Index: lib/Target/AMDGPU/AMDGPU.h =================================================================== --- lib/Target/AMDGPU/AMDGPU.h +++ lib/Target/AMDGPU/AMDGPU.h @@ -48,6 +48,7 @@ FunctionPass *createSIFixSGPRCopiesPass(); FunctionPass *createSIDebuggerInsertNopsPass(); FunctionPass *createSIInsertWaitsPass(); +FunctionPass *createSIInsertWaitcntsPass(); FunctionPass *createAMDGPUCodeGenPreparePass(const GCNTargetMachine *TM = nullptr); ModulePass *createAMDGPUAnnotateKernelFeaturesPass(const TargetMachine *TM = nullptr); @@ -125,6 +126,9 @@ void initializeSIInsertWaitsPass(PassRegistry&); extern char &SIInsertWaitsID; +void initializeSIInsertWaitcntsPass(PassRegistry&); +extern char &SIInsertWaitcntsID; + void initializeAMDGPUUnifyDivergentExitNodesPass(PassRegistry&); extern char &AMDGPUUnifyDivergentExitNodesID; Index: lib/Target/AMDGPU/AMDGPUTargetMachine.cpp =================================================================== --- lib/Target/AMDGPU/AMDGPUTargetMachine.cpp +++ lib/Target/AMDGPU/AMDGPUTargetMachine.cpp @@ -112,6 +112,12 @@ cl::desc("Enable AMDGPU Alias Analysis"), cl::init(true)); +// Option to enable new waitcnt insertion pass. +static cl::opt EnableSIInsertWaitcntsPass( + "enable-si-insert-waitcnts", + cl::desc("Use new waitcnt insertion pass"), + cl::init(false)); + extern "C" void LLVMInitializeAMDGPUTarget() { // Register the target RegisterTargetMachine X(getTheAMDGPUTarget()); @@ -134,6 +140,7 @@ initializeAMDGPUUnifyMetadataPass(*PR); initializeSIAnnotateControlFlowPass(*PR); initializeSIInsertWaitsPass(*PR); + initializeSIInsertWaitcntsPass(*PR); initializeSIWholeQuadModePass(*PR); initializeSILowerControlFlowPass(*PR); initializeSIInsertSkipsPass(*PR); @@ -810,7 +817,10 @@ // cases. addPass(&PostRAHazardRecognizerID); - addPass(createSIInsertWaitsPass()); + if (EnableSIInsertWaitcntsPass) + addPass(createSIInsertWaitcntsPass()); + else + addPass(createSIInsertWaitsPass()); addPass(createSIShrinkInstructionsPass()); addPass(&SIInsertSkipsPassID); addPass(createSIDebuggerInsertNopsPass()); Index: lib/Target/AMDGPU/CMakeLists.txt =================================================================== --- lib/Target/AMDGPU/CMakeLists.txt +++ lib/Target/AMDGPU/CMakeLists.txt @@ -82,6 +82,7 @@ SIFrameLowering.cpp SIInsertSkips.cpp SIInsertWaits.cpp + SIInsertWaitcnts.cpp SIInstrInfo.cpp SIISelLowering.cpp SILoadStoreOptimizer.cpp Index: lib/Target/AMDGPU/DSInstructions.td =================================================================== --- lib/Target/AMDGPU/DSInstructions.td +++ lib/Target/AMDGPU/DSInstructions.td @@ -253,6 +253,8 @@ [(set i32:$vdst, (node (DS1Addr1Offset i32:$addr, i16:$offset), i32:$data0))] > { + let LGKM_CNT = 0; + let mayLoad = 0; let mayStore = 0; let isConvergent = 1; Index: lib/Target/AMDGPU/SIInsertWaitcnts.cpp =================================================================== --- /dev/null +++ lib/Target/AMDGPU/SIInsertWaitcnts.cpp @@ -0,0 +1,1863 @@ +//===-- 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 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 BlockVisitedSet; + DenseSet CompilerGeneratedWaitcntSet; + DenseSet VCCZBugHandledSet; + + DenseMap> + BlockWaitcntBracketsMap; + + DenseSet BlockWaitcntProcessedSet; + + DenseMap> LoopWaitcntDataMap; + + std::vector> 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(); + 