diff options
| -rw-r--r-- | lib/CodeGen/ScheduleDAGInstrs.cpp | 330 | ||||
| -rw-r--r-- | lib/CodeGen/ScheduleDAGInstrs.h | 7 |
2 files changed, 182 insertions, 155 deletions
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp index c9255b0..955fcc9 100644 --- a/lib/CodeGen/ScheduleDAGInstrs.cpp +++ b/lib/CodeGen/ScheduleDAGInstrs.cpp @@ -37,7 +37,7 @@ ScheduleDAGInstrs::ScheduleDAGInstrs(MachineFunction &mf, bool IsPostRAFlag) : ScheduleDAG(mf), MLI(mli), MDT(mdt), MFI(mf.getFrameInfo()), InstrItins(mf.getTarget().getInstrItineraryData()), IsPostRA(IsPostRAFlag), - Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()), + UnitLatencies(false), Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()), LoopRegs(MLI, MDT), FirstDbgValue(0) { DbgValues.clear(); } @@ -52,6 +52,9 @@ void ScheduleDAGInstrs::Run(MachineBasicBlock *bb, Begin = begin; InsertPosIndex = endcount; + // Check to see if the scheduler cares about latencies. + UnitLatencies = ForceUnitLatencies(); + ScheduleDAG::Run(bb, end); } @@ -181,6 +184,172 @@ void ScheduleDAGInstrs::AddSchedBarrierDeps() { } } +/// addPhysRegDeps - Add register dependencies (data, anti, and output) from +/// this SUnit to following instructions in the same scheduling region that +/// depend the physical register referenced at OperIdx. +void ScheduleDAGInstrs::addPhysRegDeps(SUnit *SU, unsigned OperIdx) { + const MachineInstr *MI = SU->getInstr(); + const MachineOperand &MO = MI->getOperand(OperIdx); + unsigned Reg = MO.getReg(); + + // Ask the target if address-backscheduling is desirable, and if so how much. + const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>(); + unsigned SpecialAddressLatency = ST.getSpecialAddressLatency(); + + // Optionally add output and anti dependencies. For anti + // dependencies we use a latency of 0 because for a multi-issue + // target we want to allow the defining instruction to issue + // in the same cycle as the using instruction. + // TODO: Using a latency of 1 here for output dependencies assumes + // there's no cost for reusing registers. + SDep::Kind Kind = MO.isUse() ? SDep::Anti : SDep::Output; + for (const unsigned *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias) { + std::vector<SUnit *> &DefList = Defs[*Alias]; + for (unsigned i = 0, e = DefList.size(); i != e; ++i) { + SUnit *DefSU = DefList[i]; + if (DefSU == &ExitSU) + continue; + if (DefSU != SU && + (Kind != SDep::Output || !MO.isDead() || + !DefSU->getInstr()->registerDefIsDead(*Alias))) { + if (Kind == SDep::Anti) + DefSU->addPred(SDep(SU, Kind, 0, /*Reg=*/*Alias)); + else { + unsigned AOLat = TII->getOutputLatency(InstrItins, MI, OperIdx, + DefSU->getInstr()); + DefSU->addPred(SDep(SU, Kind, AOLat, /*Reg=*/*Alias)); + } + } + } + } + + // Retrieve the UseList to add data dependencies and update uses. + std::vector<SUnit *> &UseList = Uses[Reg]; + if (MO.isDef()) { + // Update DefList. Defs are pushed in the order they are visited and + // never reordered. + std::vector<SUnit *> &DefList = Defs[Reg]; + + // Add any data dependencies. + unsigned DataLatency = SU->Latency; + for (unsigned i = 0, e = UseList.size(); i != e; ++i) { + SUnit *UseSU = UseList[i]; + if (UseSU == SU) + continue; + unsigned LDataLatency = DataLatency; + // Optionally add in a special extra latency for nodes that + // feed addresses. + // TODO: Do this for register aliases too. + // TODO: Perhaps we should get rid of + // SpecialAddressLatency and just move this into + // adjustSchedDependency for the targets that care about it. + if (SpecialAddressLatency != 0 && !UnitLatencies && + UseSU != &ExitSU) { + MachineInstr *UseMI = UseSU->getInstr(); + const MCInstrDesc &UseMCID = UseMI->getDesc(); + int RegUseIndex = UseMI->findRegisterUseOperandIdx(Reg); + assert(RegUseIndex >= 0 && "UseMI doesn's use