| //===-- SIInsertWaitcnts.cpp - Insert Wait Instructions --------------------===/ |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| /// \file |
| /// \brief Insert wait instructions for memory reads and writes. |
| /// |
| /// Memory reads and writes are issued asynchronously, so we need to insert |
| /// S_WAITCNT instructions when we want to access any of their results or |
| /// overwrite any register that's used asynchronously. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "AMDGPU.h" |
| #include "AMDGPUSubtarget.h" |
| #include "SIDefines.h" |
| #include "SIInstrInfo.h" |
| #include "SIMachineFunctionInfo.h" |
| #include "Utils/AMDGPUBaseInfo.h" |
| #include "llvm/ADT/PostOrderIterator.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineFunctionPass.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| |
| #define DEBUG_TYPE "si-insert-waitcnts" |
| |
| using namespace llvm; |
| |
| namespace { |
| |
| // Class of object that encapsulates latest instruction counter score |
| // associated with the operand. Used for determining whether |
| // s_waitcnt instruction needs to be emited. |
| |
| #define CNT_MASK(t) (1u << (t)) |
| |
| enum InstCounterType { VM_CNT = 0, LGKM_CNT, EXP_CNT, NUM_INST_CNTS }; |
| |
| typedef std::pair<signed, signed> RegInterval; |
| |
| struct { |
| int32_t VmcntMax; |
| int32_t ExpcntMax; |
| int32_t LgkmcntMax; |
| int32_t NumVGPRsMax; |
| int32_t NumSGPRsMax; |
| } HardwareLimits; |
| |
| struct { |
| unsigned VGPR0; |
| unsigned VGPRL; |
| unsigned SGPR0; |
| unsigned SGPRL; |
| } RegisterEncoding; |
| |
| enum WaitEventType { |
| VMEM_ACCESS, // vector-memory read & write |
| LDS_ACCESS, // lds read & write |
| GDS_ACCESS, // gds read & write |
| SQ_MESSAGE, // send message |
| SMEM_ACCESS, // scalar-memory read & write |
| EXP_GPR_LOCK, // export holding on its data src |
| GDS_GPR_LOCK, // GDS holding on its data and addr src |
| EXP_POS_ACCESS, // write to export position |
| EXP_PARAM_ACCESS, // write to export parameter |
| VMW_GPR_LOCK, // vector-memory write holding on its data src |
| NUM_WAIT_EVENTS, |
| }; |
| |
| // The mapping is: |
| // 0 .. SQ_MAX_PGM_VGPRS-1 real VGPRs |
| // SQ_MAX_PGM_VGPRS .. NUM_ALL_VGPRS-1 extra VGPR-like slots |
| // NUM_ALL_VGPRS .. NUM_ALL_VGPRS+SQ_MAX_PGM_SGPRS-1 real SGPRs |
| // We reserve a fixed number of VGPR slots in the scoring tables for |
| // special tokens like SCMEM_LDS (needed for buffer load to LDS). |
| enum RegisterMapping { |
| SQ_MAX_PGM_VGPRS = 256, // Maximum programmable VGPRs across all targets. |
| SQ_MAX_PGM_SGPRS = 256, // Maximum programmable SGPRs across all targets. |
| NUM_EXTRA_VGPRS = 1, // A reserved slot for DS. |
| EXTRA_VGPR_LDS = 0, // This is a placeholder the Shader algorithm uses. |
| NUM_ALL_VGPRS = SQ_MAX_PGM_VGPRS + NUM_EXTRA_VGPRS, // Where SGPR starts. |
| }; |
| |
| #define ForAllWaitEventType(w) \ |
| for (enum WaitEventType w = (enum WaitEventType)0; \ |
| (w) < (enum WaitEventType)NUM_WAIT_EVENTS; \ |
| (w) = (enum WaitEventType)((w) + 1)) |
| |
| // This is a per-basic-block object that maintains current score brackets |
| // of each wait-counter, and a per-register scoreboard for each wait-couner. |
| // We also maintain the latest score for every event type that can change the |
| // waitcnt in order to know if there are multiple types of events within |
| // the brackets. When multiple types of event happen in the bracket, |
| // wait-count may get decreased out of order, therefore we need to put in |
| // "s_waitcnt 0" before use. |
| class BlockWaitcntBrackets { |
| public: |
| static int32_t getWaitCountMax(InstCounterType T) { |
| switch (T) { |
| case VM_CNT: |
| return HardwareLimits.VmcntMax; |
| case LGKM_CNT: |
| return HardwareLimits.LgkmcntMax; |
| case EXP_CNT: |
| return HardwareLimits.ExpcntMax; |
| default: |
| break; |
| } |
| return 0; |
| }; |
| |
| void setScoreLB(InstCounterType T, int32_t Val) { |
| assert(T < NUM_INST_CNTS); |
| if (T >= NUM_INST_CNTS) |
| return; |
| ScoreLBs[T] = Val; |
| }; |
| |
| void setScoreUB(InstCounterType T, int32_t Val) { |
| assert(T < NUM_INST_CNTS); |
| if (T >= NUM_INST_CNTS) |
| return; |
| ScoreUBs[T] = Val; |
| if (T == EXP_CNT) { |
| int32_t UB = (int)(ScoreUBs[T] - getWaitCountMax(EXP_CNT)); |
| if (ScoreLBs[T] < UB) |
| ScoreLBs[T] = UB; |
| } |
| }; |
| |
| int32_t getScoreLB(InstCounterType T) { |
| assert(T < NUM_INST_CNTS); |
| if (T >= NUM_INST_CNTS) |
| return 0; |
| return ScoreLBs[T]; |
| }; |
| |
| int32_t getScoreUB(InstCounterType T) { |
| assert(T < NUM_INST_CNTS); |
| if (T >= NUM_INST_CNTS) |
| return 0; |
| return ScoreUBs[T]; |
| }; |
| |
| // Mapping from event to counter. |
| InstCounterType eventCounter(WaitEventType E) { |
| switch (E) { |
| case VMEM_ACCESS: |
| return VM_CNT; |
| case LDS_ACCESS: |
| case GDS_ACCESS: |
| case SQ_MESSAGE: |
| case SMEM_ACCESS: |
| return LGKM_CNT; |
| case EXP_GPR_LOCK: |
| case GDS_GPR_LOCK: |
| case VMW_GPR_LOCK: |
| case EXP_POS_ACCESS: |
| case EXP_PARAM_ACCESS: |
| return EXP_CNT; |
| default: |
| llvm_unreachable("unhandled event type"); |
| } |
| return NUM_INST_CNTS; |
| } |
| |
| void setRegScore(int GprNo, InstCounterType T, int32_t Val) { |
| if (GprNo < NUM_ALL_VGPRS) { |
| if (GprNo > VgprUB) { |
| VgprUB = GprNo; |
| } |
| VgprScores[T][GprNo] = Val; |
| } else { |
| assert(T == LGKM_CNT); |
| if (GprNo - NUM_ALL_VGPRS > SgprUB) { |
| SgprUB = GprNo - NUM_ALL_VGPRS; |
| } |
| SgprScores[GprNo - NUM_ALL_VGPRS] = Val; |
| } |
| } |
| |
| int32_t getRegScore(int GprNo, InstCounterType T) { |
| if (GprNo < NUM_ALL_VGPRS) { |
| return VgprScores[T][GprNo]; |
| } |
| return SgprScores[GprNo - NUM_ALL_VGPRS]; |
| } |
| |
| void clear() { |
| memset(ScoreLBs, 0, sizeof(ScoreLBs)); |
| memset(ScoreUBs, 0, sizeof(ScoreUBs)); |
| memset(EventUBs, 0, sizeof(EventUBs)); |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| memset(VgprScores[T], 0, sizeof(VgprScores[T])); |
| } |
| memset(SgprScores, 0, sizeof(SgprScores)); |
| } |
| |
| RegInterval getRegInterval(const MachineInstr *MI, const SIInstrInfo *TII, |
| const MachineRegisterInfo *MRI, |
| const SIRegisterInfo *TRI, unsigned OpNo, |
| bool Def) const; |
| |
| void setExpScore(const MachineInstr *MI, const SIInstrInfo *TII, |
| const SIRegisterInfo *TRI, const MachineRegisterInfo *MRI, |
| unsigned OpNo, int32_t Val); |
| |
| void setWaitAtBeginning() { WaitAtBeginning = true; } |
| void clearWaitAtBeginning() { WaitAtBeginning = false; } |
| bool getWaitAtBeginning() const { return WaitAtBeginning; } |
| void setEventUB(enum WaitEventType W, int32_t Val) { EventUBs[W] = Val; } |
| int32_t getMaxVGPR() const { return VgprUB; } |
| int32_t getMaxSGPR() const { return SgprUB; } |
| int32_t getEventUB(enum WaitEventType W) const { |
| assert(W < NUM_WAIT_EVENTS); |
| return EventUBs[W]; |
| } |
| bool counterOutOfOrder(InstCounterType T); |
| unsigned int updateByWait(InstCounterType T, int ScoreToWait); |
| void updateByEvent(const SIInstrInfo *TII, const SIRegisterInfo *TRI, |
| const MachineRegisterInfo *MRI, WaitEventType E, |
| MachineInstr &MI); |
| |
| BlockWaitcntBrackets() |
| : WaitAtBeginning(false), ValidLoop(false), MixedExpTypes(false), |
| LoopRegion(NULL), PostOrder(0), Waitcnt(NULL), VgprUB(0), SgprUB(0) { |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| memset(VgprScores[T], 0, sizeof(VgprScores[T])); |
| } |
| } |
| ~BlockWaitcntBrackets(){}; |
| |
| bool hasPendingSMEM() const { |
| return (EventUBs[SMEM_ACCESS] > ScoreLBs[LGKM_CNT] && |
| EventUBs[SMEM_ACCESS] <= ScoreUBs[LGKM_CNT]); |
| } |
| |
| bool hasPendingFlat() const { |
| return ((LastFlat[LGKM_CNT] > ScoreLBs[LGKM_CNT] && |
| LastFlat[LGKM_CNT] <= ScoreUBs[LGKM_CNT]) || |
| (LastFlat[VM_CNT] > ScoreLBs[VM_CNT] && |
| LastFlat[VM_CNT] <= ScoreUBs[VM_CNT])); |
| } |
| |
| void setPendingFlat() { |
| LastFlat[VM_CNT] = ScoreUBs[VM_CNT]; |
| LastFlat[LGKM_CNT] = ScoreUBs[LGKM_CNT]; |
| } |
| |
| int pendingFlat(InstCounterType Ct) const { return LastFlat[Ct]; } |
| |
| void setLastFlat(InstCounterType Ct, int Val) { LastFlat[Ct] = Val; } |
| |
| bool getRevisitLoop() const { return RevisitLoop; } |
| void setRevisitLoop(bool RevisitLoopIn) { RevisitLoop = RevisitLoopIn; } |
| |
