| //===- ScheduleDAG.cpp - Implement the ScheduleDAG class ------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| /// \file Implements the ScheduleDAG class, which is a base class used by |
| /// scheduling implementation classes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/CodeGen/ScheduleDAG.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/ADT/iterator_range.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/ScheduleHazardRecognizer.h" |
| #include "llvm/CodeGen/SelectionDAGNodes.h" |
| #include "llvm/CodeGen/TargetInstrInfo.h" |
| #include "llvm/CodeGen/TargetRegisterInfo.h" |
| #include "llvm/CodeGen/TargetSubtargetInfo.h" |
| #include "llvm/Config/llvm-config.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <iterator> |
| #include <limits> |
| #include <utility> |
| #include <vector> |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "pre-RA-sched" |
| |
| STATISTIC(NumNewPredsAdded, "Number of times a single predecessor was added"); |
| STATISTIC(NumTopoInits, |
| "Number of times the topological order has been recomputed"); |
| |
| #ifndef NDEBUG |
| static cl::opt<bool> StressSchedOpt( |
| "stress-sched", cl::Hidden, cl::init(false), |
| cl::desc("Stress test instruction scheduling")); |
| #endif |
| |
| void SchedulingPriorityQueue::anchor() {} |
| |
| ScheduleDAG::ScheduleDAG(MachineFunction &mf) |
| : TM(mf.getTarget()), TII(mf.getSubtarget().getInstrInfo()), |
| TRI(mf.getSubtarget().getRegisterInfo()), MF(mf), |
| MRI(mf.getRegInfo()) { |
| #ifndef NDEBUG |
| StressSched = StressSchedOpt; |
| #endif |
| } |
| |
| ScheduleDAG::~ScheduleDAG() = default; |
| |
| void ScheduleDAG::clearDAG() { |
| SUnits.clear(); |
| EntrySU = SUnit(); |
| ExitSU = SUnit(); |
| } |
| |
| const MCInstrDesc *ScheduleDAG::getNodeDesc(const SDNode *Node) const { |
| if (!Node || !Node->isMachineOpcode()) return nullptr; |
| return &TII->get(Node->getMachineOpcode()); |
| } |
| |
| LLVM_DUMP_METHOD void SDep::dump(const TargetRegisterInfo *TRI) const { |
| switch (getKind()) { |
| case Data: dbgs() << "Data"; break; |
| case Anti: dbgs() << "Anti"; break; |
| case Output: dbgs() << "Out "; break; |
| case Order: dbgs() << "Ord "; break; |
| } |
| |
| switch (getKind()) { |
| case Data: |
| dbgs() << " Latency=" << getLatency(); |
| if (TRI && isAssignedRegDep()) |
| dbgs() << " Reg=" << printReg(getReg(), TRI); |
| break; |
| case Anti: |
| case Output: |
| dbgs() << " Latency=" << getLatency(); |
| break; |
| case Order: |
| dbgs() << " Latency=" << getLatency(); |
| switch(Contents.OrdKind) { |
| case Barrier: dbgs() << " Barrier"; break; |
| case MayAliasMem: |
| case MustAliasMem: dbgs() << " Memory"; break; |
| case Artificial: dbgs() << " Artificial"; break; |
| case Weak: dbgs() << " Weak"; break; |
| case Cluster: dbgs() << " Cluster"; break; |
| } |
| break; |
| } |
| } |
| |
| bool SUnit::addPred(const SDep &D, bool Required) { |
| // If this node already has this dependence, don't add a redundant one. |
| for (SDep &PredDep : Preds) { |
| // Zero-latency weak edges may be added purely for heuristic ordering. Don't |
