diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp | 727 |
1 files changed, 507 insertions, 220 deletions
diff --git a/contrib/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/contrib/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp index a4d4a93e6dd5..71e7a21ef2bc 100644 --- a/contrib/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp +++ b/contrib/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp @@ -12,8 +12,11 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "sched-instrs" -#include "llvm/Operator.h" +#define DEBUG_TYPE "misched" +#include "llvm/CodeGen/ScheduleDAGInstrs.h" +#include "llvm/ADT/MapVector.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallSet.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/CodeGen/LiveIntervalAnalysis.h" @@ -22,19 +25,17 @@ #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/PseudoSourceValue.h" #include "llvm/CodeGen/RegisterPressure.h" -#include "llvm/CodeGen/ScheduleDAGILP.h" -#include "llvm/CodeGen/ScheduleDAGInstrs.h" +#include "llvm/CodeGen/ScheduleDFS.h" +#include "llvm/IR/Operator.h" #include "llvm/MC/MCInstrItineraries.h" -#include "llvm/Target/TargetMachine.h" -#include "llvm/Target/TargetInstrInfo.h" -#include "llvm/Target/TargetRegisterInfo.h" -#include "llvm/Target/TargetSubtargetInfo.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/Format.h" #include "llvm/Support/raw_ostream.h" -#include "llvm/ADT/SmallSet.h" -#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetSubtargetInfo.h" using namespace llvm; static cl::opt<bool> EnableAASchedMI("enable-aa-sched-mi", cl::Hidden, @@ -66,7 +67,7 @@ static const Value *getUnderlyingObjectFromInt(const Value *V) { // regular getUnderlyingObjectFromInt. if (U->getOpcode() == Instruction::PtrToInt) return U->getOperand(0); - // If we find an add of a constant or a multiplied value, it's + // If we find an add of a constant, a multiplied value, or a phi, it's // likely that the other operand will lead us to the base // object. We don't have to worry about the case where the // object address is somehow being computed by the multiply, @@ -74,7 +75,8 @@ static const Value *getUnderlyingObjectFromInt(const Value *V) { // identifiable object. if (U->getOpcode() != Instruction::Add || (!isa<ConstantInt>(U->getOperand(1)) && - Operator::getOpcode(U->getOperand(1)) != Instruction::Mul)) + Operator::getOpcode(U->getOperand(1)) != Instruction::Mul && + !isa<PHINode>(U->getOperand(1)))) return V; V = U->getOperand(0); } else { @@ -84,56 +86,77 @@ static const Value *getUnderlyingObjectFromInt(const Value *V) { } while (1); } -/// getUnderlyingObject - This is a wrapper around GetUnderlyingObject +/// getUnderlyingObjects - This is a wrapper around GetUnderlyingObjects /// 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. +static void getUnderlyingObjects(const Value *V, + SmallVectorImpl<Value *> &Objects) { + SmallPtrSet<const Value*, 16> Visited; + SmallVector<const Value *, 4> Working(1, V); do { - V = GetUnderlyingObject(V); - // If it found an inttoptr, use special code to continue climing. - if (Operator::getOpcode(V) != Instruction::IntToPtr) - break; - const Value *O = getUnderlyingObjectFromInt(cast<User>(V)->getOperand(0)); - // If that succeeded in finding a pointer, continue the search. - if (!O->getType()->isPointerTy()) - break; - V = O; - } while (1); - return V; + V = Working.pop_back_val(); + + SmallVector<Value *, 4> Objs; + GetUnderlyingObjects(const_cast<Value *>(V), Objs); + + for (SmallVector<Value *, 4>::iterator I = Objs.begin(), IE = Objs.end(); + I != IE; ++I) { + V = *I; + if (!Visited.insert(V)) + continue; + if (Operator::getOpcode(V) == Instruction::IntToPtr) { + const Value *O = + getUnderlyingObjectFromInt(cast<User>(V)->getOperand(0)); + if (O->getType()->isPointerTy()) { + Working.push_back(O); + continue; + } + } + Objects.push_back(const_cast<Value *>(V)); + } + } while (!Working.empty()); } -/// getUnderlyingObjectForInstr - If this machine instr has memory reference +/// getUnderlyingObjectsForInstr - If this machine instr has memory reference /// information and it can be tracked to a normal reference to a known -/// object, return the Value for that object. Otherwise return null. -static const Value *getUnderlyingObjectForInstr(const MachineInstr *MI, - const MachineFrameInfo *MFI, - bool &MayAlias) { - MayAlias = true; +/// object, return the Value for that object. +static void getUnderlyingObjectsForInstr(const MachineInstr *MI, + const MachineFrameInfo *MFI, + SmallVectorImpl<std::pair<const Value *, bool> > &Objects) { if (!MI->hasOneMemOperand() || !