-//===----- ScheduleDAGList.cpp - Reg pressure reduction list scheduler ----===//
+//===----- ScheduleDAGRRList.cpp - Reg pressure reduction list scheduler --===//
//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Evan Cheng and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "sched"
+#define DEBUG_TYPE "pre-RA-sched"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
-#include "llvm/CodeGen/SSARegMap.h"
-#include "llvm/Target/MRegisterInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/PriorityQueue.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
#include <climits>
-#include <iostream>
-#include <queue>
#include "llvm/Support/CommandLine.h"
using namespace llvm;
+STATISTIC(NumBacktracks, "Number of times scheduler backtracked");
+STATISTIC(NumUnfolds, "Number of nodes unfolded");
+STATISTIC(NumDups, "Number of duplicated nodes");
+STATISTIC(NumCCCopies, "Number of cross class copies");
+
static RegisterScheduler
burrListDAGScheduler("list-burr",
- " Bottom-up register reduction list scheduling",
+ "Bottom-up register reduction list scheduling",
createBURRListDAGScheduler);
static RegisterScheduler
tdrListrDAGScheduler("list-tdrr",
- " Top-down register reduction list scheduling",
+ "Top-down register reduction list scheduling",
createTDRRListDAGScheduler);
namespace {
/// ScheduleDAGRRList - The actual register reduction list scheduler
/// implementation. This supports both top-down and bottom-up scheduling.
///
-
class VISIBILITY_HIDDEN ScheduleDAGRRList : public ScheduleDAG {
private:
/// isBottomUp - This is true if the scheduling problem is bottom-up, false if
/// it is top-down.
bool isBottomUp;
+
+ /// Fast - True if we are performing fast scheduling.
+ ///
+ bool Fast;
/// AvailableQueue - The priority queue to use for the available SUnits.
- ///
SchedulingPriorityQueue *AvailableQueue;
+ /// LiveRegDefs - A set of physical registers and their definition
+ /// that are "live". These nodes must be scheduled before any other nodes that
+ /// modifies the registers can be scheduled.
+ unsigned NumLiveRegs;
+ std::vector<SUnit*> LiveRegDefs;
+ std::vector<unsigned> LiveRegCycles;
+
public:
ScheduleDAGRRList(SelectionDAG &dag, MachineBasicBlock *bb,
- const TargetMachine &tm, bool isbottomup,
- SchedulingPriorityQueue *availqueue)
- : ScheduleDAG(dag, bb, tm), isBottomUp(isbottomup),
+ const TargetMachine &tm, bool isbottomup, bool f,
+ SchedulingPriorityQueue *availqueue)
+ : ScheduleDAG(dag, bb, tm), isBottomUp(isbottomup), Fast(f),
AvailableQueue(availqueue) {
}
void Schedule();
+ /// IsReachable - Checks if SU is reachable from TargetSU.
+ bool IsReachable(const SUnit *SU, const SUnit *TargetSU);
+
+ /// willCreateCycle - Returns true if adding an edge from SU to TargetSU will
+ /// create a cycle.
+ bool WillCreateCycle(SUnit *SU, SUnit *TargetSU);
+
+ /// AddPred - This adds the specified node X as a predecessor of
+ /// the current node Y if not already.
+ /// This returns true if this is a new predecessor.
+ /// Updates the topological ordering if required.
+ bool AddPred(SUnit *Y, SUnit *X, bool isCtrl, bool isSpecial,
+ unsigned PhyReg = 0, int Cost = 1);
+
+ /// RemovePred - This removes the specified node N from the predecessors of
+ /// the current node M. Updates the topological ordering if required.
+ bool RemovePred(SUnit *M, SUnit *N, bool isCtrl, bool isSpecial);
+
private:
- void ReleasePred(SUnit *PredSU, bool isChain, unsigned CurCycle);
- void ReleaseSucc(SUnit *SuccSU, bool isChain, unsigned CurCycle);
- void ScheduleNodeBottomUp(SUnit *SU, unsigned CurCycle);
- void ScheduleNodeTopDown(SUnit *SU, unsigned CurCycle);
+ void ReleasePred(SUnit*, bool, unsigned);
+ void ReleaseSucc(SUnit*, bool isChain, unsigned);
+ void CapturePred(SUnit*, SUnit*, bool);
+ void ScheduleNodeBottomUp(SUnit*, unsigned);
+ void ScheduleNodeTopDown(SUnit*, unsigned);
+ void UnscheduleNodeBottomUp(SUnit*);
+ void BacktrackBottomUp(SUnit*, unsigned, unsigned&);
+ SUnit *CopyAndMoveSuccessors(SUnit*);
+ void InsertCCCopiesAndMoveSuccs(SUnit*, unsigned,
+ const TargetRegisterClass*,
+ const TargetRegisterClass*,
+ SmallVector<SUnit*, 2>&);
+ bool DelayForLiveRegsBottomUp(SUnit*, SmallVector<unsigned, 4>&);
void ListScheduleTopDown();
void ListScheduleBottomUp();
void CommuteNodesToReducePressure();
+
+
+ /// CreateNewSUnit - Creates a new SUnit and returns a pointer to it.
