X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FScheduleDAGInstrs.cpp;h=f17023eabb72e01bed897638ea14e070a21d132a;hb=c249e4855883d7b799db61edc839cbfaff50ae81;hp=e532ade5f683fa5d6e7db3ffd4fc01c56a870058;hpb=bfdf7f38523bd38ae0538861a2bfd8bdc46e5c33;p=oota-llvm.git diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp index e532ade5f68..f17023eabb7 100644 --- a/lib/CodeGen/ScheduleDAGInstrs.cpp +++ b/lib/CodeGen/ScheduleDAGInstrs.cpp @@ -16,6 +16,7 @@ #include "ScheduleDAGInstrs.h" #include "llvm/Operator.h" #include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/ValueTracking.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineMemOperand.h" #include "llvm/CodeGen/MachineRegisterInfo.h" @@ -32,8 +33,9 @@ using namespace llvm; ScheduleDAGInstrs::ScheduleDAGInstrs(MachineFunction &mf, const MachineLoopInfo &mli, const MachineDominatorTree &mdt) - : ScheduleDAG(mf), MLI(mli), MDT(mdt), LoopRegs(MLI, MDT) { - MFI = mf.getFrameInfo(); + : ScheduleDAG(mf), MLI(mli), MDT(mdt), MFI(mf.getFrameInfo()), + InstrItins(mf.getTarget().getInstrItineraryData()), + Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()), LoopRegs(MLI, MDT) { DbgValueVec.clear(); } @@ -77,12 +79,12 @@ static const Value *getUnderlyingObjectFromInt(const Value *V) { } while (1); } -/// getUnderlyingObject - This is a wrapper around Value::getUnderlyingObject +/// getUnderlyingObject - This is a wrapper around GetUnderlyingObject /// and adds support for basic ptrtoint+arithmetic+inttoptr sequences. static const Value *getUnderlyingObject(const Value *V) { // First just call Value::getUnderlyingObject to let it do what it does. do { - V = V->getUnderlyingObject(); + V = GetUnderlyingObject(V); // If it found an inttoptr, use special code to continue climing. if (Operator::getOpcode(V) != Instruction::IntToPtr) break; @@ -140,6 +142,46 @@ void ScheduleDAGInstrs::StartBlock(MachineBasicBlock *BB) { } } +/// AddSchedBarrierDeps - Add dependencies from instructions in the current +/// list of instructions being scheduled to scheduling barrier by adding +/// the exit SU to the register defs and use list. This is because we want to +/// make sure instructions which define registers that are either used by +/// the terminator or are live-out are properly scheduled. This is +/// especially important when the definition latency of the return value(s) +/// are too high to be hidden by the branch or when the liveout registers +/// used by instructions in the fallthrough block. +void ScheduleDAGInstrs::AddSchedBarrierDeps() { + MachineInstr *ExitMI = InsertPos != BB->end() ? &*InsertPos : 0; + ExitSU.setInstr(ExitMI); + bool AllDepKnown = ExitMI && + (ExitMI->getDesc().isCall() || ExitMI->getDesc().isBarrier()); + if (ExitMI && AllDepKnown) { + // If it's a call or a barrier, add dependencies on the defs and uses of + // instruction. + for (unsigned i = 0, e = ExitMI->getNumOperands(); i != e; ++i) { + const MachineOperand &MO = ExitMI->getOperand(i); + if (!MO.isReg() || MO.isDef()) continue; + unsigned Reg = MO.getReg(); + if (Reg == 0) continue; + + assert(TRI->isPhysicalRegister(Reg) && "Virtual register encountered!"); + Uses[Reg].push_back(&ExitSU); + } + } else { + // For others, e.g. fallthrough, conditional branch, assume the exit + // uses all the registers that are livein to the successor blocks. + SmallSet Seen; + for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(), + SE = BB->succ_end(); SI != SE; ++SI) + for (MachineBasicBlock::livein_iterator I = (*SI)->livein_begin(), + E = (*SI)->livein_end(); I != E; ++I) { + unsigned Reg = *I; + if (Seen.insert(Reg)) + Uses[Reg].push_back(&ExitSU); + } + } +} + void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { // We'll be allocating one SUnit for each instruction, plus one for // the region exit node. @@ -159,8 +201,9 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { std::map > AliasMemUses, NonAliasMemUses; // Keep track of dangling debug references to registers. - std::pair - DanglingDebugValue[TargetRegisterInfo::FirstVirtualRegister]; + std::vector > + DanglingDebugValue(TRI->getNumRegs(), + std::make_pair(static_cast(0), 0)); // Check to see if the scheduler cares about