| void setPostOrder(int32_t PostOrderIn) { PostOrder = PostOrderIn; } |
| int32_t getPostOrder() const { return PostOrder; } |
| |
| void setWaitcnt(MachineInstr *WaitcntIn) { Waitcnt = WaitcntIn; } |
| void clearWaitcnt() { Waitcnt = NULL; } |
| MachineInstr *getWaitcnt() const { return Waitcnt; } |
| |
| bool mixedExpTypes() const { return MixedExpTypes; } |
| void setMixedExpTypes(bool MixedExpTypesIn) { |
| MixedExpTypes = MixedExpTypesIn; |
| } |
| |
| void print(raw_ostream &); |
| void dump() { print(dbgs()); } |
| |
| private: |
| bool WaitAtBeginning; |
| bool RevisitLoop; |
| bool ValidLoop; |
| bool MixedExpTypes; |
| MachineLoop *LoopRegion; |
| int32_t PostOrder; |
| MachineInstr *Waitcnt; |
| int32_t ScoreLBs[NUM_INST_CNTS] = {0}; |
| int32_t ScoreUBs[NUM_INST_CNTS] = {0}; |
| int32_t EventUBs[NUM_WAIT_EVENTS] = {0}; |
| // Remember the last flat memory operation. |
| int32_t LastFlat[NUM_INST_CNTS] = {0}; |
| // wait_cnt scores for every vgpr. |
| // Keep track of the VgprUB and SgprUB to make merge at join efficient. |
| int32_t VgprUB; |
| int32_t SgprUB; |
| int32_t VgprScores[NUM_INST_CNTS][NUM_ALL_VGPRS]; |
| // Wait cnt scores for every sgpr, only lgkmcnt is relevant. |
| int32_t SgprScores[SQ_MAX_PGM_SGPRS] = {0}; |
| }; |
| |
| // This is a per-loop-region object that records waitcnt status at the end of |
| // loop footer from the previous iteration. We also maintain an iteration |
| // count to track the number of times the loop has been visited. When it |
| // doesn't converge naturally, we force convergence by inserting s_waitcnt 0 |
| // at the end of the loop footer. |
| class LoopWaitcntData { |
| public: |
| void incIterCnt() { IterCnt++; } |
| void resetIterCnt() { IterCnt = 0; } |
| int32_t getIterCnt() { return IterCnt; } |
| |
| LoopWaitcntData() : LfWaitcnt(NULL), IterCnt(0) {} |
| ~LoopWaitcntData(){}; |
| |
| void setWaitcnt(MachineInstr *WaitcntIn) { LfWaitcnt = WaitcntIn; } |
| MachineInstr *getWaitcnt() const { return LfWaitcnt; } |
| |
| void print() { |
| DEBUG(dbgs() << " iteration " << IterCnt << '\n';); |
| return; |
| } |
| |
| private: |
| // s_waitcnt added at the end of loop footer to stablize wait scores |
| // at the end of the loop footer. |
| MachineInstr *LfWaitcnt; |
| // Number of iterations the loop has been visited, not including the initial |
| // walk over. |
| int32_t IterCnt; |
| }; |
| |
| class SIInsertWaitcnts : public MachineFunctionPass { |
| |
| private: |
| const SISubtarget *ST; |
| const SIInstrInfo *TII; |
| const SIRegisterInfo *TRI; |
| const MachineRegisterInfo *MRI; |
| const MachineLoopInfo *MLI; |
| AMDGPU::IsaInfo::IsaVersion IV; |
| AMDGPUAS AMDGPUASI; |
| |
| DenseSet<MachineBasicBlock *> BlockVisitedSet; |
| DenseSet<MachineInstr *> CompilerGeneratedWaitcntSet; |
| DenseSet<MachineInstr *> VCCZBugHandledSet; |
| |
| DenseMap<MachineBasicBlock *, std::unique_ptr<BlockWaitcntBrackets>> |
| BlockWaitcntBracketsMap; |
| |
| DenseSet<MachineBasicBlock *> BlockWaitcntProcessedSet; |
| |
| DenseMap<MachineLoop *, std::unique_ptr<LoopWaitcntData>> LoopWaitcntDataMap; |
| |
| std::vector<std::unique_ptr<BlockWaitcntBrackets>> KillWaitBrackets; |
| |
| public: |
| static char ID; |
| |
| SIInsertWaitcnts() |
| : MachineFunctionPass(ID), ST(nullptr), TII(nullptr), TRI(nullptr), |
| MRI(nullptr), MLI(nullptr) {} |
| |
| bool runOnMachineFunction(MachineFunction &MF) override; |
| |
| StringRef getPassName() const override { |
| return "SI insert wait instructions"; |
| } |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| AU.setPreservesCFG(); |
| AU.addRequired<MachineLoopInfo>(); |
| MachineFunctionPass::getAnalysisUsage(AU); |
| } |
| |
| void addKillWaitBracket(BlockWaitcntBrackets *Bracket) { |
| // The waitcnt information is copied because it changes as the block is |
| // traversed. |
| KillWaitBrackets.push_back(make_unique<BlockWaitcntBrackets>(*Bracket)); |
| } |
| |
| MachineInstr *generateSWaitCntInstBefore(MachineInstr &MI, |
| BlockWaitcntBrackets *ScoreBrackets); |
| void updateEventWaitCntAfter(MachineInstr &Inst, |
| BlockWaitcntBrackets *ScoreBrackets); |
| void mergeInputScoreBrackets(MachineBasicBlock &Block); |
| MachineBasicBlock *loopBottom(const MachineLoop *Loop); |
| void insertWaitcntInBlock(MachineFunction &MF, MachineBasicBlock &Block); |
| void insertWaitcntBeforeCF(MachineBasicBlock &Block, MachineInstr *Inst); |
| }; |
| |
| } // End anonymous namespace. |
| |
| RegInterval BlockWaitcntBrackets::getRegInterval(const MachineInstr *MI, |
| const SIInstrInfo *TII, |
| const MachineRegisterInfo *MRI, |
| const SIRegisterInfo *TRI, |
| unsigned OpNo, |
| bool Def) const { |
| const MachineOperand &Op = MI->getOperand(OpNo); |
| if (!Op.isReg() || !TRI->isInAllocatableClass(Op.getReg()) || |
| (Def && !Op.isDef())) |
| return {-1, -1}; |
| |
| // A use via a PW operand does not need a waitcnt. |
| // A partial write is not a WAW. |
| assert(!Op.getSubReg() || !Op.isUndef()); |
| |
| RegInterval Result; |
| const MachineRegisterInfo &MRIA = *MRI; |
| |
| unsigned Reg = TRI->getEncodingValue(Op.getReg()); |
| |
| if (TRI->isVGPR(MRIA, Op.getReg())) { |
| assert(Reg >= RegisterEncoding.VGPR0 && Reg <= RegisterEncoding.VGPRL); |
| Result.first = Reg - RegisterEncoding.VGPR0; |
| assert(Result.first >= 0 && Result.first < SQ_MAX_PGM_VGPRS); |
| } else if (TRI->isSGPRReg(MRIA, Op.getReg())) { |
| assert(Reg >= RegisterEncoding.SGPR0 && Reg < SQ_MAX_PGM_SGPRS); |
| Result.first = Reg - RegisterEncoding.SGPR0 + NUM_ALL_VGPRS; |
| assert(Result.first >= NUM_ALL_VGPRS && |
| Result.first < SQ_MAX_PGM_SGPRS + NUM_ALL_VGPRS); |
| } |
| // TODO: Handle TTMP |
| // else if (TRI->isTTMP(MRIA, Reg.getReg())) ... |
| else |
| return {-1, -1}; |
| |
| const MachineInstr &MIA = *MI; |
| const TargetRegisterClass *RC = TII->getOpRegClass(MIA, OpNo); |
| unsigned Size = RC->getSize(); |
| Result.second = Result.first + (Size / 4); |
| |
| return Result; |
| } |
| |
| void BlockWaitcntBrackets::setExpScore(const MachineInstr *MI, |
| const SIInstrInfo *TII, |
| const SIRegisterInfo *TRI, |
| const MachineRegisterInfo *MRI, |
| unsigned OpNo, int32_t Val) { |
| RegInterval Interval = getRegInterval(MI, TII, MRI, TRI, OpNo, false); |
| DEBUG({ |
| const MachineOperand &Opnd = MI->getOperand(OpNo); |
| assert(TRI->isVGPR(*MRI, Opnd.getReg())); |
| }); |
| for (signed RegNo = Interval.first; RegNo < Interval.second; ++RegNo) { |
| setRegScore(RegNo, EXP_CNT, Val); |
| } |
| } |
| |
| void BlockWaitcntBrackets::updateByEvent(const SIInstrInfo *TII, |
| const SIRegisterInfo *TRI, |
| const MachineRegisterInfo *MRI, |
| WaitEventType E, MachineInstr &Inst) { |
| const MachineRegisterInfo &MRIA = *MRI; |
| InstCounterType T = eventCounter(E); |
| int32_t CurrScore = getScoreUB(T) + 1; |
| // EventUB and ScoreUB need to be update regardless if this event changes |
| // the score of a register or not. |
| // Examples including vm_cnt when buffer-store or lgkm_cnt when send-message. |
| EventUBs[E] = CurrScore; |
| setScoreUB(T, CurrScore); |
| |
| if (T == EXP_CNT) { |
| // Check for mixed export types. If they are mixed, then a waitcnt exp(0) |
| // is required. |
| if (!MixedExpTypes) { |
| MixedExpTypes = counterOutOfOrder(EXP_CNT); |
| } |
| |
| // Put score on the source vgprs. If this is a store, just use those |
| // specific register(s). |
| if (TII->isDS(Inst) && (Inst.mayStore() || Inst.mayLoad())) { |
| // All GDS operations must protect their address register (same as |
| // export.) |
| if (Inst.getOpcode() != AMDGPU::DS_APPEND && |
| Inst.getOpcode() != AMDGPU::DS_CONSUME) { |
| setExpScore( |
| &Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::addr), |
| CurrScore); |
| } |
| if (Inst.mayStore()) { |
| setExpScore( |
| &Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data0), |
| CurrScore); |
| if (AMDGPU::getNamedOperandIdx(Inst.getOpcode(), |
| AMDGPU::OpName::data1) != -1) { |
| setExpScore(&Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), |
| AMDGPU::OpName::data1), |
| CurrScore); |
| } |
| } else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1 && |
| Inst.getOpcode() != AMDGPU::DS_GWS_INIT && |
| Inst.getOpcode() != AMDGPU::DS_GWS_SEMA_V && |
| Inst.getOpcode() != AMDGPU::DS_GWS_SEMA_BR && |