| // add them if another kind of edge already exists. |
| if (!Required && PredDep.getSUnit() == D.getSUnit()) |
| return false; |
| if (PredDep.overlaps(D)) { |
| // Extend the latency if needed. Equivalent to |
| // removePred(PredDep) + addPred(D). |
| if (PredDep.getLatency() < D.getLatency()) { |
| SUnit *PredSU = PredDep.getSUnit(); |
| // Find the corresponding successor in N. |
| SDep ForwardD = PredDep; |
| ForwardD.setSUnit(this); |
| for (SDep &SuccDep : PredSU->Succs) { |
| if (SuccDep == ForwardD) { |
| SuccDep.setLatency(D.getLatency()); |
| break; |
| } |
| } |
| PredDep.setLatency(D.getLatency()); |
| } |
| return false; |
| } |
| } |
| // Now add a corresponding succ to N. |
| SDep P = D; |
| P.setSUnit(this); |
| SUnit *N = D.getSUnit(); |
| // Update the bookkeeping. |
| if (D.getKind() == SDep::Data) { |
| assert(NumPreds < std::numeric_limits<unsigned>::max() && |
| "NumPreds will overflow!"); |
| assert(N->NumSuccs < std::numeric_limits<unsigned>::max() && |
| "NumSuccs will overflow!"); |
| ++NumPreds; |
| ++N->NumSuccs; |
| } |
| if (!N->isScheduled) { |
| if (D.isWeak()) { |
| ++WeakPredsLeft; |
| } |
| else { |
| assert(NumPredsLeft < std::numeric_limits<unsigned>::max() && |
| "NumPredsLeft will overflow!"); |
| ++NumPredsLeft; |
| } |
| } |
| if (!isScheduled) { |
| if (D.isWeak()) { |
| ++N->WeakSuccsLeft; |
| } |
| else { |
| assert(N->NumSuccsLeft < std::numeric_limits<unsigned>::max() && |
| "NumSuccsLeft will overflow!"); |
| ++N->NumSuccsLeft; |
| } |
| } |
| Preds.push_back(D); |
| N->Succs.push_back(P); |
| if (P.getLatency() != 0) { |
| this->setDepthDirty(); |
| N->setHeightDirty(); |
| } |
| return true; |
| } |
| |
| void SUnit::removePred(const SDep &D) { |
| // Find the matching predecessor. |
| SmallVectorImpl<SDep>::iterator I = llvm::find(Preds, D); |
| if (I == Preds.end()) |
| return; |
| // Find the corresponding successor in N. |
| SDep P = D; |
| P.setSUnit(this); |
| SUnit *N = D.getSUnit(); |
| SmallVectorImpl<SDep>::iterator Succ = llvm::find(N->Succs, P); |
| assert(Succ != N->Succs.end() && "Mismatching preds / succs lists!"); |
| N->Succs.erase(Succ); |
| Preds.erase(I); |
| // Update the bookkeeping. |
| if (P.getKind() == SDep::Data) { |
| assert(NumPreds > 0 && "NumPreds will underflow!"); |
| assert(N->NumSuccs > 0 && "NumSuccs will underflow!"); |
| --NumPreds; |
| --N->NumSuccs; |
| } |
| if (!N->isScheduled) { |
| if (D.isWeak()) |
| --WeakPredsLeft; |
| else { |
| assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!"); |
| --NumPredsLeft; |
| } |
| } |
| if (!isScheduled) { |
| if (D.isWeak()) |
| --N->WeakSuccsLeft; |
| else { |
| assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!"); |
| --N->NumSuccsLeft; |
| } |
| } |
| if (P.getLatency() != 0) { |
| this->setDepthDirty(); |
| N->setHeightDirty(); |
| } |
| } |
| |
| void SUnit::setDepthDirty() { |
| if (!isDepthCurrent) return; |
| SmallVector<SUnit*, 8> WorkList; |
| WorkList.push_back(this); |
| do { |
| SUnit *SU = WorkList.pop_back_val(); |