latencies. bool UnitLatencies = ForceUnitLatencies(); @@ -172,7 +215,10 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { // Remove any stale debug info; sometimes BuildSchedGraph is called again // without emitting the info from the previous call. DbgValueVec.clear(); - std::memset(DanglingDebugValue, 0, sizeof(DanglingDebugValue)); + + // Model data dependencies between instructions being scheduled and the + // ExitSU. + AddSchedBarrierDeps(); // Walk the list of instructions, from bottom moving up. for (MachineBasicBlock::iterator MII = InsertPos, MIE = Begin; @@ -193,6 +239,8 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { "Cannot schedule terminators or labels!"); // Create the SUnit for this MI. SUnit *SU = NewSUnit(MI); + SU->isCall = TID.isCall(); + SU->isCommutable = TID.isCommutable(); // Assign the Latency field of SU using target-provided information. if (UnitLatencies) @@ -210,7 +258,7 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { assert(TRI->isPhysicalRegister(Reg) && "Virtual register encountered!"); if (MO.isDef() && DanglingDebugValue[Reg].first!=0) { - SU->setDbgInstr(DanglingDebugValue[Reg].first); + SU->DbgInstrList.push_back(DanglingDebugValue[Reg].first); DbgValueVec[DanglingDebugValue[Reg].second] = 0; DanglingDebugValue[Reg] = std::make_pair((MachineInstr*)0, 0); } @@ -227,6 +275,8 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { unsigned AOLatency = (Kind == SDep::Anti) ? 0 : 1; 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(Reg))) @@ -236,6 +286,8 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { std::vector &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))) @@ -248,48 +300,49 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { unsigned DataLatency = SU->Latency; for (unsigned i = 0, e = UseList.size(); i != e; ++i) { SUnit *UseSU = UseList[i]; - if (UseSU != SU) { - 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) { - MachineInstr *UseMI = UseSU->getInstr(); - const TargetInstrDesc &UseTID = UseMI->getDesc(); - int RegUseIndex = UseMI->findRegisterUseOperandIdx(Reg); - assert(RegUseIndex >= 0 && "UseMI doesn's use register!"); - if ((UseTID.mayLoad() || UseTID.mayStore()) && - (unsigned)RegUseIndex < UseTID.getNumOperands() && - UseTID.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, (SDep &)dep); - ST.adjustSchedDependency(SU, UseSU, (SDep &)dep); - } - UseSU->addPred(dep); + 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 TargetInstrDesc &UseTID = UseMI->getDesc(); + int RegUseIndex = UseMI->findRegisterUseOperandIdx(Reg); + assert(RegUseIndex >= 0 && "UseMI doesn's use register!"); + if (RegUseIndex >= 0 && + (UseTID.mayLoad() || UseTID.mayStore()) && + (unsigned)RegUseIndex < UseTID.getNumOperands() && + UseTID.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(dep)); + ST.adjustSchedDependency(SU, UseSU, const_cast(dep)); + } + UseSU->addPred(dep); } for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { std::vector &UseList = Uses[*Alias]; for (unsigned i = 0, e = UseList.size(); i != e; ++i) { SUnit *UseSU = UseList[i]; - if (UseSU != SU) { - const SDep& dep = SDep(SU, SDep::Data, DataLatency, *Alias); - if (!UnitLatencies) { - ComputeOperandLatency(SU, UseSU, (SDep &)dep); - ST.adjustSchedDependency(SU, UseSU, (SDep &)dep); - } - UseSU->addPred(dep); + if (UseSU == SU) + continue; + const SDep& dep = SDep(SU, SDep::Data, DataLatency, *Alias); + if (!UnitLatencies) { + ComputeOperandLatency(SU, UseSU, const_cast(dep)); + ST.adjustSchedDependency(SU, UseSU, const_cast(dep)); } + UseSU->addPred(dep); } } @@ -357,7 +410,7 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { // produce more precise dependence information. #define STORE_LOAD_LATENCY 1 unsigned TrueMemOrderLatency = 0; - if (TID.isCall() || TID.hasUnmodeledSideEffects() || + if (TID.isCall() || MI->hasUnmodeledSideEffects() || (MI->hasVolatileMemoryRef() && (!TID.mayLoad() || !MI->isInvariantLoad(AA)))) { // Be conservative with these and add dependencies on all memory @@ -446,6 +499,14 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) { // Treat all other stores conservatively. goto new_alias_chain; } + + if (!ExitSU.isPred(SU)) + // Push store's up a