| Inst.getOpcode() != AMDGPU::DS_GWS_SEMA_P && |
| Inst.getOpcode() != AMDGPU::DS_GWS_BARRIER && |
| Inst.getOpcode() != AMDGPU::DS_APPEND && |
| Inst.getOpcode() != AMDGPU::DS_CONSUME && |
| Inst.getOpcode() != AMDGPU::DS_ORDERED_COUNT) { |
| for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) { |
| const MachineOperand &Op = Inst.getOperand(I); |
| if (Op.isReg() && !Op.isDef() && TRI->isVGPR(MRIA, Op.getReg())) { |
| setExpScore(&Inst, TII, TRI, MRI, I, CurrScore); |
| } |
| } |
| } |
| } else if (TII->isFLAT(Inst)) { |
| if (Inst.mayStore()) { |
| setExpScore( |
| &Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data), |
| CurrScore); |
| } else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1) { |
| setExpScore( |
| &Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data), |
| CurrScore); |
| } |
| } else if (TII->isMIMG(Inst)) { |
| if (Inst.mayStore()) { |
| setExpScore(&Inst, TII, TRI, MRI, 0, CurrScore); |
| } else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1) { |
| setExpScore( |
| &Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data), |
| CurrScore); |
| } |
| } else if (TII->isMTBUF(Inst)) { |
| if (Inst.mayStore()) { |
| setExpScore(&Inst, TII, TRI, MRI, 0, CurrScore); |
| } |
| } else if (TII->isMUBUF(Inst)) { |
| if (Inst.mayStore()) { |
| setExpScore(&Inst, TII, TRI, MRI, 0, CurrScore); |
| } else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1) { |
| setExpScore( |
| &Inst, TII, TRI, MRI, |
| AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data), |
| CurrScore); |
| } |
| } else { |
| if (TII->isEXP(Inst)) { |
| // For export the destination registers are really temps that |
| // can be used as the actual source after export patching, so |
| // we need to treat them like sources and set the EXP_CNT |
| // score. |
| for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) { |
| MachineOperand &DefMO = Inst.getOperand(I); |
| if (DefMO.isReg() && DefMO.isDef() && |
| TRI->isVGPR(MRIA, DefMO.getReg())) { |
| setRegScore(TRI->getEncodingValue(DefMO.getReg()), EXP_CNT, |
| CurrScore); |
| } |
| } |
| } |
| for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) { |
| MachineOperand &MO = Inst.getOperand(I); |
| if (MO.isReg() && !MO.isDef() && TRI->isVGPR(MRIA, MO.getReg())) { |
| setExpScore(&Inst, TII, TRI, MRI, I, CurrScore); |
| } |
| } |
| } |
| #if 0 // TODO: check if this is handled by MUBUF code above. |
| } else if (Inst.getOpcode() == AMDGPU::BUFFER_STORE_DWORD || |
| Inst.getOpcode() == AMDGPU::BUFFER_STORE_DWORDX2 || |
| Inst.getOpcode() == AMDGPU::BUFFER_STORE_DWORDX4) { |
| MachineOperand *MO = TII->getNamedOperand(Inst, AMDGPU::OpName::data); |
| unsigned OpNo;//TODO: find the OpNo for this operand; |
| RegInterval Interval = getRegInterval(&Inst, TII, MRI, TRI, OpNo, false); |
| for (signed RegNo = Interval.first; RegNo < Interval.second; |
| ++RegNo) { |
| setRegScore(RegNo + NUM_ALL_VGPRS, t, CurrScore); |
| } |
| #endif |
| } else { |
| // Match the score to the destination registers. |
| for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) { |
| RegInterval Interval = getRegInterval(&Inst, TII, MRI, TRI, I, true); |
| if (T == VM_CNT && Interval.first >= NUM_ALL_VGPRS) |
| continue; |
| for (signed RegNo = Interval.first; RegNo < Interval.second; ++RegNo) { |
| setRegScore(RegNo, T, CurrScore); |
| } |
| } |
| if (TII->isDS(Inst) && Inst.mayStore()) { |
| setRegScore(SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS, T, CurrScore); |
| } |
| } |
| } |
| |
| void BlockWaitcntBrackets::print(raw_ostream &OS) { |
| OS << '\n'; |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| int LB = getScoreLB(T); |
| int UB = getScoreUB(T); |
| |
| switch (T) { |
| case VM_CNT: |
| OS << " VM_CNT(" << UB - LB << "): "; |
| break; |
| case LGKM_CNT: |
| OS << " LGKM_CNT(" << UB - LB << "): "; |
| break; |
| case EXP_CNT: |
| OS << " EXP_CNT(" << UB - LB << "): "; |
| break; |
| default: |
| OS << " UNKNOWN(" << UB - LB << "): "; |
| break; |
| } |
| |
| if (LB < UB) { |
| // Print vgpr scores. |
| for (int J = 0; J <= getMaxVGPR(); J++) { |
| int RegScore = getRegScore(J, T); |
| if (RegScore <= LB) |
| continue; |
| int RelScore = RegScore - LB - 1; |
| if (J < SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS) { |
| OS << RelScore << ":v" << J << " "; |
| } else { |
| OS << RelScore << ":ds "; |
| } |
| } |
| // Also need to print sgpr scores for lgkm_cnt. |
| if (T == LGKM_CNT) { |
| for (int J = 0; J <= getMaxSGPR(); J++) { |
| int RegScore = getRegScore(J + NUM_ALL_VGPRS, LGKM_CNT); |
| if (RegScore <= LB) |
| continue; |
| int RelScore = RegScore - LB - 1; |
| OS << RelScore << ":s" << J << " "; |
| } |
| } |
| } |
| OS << '\n'; |
| } |
| OS << '\n'; |
| return; |
| } |
| |
| unsigned int BlockWaitcntBrackets::updateByWait(InstCounterType T, |
| int ScoreToWait) { |
| unsigned int NeedWait = 0; |
| if (ScoreToWait == -1) { |
| // The score to wait is unknown. This implies that it was not encountered |
| // during the path of the CFG walk done during the current traversal but |
| // may be seen on a different path. Emit an s_wait counter with a |
| // conservative value of 0 for the counter. |
| NeedWait = CNT_MASK(T); |
| setScoreLB(T, getScoreUB(T)); |
| return NeedWait; |
| } |
| |
| // If the score of src_operand falls within the bracket, we need an |
| // s_waitcnt instruction. |
| const int32_t LB = getScoreLB(T); |
| const int32_t UB = getScoreUB(T); |
| if ((UB >= ScoreToWait) && (ScoreToWait > LB)) { |
| if (T == VM_CNT && hasPendingFlat()) { |
| // If there is a pending FLAT operation, and this is a VM waitcnt, |
| // then we need to force a waitcnt 0 for VM. |
| NeedWait = CNT_MASK(T); |
| setScoreLB(T, getScoreUB(T)); |
| } else if (counterOutOfOrder(T)) { |
| // Counter can get decremented out-of-order when there |
| // are multiple types event in the brack. Also emit an s_wait counter |
| // with a conservative value of 0 for the counter. |
| NeedWait = CNT_MASK(T); |
| setScoreLB(T, getScoreUB(T)); |
| } else { |
| NeedWait = CNT_MASK(T); |
| setScoreLB(T, ScoreToWait); |
| } |
| } |
| |
| return NeedWait; |
| } |
| |
| // Where there are multiple types of event in the bracket of a counter, |
| // the decrement may go out of order. |
| bool BlockWaitcntBrackets::counterOutOfOrder(InstCounterType T) { |
| switch (T) { |
| case VM_CNT: |
| return false; |
| case LGKM_CNT: { |
| if (EventUBs[SMEM_ACCESS] > ScoreLBs[LGKM_CNT] && |
| EventUBs[SMEM_ACCESS] <= ScoreUBs[LGKM_CNT]) { |
| // Scalar memory read always can go out of order. |
| return true; |
| } |
| int NumEventTypes = 0; |
| if (EventUBs[LDS_ACCESS] > ScoreLBs[LGKM_CNT] && |
| EventUBs[LDS_ACCESS] <= ScoreUBs[LGKM_CNT]) { |
| NumEventTypes++; |
| } |
| if (EventUBs[GDS_ACCESS] > ScoreLBs[LGKM_CNT] && |
| EventUBs[GDS_ACCESS] <= ScoreUBs[LGKM_CNT]) { |
| NumEventTypes++; |
| } |
| if (EventUBs[SQ_MESSAGE] > ScoreLBs[LGKM_CNT] && |
| EventUBs[SQ_MESSAGE] <= ScoreUBs[LGKM_CNT]) { |
| NumEventTypes++; |
| } |
| if (NumEventTypes <= 1) { |
| return false; |
| } |
| break; |
| } |
| case EXP_CNT: { |
| // If there has been a mixture of export types, then a waitcnt exp(0) is |
| // required. |
| if (MixedExpTypes) |
| return true; |
| int NumEventTypes = 0; |
| if (EventUBs[EXP_GPR_LOCK] > ScoreLBs[EXP_CNT] && |
| EventUBs[EXP_GPR_LOCK] <= ScoreUBs[EXP_CNT]) { |
| NumEventTypes++; |
| } |
| if (EventUBs[GDS_GPR_LOCK] > ScoreLBs[EXP_CNT] && |
| EventUBs[GDS_GPR_LOCK] <= ScoreUBs[EXP_CNT]) { |
| NumEventTypes++; |
| } |
| if (EventUBs[VMW_GPR_LOCK] > ScoreLBs[EXP_CNT] && |
| EventUBs[VMW_GPR_LOCK] <= ScoreUBs[EXP_CNT]) { |
| NumEventTypes++; |
| } |
| if (EventUBs[EXP_PARAM_ACCESS] > ScoreLBs[EXP_CNT] && |
| EventUBs[EXP_PARAM_ACCESS] <= ScoreUBs[EXP_CNT]) { |
| NumEventTypes++; |
| } |
| |
| if (EventUBs[EXP_POS_ACCESS] > ScoreLBs[EXP_CNT] && |
| EventUBs[EXP_POS_ACCESS] <= ScoreUBs[EXP_CNT]) { |
| NumEventTypes++; |
| } |
| |
| if (NumEventTypes <= 1) { |
| return false; |
| } |
| break; |
| } |
| default: |
| break; |
| } |
| return true; |
| } |
| |
| INITIALIZE_PASS_BEGIN(SIInsertWaitcnts, DEBUG_TYPE, "SI Insert Waitcnts", false, |
| false) |
| INITIALIZE_PASS_END(SIInsertWaitcnts, DEBUG_TYPE, "SI Insert Waitcnts", false, |
| false) |
| |