| SU->isDepthCurrent = false; |
| for (SDep &SuccDep : SU->Succs) { |
| SUnit *SuccSU = SuccDep.getSUnit(); |
| if (SuccSU->isDepthCurrent) |
| WorkList.push_back(SuccSU); |
| } |
| } while (!WorkList.empty()); |
| } |
| |
| void SUnit::setHeightDirty() { |
| if (!isHeightCurrent) return; |
| SmallVector<SUnit*, 8> WorkList; |
| WorkList.push_back(this); |
| do { |
| SUnit *SU = WorkList.pop_back_val(); |
| SU->isHeightCurrent = false; |
| for (SDep &PredDep : SU->Preds) { |
| SUnit *PredSU = PredDep.getSUnit(); |
| if (PredSU->isHeightCurrent) |
| WorkList.push_back(PredSU); |
| } |
| } while (!WorkList.empty()); |
| } |
| |
| void SUnit::setDepthToAtLeast(unsigned NewDepth) { |
| if (NewDepth <= getDepth()) |
| return; |
| setDepthDirty(); |
| Depth = NewDepth; |
| isDepthCurrent = true; |
| } |
| |
| void SUnit::setHeightToAtLeast(unsigned NewHeight) { |
| if (NewHeight <= getHeight()) |
| return; |
| setHeightDirty(); |
| Height = NewHeight; |
| isHeightCurrent = true; |
| } |
| |
| /// Calculates the maximal path from the node to the exit. |
| void SUnit::ComputeDepth() { |
| SmallVector<SUnit*, 8> WorkList; |
| WorkList.push_back(this); |
| do { |
| SUnit *Cur = WorkList.back(); |
| |
| bool Done = true; |
| unsigned MaxPredDepth = 0; |
| for (const SDep &PredDep : Cur->Preds) { |
| SUnit *PredSU = PredDep.getSUnit(); |
| if (PredSU->isDepthCurrent) |
| MaxPredDepth = std::max(MaxPredDepth, |
| PredSU->Depth + PredDep.getLatency()); |
| else { |
| Done = false; |
| WorkList.push_back(PredSU); |
| } |
| } |
| |
| if (Done) { |
| WorkList.pop_back(); |
| if (MaxPredDepth != Cur->Depth) { |
| Cur->setDepthDirty(); |
| Cur->Depth = MaxPredDepth; |
| } |
| Cur->isDepthCurrent = true; |
| } |
| } while (!WorkList.empty()); |
| } |
| |
| /// Calculates the maximal path from the node to the entry. |
| void SUnit::ComputeHeight() { |
| SmallVector<SUnit*, 8> WorkList; |
| WorkList.push_back(this); |
| do { |
| SUnit *Cur = WorkList.back(); |
| |
| bool Done = true; |
| unsigned MaxSuccHeight = 0; |
| for (const SDep &SuccDep : Cur->Succs) { |
| SUnit *SuccSU = SuccDep.getSUnit(); |
| if (SuccSU->isHeightCurrent) |
| MaxSuccHeight = std::max(MaxSuccHeight, |
| SuccSU->Height + SuccDep.getLatency()); |
| else { |
| Done = false; |
| WorkList.push_back(SuccSU); |
| } |
| } |
| |
| if (Done) { |
| WorkList.pop_back(); |
| if (MaxSuccHeight != Cur->Height) { |
| Cur->setHeightDirty(); |
| Cur->Height = MaxSuccHeight; |
| } |
| Cur->isHeightCurrent = true; |
| } |
| } while (!WorkList.empty()); |
| } |
| |
| void SUnit::biasCriticalPath() { |
| if (NumPreds < 2) |
| return; |
| |
| SUnit::pred_iterator BestI = Preds.begin(); |
| unsigned MaxDepth = BestI->getSUnit()->getDepth(); |
| for (SUnit::pred_iterator I = std::next(BestI), E = Preds.end(); I != E; |
| ++I) { |
| if (I->getKind() == SDep::Data && I->getSUnit()->getDepth() > MaxDepth) |
| BestI = I; |
| } |
| if (BestI != Preds.begin()) |
| std::swap(*Preds.begin(), *BestI); |
| } |
| |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| LLVM_DUMP_METHOD void SUnit::dumpAttributes() const { |