bit to avoid them getting in between cmp + // and branches. + ExitSU.addPred(SDep(SU, SDep::Order, 0, + /*Reg=*/0, /*isNormalMemory=*/false, + /*isMustAlias=*/false, + /*isArtificial=*/true)); } else if (TID.mayLoad()) { bool MayAlias = true; TrueMemOrderLatency = 0; @@ -498,23 +559,22 @@ void ScheduleDAGInstrs::FinishBlock() { } void ScheduleDAGInstrs::ComputeLatency(SUnit *SU) { - const InstrItineraryData &InstrItins = TM.getInstrItineraryData(); - // Compute the latency for the node. - SU->Latency = - InstrItins.getStageLatency(SU->getInstr()->getDesc().getSchedClass()); + if (!InstrItins || InstrItins->isEmpty()) { + SU->Latency = 1; - // Simplistic target-independent heuristic: assume that loads take - // extra time. - if (InstrItins.isEmpty()) + // Simplistic target-independent heuristic: assume that loads take + // extra time. if (SU->getInstr()->getDesc().mayLoad()) SU->Latency += 2; + } else { + SU->Latency = TII->getInstrLatency(InstrItins, SU->getInstr()); + } } void ScheduleDAGInstrs::ComputeOperandLatency(SUnit *Def, SUnit *Use, SDep& dep) const { - const InstrItineraryData &InstrItins = TM.getInstrItineraryData(); - if (InstrItins.isEmpty()) + if (!InstrItins || InstrItins->isEmpty()) return; // For a data dependency with a known register... @@ -528,13 +588,21 @@ void ScheduleDAGInstrs::ComputeOperandLatency(SUnit *Def, SUnit *Use, MachineInstr *DefMI = Def->getInstr(); int DefIdx = DefMI->findRegisterDefOperandIdx(Reg); if (DefIdx != -1) { - int DefCycle = InstrItins.getOperandCycle(DefMI->getDesc().getSchedClass(), DefIdx); - if (DefCycle >= 0) { - MachineInstr *UseMI = Use->getInstr(); - const unsigned UseClass = UseMI->getDesc().getSchedClass(); - - // For all uses of the register, calculate the maxmimum latency - int Latency = -1; + const MachineOperand &MO = DefMI->getOperand(DefIdx); + if (MO.isReg() && MO.isImplicit() && + DefIdx >= (int)DefMI->getDesc().getNumOperands()) { + // This is an implicit def, getOperandLatency() won't return the correct + // latency. e.g. + // %D6, %D7 = VLD1q16 %R2, 0, ..., %Q3 + // %Q1 = VMULv8i16 %Q1, %Q3, ... + // What we want is to compute latency between def of %D6/%D7 and use of + // %Q3 instead. + DefIdx = DefMI->findRegisterDefOperandIdx(Reg, false, true, TRI); + } + MachineInstr *UseMI = Use->getInstr(); + // For all uses of the register, calculate the maxmimum latency + int Latency = -1; + if (UseMI) { for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) { const MachineOperand &MO = UseMI->getOperand(i); if (!MO.isReg() || !MO.isUse()) @@ -543,15 +611,21 @@ void ScheduleDAGInstrs::ComputeOperandLatency(SUnit *Def, SUnit *Use, if (MOReg != Reg) continue; - int UseCycle = InstrItins.getOperandCycle(UseClass, i); - if (UseCycle >= 0) - Latency = std::max(Latency, DefCycle - UseCycle + 1); + int UseCycle = TII->getOperandLatency(InstrItins, DefMI, DefIdx, + UseMI, i); + Latency = std::max(Latency, UseCycle); } - - // If we found a latency, then replace the existing dependence latency. - if (Latency >= 0) - dep.setLatency(Latency); + } else { + // UseMI is null, then it must be a scheduling barrier. + if (!InstrItins || InstrItins->isEmpty()) + return; + unsigned DefClass = DefMI->getDesc().getSchedClass(); + Latency = InstrItins->getOperandCycle(DefClass, DefIdx); } + + // If we found a latency, then replace the existing dependence latency. + if (Latency >= 0) + dep.setLatency(Latency); } } @@ -572,8 +646,7 @@ std::string ScheduleDAGInstrs::getGraphNodeLabel(const SUnit *SU) const { } // EmitSchedule - Emit the machine code in scheduled order. -MachineBasicBlock *ScheduleDAGInstrs:: -EmitSchedule(DenseMap *EM) { +MachineBasicBlock *ScheduleDAGInstrs::EmitSchedule() { // For MachineInstr-based scheduling, we're rescheduling the instructions in // the block, so start by removing them from the block. while (Begin != InsertPos) { @@ -600,8 +673,8 @@ EmitSchedule(DenseMap *EM) { } BB->insert(InsertPos, SU->getInstr()); - if (SU->getDbgInstr()) - BB->insert(InsertPos, SU->getDbgInstr()); + for (unsigned i = 0, e = SU->DbgInstrList.size() ; i < e ; ++i) + BB->insert(InsertPos, SU->DbgInstrList[i]); } // Update the Begin iterator, as the first instruction in the block