| char SIInsertWaitcnts::ID = 0; |
| |
| char &llvm::SIInsertWaitcntsID = SIInsertWaitcnts::ID; |
| |
| FunctionPass *llvm::createSIInsertWaitcntsPass() { |
| return new SIInsertWaitcnts(); |
| } |
| |
| static bool readsVCCZ(const MachineInstr &MI) { |
| unsigned Opc = MI.getOpcode(); |
| return (Opc == AMDGPU::S_CBRANCH_VCCNZ || Opc == AMDGPU::S_CBRANCH_VCCZ) && |
| !MI.getOperand(1).isUndef(); |
| } |
| |
| /// \brief Generate s_waitcnt instruction to be placed before cur_Inst. |
| /// Instructions of a given type are returned in order, |
| /// but instructions of different types can complete out of order. |
| /// We rely on this in-order completion |
| /// and simply assign a score to the memory access instructions. |
| /// We keep track of the active "score bracket" to determine |
| /// if an access of a memory read requires an s_waitcnt |
| /// and if so what the value of each counter is. |
| /// The "score bracket" is bound by the lower bound and upper bound |
| /// scores (*_score_LB and *_score_ub respectively). |
| MachineInstr *SIInsertWaitcnts::generateSWaitCntInstBefore( |
| MachineInstr &MI, BlockWaitcntBrackets *ScoreBrackets) { |
| // To emit, or not to emit - that's the question! |
| // Start with an assumption that there is no need to emit. |
| unsigned int EmitSwaitcnt = 0; |
| // s_waitcnt instruction to return; default is NULL. |
| MachineInstr *SWaitInst = nullptr; |
| // No need to wait before phi. If a phi-move exists, then the wait should |
| // has been inserted before the move. If a phi-move does not exist, then |
| // wait should be inserted before the real use. The same is true for |
| // sc-merge. It is not a coincident that all these cases correspond to the |
| // instructions that are skipped in the assembling loop. |
| bool NeedLineMapping = false; // TODO: Check on this. |
| if (MI.isDebugValue() && |
| // TODO: any other opcode? |
| !NeedLineMapping) { |
| return SWaitInst; |
| } |
| |
| // See if an s_waitcnt is forced at block entry, or is needed at |
| // program end. |
| if (ScoreBrackets->getWaitAtBeginning()) { |
| // Note that we have already cleared the state, so we don't need to update |
| // it. |
| ScoreBrackets->clearWaitAtBeginning(); |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| EmitSwaitcnt |= CNT_MASK(T); |
| ScoreBrackets->setScoreLB(T, ScoreBrackets->getScoreUB(T)); |
| } |
| } |
| |
| // See if this instruction has a forced S_WAITCNT VM. |
| // TODO: Handle other cases of NeedsWaitcntVmBefore() |
| else if (MI.getOpcode() == AMDGPU::BUFFER_WBINVL1 || |
| MI.getOpcode() == AMDGPU::BUFFER_WBINVL1_SC || |
| MI.getOpcode() == AMDGPU::BUFFER_WBINVL1_VOL) { |
| EmitSwaitcnt |= |
| ScoreBrackets->updateByWait(VM_CNT, ScoreBrackets->getScoreUB(VM_CNT)); |
| } |
| |
| // All waits must be resolved at call return. |
| // NOTE: this could be improved with knowledge of all call sites or |
| // with knowledge of the called routines. |
| if (MI.getOpcode() == AMDGPU::RETURN || |
| MI.getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG) { |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| if (ScoreBrackets->getScoreUB(T) > ScoreBrackets->getScoreLB(T)) { |
| ScoreBrackets->setScoreLB(T, ScoreBrackets->getScoreUB(T)); |
| EmitSwaitcnt |= CNT_MASK(T); |
| } |
| } |
| } |
| // Resolve vm waits before gs-done. |
| else if ((MI.getOpcode() == AMDGPU::S_SENDMSG || |
| MI.getOpcode() == AMDGPU::S_SENDMSGHALT) && |
| ((MI.getOperand(0).getImm() & AMDGPU::SendMsg::ID_MASK_) == |
| AMDGPU::SendMsg::ID_GS_DONE)) { |
| if (ScoreBrackets->getScoreUB(VM_CNT) > ScoreBrackets->getScoreLB(VM_CNT)) { |
| ScoreBrackets->setScoreLB(VM_CNT, ScoreBrackets->getScoreUB(VM_CNT)); |
| EmitSwaitcnt |= CNT_MASK(VM_CNT); |
| } |
| } |
| #if 0 // TODO: the following blocks of logic when we have fence. |
| else if (MI.getOpcode() == SC_FENCE) { |
| const unsigned int group_size = |
| context->shader_info->GetMaxThreadGroupSize(); |
| // group_size == 0 means thread group size is unknown at compile time |
| const bool group_is_multi_wave = |
| (group_size == 0 || group_size > target_info->GetWaveFrontSize()); |
| const bool fence_is_global = !((SCInstInternalMisc*)Inst)->IsGroupFence(); |
| |
| for (unsigned int i = 0; i < Inst->NumSrcOperands(); i++) { |
| SCRegType src_type = Inst->GetSrcType(i); |
| switch (src_type) { |
| case SCMEM_LDS: |
| if (group_is_multi_wave || |
| context->OptFlagIsOn(OPT_R1100_LDSMEM_FENCE_CHICKEN_BIT)) { |
| EmitSwaitcnt |= ScoreBrackets->updateByWait(LGKM_CNT, |
| ScoreBrackets->getScoreUB(LGKM_CNT)); |
| // LDS may have to wait for VM_CNT after buffer load to LDS |
| if (target_info->HasBufferLoadToLDS()) { |
| EmitSwaitcnt |= ScoreBrackets->updateByWait(VM_CNT, |
| ScoreBrackets->getScoreUB(VM_CNT)); |
| } |
| } |
| break; |
| |
| case SCMEM_GDS: |
| if (group_is_multi_wave || fence_is_global) { |
| EmitSwaitcnt |= ScoreBrackets->updateByWait(EXP_CNT, |
| ScoreBrackets->getScoreUB(EXP_CNT)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait(LGKM_CNT, |
| ScoreBrackets->getScoreUB(LGKM_CNT)); |
| } |
| break; |
| |
| case SCMEM_UAV: |
| case SCMEM_TFBUF: |
| case SCMEM_RING: |
| case SCMEM_SCATTER: |
| if (group_is_multi_wave || fence_is_global) { |
| EmitSwaitcnt |= ScoreBrackets->updateByWait(EXP_CNT, |
| ScoreBrackets->getScoreUB(EXP_CNT)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait(VM_CNT, |
| ScoreBrackets->getScoreUB(VM_CNT)); |
| } |
| break; |
| |
| case SCMEM_SCRATCH: |
| default: |
| break; |
| } |
| } |
| } |
| #endif |
| |
| // Export & GDS instructions do not read the EXEC mask until after the export |
| // is granted (which can occur well after the instruction is issued). |
| // The shader program must flush all EXP operations on the export-count |
| // before overwriting the EXEC mask. |
| else { |
| if (MI.modifiesRegister(AMDGPU::EXEC, TRI)) { |
| // Export and GDS are tracked individually, either may trigger a waitcnt |
| // for EXEC. |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getEventUB(EXP_GPR_LOCK)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getEventUB(EXP_PARAM_ACCESS)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getEventUB(EXP_POS_ACCESS)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getEventUB(GDS_GPR_LOCK)); |
| } |
| |
| #if 0 // TODO: the following code to handle CALL. |
| // The argument passing for CALLs should suffice for VM_CNT and LGKM_CNT. |
| // However, there is a problem with EXP_CNT, because the call cannot |
| // easily tell if a register is used in the function, and if it did, then |
| // the referring instruction would have to have an S_WAITCNT, which is |
| // dependent on all call sites. So Instead, force S_WAITCNT for EXP_CNTs |
| // before the call. |
| if (MI.getOpcode() == SC_CALL) { |
| if (ScoreBrackets->getScoreUB(EXP_CNT) > |
| ScoreBrackets->getScoreLB(EXP_CNT)) { |
| ScoreBrackets->setScoreLB(EXP_CNT, ScoreBrackets->getScoreUB(EXP_CNT)); |
| EmitSwaitcnt |= CNT_MASK(EXP_CNT); |
| } |
| } |
| #endif |
| |
| // Look at the source operands of every instruction to see if |
| // any of them results from a previous memory operation that affects |
| // its current usage. If so, an s_waitcnt instruction needs to be |
| // emitted. |
| // If the source operand was defined by a load, add the s_waitcnt |
| // instruction. |
| for (const MachineMemOperand *Memop : MI.memoperands()) { |
| unsigned AS = Memop->getAddrSpace(); |
| if (AS != AMDGPUASI.LOCAL_ADDRESS) |
| continue; |
| unsigned RegNo = SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS; |
| // VM_CNT is only relevant to vgpr or LDS. |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| VM_CNT, ScoreBrackets->getRegScore(RegNo, VM_CNT)); |
| } |
| for (unsigned I = 0, E = MI.getNumOperands(); I != E; ++I) { |
| const MachineOperand &Op = MI.getOperand(I); |
| const MachineRegisterInfo &MRIA = *MRI; |
| RegInterval Interval = |
| ScoreBrackets->getRegInterval(&MI, TII, MRI, TRI, I, false); |
| for (signed RegNo = Interval.first; RegNo < Interval.second; ++RegNo) { |
| if (TRI->isVGPR(MRIA, Op.getReg())) { |
| // VM_CNT is only relevant to vgpr or LDS. |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| VM_CNT, ScoreBrackets->getRegScore(RegNo, VM_CNT)); |