register!"); + if (RegUseIndex >= 0 && + (UseMI->mayLoad() || UseMI->mayStore()) && + (unsigned)RegUseIndex < UseMCID.getNumOperands() && + UseMCID.OpInfo[RegUseIndex].isLookupPtrRegClass()) + LDataLatency += SpecialAddressLatency; + } + // Adjust the dependence latency using operand def/use + // information (if any), and then allow the target to + // perform its own adjustments. + const SDep& dep = SDep(SU, SDep::Data, LDataLatency, Reg); + if (!UnitLatencies) { + ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep)); + ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep)); + } + UseSU->addPred(dep); + } + for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + std::vector<SUnit *> &UseList = Uses[*Alias]; + for (unsigned i = 0, e = UseList.size(); i != e; ++i) { + SUnit *UseSU = UseList[i]; + if (UseSU == SU) + continue; + const SDep& dep = SDep(SU, SDep::Data, DataLatency, *Alias); + if (!UnitLatencies) { + ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep)); + ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep)); + } + UseSU->addPred(dep); + } + } + + // If a def is going to wrap back around to the top of the loop, + // backschedule it. + if (!UnitLatencies && DefList.empty()) { + LoopDependencies::LoopDeps::iterator I = LoopRegs.Deps.find(Reg); + if (I != LoopRegs.Deps.end()) { + const MachineOperand *UseMO = I->second.first; + unsigned Count = I->second.second; + const MachineInstr *UseMI = UseMO->getParent(); + unsigned UseMOIdx = UseMO - &UseMI->getOperand(0); + const MCInstrDesc &UseMCID = UseMI->getDesc(); + // TODO: If we knew the total depth of the region here, we could + // handle the case where the whole loop is inside the region but + // is large enough that the isScheduleHigh trick isn't needed. + if (UseMOIdx < UseMCID.getNumOperands()) { + // Currently, we only support scheduling regions consisting of + // single basic blocks. Check to see if the instruction is in + // the same region by checking to see if it has the same parent. + if (UseMI->getParent() != MI->getParent()) { + unsigned Latency = SU->Latency; + if (UseMCID.OpInfo[UseMOIdx].isLookupPtrRegClass()) + Latency += SpecialAddressLatency; + // This is a wild guess as to the portion of the latency which + // will be overlapped by work done outside the current + // scheduling region. + Latency -= std::min(Latency, Count); + // Add the artificial edge. + ExitSU.addPred(SDep(SU, SDep::Order, Latency, + /*Reg=*/0, /*isNormalMemory=*/false, + /*isMustAlias=*/false, + /*isArtificial=*/true)); + } else if (SpecialAddressLatency > 0 && + UseMCID.OpInfo[UseMOIdx].isLookupPtrRegClass()) { + // The entire loop body is within the current scheduling region + // and the latency of this operation is assumed to be greater + // than the latency of the loop. + // TODO: Recursively mark data-edge predecessors as + // isScheduleHigh too. + SU->isScheduleHigh = true; + } + } + LoopRegs.Deps.erase(I); + } + } + + UseList.clear(); + if (!MO.isDead()) + DefList.clear(); + + // Calls will not be reordered because of chain dependencies (see + // below). Since call operands are dead, calls may continue to be added + // to the DefList making dependence checking quadratic in the size of + // the block. Instead, we leave only one call at the back of the + // DefList. + if (SU->isCall) { + while (!DefList.empty() && DefList.back()->isCall) + DefList.pop_back(); + } + DefList.push_back(SU); + } else { + UseList.push_back(SU); + } +} + +/// addVirtRegDeps - Add register dependencies (data, anti, and output) from +/// this SUnit to following instructions in the same scheduling region that +/// depend the virtual register referenced at OperIdx. +void ScheduleDAGInstrs::addVirtRegDeps(SUnit *SU, unsigned OperIdx) { + assert(false && "unimplemented"); +} + void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { // We'll be allocating one SUnit for each instruction, plus one for // the region exit node. @@ -199,13 +368,6 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { std::map<const Value *, SUnit *> AliasMemDefs, NonAliasMemDefs; std::map<const Value *, std::vector<SUnit *> > AliasMemUses, NonAliasMemUses; - // Check to see if the scheduler cares about latencies. - bool UnitLatencies = ForceUnitLatencies(); - - // Ask the target if address-backscheduling is desirable, and if so how much. - const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>(); - unsigned SpecialAddressLatency = ST.getSpecialAddressLatency(); - // Remove any stale debug info; sometimes BuildSchedGraph is called again // without emitting the info from the previous call. DbgValues.clear(); @@ -254,153 +416,11 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { unsigned Reg = MO.getReg(); if (Reg == 0) continue; - assert(!IsPostRA || TRI->isPhysicalRegister(Reg) && - "Virtual register encountered!"); - - // Optionally add output and anti dependencies. For anti - // dependencies we use a latency of 0 because for a multi-issue - // target we want to allow the defining instruction to issue - // in the same cycle as the using instruction. - // TODO: Using a latency of 1 here for output dependencies assumes - // there's no cost for reusing registers. - SDep::Kind Kind = MO.isUse() ? SDep::Anti : SDep::Output; - for (const unsigned *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias) { - std::vector<SUnit *> &DefList = Defs[*Alias]; - for (unsigned i = 0, e = DefList.size(); i != e; ++i) { - SUnit *DefSU = DefList[i]; - if (DefSU == &ExitSU) - continue; - if (DefSU != SU && - (Kind != SDep::Output || !MO.isDead() || - !DefSU->getInstr()->registerDefIsDead(*Alias))) { - if (Kind == SDep::Anti) - DefSU->addPred(SDep(SU, Kind, 0, /*Reg=*/*Alias)); - else { - unsigned AOLat = TII->getOutputLatency(InstrItins, MI, j, - DefSU->getInstr()); - DefSU->addPred(SDep(SU, Kind, AOLat, /*Reg=*/*Alias)); - } - } - } - } - - // Retrieve the UseList to add data dependencies and update uses. - std::vector<SUnit *> &UseList = Uses[Reg]; - if (MO.isDef()) { - // Update DefList. Defs are pushed in the order they are visited and - // never reordered. - std::vector<SUnit *> &DefList = Defs[Reg]; - - // Add any data dependencies. - unsigned DataLatency = SU->Latency; - for (unsigned i = 0, e = UseList.size(); i != e; ++i) { - SUnit *UseSU = UseList[i]; - if (UseSU == SU) - continue; - unsigned LDataLatency = DataLatency; - // Optionally add in a special extra latency for nodes that - // feed addresses. - // TODO: Do this for register aliases too. - // TODO: Perhaps we should get rid of - // SpecialAddressLatency and just move this into - // adjustSchedDependency for the targets that care about it. - if (SpecialAddressLatency != 0 && !UnitLatencies && - UseSU != &ExitSU) { - MachineInstr *UseMI = UseSU->getInstr(); - const MCInstrDesc &UseMCID = UseMI->getDesc(); - int RegUseIndex = UseMI->findRegisterUseOperandIdx(Reg); - assert(RegUseIndex >= 0 && "UseMI doesn's use register!"); - if (RegUseIndex >= 0 && - (UseMI->mayLoad() || UseMI->mayStore()) && - (unsigned)RegUseIndex < UseMCID.getNumOperands() && - UseMCID.OpInfo[RegUseIndex].isLookupPtrRegClass()) - LDataLatency += SpecialAddressLatency; - } - // Adjust the dependence latency using operand def/use - // information (if any), and then allow the target to - // perform its own adjustments. - const SDep& dep = SDep(SU, SDep::Data, LDataLatency, Reg); - if (!UnitLatencies) { - ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep)); - ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep)); - } - UseSU->addPred(dep); - } - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { - std::vector<SUnit *> &UseList = Uses[*Alias]; - for (unsigned i = 0, e = UseList.size(); i != e; ++i) { - SUnit *UseSU = UseList[i]; - if (UseSU == SU) - continue; - const SDep& dep = SDep(SU, SDep::Data, DataLatency, *Alias); - if (!UnitLatencies) { - ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep)); - ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep)); - } - UseSU->addPred(dep); - } - } - - // If a def is going to wrap back around to the top of the loop, - // backschedule it. - if (!UnitLatencies && DefList.empty()) { - LoopDependencies::LoopDeps::iterator I = LoopRegs.Deps.find(Reg); - if (I != LoopRegs.Deps.end()) { - const MachineOperand *UseMO = I->second.first; - unsigned Count = I->second.second; - const MachineInstr *UseMI = UseMO->getParent(); - unsigned UseMOIdx = UseMO - &UseMI->getOperand(0); - const MCInstrDesc &UseMCID = UseMI->getDesc(); - // TODO: If we knew the total depth of the region here, we could - // handle the case where the whole loop is inside the region but - // is large enough that the isScheduleHigh trick isn't needed. - if (UseMOIdx < UseMCID.getNumOperands()) { - // Currently, we only support scheduling regions consisting of - // single basic blocks. Check to see if the instruction is in - // the same region by checking to see if it has the same parent. - if (UseMI->getParent() != MI->getParent()) { - unsigned Latency = SU->Latency; - if (UseMCID.OpInfo[UseMOIdx].isLookupPtrRegClass()) - Latency += SpecialAddressLatency; - // This is a wild guess as to the portion of the latency which - // will be overlapped by work done outside the current - // scheduling region. - Latency -= std::min(Latency, Count); - // Add the artificial edge. - ExitSU.addPred(SDep(SU, SDep::Order, Latency, - /*Reg=*/0, /*isNormalMemory=*/false, - /*isMustAlias=*/false, - /*isArtificial=*/true)); - } else if (SpecialAddressLatency > 0 && - UseMCID.OpInfo[UseMOIdx].isLookupPtrRegClass()) { - // The entire loop body is within the current scheduling region - // and the latency of this operation is assumed to be greater - // than the latency of the loop. - // TODO: Recursively mark data-edge predecessors as - // isScheduleHigh too. - SU->isScheduleHigh = true; - } - } - LoopRegs.Deps.erase(I); - } - } - - UseList.clear(); - if (!MO.isDead()) - DefList.clear(); - - // Calls will not be reordered because of chain dependencies (see - // below). Since call operands are dead, calls may continue to be added - // to the DefList making dependence checking quadratic in the size of - // the block. Instead, we leave only one call at the back of the - // DefList. - if (SU->isCall) { - while (!DefList.empty() && DefList.back()->isCall) - DefList.pop_back(); - } - DefList.push_back(SU); - } else { - UseList.push_back(SU); + if (TRI->isPhysicalRegister(Reg)) + addPhysRegDeps(SU, j); + else { + assert(!IsPostRA && "Virtual register encountered!"); + addVirtRegDeps(SU, j); } } diff --git a/lib/CodeGen/ScheduleDAGInstrs.h b/lib/CodeGen/ScheduleDAGInstrs.h index f393289..55da5c0 100644 --- a/lib/CodeGen/ScheduleDAGInstrs.h +++ b/lib/CodeGen/ScheduleDAGInstrs.h @@ -107,6 +107,9 @@ namespace llvm { /// isPostRA flag indicates vregs cannot be present. bool IsPostRA; + /// UnitLatencies flag forces single-cycle data dependencies. + bool UnitLatencies; + /// Defs, Uses - Remember where defs and uses of each register are as we /// iterate upward through the instructions. This is allocated here instead /// of inside BuildSchedGraph to avoid the need for it to be initialized and @@ -205,6 +208,10 @@ namespace llvm { virtual void dumpNode(const SUnit *SU) const; virtual std::string getGraphNodeLabel(const SUnit *SU) const; + + protected: + void addPhysRegDeps(SUnit *SU, unsigned OperIdx); + void addVirtRegDeps(SUnit *SU, unsigned OperIdx); }; } |