(*MI->memoperands_begin())->getValue() || (*MI->memoperands_begin())->isVolatile()) - return 0; + return; const Value *V = (*MI->memoperands_begin())->getValue(); if (!V) - return 0; - - V = getUnderlyingObject(V); - if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V)) { - // For now, ignore PseudoSourceValues which may alias LLVM IR values - // because the code that uses this function has no way to cope with - // such aliases. - if (PSV->isAliased(MFI)) - return 0; - - MayAlias = PSV->mayAlias(MFI); - return V; - } + return; + + SmallVector<Value *, 4> Objs; + getUnderlyingObjects(V, Objs); - if (isIdentifiedObject(V)) - return V; + for (SmallVector<Value *, 4>::iterator I = Objs.begin(), IE = Objs.end(); + I != IE; ++I) { + bool MayAlias = true; + V = *I; + + if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V)) { + // For now, ignore PseudoSourceValues which may alias LLVM IR values + // because the code that uses this function has no way to cope with + // such aliases. - return 0; + if (PSV->isAliased(MFI)) { + Objects.clear(); + return; + } + + MayAlias = PSV->mayAlias(MFI); + } else if (!isIdentifiedObject(V)) { + Objects.clear(); + return; + } + + Objects.push_back(std::make_pair(V, MayAlias)); + } } void ScheduleDAGInstrs::startBlock(MachineBasicBlock *bb) { @@ -145,20 +168,6 @@ void ScheduleDAGInstrs::finishBlock() { BB = 0; } -/// Initialize the map with the number of registers. -void Reg2SUnitsMap::setRegLimit(unsigned Limit) { - PhysRegSet.setUniverse(Limit); - SUnits.resize(Limit); -} - -/// Clear the map without deallocating storage. -void Reg2SUnitsMap::clear() { - for (const_iterator I = reg_begin(), E = reg_end(); I != E; ++I) { - SUnits[*I].clear(); - } - PhysRegSet.clear(); -} - /// Initialize the DAG and common scheduler state for the current scheduling /// region. This does not actually create the DAG, only clears it. The /// scheduling driver may call BuildSchedGraph multiple times per scheduling @@ -205,10 +214,11 @@ void ScheduleDAGInstrs::addSchedBarrierDeps() { if (Reg == 0) continue; if (TRI->isPhysicalRegister(Reg)) - Uses[Reg].push_back(PhysRegSUOper(&ExitSU, -1)); + Uses.insert(PhysRegSUOper(&ExitSU, -1, Reg)); else { assert(!IsPostRA && "Virtual register encountered after regalloc."); - addVRegUseDeps(&ExitSU, i); + if (MO.readsReg()) // ignore undef operands + addVRegUseDeps(&ExitSU, i); } } } else { @@ -221,7 +231,7 @@ void ScheduleDAGInstrs::addSchedBarrierDeps() { E = (*SI)->livein_end(); I != E; ++I) { unsigned Reg = *I; if (!Uses.contains(Reg)) - Uses[Reg].push_back(PhysRegSUOper(&ExitSU, -1)); + Uses.insert(PhysRegSUOper(&ExitSU, -1, Reg)); } } } @@ -239,27 +249,31 @@ void ScheduleDAGInstrs::addPhysRegDataDeps(SUnit *SU, unsigned OperIdx) { Alias.isValid(); ++Alias) { if (!Uses.contains(*Alias)) continue; - std::vector<PhysRegSUOper> &UseList = Uses[*Alias]; - for (unsigned i = 0, e = UseList.size(); i != e; ++i) { - SUnit *UseSU = UseList[i].SU; + for (Reg2SUnitsMap::iterator I = Uses.find(*Alias); I != Uses.end(); ++I) { + SUnit *UseSU = I->SU; if (UseSU == SU) continue; - SDep dep(SU, SDep::Data, *Alias); - // Adjust the dependence latency using operand def/use information, // then allow the target to perform its own adjustments. - int UseOp = UseList[i].OpIdx; - MachineInstr *RegUse = UseOp < 0 ? 0 : UseSU->getInstr(); - dep.setLatency( + int UseOp = I->OpIdx; + MachineInstr *RegUse = 0; + SDep Dep; + if (UseOp < 0) + Dep = SDep(SU, SDep::Artificial); + else { + Dep = SDep(SU, SDep::Data, *Alias); + RegUse = UseSU->getInstr(); + Dep.setMinLatency( + SchedModel.computeOperandLatency(SU->getInstr(), OperIdx, + RegUse, UseOp, /*FindMin=*/true)); + } + Dep.setLatency( SchedModel.computeOperandLatency(SU->getInstr(), OperIdx, RegUse, UseOp, /*FindMin=*/false)); - dep.setMinLatency( - SchedModel.computeOperandLatency(SU->getInstr(), OperIdx, - RegUse, UseOp, /*FindMin=*/true)); - ST.adjustSchedDependency(SU, UseSU, dep); - UseSU->addPred(dep); + ST.adjustSchedDependency(SU, UseSU, Dep); + UseSU->addPred(Dep); } } } @@ -282,9 +296,8 @@ void ScheduleDAGInstrs::addPhysRegDeps(SUnit *SU, unsigned OperIdx) { Alias.isValid(); ++Alias) { if (!Defs.contains(*Alias)) continue; - std::vector<PhysRegSUOper> &DefList = Defs[*Alias]; - for (unsigned i = 0, e = DefList.size(); i != e; ++i) { - SUnit *DefSU = DefList[i].SU; + for (Reg2SUnitsMap::iterator I = Defs.find(*Alias); I != Defs.end(); ++I) { + SUnit *DefSU = I->SU; if (DefSU == &ExitSU) continue; if (DefSU != SU && @@ -308,33 +321,37 @@ void ScheduleDAGInstrs::addPhysRegDeps(SUnit *SU, unsigned OperIdx) { // Either insert a new Reg2SUnits entry with an empty SUnits list, or // retrieve the existing SUnits list for this register's uses. // Push this SUnit on the use list. - Uses[MO.getReg()].push_back(PhysRegSUOper(SU, OperIdx)); + Uses.insert(PhysRegSUOper(SU, OperIdx, MO.getReg())); } else { addPhysRegDataDeps(SU, OperIdx); - - // Either insert a new Reg2SUnits entry with an empty SUnits list, or - // retrieve the existing SUnits list for this register's defs. - std::vector<PhysRegSUOper> &DefList = Defs[MO.getReg()]; + unsigned Reg = MO.getReg(); // clear this register's use list - if (Uses.contains(MO.getReg())) - Uses[MO.getReg()].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().SU->isCall) - DefList.pop_back(); + if (Uses.contains(Reg)) + Uses.eraseAll(Reg); + + if (!MO.isDead()) { + Defs.eraseAll(Reg); + } else if (SU->isCall) { + // 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. + Reg2SUnitsMap::RangePair P = Defs.equal_range(Reg); + Reg2SUnitsMap::iterator B = P.first; + Reg2SUnitsMap::iterator I = P.second; + for (bool isBegin = I == B; !isBegin; /* empty */) { + isBegin = (--I) == B; + if (!I->SU->isCall) + break; + I = Defs.erase(I); + } } + // Defs are pushed in the order they are visited and never reordered. - DefList.push_back(PhysRegSUOper(SU, OperIdx)); + Defs.insert(PhysRegSUOper(SU, OperIdx, Reg)); } } @@ -445,23 +462,29 @@ static inline bool isUnsafeMemoryObject(MachineInstr *MI, if ((*MI->memoperands_begin())->isVolatile() || MI->hasUnmodeledSideEffects()) return true; - const Value *V = (*MI->memoperands_begin())->getValue(); if (!V) return true; - V = getUnderlyingObject(V); - if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V)) { - // Similarly to getUnderlyingObjectForInstr: - // For now, ignore PseudoSourceValues which may alias LLVM IR values - // because the code that uses this function has no way to cope with - // such aliases. - if (PSV->isAliased(MFI)) + SmallVector<Value *, 4> Objs; + getUnderlyingObjects(V, Objs); + for (SmallVector<Value *, 4>::iterator I = Objs.begin(), + IE = Objs.end(); I != IE; ++I) { + V = *I; + + if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V)) { + // Similarly to getUnderlyingObjectForInstr: + // For now, ignore PseudoSourceValues which may alias LLVM IR values + // because the code that uses this function has no way to cope with + // such aliases. + if (PSV->isAliased(MFI)) + return true; + } + + // Does this pointer refer to a distinct and identifiable object? + if (!isIdentifiedObject(V)) return true; } - // Does this pointer refer to a distinct and identifiable object? - if (!isIdentifiedObject(V)) - return true; return false; } @@ -680,8 +703,8 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, // so that they can be given more precise dependencies. We track // separately the known memory locations that may alias and those // that are known not to alias - std::map<const Value *, SUnit *> AliasMemDefs, NonAliasMemDefs; - std::map<const Value *, std::vector<SUnit *> > AliasMemUses, NonAliasMemUses; + MapVector<const Value *, SUnit *> AliasMemDefs, NonAliasMemDefs; + MapVector<const Value *, std::vector<SUnit *> > AliasMemUses, NonAliasMemUses; std::set<SUnit*> RejectMemNodes; // Remove any stale debug info; sometimes BuildSchedGraph is called again @@ -691,8 +714,8 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, assert(Defs.empty() && Uses.empty() && "Only BuildGraph should update Defs/Uses"); - Defs.setRegLimit(TRI->getNumRegs()); - Uses.setRegLimit(TRI->getNumRegs()); + Defs.setUniverse(TRI->getNumRegs()); + Uses.setUniverse(TRI->getNumRegs()); assert(VRegDefs.empty() && "Only BuildSchedGraph may access VRegDefs"); // FIXME: Allow SparseSet to reserve space for the creation of virtual @@ -705,17 +728,17 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, addSchedBarrierDeps(); // Walk the list of instructions, from bottom moving up. - MachineInstr *PrevMI = NULL; + MachineInstr *DbgMI = NULL; for (MachineBasicBlock::iterator MII = RegionEnd, MIE = RegionBegin; MII != MIE; --MII) { MachineInstr *MI = prior(MII); - if (MI && PrevMI) { - DbgValues.push_back(std::make_pair(PrevMI, MI)); - PrevMI = NULL; + if (MI && DbgMI) { + DbgValues.push_back(std::make_pair(DbgMI, MI)); + DbgMI = NULL; } if (MI->isDebugValue()) { - PrevMI = MI; + DbgMI = MI; continue; } if (RPTracker) { @@ -723,13 +746,14 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, assert(RPTracker->getPos() == prior(MII) && "RPTracker can't find MI"); } - assert((!MI->isTerminator() || CanHandleTerminators) && !MI->isLabel() && + assert((CanHandleTerminators || (!MI->isTerminator() && !MI->isLabel())) && "Cannot schedule terminators or labels!"); SUnit *SU = MISUnitMap[MI]; assert(SU && "No SUnit mapped to this MI"); // Add register-based dependencies (data, anti, and output). + bool HasVRegDef = false; for (unsigned j = 0, n = MI->getNumOperands(); j != n; ++j) { const MachineOperand &MO = MI->getOperand(j); if (!MO.isReg()) continue; @@ -740,12 +764,26 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, addPhysRegDeps(SU, j); else { assert(!IsPostRA && "Virtual register encountered!"); - if (MO.isDef()) + if (MO.isDef()) { + HasVRegDef = true; addVRegDefDeps(SU, j); + } else if (MO.readsReg()) // ignore undef operands addVRegUseDeps(SU, j); } } + // If we haven't seen any uses in this scheduling region, create a + // dependence edge to ExitSU to model the live-out latency. This is required + // for vreg defs with no in-region use, and prefetches with no vreg def. + // + // FIXME: NumDataSuccs would be more precise than NumSuccs here. This + // check currently relies on being called before adding chain deps. + if (SU->NumSuccs == 0 && SU->Latency > 1 + && (HasVRegDef || MI->mayLoad())) { + SDep Dep(SU, SDep::Artificial); + Dep.setLatency(SU->Latency - 1); + ExitSU.addPred(Dep); + } // Add chain dependencies. // Chain dependencies used to enforce memory order should have @@ -760,11 +798,11 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, if (isGlobalMemoryObject(AA, MI)) { // Be conservative with these and add dependencies on all memory // references, even those that are known to not alias. - for (std::map<const Value *, SUnit *>::iterator I = + for (MapVector<const Value *, SUnit *>::iterator I = NonAliasMemDefs.begin(), E = NonAliasMemDefs.end(); I != E; ++I) { I->second->addPred(SDep(SU, SDep::Barrier)); } - for (std::map<const Value *, std::vector<SUnit *> >::iterator I = + for (MapVector<const Value *, std::vector<SUnit *> >::iterator I = NonAliasMemUses.begin(), E = NonAliasMemUses.end(); I != E; ++I) { for (unsigned i = 0, e = I->second.size(); i != e; ++i) { SDep Dep(SU, SDep::Barrier); @@ -798,10 +836,10 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, for (unsigned k = 0, m = PendingLoads.size(); k != m; ++k) addChainDependency(AA, MFI, SU, PendingLoads[k], RejectMemNodes, TrueMemOrderLatency); - for (std::map<const Value *, SUnit *>::iterator I = AliasMemDefs.begin(), + for (MapVector<const Value *, SUnit *>::iterator I = AliasMemDefs.begin(), E = AliasMemDefs.end(); I != E; ++I) addChainDependency(AA, MFI, SU, I->second, RejectMemNodes); - for (std::map<const Value *, std::vector<SUnit *> >::iterator I = + for (MapVector<const Value *, std::vector<SUnit *> >::iterator I = AliasMemUses.begin(), E = AliasMemUses.end(); I != E; ++I) { for (unsigned i = 0, e = I->second.size(); i != e; ++i) addChainDependency(AA, MFI, SU, I->second[i], RejectMemNodes, @@ -813,60 +851,70 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, AliasMemDefs.clear(); AliasMemUses.clear(); } else if (MI->mayStore()) { - bool MayAlias = true; - if (const Value *V = getUnderlyingObjectForInstr(MI, MFI, MayAlias)) { + SmallVector<std::pair<const Value *, bool>, 4> Objs; + getUnderlyingObjectsForInstr(MI, MFI, Objs); + + if (Objs.empty()) { + // Treat all other stores conservatively. + goto new_alias_chain; + } + + bool MayAlias = false; + for (SmallVector<std::pair<const Value *, bool>, 4>::iterator + K = Objs.begin(), KE = Objs.end(); K != KE; ++K) { + const Value *V = K->first; + bool ThisMayAlias = K->second; + if (ThisMayAlias) + MayAlias = true; + // A store to a specific PseudoSourceValue. Add precise dependencies. // Record the def in MemDefs, first adding a dep if there is // an existing def. - std::map<const Value *, SUnit *>::iterator I = - ((MayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V)); - std::map<const Value *, SUnit *>::iterator IE = - ((MayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end()); + MapVector<const Value *, SUnit *>::iterator I = + ((ThisMayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V)); + MapVector<const Value *, SUnit *>::iterator IE = + ((ThisMayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end()); if (I != IE) { - addChainDependency(AA, MFI, SU, I->second, RejectMemNodes, - 0, true); + addChainDependency(AA, MFI, SU, I->second, RejectMemNodes, 0, true); I->second = SU; } else { - if (MayAlias) + if (ThisMayAlias) AliasMemDefs[V] = SU; else NonAliasMemDefs[V] = SU; } // Handle the uses in MemUses, if there are any. - std::map<const Value *, std::vector<SUnit *> >::iterator J = - ((MayAlias) ? AliasMemUses.find(V) : NonAliasMemUses.find(V)); - std::map<const Value *, std::vector<SUnit *> >::iterator JE = - ((MayAlias) ? AliasMemUses.end() : NonAliasMemUses.end()); + MapVector<const Value *, std::vector<SUnit *> >::iterator J = + ((ThisMayAlias) ? AliasMemUses.find(V) : NonAliasMemUses.find(V)); + MapVector<const Value *, std::vector<SUnit *> >::iterator JE = + ((ThisMayAlias) ? AliasMemUses.end() : NonAliasMemUses.end()); if (J != JE) { for (unsigned i = 0, e = J->second.size(); i != e; ++i) addChainDependency(AA, MFI, SU, J->second[i], RejectMemNodes, TrueMemOrderLatency, true); J->second.clear(); } - if (MayAlias) { - // Add dependencies from all the PendingLoads, i.e. loads - // with no underlying object. - for (unsigned k = 0, m = PendingLoads.size(); k != m; ++k) - addChainDependency(AA, MFI, SU, PendingLoads[k], RejectMemNodes, - TrueMemOrderLatency); - // Add dependence on alias chain, if needed. - if (AliasChain) - addChainDependency(AA, MFI, SU, AliasChain, RejectMemNodes); - // But we also should check dependent instructions for the - // SU in question. - adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes, - TrueMemOrderLatency); - } - // Add dependence on barrier chain, if needed. - // There is no point to check aliasing on barrier event. Even if - // SU and barrier _could_ be reordered, they should not. In addition, - // we have lost all RejectMemNodes below barrier. - if (BarrierChain) - BarrierChain->addPred(SDep(SU, SDep::Barrier)); - } else { - // Treat all other stores conservatively. - goto new_alias_chain; } + if (MayAlias) { + // Add dependencies from all the PendingLoads, i.e. loads + // with no underlying object. + for (unsigned k = 0, m = PendingLoads.size(); k != m; ++k) + addChainDependency(AA, MFI, SU, PendingLoads[k], RejectMemNodes, + TrueMemOrderLatency); + // Add dependence on alias chain, if needed. + if (AliasChain) + addChainDependency(AA, MFI, SU, AliasChain, RejectMemNodes); + // But we also should check dependent instructions for the + // SU in question. + adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes, + TrueMemOrderLatency); + } + // Add dependence on barrier chain, if needed. + // There is no point to check aliasing on barrier event. Even if + // SU and barrier _could_ be reordered, they should not. In addition, + // we have lost all RejectMemNodes below barrier. + if (BarrierChain) + BarrierChain->addPred(SDep(SU, SDep::Barrier)); if (!ExitSU.isPred(SU)) // Push store's up a bit to avoid them getting in between cmp @@ -877,28 +925,41 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, if (MI->isInvariantLoad(AA)) { // Invariant load, no chain dependencies needed! } else { - if (const Value *V = - getUnderlyingObjectForInstr(MI, MFI, MayAlias)) { - // A load from a specific PseudoSourceValue. Add precise dependencies. - std::map<const Value *, SUnit *>::iterator I = - ((MayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V)); - std::map<const Value *, SUnit *>::iterator IE = - ((MayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end()); - if (I != IE) - addChainDependency(AA, MFI, SU, I->second, RejectMemNodes, 0, true); - if (MayAlias) - AliasMemUses[V].push_back(SU); - else - NonAliasMemUses[V].push_back(SU); - } else { + SmallVector<std::pair<const Value *, bool>, 4> Objs; + getUnderlyingObjectsForInstr(MI, MFI, Objs); + + if (Objs.empty()) { // A load with no underlying object. Depend on all // potentially aliasing stores. - for (std::map<const Value *, SUnit *>::iterator I = + for (MapVector<const Value *, SUnit *>::iterator I = AliasMemDefs.begin(), E = AliasMemDefs.end(); I != E; ++I) addChainDependency(AA, MFI, SU, I->second, RejectMemNodes); PendingLoads.push_back(SU); MayAlias = true; + } else { + MayAlias = false; + } + + for (SmallVector<std::pair<const Value *, bool>, 4>::iterator + J = Objs.begin(), JE = Objs.end(); J != JE; ++J) { + const Value *V = J->first; + bool ThisMayAlias = J->second; + + if (ThisMayAlias) + MayAlias = true; + + // A load from a specific PseudoSourceValue. Add precise dependencies. + MapVector<const Value *, SUnit *>::iterator I = + ((ThisMayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V)); + MapVector<const Value *, SUnit *>::iterator IE = + ((ThisMayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end()); + if (I != IE) + addChainDependency(AA, MFI, SU, I->second, RejectMemNodes, 0, true); + if (ThisMayAlias) + AliasMemUses[V].push_back(SU); + else + NonAliasMemUses[V].push_back(SU); } if (MayAlias) adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes, /*Latency=*/0); @@ -910,8 +971,8 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA, } } } - if (PrevMI) - FirstDbgValue = PrevMI; + if (DbgMI) + FirstDbgValue = DbgMI; Defs.clear(); Uses.clear(); @@ -933,7 +994,7 @@ std::string ScheduleDAGInstrs::getGraphNodeLabel(const SUnit *SU) const { else if (SU == &ExitSU) oss << "<exit>"; else - SU->getInstr()->print(oss); + SU->getInstr()->print(oss, &TM, /*SkipOpers=*/true); return oss.str(); } @@ -943,6 +1004,203 @@ std::string ScheduleDAGInstrs::getDAGName() const { return "dag." + BB->getFullName(); } +//===----------------------------------------------------------------------===// +// SchedDFSResult Implementation +//===----------------------------------------------------------------------===// + +namespace llvm { +/// \brief Internal state used to compute SchedDFSResult. +class SchedDFSImpl { + SchedDFSResult &R; + + /// Join DAG nodes into equivalence classes by their subtree. + IntEqClasses SubtreeClasses; + /// List PredSU, SuccSU pairs that represent data edges between subtrees. + std::vector<std::pair<const SUnit*, const SUnit*> > ConnectionPairs; + + struct RootData { + unsigned NodeID; + unsigned ParentNodeID; // Parent node (member of the parent subtree). + unsigned SubInstrCount; // Instr count in this tree only, not children. + + RootData(unsigned id): NodeID(id), + ParentNodeID(SchedDFSResult::InvalidSubtreeID), + SubInstrCount(0) {} + + unsigned getSparseSetIndex() const { return NodeID; } + }; + + SparseSet<RootData> RootSet; + +public: + SchedDFSImpl(SchedDFSResult &r): R(r), SubtreeClasses(R.DFSNodeData.size()) { + RootSet.setUniverse(R.DFSNodeData.size()); + } + + /// Return true if this node been visited by the DFS traversal. + /// + /// During visitPostorderNode the Node's SubtreeID is assigned to the Node + /// ID. Later, SubtreeID is updated but remains valid. + bool isVisited(const SUnit *SU) const { + return R.DFSNodeData[SU->NodeNum].SubtreeID + != SchedDFSResult::InvalidSubtreeID; + } + + /// Initialize this node's instruction count. We don't need to flag the node + /// visited until visitPostorder because the DAG cannot have cycles. + void visitPreorder(const SUnit *SU) { + R.DFSNodeData[SU->NodeNum].InstrCount = + SU->getInstr()->isTransient() ? 0 : 1; + } + + /// Called once for each node after all predecessors are visited. Revisit this + /// node's predecessors and potentially join them now that we know the ILP of + /// the other predecessors. + void visitPostorderNode(const SUnit *SU) { + // Mark this node as the root of a subtree. It may be joined with its + // successors later. + R.DFSNodeData[SU->NodeNum].SubtreeID = SU->NodeNum; + RootData RData(SU->NodeNum); + RData.SubInstrCount = SU->getInstr()->isTransient() ? 0 : 1; + + // If any predecessors are still in their own subtree, they either cannot be + // joined or are large enough to remain separate. If this parent node's + // total instruction count is not greater than a child subtree by at least + // the subtree limit, then try to join it now since splitting subtrees is + // only useful if multiple high-pressure paths are possible. + unsigned InstrCount = R.DFSNodeData[SU->NodeNum].InstrCount; + for (SUnit::const_pred_iterator + PI = SU->Preds.begin(), PE = SU->Preds.end(); PI != PE; ++PI) { + if (PI->getKind() != SDep::Data) + continue; + unsigned PredNum = PI->getSUnit()->NodeNum; + if ((InstrCount - R.DFSNodeData[PredNum].InstrCount) < R.SubtreeLimit) + joinPredSubtree(*PI, SU, /*CheckLimit=*/false); + + // Either link or merge the TreeData entry from the child to the parent. + if (R.DFSNodeData[PredNum].SubtreeID == PredNum) { + // If the predecessor's parent is invalid, this is a tree edge and the + // current node is the parent. + if (RootSet[PredNum].ParentNodeID == SchedDFSResult::InvalidSubtreeID) + RootSet[PredNum].ParentNodeID = SU->NodeNum; + } + else if (RootSet.count(PredNum)) { + // The predecessor is not a root, but is still in the root set. This + // must be the new parent that it was just joined to. Note that + // RootSet[PredNum].ParentNodeID may either be invalid or may still be + // set to the original parent. + RData.SubInstrCount += RootSet[PredNum].SubInstrCount; + RootSet.erase(PredNum); + } + } + RootSet[SU->NodeNum] = RData; + } + + /// Called once for each tree edge after calling visitPostOrderNode on the + /// predecessor. Increment the parent node's instruction count and + /// preemptively join this subtree to its parent's if it is small enough. + void visitPostorderEdge(const SDep &PredDep, const SUnit *Succ) { + R.DFSNodeData[Succ->NodeNum].InstrCount + += R.DFSNodeData[PredDep.getSUnit()->NodeNum].InstrCount; + joinPredSubtree(PredDep, Succ); + } + + /// Add a connection for cross edges. + void visitCrossEdge(const SDep &PredDep, const SUnit *Succ) { + ConnectionPairs.push_back(std::make_pair(PredDep.getSUnit(), Succ)); + } + + /// Set each node's subtree ID to the representative ID and record connections + /// between trees. + void finalize() { + SubtreeClasses.compress(); + R.DFSTreeData.resize(SubtreeClasses.getNumClasses()); + assert(SubtreeClasses.getNumClasses() == RootSet.size() + && "number of roots should match trees"); + for (SparseSet<RootData>::const_iterator + RI = RootSet.begin(), RE = RootSet.end(); RI != RE; ++RI) { + unsigned TreeID = SubtreeClasses[RI->NodeID]; + if (RI->ParentNodeID != SchedDFSResult::InvalidSubtreeID) + R.DFSTreeData[TreeID].ParentTreeID = SubtreeClasses[RI->ParentNodeID]; + R.DFSTreeData[TreeID].SubInstrCount = RI->SubInstrCount; + // Note that SubInstrCount may be greater than InstrCount if we joined + // subtrees across a cross edge. InstrCount will be attributed to the + // original parent, while SubInstrCount will be attributed to the joined + // parent. + } + R.SubtreeConnections.resize(SubtreeClasses.getNumClasses()); + R.SubtreeConnectLevels.resize(SubtreeClasses.getNumClasses()); + DEBUG(dbgs() << R.getNumSubtrees() << " subtrees:\n"); + for (unsigned Idx = 0, End = R.DFSNodeData.size(); Idx != End; ++Idx) { + R.DFSNodeData[Idx].SubtreeID = SubtreeClasses[Idx]; + DEBUG(dbgs() << " SU(" << Idx << ") in tree " + << R.DFSNodeData[Idx].SubtreeID << '\n'); + } + for (std::vector<std::pair<const SUnit*, const SUnit*> >::const_iterator + I = ConnectionPairs.begin(), E = ConnectionPairs.end(); + I != E; ++I) { + unsigned PredTree = SubtreeClasses[I->first->NodeNum]; + unsigned SuccTree = SubtreeClasses[I->second->NodeNum]; + if (PredTree == SuccTree) + continue; + unsigned Depth = I->first->getDepth(); + addConnection(PredTree, SuccTree, Depth); + addConnection(SuccTree, PredTree, Depth); + } + } + +protected: + /// Join the predecessor subtree with the successor that is its DFS + /// parent. Apply some heuristics before joining. + bool joinPredSubtree(const SDep &PredDep, const SUnit *Succ, + bool CheckLimit = true) { + assert(PredDep.getKind() == SDep::Data && "Subtrees are for data edges"); + + // Check if the predecessor is already joined. + const SUnit *PredSU = PredDep.getSUnit(); + unsigned PredNum = PredSU->NodeNum; + if (R.DFSNodeData[PredNum].SubtreeID != PredNum) + return false; + + // Four is the magic number of successors before a node is considered a + // pinch point. + unsigned NumDataSucs = 0; + for (SUnit::const_succ_iterator SI = PredSU->Succs.begin(), + SE = PredSU->Succs.end(); SI != SE; ++SI) { + if (SI->getKind() == SDep::Data) { + if (++NumDataSucs >= 4) + return false; + } + } + if (CheckLimit && R.DFSNodeData[PredNum].InstrCount > R.SubtreeLimit) + return false; + R.DFSNodeData[PredNum].SubtreeID = Succ->NodeNum; + SubtreeClasses.join(Succ->NodeNum, PredNum); + return true; + } + + /// Called by finalize() to record a connection between trees. + void addConnection(unsigned FromTree, unsigned ToTree, unsigned Depth) { + if (!Depth) + return; + + do { + SmallVectorImpl<SchedDFSResult::Connection> &Connections = + R.SubtreeConnections[FromTree]; + for (SmallVectorImpl<SchedDFSResult::Connection>::iterator + I = Connections.begin(), E = Connections.end(); I != E; ++I) { + if (I->TreeID == ToTree) { + I->Level = std::max(I->Level, Depth); + return; + } + } + Connections.push_back(SchedDFSResult::Connection(ToTree, Depth)); + FromTree = R.DFSTreeData[FromTree].ParentTreeID; + } while (FromTree != SchedDFSResult::InvalidSubtreeID); + } +}; +} // namespace llvm + namespace { /// \brief Manage the stack used by a reverse depth-first search over the DAG. class SchedDAGReverseDFS { @@ -955,7 +1213,10 @@ public: } void advance() { ++DFSStack.back().second; } - void backtrack() { DFSStack.pop_back(); } + const SDep *backtrack() { + DFSStack.pop_back(); + return DFSStack.empty() ? 