| } |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| LGKM_CNT, ScoreBrackets->getRegScore(RegNo, LGKM_CNT)); |
| } |
| } |
| // End of for loop that looks at all source operands to decide vm_wait_cnt |
| // and lgk_wait_cnt. |
| |
| // Two cases are handled for destination operands: |
| // 1) If the destination operand was defined by a load, add the s_waitcnt |
| // instruction to guarantee the right WAW order. |
| // 2) If a destination operand that was used by a recent export/store ins, |
| // add s_waitcnt on exp_cnt to guarantee the WAR order. |
| if (MI.mayStore()) { |
| for (const MachineMemOperand *Memop : MI.memoperands()) { |
| unsigned AS = Memop->getAddrSpace(); |
| if (AS != AMDGPUASI.LOCAL_ADDRESS) |
| continue; |
| unsigned RegNo = SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS; |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| VM_CNT, ScoreBrackets->getRegScore(RegNo, VM_CNT)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getRegScore(RegNo, EXP_CNT)); |
| } |
| } |
| for (unsigned I = 0, E = MI.getNumOperands(); I != E; ++I) { |
| MachineOperand &Def = MI.getOperand(I); |
| const MachineRegisterInfo &MRIA = *MRI; |
| RegInterval Interval = |
| ScoreBrackets->getRegInterval(&MI, TII, MRI, TRI, I, true); |
| for (signed RegNo = Interval.first; RegNo < Interval.second; ++RegNo) { |
| if (TRI->isVGPR(MRIA, Def.getReg())) { |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| VM_CNT, ScoreBrackets->getRegScore(RegNo, VM_CNT)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getRegScore(RegNo, EXP_CNT)); |
| } |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| LGKM_CNT, ScoreBrackets->getRegScore(RegNo, LGKM_CNT)); |
| } |
| } // End of for loop that looks at all dest operands. |
| } |
| |
| // TODO: Tie force zero to a compiler triage option. |
| bool ForceZero = false; |
| |
| // Check to see if this is an S_BARRIER, and if an implicit S_WAITCNT 0 |
| // occurs before the instruction. Doing it here prevents any additional |
| // S_WAITCNTs from being emitted if the instruction was marked as |
| // requiring a WAITCNT beforehand. |
| if (MI.getOpcode() == AMDGPU::S_BARRIER && ST->needWaitcntBeforeBarrier()) { |
| EmitSwaitcnt |= |
| ScoreBrackets->updateByWait(VM_CNT, ScoreBrackets->getScoreUB(VM_CNT)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| EXP_CNT, ScoreBrackets->getScoreUB(EXP_CNT)); |
| EmitSwaitcnt |= ScoreBrackets->updateByWait( |
| LGKM_CNT, ScoreBrackets->getScoreUB(LGKM_CNT)); |
| } |
| |
| // TODO: Remove this work-around, enable the assert for Bug 457939 |
| // after fixing the scheduler. Also, the Shader Compiler code is |
| // independent of target. |
| if (readsVCCZ(MI) && ST->getGeneration() <= SISubtarget::SEA_ISLANDS) { |
| if (ScoreBrackets->getScoreLB(LGKM_CNT) < |
| ScoreBrackets->getScoreUB(LGKM_CNT) && |
| ScoreBrackets->hasPendingSMEM()) { |
| // Wait on everything, not just LGKM. vccz reads usually come from |
| // terminators, and we always wait on everything at the end of the |
| // block, so if we only wait on LGKM here, we might end up with |
| // another s_waitcnt inserted right after this if there are non-LGKM |
| // instructions still outstanding. |
| ForceZero = true; |
| EmitSwaitcnt = true; |
| } |
| } |
| |
| // Does this operand processing indicate s_wait counter update? |
| if (EmitSwaitcnt) { |
| int CntVal[NUM_INST_CNTS]; |
| |
| bool UseDefaultWaitcntStrategy = true; |
| if (ForceZero) { |
| // Force all waitcnts to 0. |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| ScoreBrackets->setScoreLB(T, ScoreBrackets->getScoreUB(T)); |
| } |
| CntVal[VM_CNT] = 0; |
| CntVal[EXP_CNT] = 0; |
| CntVal[LGKM_CNT] = 0; |
| UseDefaultWaitcntStrategy = false; |
| } |
| |
| if (UseDefaultWaitcntStrategy) { |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| if (EmitSwaitcnt & CNT_MASK(T)) { |
| int Delta = |
| ScoreBrackets->getScoreUB(T) - ScoreBrackets->getScoreLB(T); |
| int MaxDelta = ScoreBrackets->getWaitCountMax(T); |
| if (Delta >= MaxDelta) { |
| Delta = -1; |
| if (T != EXP_CNT) { |
| ScoreBrackets->setScoreLB( |
| T, ScoreBrackets->getScoreUB(T) - MaxDelta); |
| } |
| EmitSwaitcnt &= ~CNT_MASK(T); |
| } |
| CntVal[T] = Delta; |
| } else { |
| // If we are not waiting for a particular counter then encode |
| // it as -1 which means "don't care." |
| CntVal[T] = -1; |
| } |
| } |
| } |
| |
| // If we are not waiting on any counter we can skip the wait altogether. |
| if (EmitSwaitcnt != 0) { |
| MachineInstr *OldWaitcnt = ScoreBrackets->getWaitcnt(); |
| int Imm = (!OldWaitcnt) ? 0 : OldWaitcnt->getOperand(0).getImm(); |
| if (!OldWaitcnt || (AMDGPU::decodeVmcnt(IV, Imm) != |
| (CntVal[VM_CNT] & AMDGPU::getVmcntBitMask(IV))) || |
| (AMDGPU::decodeExpcnt(IV, Imm) != |
| (CntVal[EXP_CNT] & AMDGPU::getExpcntBitMask(IV))) || |
| (AMDGPU::decodeLgkmcnt(IV, Imm) != |
| (CntVal[LGKM_CNT] & AMDGPU::getLgkmcntBitMask(IV)))) { |
| MachineLoop *ContainingLoop = MLI->getLoopFor(MI.getParent()); |
| if (ContainingLoop) { |
| MachineBasicBlock *TBB = ContainingLoop->getTopBlock(); |
| BlockWaitcntBrackets *ScoreBracket = |
| BlockWaitcntBracketsMap[TBB].get(); |
| if (!ScoreBracket) { |
| assert(BlockVisitedSet.find(TBB) == BlockVisitedSet.end()); |
| BlockWaitcntBracketsMap[TBB] = make_unique<BlockWaitcntBrackets>(); |
| ScoreBracket = BlockWaitcntBracketsMap[TBB].get(); |
| } |
| ScoreBracket->setRevisitLoop(true); |
| DEBUG(dbgs() << "set-revisit: block" |
| << ContainingLoop->getTopBlock()->getNumber() << '\n';); |
| } |
| } |
| |
| // Update an existing waitcount, or make a new one. |
| MachineFunction &MF = *MI.getParent()->getParent(); |
| if (OldWaitcnt && OldWaitcnt->getOpcode() != AMDGPU::S_WAITCNT) { |
| SWaitInst = OldWaitcnt; |
| } else { |
| SWaitInst = MF.CreateMachineInstr(TII->get(AMDGPU::S_WAITCNT), |
| MI.getDebugLoc()); |
| CompilerGeneratedWaitcntSet.insert(SWaitInst); |
| } |
| |
| const MachineOperand &Op = |
| MachineOperand::CreateImm(AMDGPU::encodeWaitcnt( |
| IV, CntVal[VM_CNT], CntVal[EXP_CNT], CntVal[LGKM_CNT])); |
| SWaitInst->addOperand(MF, Op); |
| |
| if (CntVal[EXP_CNT] == 0) { |
| ScoreBrackets->setMixedExpTypes(false); |
| } |
| } |
| } |
| |
| return SWaitInst; |
| } |
| |
| void SIInsertWaitcnts::insertWaitcntBeforeCF(MachineBasicBlock &MBB, |
| MachineInstr *Waitcnt) { |
| if (MBB.empty()) { |
| MBB.push_back(Waitcnt); |
| return; |
| } |
| |
| MachineBasicBlock::iterator It = MBB.end(); |
| MachineInstr *MI = &*(--It); |
| if (MI->isBranch()) { |
| MBB.insert(It, Waitcnt); |
| } else { |
| MBB.push_back(Waitcnt); |
| } |
| |
| return; |
| } |
| |
| void SIInsertWaitcnts::updateEventWaitCntAfter( |
| MachineInstr &Inst, BlockWaitcntBrackets *ScoreBrackets) { |
| // Now look at the instruction opcode. If it is a memory access |
| // instruction, update the upper-bound of the appropriate counter's |
| // bracket and the destination operand scores. |
| // TODO: Use the (TSFlags & SIInstrFlags::LGKM_CNT) property everywhere. |
| if (TII->isDS(Inst) && (Inst.mayLoad() || Inst.mayStore())) { |
| if (TII->getNamedOperand(Inst, AMDGPU::OpName::gds)->getImm() != 0) { |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, GDS_ACCESS, Inst); |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, GDS_GPR_LOCK, Inst); |
| } else { |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, LDS_ACCESS, Inst); |
| } |
| } else if (TII->isFLAT(Inst)) { |
| assert(Inst.mayLoad() || Inst.mayStore()); |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_ACCESS, Inst); |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, LDS_ACCESS, Inst); |
| |
| // This is a flat memory operation. Check to see if it has memory |
| // tokens for both LDS and Memory, and if so mark it as a flat. |
| bool FoundLDSMem = false; |
| for (const MachineMemOperand *Memop : Inst.memoperands()) { |
| unsigned AS = Memop->getAddrSpace(); |
| if (AS == AMDGPUASI.LOCAL_ADDRESS || AS == AMDGPUASI.FLAT_ADDRESS) |
| FoundLDSMem = true; |
| } |
| |
| // This is a flat memory operation, so note it - it will require |
| // that both the VM and LGKM be flushed to zero if it is pending when |
| // a VM or LGKM dependency occurs. |
| if (FoundLDSMem) { |
| ScoreBrackets->setPendingFlat(); |
| } |
| } else if (SIInstrInfo::isVMEM(Inst) && |
| // TODO: get a better carve out. |
