeqInfo &CompatibleRSI,
- std::vector<std::pair<unsigned, unsigned> > &RemapChan) {
- for (MachineInstr::mop_iterator MOp = RSI.Instr->operands_begin(),
- MOE = RSI.Instr->operands_end(); MOp != MOE; ++MOp) {
- if (!MOp->isReg())
- continue;
- if (PreviousRegSeqByReg[MOp->getReg()].empty())
- continue;
- for (MachineInstr *MI : PreviousRegSeqByReg[MOp->getReg()]) {
- CompatibleRSI = PreviousRegSeq[MI];
- if (RSI == CompatibleRSI)
- continue;
- if (tryMergeVector(&CompatibleRSI, &RSI, RemapChan))
- return true;
- }
- }
- return false;
-}
-
-bool R600VectorRegMerger::tryMergeUsingFreeSlot(RegSeqInfo &RSI,
- RegSeqInfo &CompatibleRSI,
- std::vector<std::pair<unsigned, unsigned> > &RemapChan) {
- unsigned NeededUndefs = 4 - RSI.UndefReg.size();
- if (PreviousRegSeqByUndefCount[NeededUndefs].empty())
- return false;
- std::vector<MachineInstr *> &MIs =
- PreviousRegSeqByUndefCount[NeededUndefs];
- CompatibleRSI = PreviousRegSeq[MIs.back()];
- tryMergeVector(&CompatibleRSI, &RSI, RemapChan);
- return true;
-}
-
-void R600VectorRegMerger::trackRSI(const RegSeqInfo &RSI) {
- for (DenseMap<unsigned, unsigned>::const_iterator
- It = RSI.RegToChan.begin(), E = RSI.RegToChan.end(); It != E; ++It) {
- PreviousRegSeqByReg[(*It).first].push_back(RSI.Instr);
- }
- PreviousRegSeqByUndefCount[RSI.UndefReg.size()].push_back(RSI.Instr);
- PreviousRegSeq[RSI.Instr] = RSI;
-}
-
-bool R600VectorRegMerger::runOnMachineFunction(MachineFunction &Fn) {
- TII = static_cast<const R600InstrInfo *>(Fn.getSubtarget().getInstrInfo());
- MRI = &(Fn.getRegInfo());
- for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
- MBB != MBBe; ++MBB) {
- MachineBasicBlock *MB = MBB;
- PreviousRegSeq.clear();
- PreviousRegSeqByReg.clear();
- PreviousRegSeqByUndefCount.clear();
-
- for (MachineBasicBlock::iterator MII = MB->begin(), MIIE = MB->end();
- MII != MIIE; ++MII) {
- MachineInstr *MI = MII;
- if (MI->getOpcode() != AMDGPU::REG_SEQUENCE) {
- if (TII->get(MI->getOpcode()).TSFlags & R600_InstFlag::TEX_INST) {
- unsigned Reg = MI->getOperand(1).getReg();
- for (MachineRegisterInfo::def_instr_iterator
- It = MRI->def_instr_begin(Reg), E = MRI->def_instr_end();
- It != E; ++It) {
- RemoveMI(&(*It));
- }
- }
- continue;
- }
-
-
- RegSeqInfo RSI(*MRI, MI);
-
- // All uses of MI are swizzeable ?
- unsigned Reg = MI->getOperand(0).getReg();
- if (!areAllUsesSwizzeable(Reg))
- continue;
-
- DEBUG (dbgs() << "Trying to optimize ";
- MI->dump();
- );
-
- RegSeqInfo CandidateRSI;
- std::vector<std::pair<unsigned, unsigned> > RemapChan;
- DEBUG(dbgs() << "Using common slots...\n";);
- if (tryMergeUsingCommonSlot(RSI, CandidateRSI, RemapChan)) {
- // Remove CandidateRSI mapping
- RemoveMI(CandidateRSI.Instr);
- MII = RebuildVector(&RSI, &CandidateRSI, RemapChan);
- trackRSI(RSI);
- continue;
- }
- DEBUG(dbgs() << "Using free slots...\n";);
- RemapChan.clear();
- if (tryMergeUsingFreeSlot(RSI, CandidateRSI, RemapChan)) {
- RemoveMI(CandidateRSI.Instr);
- MII = RebuildVector(&RSI, &CandidateRSI, RemapChan);
- trackRSI(RSI);
- continue;
- }
- //Failed to merge
- trackRSI(RSI);
- }
- }
- return false;
-}
-
-}
-
-llvm::FunctionPass *llvm::createR600VectorRegMerger(TargetMachine &tm) {
- return new R600VectorRegMerger(tm);
-}