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(*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(); + 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(); + TII = ST->getInstrInfo(); + TRI = &TII->getRegisterInfo(); + MRI = &MF.getRegInfo(); + MLI = &getAnalysis(); + 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 RPOT(&MF); + bool Modified = false; + for (ReversePostOrderTraversal::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(); + ScoreBrackets = BlockWaitcntBracketsMap[&MBB].get(); + } + ScoreBrackets->setPostOrder(MBB.getNumber()); + MachineLoop *ContainingLoop = MLI->getLoopFor(&MBB); + if (ContainingLoop && LoopWaitcntDataMap[ContainingLoop] == nullptr) + LoopWaitcntDataMap[ContainingLoop] = make_unique(); + + // 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::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 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; +} Index: test/CodeGen/AMDGPU/llvm.amdgcn.ds.bpermute.ll =================================================================== --- test/CodeGen/AMDGPU/llvm.amdgcn.ds.bpermute.ll +++ test/CodeGen/AMDGPU/llvm.amdgcn.ds.bpermute.ll @@ -4,7 +4,6 @@ ; FUNC-LABEL: {{^}}ds_bpermute: ; CHECK: ds_bpermute_b32 v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}} -; CHECK: s_waitcnt lgkmcnt define amdgpu_kernel void @ds_bpermute(i32 addrspace(1)* %out, i32 %index, i32 %src) nounwind { %bpermute = call i32 @llvm.amdgcn.ds.bpermute(i32 %index, i32 %src) #0 store i32 %bpermute, i32 addrspace(1)* %out, align 4 @@ -13,7 +12,6 @@ ; CHECK-LABEL: {{^}}ds_bpermute_imm_offset: ; CHECK: ds_bpermute_b32 v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}} offset:4 -; CHECK: s_waitcnt lgkmcnt define amdgpu_kernel void @ds_bpermute_imm_offset(i32 addrspace(1)* %out, i32 %base_index, i32 %src) nounwind { %index = add i32 %base_index, 4 %bpermute = call i32 @llvm.amdgcn.ds.bpermute(i32 %index, i32 %src) #0 @@ -23,7 +21,6 @@ ; CHECK-LABEL: {{^}}ds_bpermute_imm_index: ; CHECK: ds_bpermute_b32 v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}} offset:64 -; CHECK: s_waitcnt lgkmcnt define amdgpu_kernel void @ds_bpermute_imm_index(i32 addrspace(1)* %out, i32 %base_index, i32 %src) nounwind { %bpermute = call i32 @llvm.amdgcn.ds.bpermute(i32 64, i32 %src) #0 store i32 %bpermute, i32 addrspace(1)* %out, align 4 Index: test/CodeGen/AMDGPU/llvm.amdgcn.ds.permute.ll =================================================================== --- test/CodeGen/AMDGPU/llvm.amdgcn.ds.permute.ll +++ test/CodeGen/AMDGPU/llvm.amdgcn.ds.permute.ll @@ -4,7 +4,6 @@ ; CHECK-LABEL: {{^}}ds_permute: ; CHECK: ds_permute_b32 v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}} -; CHECK: s_waitcnt lgkmcnt define amdgpu_kernel void @ds_permute(i32 addrspace(1)* %out, i32 %index, i32 %src) nounwind { %bpermute = call i32 @llvm.amdgcn.ds.permute(i32 %index, i32 %src) #0 store i32 %bpermute, i32 addrspace(1)* %out, align 4 @@ -13,7 +12,6 @@ ; CHECK-LABEL: {{^}}ds_permute_imm_offset: ; CHECK: ds_permute_b32 v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}} offset:4 -; CHECK: s_waitcnt lgkmcnt define amdgpu_kernel void @ds_permute_imm_offset(i32 addrspace(1)* %out, i32 %base_index, i32 %src) nounwind { %index = add i32 %base_index, 4 %bpermute = call i32 @llvm.amdgcn.ds.permute(i32 %index, i32 %src) #0