| Inst.getOpcode() != AMDGPU::BUFFER_WBINVL1 && |
| Inst.getOpcode() != AMDGPU::BUFFER_WBINVL1_SC && |
| Inst.getOpcode() != AMDGPU::BUFFER_WBINVL1_VOL) { |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_ACCESS, Inst); |
| if ( // TODO: assumed yes -- target_info->MemWriteNeedsExpWait() && |
| (Inst.mayStore() || AMDGPU::getAtomicNoRetOp(Inst.getOpcode()))) { |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, VMW_GPR_LOCK, Inst); |
| } |
| } else if (TII->isSMRD(Inst)) { |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, SMEM_ACCESS, Inst); |
| } else { |
| switch (Inst.getOpcode()) { |
| case AMDGPU::S_SENDMSG: |
| case AMDGPU::S_SENDMSGHALT: |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, SQ_MESSAGE, Inst); |
| break; |
| case AMDGPU::EXP: |
| case AMDGPU::EXP_DONE: { |
| int Imm = TII->getNamedOperand(Inst, AMDGPU::OpName::tgt)->getImm(); |
| if (Imm >= 32 && Imm <= 63) |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, EXP_PARAM_ACCESS, Inst); |
| else if (Imm >= 12 && Imm <= 15) |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, EXP_POS_ACCESS, Inst); |
| else |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, EXP_GPR_LOCK, Inst); |
| break; |
| } |
| case AMDGPU::S_MEMTIME: |
| case AMDGPU::S_MEMREALTIME: |
| ScoreBrackets->updateByEvent(TII, TRI, MRI, SMEM_ACCESS, Inst); |
| break; |
| default: |
| break; |
| } |
| } |
| } |
| |
| void SIInsertWaitcnts::mergeInputScoreBrackets(MachineBasicBlock &Block) { |
| BlockWaitcntBrackets *ScoreBrackets = BlockWaitcntBracketsMap[&Block].get(); |
| int32_t MaxPending[NUM_INST_CNTS] = {0}; |
| int32_t MaxFlat[NUM_INST_CNTS] = {0}; |
| bool MixedExpTypes = false; |
| |
| // Clear the score bracket state. |
| ScoreBrackets->clear(); |
| |
| // Compute the number of pending elements on block entry. |
| |
| // IMPORTANT NOTE: If iterative handling of loops is added, the code will |
| // need to handle single BBs with backedges to themselves. This means that |
| // they will need to retain and not clear their initial state. |
| |
| // See if there are any uninitialized predecessors. If so, emit an |
| // s_waitcnt 0 at the beginning of the block. |
| for (MachineBasicBlock *pred : Block.predecessors()) { |
| BlockWaitcntBrackets *PredScoreBrackets = |
| BlockWaitcntBracketsMap[pred].get(); |
| bool Visited = BlockVisitedSet.find(pred) != BlockVisitedSet.end(); |
| if (!Visited || PredScoreBrackets->getWaitAtBeginning()) { |
| break; |
| } |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| int span = |
| PredScoreBrackets->getScoreUB(T) - PredScoreBrackets->getScoreLB(T); |
| MaxPending[T] = std::max(MaxPending[T], span); |
| span = |
| PredScoreBrackets->pendingFlat(T) - PredScoreBrackets->getScoreLB(T); |
| MaxFlat[T] = std::max(MaxFlat[T], span); |
| } |
| |
| MixedExpTypes |= PredScoreBrackets->mixedExpTypes(); |
| } |
| |
| // TODO: Is SC Block->IsMainExit() same as Block.succ_empty()? |
| // Also handle kills for exit block. |
| if (Block.succ_empty() && !KillWaitBrackets.empty()) { |
| for (unsigned int I = 0; I < KillWaitBrackets.size(); I++) { |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| int Span = KillWaitBrackets[I]->getScoreUB(T) - |
| KillWaitBrackets[I]->getScoreLB(T); |
| MaxPending[T] = std::max(MaxPending[T], Span); |
| Span = KillWaitBrackets[I]->pendingFlat(T) - |
| KillWaitBrackets[I]->getScoreLB(T); |
| MaxFlat[T] = std::max(MaxFlat[T], Span); |
| } |
| |
| MixedExpTypes |= KillWaitBrackets[I]->mixedExpTypes(); |
| } |
| } |
| |
| // Special handling for GDS_GPR_LOCK and EXP_GPR_LOCK. |
| for (MachineBasicBlock *Pred : Block.predecessors()) { |
| BlockWaitcntBrackets *PredScoreBrackets = |
| BlockWaitcntBracketsMap[Pred].get(); |
| bool Visited = BlockVisitedSet.find(Pred) != BlockVisitedSet.end(); |
| if (!Visited || PredScoreBrackets->getWaitAtBeginning()) { |
| break; |
| } |
| |
| int GDSSpan = PredScoreBrackets->getEventUB(GDS_GPR_LOCK) - |
| PredScoreBrackets->getScoreLB(EXP_CNT); |
| MaxPending[EXP_CNT] = std::max(MaxPending[EXP_CNT], GDSSpan); |
| int EXPSpan = PredScoreBrackets->getEventUB(EXP_GPR_LOCK) - |
| PredScoreBrackets->getScoreLB(EXP_CNT); |
| MaxPending[EXP_CNT] = std::max(MaxPending[EXP_CNT], EXPSpan); |
| } |
| |
| // TODO: Is SC Block->IsMainExit() same as Block.succ_empty()? |
| if (Block.succ_empty() && !KillWaitBrackets.empty()) { |
| for (unsigned int I = 0; I < KillWaitBrackets.size(); I++) { |
| int GDSSpan = KillWaitBrackets[I]->getEventUB(GDS_GPR_LOCK) - |
| KillWaitBrackets[I]->getScoreLB(EXP_CNT); |
| MaxPending[EXP_CNT] = std::max(MaxPending[EXP_CNT], GDSSpan); |
| int EXPSpan = KillWaitBrackets[I]->getEventUB(EXP_GPR_LOCK) - |
| KillWaitBrackets[I]->getScoreLB(EXP_CNT); |
| MaxPending[EXP_CNT] = std::max(MaxPending[EXP_CNT], EXPSpan); |
| } |
| } |
| |
| #if 0 |
| // LC does not (unlike) add a waitcnt at beginning. Leaving it as marker. |
| // TODO: how does LC distinguish between function entry and main entry? |
| // If this is the entry to a function, force a wait. |
| MachineBasicBlock &Entry = Block.getParent()->front(); |
| if (Entry.getNumber() == Block.getNumber()) { |
| ScoreBrackets->setWaitAtBeginning(); |
| return; |
| } |
| #endif |
| |
| // Now set the current Block's brackets to the largest ending bracket. |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| ScoreBrackets->setScoreUB(T, MaxPending[T]); |
| ScoreBrackets->setScoreLB(T, 0); |
| ScoreBrackets->setLastFlat(T, MaxFlat[T]); |
| } |
| |
| ScoreBrackets->setMixedExpTypes(MixedExpTypes); |
| |
| // Set the register scoreboard. |
| for (MachineBasicBlock *Pred : Block.predecessors()) { |
| if (BlockVisitedSet.find(Pred) == BlockVisitedSet.end()) { |
| break; |
| } |
| |
| BlockWaitcntBrackets *PredScoreBrackets = |
| BlockWaitcntBracketsMap[Pred].get(); |
| |
| // Now merge the gpr_reg_score information |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| int PredLB = PredScoreBrackets->getScoreLB(T); |
| int PredUB = PredScoreBrackets->getScoreUB(T); |
| if (PredLB < PredUB) { |
| int PredScale = MaxPending[T] - PredUB; |
| // Merge vgpr scores. |
| for (int J = 0; J <= PredScoreBrackets->getMaxVGPR(); J++) { |
| int PredRegScore = PredScoreBrackets->getRegScore(J, T); |
| if (PredRegScore <= PredLB) |
| continue; |
| int NewRegScore = PredScale + PredRegScore; |
| ScoreBrackets->setRegScore( |
| J, T, std::max(ScoreBrackets->getRegScore(J, T), NewRegScore)); |
| } |
| // Also need to merge sgpr scores for lgkm_cnt. |
| if (T == LGKM_CNT) { |
| for (int J = 0; J <= PredScoreBrackets->getMaxSGPR(); J++) { |
| int PredRegScore = |
| PredScoreBrackets->getRegScore(J + NUM_ALL_VGPRS, LGKM_CNT); |
| if (PredRegScore <= PredLB) |
| continue; |
| int NewRegScore = PredScale + PredRegScore; |
| ScoreBrackets->setRegScore( |
| J + NUM_ALL_VGPRS, LGKM_CNT, |
| std::max( |
| ScoreBrackets->getRegScore(J + NUM_ALL_VGPRS, LGKM_CNT), |
| NewRegScore)); |
| } |
| } |
| } |
| } |
| |
| // Also merge the WaitEvent information. |
| ForAllWaitEventType(W) { |
| enum InstCounterType T = PredScoreBrackets->eventCounter(W); |
| int PredEventUB = PredScoreBrackets->getEventUB(W); |
| if (PredEventUB > PredScoreBrackets->getScoreLB(T)) { |
| int NewEventUB = |
| MaxPending[T] + PredEventUB - PredScoreBrackets->getScoreUB(T); |
| if (NewEventUB > 0) { |
| ScoreBrackets->setEventUB( |
| W, std::max(ScoreBrackets->getEventUB(W), NewEventUB)); |
| } |
| } |
| } |
| } |
| |
| // TODO: Is SC Block->IsMainExit() same as Block.succ_empty()? |
| // Set the register scoreboard. |
| if (Block.succ_empty() && !KillWaitBrackets.empty()) { |
| for (unsigned int I = 0; I < KillWaitBrackets.size(); I++) { |
| // Now merge the gpr_reg_score information. |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| int PredLB = KillWaitBrackets[I]->getScoreLB(T); |
| int PredUB = KillWaitBrackets[I]->getScoreUB(T); |
| if (PredLB < PredUB) { |
| int PredScale = MaxPending[T] - PredUB; |
| // Merge vgpr scores. |
| for (int J = 0; J <= KillWaitBrackets[I]->getMaxVGPR(); J++) { |
| int PredRegScore = KillWaitBrackets[I]->getRegScore(J, T); |
| if (PredRegScore <= PredLB) |
| continue; |
| int NewRegScore = PredScale + PredRegScore; |
| ScoreBrackets->setRegScore( |
| J, T, std::max(ScoreBrackets->getRegScore(J, T), NewRegScore)); |