0 : llvm::prior(DFSStack.back().second); + } const SUnit *getCurr() const { return DFSStack.back().first; } @@ -967,57 +1228,83 @@ public: }; } // anonymous -void ScheduleDAGILP::resize(unsigned NumSUnits) { - ILPValues.resize(NumSUnits); -} - -ILPValue ScheduleDAGILP::getILP(const SUnit *SU) { - return ILPValues[SU->NodeNum]; -} - -// A leaf node has an ILP of 1/1. -static ILPValue initILP(const SUnit *SU) { - unsigned Cnt = SU->getInstr()->isTransient() ? 0 : 1; - return ILPValue(Cnt, 1 + SU->getDepth()); +static bool hasDataSucc(const SUnit *SU) { + for (SUnit::const_succ_iterator + SI = SU->Succs.begin(), SE = SU->Succs.end(); SI != SE; ++SI) { + if (SI->getKind() == SDep::Data && !SI->getSUnit()->isBoundaryNode()) + return true; + } + return false; } /// Compute an ILP metric for all nodes in the subDAG reachable via depth-first /// search from this root. -void ScheduleDAGILP::computeILP(const SUnit *Root) { +void SchedDFSResult::compute(ArrayRef<SUnit> SUnits) { if (!IsBottomUp) llvm_unreachable("Top-down ILP metric is unimplemnted"); - SchedDAGReverseDFS DFS; - // Mark a node visited by validating it. - ILPValues[Root->NodeNum] = initILP(Root); - DFS.follow(Root); - for (;;) { - // Traverse the leftmost path as far as possible. - while (DFS.getPred() != DFS.getPredEnd()) { - const SUnit *PredSU = DFS.getPred()->getSUnit(); - DFS.advance(); - // If the pred is already valid, skip it. - if (ILPValues[PredSU->NodeNum].isValid()) - continue; - ILPValues[PredSU->NodeNum] = initILP(PredSU); - DFS.follow(PredSU); + SchedDFSImpl Impl(*this); + for (ArrayRef<SUnit>::const_iterator + SI = SUnits.begin(), SE = SUnits.end(); SI != SE; ++SI) { + const SUnit *SU = &*SI; + if (Impl.isVisited(SU) || hasDataSucc(SU)) + continue; + + SchedDAGReverseDFS DFS; + Impl.visitPreorder(SU); + DFS.follow(SU); + for (;;) { + // Traverse the leftmost path as far as possible. + while (DFS.getPred() != DFS.getPredEnd()) { + const SDep &PredDep = *DFS.getPred(); + DFS.advance(); + // Ignore non-data edges. + if (PredDep.getKind() != SDep::Data + || PredDep.getSUnit()->isBoundaryNode()) { + continue; + } + // An already visited edge is a cross edge, assuming an acyclic DAG. + if (Impl.isVisited(PredDep.getSUnit())) { + Impl.visitCrossEdge(PredDep, DFS.getCurr()); + continue; + } + Impl.visitPreorder(PredDep.getSUnit()); + DFS.follow(PredDep.getSUnit()); + } + // Visit the top of the stack in postorder and backtrack. + const SUnit *Child = DFS.getCurr(); + const SDep *PredDep = DFS.backtrack(); + Impl.visitPostorderNode(Child); + if (PredDep) + Impl.visitPostorderEdge(*PredDep, DFS.getCurr()); + if (DFS.isComplete()) + break; } - // Visit the top of the stack in postorder and backtrack. - unsigned PredCount = ILPValues[DFS.getCurr()->NodeNum].InstrCount; - DFS.backtrack(); - if (DFS.isComplete()) - break; - // Add the recently finished predecessor's bottom-up descendent count. - ILPValues[DFS.getCurr()->NodeNum].InstrCount += PredCount; + } + Impl.finalize(); +} + +/// The root of the given SubtreeID was just scheduled. For all subtrees +/// connected to this tree, record the depth of the connection so that the +/// nearest connected subtrees can be prioritized. +void SchedDFSResult::scheduleTree(unsigned SubtreeID) { + for (SmallVectorImpl<Connection>::const_iterator + I = SubtreeConnections[SubtreeID].begin(), + E = SubtreeConnections[SubtreeID].end(); I != E; ++I) { + SubtreeConnectLevels[I->TreeID] = + std::max(SubtreeConnectLevels[I->TreeID], I->Level); + DEBUG(dbgs() << " Tree: " << I->TreeID + << " @" << SubtreeConnectLevels[I->TreeID] << '\n'); } } #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) void ILPValue::print(raw_ostream &OS) const { - if (!isValid()) + OS << InstrCount << " / " << Length << " = "; + if (!Length) OS << "BADILP"; - OS << InstrCount << " / " << Cycles << " = " - << format("%g", ((double)InstrCount / Cycles)); + else + OS << format("%g", ((double)InstrCount / Length)); } void ILPValue::dump() const { |