| dbgs() << " # preds left : " << NumPredsLeft << "\n"; |
| dbgs() << " # succs left : " << NumSuccsLeft << "\n"; |
| if (WeakPredsLeft) |
| dbgs() << " # weak preds left : " << WeakPredsLeft << "\n"; |
| if (WeakSuccsLeft) |
| dbgs() << " # weak succs left : " << WeakSuccsLeft << "\n"; |
| dbgs() << " # rdefs left : " << NumRegDefsLeft << "\n"; |
| dbgs() << " Latency : " << Latency << "\n"; |
| dbgs() << " Depth : " << getDepth() << "\n"; |
| dbgs() << " Height : " << getHeight() << "\n"; |
| } |
| |
| LLVM_DUMP_METHOD void ScheduleDAG::dumpNodeName(const SUnit &SU) const { |
| if (&SU == &EntrySU) |
| dbgs() << "EntrySU"; |
| else if (&SU == &ExitSU) |
| dbgs() << "ExitSU"; |
| else |
| dbgs() << "SU(" << SU.NodeNum << ")"; |
| } |
| |
| LLVM_DUMP_METHOD void ScheduleDAG::dumpNodeAll(const SUnit &SU) const { |
| dumpNode(SU); |
| SU.dumpAttributes(); |
| if (SU.Preds.size() > 0) { |
| dbgs() << " Predecessors:\n"; |
| for (const SDep &Dep : SU.Preds) { |
| dbgs() << " "; |
| dumpNodeName(*Dep.getSUnit()); |
| dbgs() << ": "; |
| Dep.dump(TRI); |
| dbgs() << '\n'; |
| } |
| } |
| if (SU.Succs.size() > 0) { |
| dbgs() << " Successors:\n"; |
| for (const SDep &Dep : SU.Succs) { |
| dbgs() << " "; |
| dumpNodeName(*Dep.getSUnit()); |
| dbgs() << ": "; |
| Dep.dump(TRI); |
| dbgs() << '\n'; |
| } |
| } |
| } |
| #endif |
| |
| #ifndef NDEBUG |
| unsigned ScheduleDAG::VerifyScheduledDAG(bool isBottomUp) { |
| bool AnyNotSched = false; |
| unsigned DeadNodes = 0; |
| for (const SUnit &SUnit : SUnits) { |
| if (!SUnit.isScheduled) { |
| if (SUnit.NumPreds == 0 && SUnit.NumSuccs == 0) { |
| ++DeadNodes; |
| continue; |
| } |
| if (!AnyNotSched) |
| dbgs() << "*** Scheduling failed! ***\n"; |
| dumpNode(SUnit); |
| dbgs() << "has not been scheduled!\n"; |
| AnyNotSched = true; |
| } |
| if (SUnit.isScheduled && |
| (isBottomUp ? SUnit.getHeight() : SUnit.getDepth()) > |
| unsigned(std::numeric_limits<int>::max())) { |
| if (!AnyNotSched) |
| dbgs() << "*** Scheduling failed! ***\n"; |
| dumpNode(SUnit); |
| dbgs() << "has an unexpected " |
| << (isBottomUp ? "Height" : "Depth") << " value!\n"; |
| AnyNotSched = true; |
| } |
| if (isBottomUp) { |
| if (SUnit.NumSuccsLeft != 0) { |
| if (!AnyNotSched) |
| dbgs() << "*** Scheduling failed! ***\n"; |
| dumpNode(SUnit); |
| dbgs() << "has successors left!\n"; |
| AnyNotSched = true; |
| } |
| } else { |
| if (SUnit.NumPredsLeft != 0) { |
| if (!AnyNotSched) |
| dbgs() << "*** Scheduling failed! ***\n"; |
| dumpNode(SUnit); |
| dbgs() << "has predecessors left!\n"; |
| AnyNotSched = true; |
| } |
| } |
| } |
| assert(!AnyNotSched); |
| return SUnits.size() - DeadNodes; |
| } |
| #endif |
| |
| void ScheduleDAGTopologicalSort::InitDAGTopologicalSorting() { |
| // The idea of the algorithm is taken from |
| // "Online algorithms for managing the topological order of |
| // a directed acyclic graph" by David J. Pearce and Paul H.J. Kelly |
| // This is the MNR algorithm, which was first introduced by |
| // A. Marchetti-Spaccamela, U. Nanni and H. Rohnert in |