| } |
| // Also need to merge sgpr scores for lgkm_cnt. |
| if (T == LGKM_CNT) { |
| for (int J = 0; J <= KillWaitBrackets[I]->getMaxSGPR(); J++) { |
| int PredRegScore = |
| KillWaitBrackets[I]->getRegScore(J + NUM_ALL_VGPRS, LGKM_CNT); |
| if (PredRegScore <= PredLB) |
| continue; |
| int NewRegScore = PredScale + PredRegScore; |
| ScoreBrackets->setRegScore( |
| J + NUM_ALL_VGPRS, LGKM_CNT, |
| std::max( |
| ScoreBrackets->getRegScore(J + NUM_ALL_VGPRS, LGKM_CNT), |
| NewRegScore)); |
| } |
| } |
| } |
| } |
| |
| // Also merge the WaitEvent information. |
| ForAllWaitEventType(W) { |
| enum InstCounterType T = KillWaitBrackets[I]->eventCounter(W); |
| int PredEventUB = KillWaitBrackets[I]->getEventUB(W); |
| if (PredEventUB > KillWaitBrackets[I]->getScoreLB(T)) { |
| int NewEventUB = |
| MaxPending[T] + PredEventUB - KillWaitBrackets[I]->getScoreUB(T); |
| if (NewEventUB > 0) { |
| ScoreBrackets->setEventUB( |
| W, std::max(ScoreBrackets->getEventUB(W), NewEventUB)); |
| } |
| } |
| } |
| } |
| } |
| |
| // Special case handling of GDS_GPR_LOCK and EXP_GPR_LOCK. Merge this for the |
| // sequencing predecessors, because changes to EXEC require waitcnts due to |
| // the delayed nature of these operations. |
| for (MachineBasicBlock *Pred : Block.predecessors()) { |
| if (BlockVisitedSet.find(Pred) == BlockVisitedSet.end()) { |
| break; |
| } |
| |
| BlockWaitcntBrackets *PredScoreBrackets = |
| BlockWaitcntBracketsMap[Pred].get(); |
| |
| int pred_gds_ub = PredScoreBrackets->getEventUB(GDS_GPR_LOCK); |
| if (pred_gds_ub > PredScoreBrackets->getScoreLB(EXP_CNT)) { |
| int new_gds_ub = MaxPending[EXP_CNT] + pred_gds_ub - |
| PredScoreBrackets->getScoreUB(EXP_CNT); |
| if (new_gds_ub > 0) { |
| ScoreBrackets->setEventUB( |
| GDS_GPR_LOCK, |
| std::max(ScoreBrackets->getEventUB(GDS_GPR_LOCK), new_gds_ub)); |
| } |
| } |
| int pred_exp_ub = PredScoreBrackets->getEventUB(EXP_GPR_LOCK); |
| if (pred_exp_ub > PredScoreBrackets->getScoreLB(EXP_CNT)) { |
| int new_exp_ub = MaxPending[EXP_CNT] + pred_exp_ub - |
| PredScoreBrackets->getScoreUB(EXP_CNT); |
| if (new_exp_ub > 0) { |
| ScoreBrackets->setEventUB( |
| EXP_GPR_LOCK, |
| std::max(ScoreBrackets->getEventUB(EXP_GPR_LOCK), new_exp_ub)); |
| } |
| } |
| } |
| } |
| |
| /// Return the "bottom" block of a loop. This differs from |
| /// MachineLoop::getBottomBlock in that it works even if the loop is |
| /// discontiguous. |
| MachineBasicBlock *SIInsertWaitcnts::loopBottom(const MachineLoop *Loop) { |
| MachineBasicBlock *Bottom = Loop->getHeader(); |
| for (MachineBasicBlock *MBB : Loop->blocks()) |
| if (MBB->getNumber() > Bottom->getNumber()) |
| Bottom = MBB; |
| return Bottom; |
| } |
| |
| // Generate s_waitcnt instructions where needed. |
| void SIInsertWaitcnts::insertWaitcntInBlock(MachineFunction &MF, |
| MachineBasicBlock &Block) { |
| // Initialize the state information. |
| mergeInputScoreBrackets(Block); |
| |
| BlockWaitcntBrackets *ScoreBrackets = BlockWaitcntBracketsMap[&Block].get(); |
| |
| DEBUG({ |
| dbgs() << "Block" << Block.getNumber(); |
| ScoreBrackets->dump(); |
| }); |
| |
| bool InsertNOP = false; |
| |
| // Walk over the instructions. |
| for (MachineBasicBlock::iterator Iter = Block.begin(), E = Block.end(); |
| Iter != E;) { |
| MachineInstr &Inst = *Iter; |
| // Remove any previously existing waitcnts. |
| if (Inst.getOpcode() == AMDGPU::S_WAITCNT) { |
| // TODO: Register the old waitcnt and optimize the following waitcnts. |
| // Leaving the previously existing waitcnts is conservatively correct. |
| if (CompilerGeneratedWaitcntSet.find(&Inst) == |
| CompilerGeneratedWaitcntSet.end()) |
| ++Iter; |
| else { |
| ScoreBrackets->setWaitcnt(&Inst); |
| ++Iter; |
| Inst.removeFromParent(); |
| } |
| continue; |
| } |
| |
| // Kill instructions generate a conditional branch to the endmain block. |
| // Merge the current waitcnt state into the endmain block information. |
| // TODO: Are there other flavors of KILL instruction? |
| if (Inst.getOpcode() == AMDGPU::KILL) { |
| addKillWaitBracket(ScoreBrackets); |
| } |
| |
| bool VCCZBugWorkAround = false; |
| if (readsVCCZ(Inst) && |
| (VCCZBugHandledSet.find(&Inst) == VCCZBugHandledSet.end())) { |
| if (ScoreBrackets->getScoreLB(LGKM_CNT) < |
| ScoreBrackets->getScoreUB(LGKM_CNT) && |
| ScoreBrackets->hasPendingSMEM()) { |
| if (ST->getGeneration() <= SISubtarget::SEA_ISLANDS) |
| VCCZBugWorkAround = true; |
| } |
| } |
| |
| // Generate an s_waitcnt instruction to be placed before |
| // cur_Inst, if needed. |
| MachineInstr *SWaitInst = generateSWaitCntInstBefore(Inst, ScoreBrackets); |
| |
| if (SWaitInst) { |
| Block.insert(Inst, SWaitInst); |
| if (ScoreBrackets->getWaitcnt() != SWaitInst) { |
| DEBUG(dbgs() << "insertWaitcntInBlock\n" |
| << "Old Instr: " << Inst << '\n' |
| << "New Instr: " << *SWaitInst << '\n';); |
| } |
| } |
| |
| updateEventWaitCntAfter(Inst, ScoreBrackets); |
| |
| #if 0 // TODO: implement resource type check controlled by options with ub = LB. |
| // If this instruction generates a S_SETVSKIP because it is an |
| // indexed resource, and we are on Tahiti, then it will also force |
| // an S_WAITCNT vmcnt(0) |
| if (RequireCheckResourceType(Inst, context)) { |
| // Force the score to as if an S_WAITCNT vmcnt(0) is emitted. |
| ScoreBrackets->setScoreLB(VM_CNT, |
| ScoreBrackets->getScoreUB(VM_CNT)); |
| } |
| #endif |
| |
| ScoreBrackets->clearWaitcnt(); |
| |
| if (SWaitInst) { |
| DEBUG({ SWaitInst->print(dbgs() << '\n'); }); |
| } |
| DEBUG({ |
| Inst.print(dbgs()); |
| ScoreBrackets->dump(); |
| }); |
| |
| // Check to see if this is a GWS instruction. If so, and if this is CI or |
| // VI, then the generated code sequence will include an S_WAITCNT 0. |
| // TODO: Are these the only GWS instructions? |
| if (Inst.getOpcode() == AMDGPU::DS_GWS_INIT || |
| Inst.getOpcode() == AMDGPU::DS_GWS_SEMA_V || |
| Inst.getOpcode() == AMDGPU::DS_GWS_SEMA_BR || |
| Inst.getOpcode() == AMDGPU::DS_GWS_SEMA_P || |
| Inst.getOpcode() == AMDGPU::DS_GWS_BARRIER) { |
| // TODO: && context->target_info->GwsRequiresMemViolTest() ) { |
| ScoreBrackets->updateByWait(VM_CNT, ScoreBrackets->getScoreUB(VM_CNT)); |
| ScoreBrackets->updateByWait(EXP_CNT, ScoreBrackets->getScoreUB(EXP_CNT)); |
| ScoreBrackets->updateByWait(LGKM_CNT, |
| ScoreBrackets->getScoreUB(LGKM_CNT)); |
| } |
| |
| // TODO: Remove this work-around after fixing the scheduler and enable the |
| // assert above. |
| if (VCCZBugWorkAround) { |
| // Restore the vccz bit. Any time a value is written to vcc, the vcc |
| // bit is updated, so we can restore the bit by reading the value of |
| // vcc and then writing it back to the register. |
| BuildMI(Block, Inst, Inst.getDebugLoc(), TII->get(AMDGPU::S_MOV_B64), |
| AMDGPU::VCC) |
| .addReg(AMDGPU::VCC); |
| VCCZBugHandledSet.insert(&Inst); |
| } |
| |
| if (ST->getGeneration() >= SISubtarget::VOLCANIC_ISLANDS) { |
| |
| // This avoids a s_nop after a waitcnt has just been inserted. |
| if (!SWaitInst && InsertNOP) { |
| BuildMI(Block, Inst, DebugLoc(), TII->get(AMDGPU::S_NOP)).addImm(0); |
| } |
| InsertNOP = false; |
| |
| // Any occurrence of consecutive VMEM or SMEM instructions forms a VMEM |
| // or SMEM clause, respectively. |
| // |
| // The temporary workaround is to break the clauses with S_NOP. |
| // |
| // The proper solution would be to allocate registers such that all source |
| // and destination registers don't overlap, e.g. this is illegal: |
| // r0 = load r2 |
| // r2 = load r0 |
| bool IsSMEM = false; |
| bool IsVMEM = false; |
| if (TII->isSMRD(Inst)) |
| IsSMEM = true; |
| else if (TII->usesVM_CNT(Inst)) |
| IsVMEM = true; |
| |
| ++Iter; |
| if (Iter == E) |
| break; |
| |
| MachineInstr &Next = *Iter; |
| |
| // TODO: How about consecutive SMEM instructions? |
| // The comments above says break the clause but the code does not. |
| // if ((TII->isSMRD(next) && isSMEM) || |
| if (!IsSMEM && TII->usesVM_CNT(Next) && IsVMEM && |
| // TODO: Enable this check when hasSoftClause is upstreamed. |
| // ST->hasSoftClauses() && |
| ST->isXNACKEnabled()) { |
| // Insert a NOP to break the clause. |
| InsertNOP = true; |
| continue; |
| } |
| |
| // There must be "S_NOP 0" between an instruction writing M0 and |
| // S_SENDMSG. |
| if ((Next.getOpcode() == AMDGPU::S_SENDMSG || |
| Next.getOpcode() == AMDGPU::S_SENDMSGHALT) && |
| Inst.definesRegister(AMDGPU::M0)) |
| InsertNOP = true; |
| |
| continue; |
| } |
| |
| ++Iter; |
| } |
| |
| // Check if we need to force convergence at loop footer. |
| MachineLoop *ContainingLoop = MLI->getLoopFor(&Block); |
| if (ContainingLoop && loopBottom(ContainingLoop) == &Block) { |
| LoopWaitcntData *WaitcntData = LoopWaitcntDataMap[ContainingLoop].get(); |
| WaitcntData->print(); |
| DEBUG(dbgs() << '\n';); |
| |
| // The iterative waitcnt insertion algorithm aims for optimal waitcnt |
| // placement and doesn't always guarantee convergence for a loop. Each |
| // loop should take at most 2 iterations for it to converge naturally. |
| // When this max is reached and result doesn't converge, we force |
| // convergence by inserting a s_waitcnt at the end of loop footer. |
| if (WaitcntData->getIterCnt() > 2) { |
| // To ensure convergence, need to make wait events at loop footer be no |
| // more than those from the previous iteration. |
| // As a simplification, Instead of tracking individual scores and |
| // generate the precise wait count, just wait on 0. |
| bool HasPending = false; |
| MachineInstr *SWaitInst = WaitcntData->getWaitcnt(); |
| for (enum InstCounterType T = VM_CNT; T < NUM_INST_CNTS; |
| T = (enum InstCounterType)(T + 1)) { |
| if (ScoreBrackets->getScoreUB(T) > ScoreBrackets->getScoreLB(T)) { |
| ScoreBrackets->setScoreLB(T, ScoreBrackets->getScoreUB(T)); |
| HasPending = true; |
| } |
| } |
| |
| if (HasPending) { |
| if (!SWaitInst) { |
| SWaitInst = Block.getParent()->CreateMachineInstr( |
| TII->get(AMDGPU::S_WAITCNT), DebugLoc()); |
| CompilerGeneratedWaitcntSet.insert(SWaitInst); |
| const MachineOperand &Op = MachineOperand::CreateImm(0); |
| SWaitInst->addOperand(MF, Op); |
| #if 0 // TODO: Format the debug output |
| OutputTransformBanner("insertWaitcntInBlock",0,"Create:",context); |
| OutputTransformAdd(SWaitInst, context); |
| #endif |
| } |
| #if 0 // TODO: ?? |
| _DEV( REPORTED_STATS->force_waitcnt_converge = 1; ) |
| #endif |
| } |
| |
| if (SWaitInst) { |
| DEBUG({ |
| SWaitInst->print(dbgs()); |
| dbgs() << "\nAdjusted score board:"; |
| ScoreBrackets->dump(); |
| }); |
| |
| // Add this waitcnt to the block. It is either newly created or |
| // created in previous iterations and added back since block traversal |
| // always remove waitcnt. |
| insertWaitcntBeforeCF(Block, SWaitInst); |
| WaitcntData->setWaitcnt(SWaitInst); |
| } |
| } |
| } |
| } |
| |
| bool SIInsertWaitcnts::runOnMachineFunction(MachineFunction &MF) { |
| ST = &MF.getSubtarget<SISubtarget>(); |
| TII = ST->getInstrInfo(); |
| TRI = &TII->getRegisterInfo(); |
| MRI = &MF.getRegInfo(); |
| MLI = &getAnalysis<MachineLoopInfo>(); |
| IV = AMDGPU::IsaInfo::getIsaVersion(ST->getFeatureBits()); |
| AMDGPUASI = ST->getAMDGPUAS(); |
| |
| HardwareLimits.VmcntMax = AMDGPU::getVmcntBitMask(IV); |
| HardwareLimits.ExpcntMax = AMDGPU::getExpcntBitMask(IV); |
| HardwareLimits.LgkmcntMax = AMDGPU::getLgkmcntBitMask(IV); |
| |
| HardwareLimits.NumVGPRsMax = ST->getAddressableNumVGPRs(); |
| HardwareLimits.NumSGPRsMax = ST->getAddressableNumSGPRs(); |
| assert(HardwareLimits.NumVGPRsMax <= SQ_MAX_PGM_VGPRS); |
| assert(HardwareLimits.NumSGPRsMax <= SQ_MAX_PGM_SGPRS); |
| |
| RegisterEncoding.VGPR0 = TRI->getEncodingValue(AMDGPU::VGPR0); |
| RegisterEncoding.VGPRL = |
| RegisterEncoding.VGPR0 + HardwareLimits.NumVGPRsMax - 1; |
| RegisterEncoding.SGPR0 = TRI->getEncodingValue(AMDGPU::SGPR0); |
| RegisterEncoding.SGPRL = |
| RegisterEncoding.SGPR0 + HardwareLimits.NumSGPRsMax - 1; |
| |
| // Walk over the blocks in reverse post-dominator order, inserting |
| // s_waitcnt where needed. |
| ReversePostOrderTraversal<MachineFunction *> RPOT(&MF); |
| bool Modified = false; |
| for (ReversePostOrderTraversal<MachineFunction *>::rpo_iterator |
| I = RPOT.begin(), |
| E = RPOT.end(), J = RPOT.begin(); |
| I != E;) { |
| MachineBasicBlock &MBB = **I; |
| |
| BlockVisitedSet.insert(&MBB); |
| |
| BlockWaitcntBrackets *ScoreBrackets = BlockWaitcntBracketsMap[&MBB].get(); |
| if (!ScoreBrackets) { |
| BlockWaitcntBracketsMap[&MBB] = make_unique<BlockWaitcntBrackets>(); |
| ScoreBrackets = BlockWaitcntBracketsMap[&MBB].get(); |
| } |
| ScoreBrackets->setPostOrder(MBB.getNumber()); |
| MachineLoop *ContainingLoop = MLI->getLoopFor(&MBB); |
| if (ContainingLoop && LoopWaitcntDataMap[ContainingLoop] == nullptr) |
| LoopWaitcntDataMap[ContainingLoop] = make_unique<LoopWaitcntData>(); |
| |
| // If we are walking into the block from before the loop, then guarantee |
| // at least 1 re-walk over the loop to propagate the information, even if |
| // no S_WAITCNT instructions were generated. |
| if (ContainingLoop && ContainingLoop->getTopBlock() == &MBB && J < I && |
| (BlockWaitcntProcessedSet.find(&MBB) == |
| BlockWaitcntProcessedSet.end())) { |
| BlockWaitcntBracketsMap[&MBB]->setRevisitLoop(true); |
| DEBUG(dbgs() << "set-revisit: block" |
| << ContainingLoop->getTopBlock()->getNumber() << '\n';); |
| } |
| |
| // Walk over the instructions. |
| insertWaitcntInBlock(MF, MBB); |
| |
| // Flag that waitcnts have been processed at least once. |
| BlockWaitcntProcessedSet.insert(&MBB); |
| |
| // See if we want to revisit the loop. |
| if (ContainingLoop && loopBottom(ContainingLoop) == &MBB) { |
| MachineBasicBlock *EntryBB = ContainingLoop->getTopBlock(); |
| BlockWaitcntBrackets *EntrySB = BlockWaitcntBracketsMap[EntryBB].get(); |
| if (EntrySB && EntrySB->getRevisitLoop()) { |
| EntrySB->setRevisitLoop(false); |
| J = I; |
| int32_t PostOrder = EntrySB->getPostOrder(); |
| // TODO: Avoid this loop. Find another way to set I. |
| for (ReversePostOrderTraversal<MachineFunction *>::rpo_iterator |
| X = RPOT.begin(), |
| Y = RPOT.end(); |
| X != Y; ++X) { |
| MachineBasicBlock &MBBX = **X; |
| if (MBBX.getNumber() == PostOrder) { |
| I = X; |
| break; |
| } |
| } |
| LoopWaitcntData *WaitcntData = LoopWaitcntDataMap[ContainingLoop].get(); |
| WaitcntData->incIterCnt(); |
| DEBUG(dbgs() << "revisit: block" << EntryBB->getNumber() << '\n';); |
| continue; |
| } else { |
| LoopWaitcntData *WaitcntData = LoopWaitcntDataMap[ContainingLoop].get(); |
| // Loop converged, reset iteration count. If this loop gets revisited, |
| // it must be from an outer loop, the counter will restart, this will |
| // ensure we don't force convergence on such revisits. |
| WaitcntData->resetIterCnt(); |
| } |
| } |
| |
| J = I; |
| ++I; |
| } |
| |
| SmallVector<MachineBasicBlock *, 4> EndPgmBlocks; |
| |
| bool HaveScalarStores = false; |
| |
| for (MachineFunction::iterator BI = MF.begin(), BE = MF.end(); BI != BE; |
| ++BI) { |
| |
| MachineBasicBlock &MBB = *BI; |
| |
| for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; |
| ++I) { |
| |
| if (!HaveScalarStores && TII->isScalarStore(*I)) |
| HaveScalarStores = true; |
| |
| if (I->getOpcode() == AMDGPU::S_ENDPGM || |
| I->getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG) |
| EndPgmBlocks.push_back(&MBB); |
| } |
| } |
| |
| if (HaveScalarStores) { |
| // If scalar writes are used, the cache must be flushed or else the next |
| // wave to reuse the same scratch memory can be clobbered. |
| // |
| // Insert s_dcache_wb at wave termination points if there were any scalar |
| // stores, and only if the cache hasn't already been flushed. This could be |
| // improved by looking across blocks for flushes in postdominating blocks |
| // from the stores but an explicitly requested flush is probably very rare. |
| for (MachineBasicBlock *MBB : EndPgmBlocks) { |
| bool SeenDCacheWB = false; |
| |
| for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); I != E; |
| ++I) { |
| |
| if (I->getOpcode() == AMDGPU::S_DCACHE_WB) |
| SeenDCacheWB = true; |
| else if (TII->isScalarStore(*I)) |
| SeenDCacheWB = false; |
| |
| // FIXME: It would be better to insert this before a waitcnt if any. |
| if ((I->getOpcode() == AMDGPU::S_ENDPGM || |
| I->getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG) && |
| !SeenDCacheWB) { |
| Modified = true; |
| BuildMI(*MBB, I, I->getDebugLoc(), TII->get(AMDGPU::S_DCACHE_WB)); |
| } |
| } |
| } |
| } |
| |
| return Modified; |
| } |