| // "Maintaining a topological order under edge insertions". |
| // |
| // Short description of the algorithm: |
| // |
| // Topological ordering, ord, of a DAG maps each node to a topological |
| // index so that for all edges X->Y it is the case that ord(X) < ord(Y). |
| // |
| // This means that if there is a path from the node X to the node Z, |
| // then ord(X) < ord(Z). |
| // |
| // This property can be used to check for reachability of nodes: |
| // if Z is reachable from X, then an insertion of the edge Z->X would |
| // create a cycle. |
| // |
| // The algorithm first computes a topological ordering for the DAG by |
| // initializing the Index2Node and Node2Index arrays and then tries to keep |
| // the ordering up-to-date after edge insertions by reordering the DAG. |
| // |
| // On insertion of the edge X->Y, the algorithm first marks by calling DFS |
| // the nodes reachable from Y, and then shifts them using Shift to lie |
| // immediately after X in Index2Node. |
| |
| // Cancel pending updates, mark as valid. |
| Dirty = false; |
| Updates.clear(); |
| |
| unsigned DAGSize = SUnits.size(); |
| std::vector<SUnit*> WorkList; |
| WorkList.reserve(DAGSize); |
| |
| Index2Node.resize(DAGSize); |
| Node2Index.resize(DAGSize); |
| |
| // Initialize the data structures. |
| if (ExitSU) |
| WorkList.push_back(ExitSU); |
| for (SUnit &SU : SUnits) { |
| int NodeNum = SU.NodeNum; |
| unsigned Degree = SU.Succs.size(); |
| // Temporarily use the Node2Index array as scratch space for degree counts. |
| Node2Index[NodeNum] = Degree; |
| |
| // Is it a node without dependencies? |
| if (Degree == 0) { |
| assert(SU.Succs.empty() && "SUnit should have no successors"); |
| // Collect leaf nodes. |
| WorkList.push_back(&SU); |
| } |
| } |
| |
| int Id = DAGSize; |
| while (!WorkList.empty()) { |
| SUnit *SU = WorkList.back(); |
| WorkList.pop_back(); |
| if (SU->NodeNum < DAGSize) |
| Allocate(SU->NodeNum, --Id); |
| for (const SDep &PredDep : SU->Preds) { |
| SUnit *SU = PredDep.getSUnit(); |
| if (SU->NodeNum < DAGSize && !--Node2Index[SU->NodeNum]) |
| // If all dependencies of the node are processed already, |
| // then the node can be computed now. |
| WorkList.push_back(SU); |
| } |
| } |
| |
| Visited.resize(DAGSize); |
| NumTopoInits++; |
| |
| #ifndef NDEBUG |
| // Check correctness of the ordering |
| for (SUnit &SU : SUnits) { |
| for (const SDep &PD : SU.Preds) { |
| assert(Node2Index[SU.NodeNum] > Node2Index[PD.getSUnit()->NodeNum] && |
| "Wrong topological sorting"); |
| } |
| } |
| #endif |
| } |
| |
| void ScheduleDAGTopologicalSort::FixOrder() { |
| // Recompute from scratch after new nodes have been added. |
| if (Dirty) { |
| InitDAGTopologicalSorting(); |
| return; |
| } |
| |
| // Otherwise apply updates one-by-one. |
| for (auto &U : Updates) |
| AddPred(U.first, U.second); |
| Updates.clear(); |
| } |
| |
| void ScheduleDAGTopologicalSort::AddPredQueued(SUnit *Y, SUnit *X) { |
| // Recomputing the order from scratch is likely more efficient than applying |
| // updates one-by-one for too many updates. The current cut-off is arbitrarily |
| // chosen. |
| Dirty = Dirty || Updates.size() > 10; |
| |
| if (Dirty) |
| return; |
| |
| Updates.emplace_back(Y, X); |
| } |
| |
| void ScheduleDAGTopologicalSort::AddPred(SUnit *Y, SUnit *X) { |
| int UpperBound, LowerBound; |
| LowerBound = Node2Index[Y->NodeNum]; |
| UpperBound = Node2Index[X->NodeNum]; |
| bool HasLoop = false; |
| // Is Ord(X) < Ord(Y) ? |
| if (LowerBound < UpperBound) { |
| // Update the topological order. |
| Visited.reset(); |
| DFS(Y, UpperBound, HasLoop); |
| assert(!HasLoop && "Inserted edge creates a loop!"); |
| // Recompute topological indexes. |
| Shift(Visited, LowerBound, UpperBound); |
| } |
| |
| NumNewPredsAdded++; |
| } |
| |
| void ScheduleDAGTopologicalSort::RemovePred(SUnit *M, SUnit *N) { |
| // InitDAGTopologicalSorting(); |
| } |
| |
| void ScheduleDAGTopologicalSort::DFS(const SUnit *SU, int UpperBound, |
| bool &HasLoop) { |
| std::vector<const SUnit*> WorkList; |
| WorkList.reserve(SUnits.size()); |
| |
| WorkList.push_back(SU); |
| do { |
| SU = WorkList.back(); |
| WorkList.pop_back(); |
| Visited.set(SU->NodeNum); |
| for (const SDep &SuccDep : llvm::reverse(SU->Succs)) { |
| unsigned s = SuccDep.getSUnit()->NodeNum; |
| // Edges to non-SUnits are allowed but ignored (e.g. ExitSU). |
| if (s >= Node2Index.size()) |
| continue; |
| if (Node2Index[s] == UpperBound) { |
| HasLoop = true; |
| return; |
| } |
| // Visit successors if not already and in affected region. |
| if (!Visited.test(s) && Node2Index[s] < UpperBound) { |
| WorkList.push_back(SuccDep.getSUnit()); |
| } |
| } |
| } while (!WorkList.empty()); |
| } |
| |
| std::vector<int> ScheduleDAGTopologicalSort::GetSubGraph(const SUnit &StartSU, |
| const SUnit &TargetSU, |
| bool &Success) { |
| std::vector<const SUnit*> WorkList; |
| int LowerBound = Node2Index[StartSU.NodeNum]; |
| int UpperBound = Node2Index[TargetSU.NodeNum]; |
| bool Found = false; |
| BitVector VisitedBack; |
| std::vector<int> Nodes; |
| |
| if (LowerBound > UpperBound) { |
| Success = false; |
| return Nodes; |
| } |
| |
| WorkList.reserve(SUnits.size()); |
| Visited.reset(); |
| |
| // Starting from StartSU, visit all successors up |
| // to UpperBound. |
| WorkList.push_back(&StartSU); |
| do { |
| const SUnit *SU = WorkList.back(); |
| WorkList.pop_back(); |
| for (int I = SU->Succs.size()-1; I >= 0; --I) { |
| const SUnit *Succ = SU->Succs[I].getSUnit(); |
| unsigned s = Succ->NodeNum; |
| // Edges to non-SUnits are allowed but ignored (e.g. ExitSU). |
| if (Succ->isBoundaryNode()) |
| continue; |
| if (Node2Index[s] == UpperBound) { |
| Found = true; |
| continue; |
| } |
| // Visit successors if not already and in affected region. |
| if (!Visited.test(s) && Node2Index[s] < UpperBound) { |
| Visited.set(s); |
| WorkList.push_back(Succ); |
| } |
| } |
| } while (!WorkList.empty()); |
| |
| if (!Found) { |
| Success = false; |
| return Nodes; |
| } |
| |
| WorkList.clear(); |
| VisitedBack.resize(SUnits.size()); |
| Found = false; |
| |
| // Starting from TargetSU, visit all predecessors up |
| // to LowerBound. SUs that are visited by the two |
| // passes are added to Nodes. |
| WorkList.push_back(&TargetSU); |
| do { |
| const SUnit *SU = WorkList.back(); |
| WorkList.pop_back(); |
| for (int I = SU->Preds.size()-1; I >= 0; --I) { |
| const SUnit *Pred = SU->Preds[I].getSUnit(); |
| unsigned s = Pred->NodeNum; |
| // Edges to non-SUnits are allowed but ignored (e.g. EntrySU). |
| if (Pred->isBoundaryNode()) |
| continue; |
| if (Node2Index[s] == LowerBound) { |
| Found = true; |
| continue; |
| } |
| if (!VisitedBack.test(s) && Visited.test(s)) { |
| VisitedBack.set(s); |
| WorkList.push_back(Pred); |
| Nodes.push_back(s); |
| } |
| } |
| } while (!WorkList.empty()); |
| |
| assert(Found && "Error in SUnit Graph!"); |
| Success = true; |
| return Nodes; |
| } |
| |
| void ScheduleDAGTopologicalSort::Shift(BitVector& Visited, int LowerBound, |
| int UpperBound) { |
| std::vector<int> L; |
| int shift = 0; |
| int i; |
| |
| for (i = LowerBound; i <= UpperBound; ++i) { |
| // w is node at topological index i. |
| int w = Index2Node[i]; |
| if (Visited.test(w)) { |
| // Unmark. |
| Visited.reset(w); |
| L.push_back(w); |
| shift = shift + 1; |
| } else { |
| Allocate(w, i - shift); |
| } |
| } |
| |
| for (unsigned LI : L) { |
| Allocate(LI, i - shift); |
| i = i + 1; |
| } |
| } |
| |
| bool ScheduleDAGTopologicalSort::WillCreateCycle(SUnit *TargetSU, SUnit *SU) { |
| FixOrder(); |
| // Is SU reachable from TargetSU via successor edges? |
| if (IsReachable(SU, TargetSU)) |
| return true; |
| for (const SDep &PredDep : TargetSU->Preds) |
| if (PredDep.isAssignedRegDep() && |
| IsReachable(SU, PredDep.getSUnit())) |
| return true; |
| return false; |
| } |
| |
| void ScheduleDAGTopologicalSort::AddSUnitWithoutPredecessors(const SUnit *SU) { |
| assert(SU->NodeNum == Index2Node.size() && "Node cannot be added at the end"); |
| assert(SU->NumPreds == 0 && "Can only add SU's with no predecessors"); |
| Node2Index.push_back(Index2Node.size()); |
| Index2Node.push_back(SU->NodeNum); |
| Visited.resize(Node2Index.size()); |
| } |
| |
| bool ScheduleDAGTopologicalSort::IsReachable(const SUnit *SU, |
| const SUnit *TargetSU) { |
| FixOrder(); |
| // If insertion of the edge SU->TargetSU would create a cycle |
| // then there is a path from TargetSU to SU. |
| int UpperBound, LowerBound; |
| LowerBound = Node2Index[TargetSU->NodeNum]; |
| UpperBound = Node2Index[SU->NodeNum]; |
| bool HasLoop = false; |
| // Is Ord(TargetSU) < Ord(SU) ? |
| if (LowerBound < UpperBound) { |
| Visited.reset(); |
| // There may be a path from TargetSU to SU. Check for it. |
| DFS(TargetSU, UpperBound, HasLoop); |
| } |
| return HasLoop; |
| } |
| |
| void ScheduleDAGTopologicalSort::Allocate(int n, int index) { |
| Node2Index[n] = index; |
| Index2Node[index] = n; |
| } |
| |
| ScheduleDAGTopologicalSort:: |
| ScheduleDAGTopologicalSort(std::vector<SUnit> &sunits, SUnit *exitsu) |
| : SUnits(sunits), ExitSU(exitsu) {} |
| |
| ScheduleHazardRecognizer::~ScheduleHazardRecognizer() = default; |