+ /// Updates the topological ordering if required.
+ SUnit *CreateNewSUnit(SDNode *N) {
+ SUnit *NewNode = NewSUnit(N);
+ // Update the topological ordering.
+ if (NewNode->NodeNum >= Node2Index.size())
+ InitDAGTopologicalSorting();
+ return NewNode;
+ }
+
+ /// CreateClone - Creates a new SUnit from an existing one.
+ /// Updates the topological ordering if required.
+ SUnit *CreateClone(SUnit *N) {
+ SUnit *NewNode = Clone(N);
+ // Update the topological ordering.
+ if (NewNode->NodeNum >= Node2Index.size())
+ InitDAGTopologicalSorting();
+ return NewNode;
+ }
+
+ /// Functions for preserving the topological ordering
+ /// even after dynamic insertions of new edges.
+ /// This allows a very fast implementation of IsReachable.
+
+ /// InitDAGTopologicalSorting - create the initial topological
+ /// ordering from the DAG to be scheduled.
+ void InitDAGTopologicalSorting();
+
+ /// DFS - make a DFS traversal and mark all nodes affected by the
+ /// edge insertion. These nodes will later get new topological indexes
+ /// by means of the Shift method.
+ void DFS(const SUnit *SU, int UpperBound, bool& HasLoop);
+
+ /// Shift - reassign topological indexes for the nodes in the DAG
+ /// to preserve the topological ordering.
+ void Shift(BitVector& Visited, int LowerBound, int UpperBound);
+
+ /// Allocate - assign the topological index to the node n.
+ void Allocate(int n, int index);
+
+ /// Index2Node - Maps topological index to the node number.
+ std::vector<int> Index2Node;
+ /// Node2Index - Maps the node number to its topological index.
+ std::vector<int> Node2Index;
+ /// Visited - a set of nodes visited during a DFS traversal.
+ BitVector Visited;
};
} // end anonymous namespace
/// Schedule - Schedule the DAG using list scheduling.
void ScheduleDAGRRList::Schedule() {
- DEBUG(std::cerr << "********** List Scheduling **********\n");
-
+ DOUT << "********** List Scheduling **********\n";
+
+ NumLiveRegs = 0;
+ LiveRegDefs.resize(TRI->getNumRegs(), NULL);
+ LiveRegCycles.resize(TRI->getNumRegs(), 0);
+
// Build scheduling units.
BuildSchedUnits();
DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su)
SUnits[su].dumpAll(&DAG));
- CalculateDepths();
- CalculateHeights();
+ if (!Fast) {
+ CalculateDepths();
+ CalculateHeights();
+ }
+ InitDAGTopologicalSorting();
AvailableQueue->initNodes(SUnits);
-
+
// Execute the actual scheduling loop Top-Down or Bottom-Up as appropriate.
if (isBottomUp)
ListScheduleBottomUp();
AvailableQueue->releaseState();
- CommuteNodesToReducePressure();
-
- DEBUG(std::cerr << "*** Final schedule ***\n");
- DEBUG(dumpSchedule());
- DEBUG(std::cerr << "\n");
-
- // Emit in scheduled order
- EmitSchedule();
+ if (!Fast)
+ CommuteNodesToReducePressure();
}
-/// CommuteNodesToReducePressure - Is a node is two-address and commutable, and
+/// CommuteNodesToReducePressure - If a node is two-address and commutable, and
/// it is not the last use of its first operand, add it to the CommuteSet if
/// possible. It will be commuted when it is translated to a MI.
void ScheduleDAGRRList::CommuteNodesToReducePressure() {
- std::set<SUnit *> OperandSeen;
- for (unsigned i = Sequence.size()-1; i != 0; --i) { // Ignore first node.
+ SmallPtrSet<SUnit*, 4> OperandSeen;
+ for (unsigned i = Sequence.size(); i != 0; ) {
+ --i;
SUnit *SU = Sequence[i];
- if (!SU) continue;
- if (SU->isTwoAddress && SU->isCommutable) {
- SDNode *OpN = SU->Node->getOperand(0).Val;
- SUnit *OpSU = SUnitMap[OpN];
- if (OpSU && OperandSeen.count(OpSU) == 1) {
- // Ok, so SU is not the last use of OpSU, but SU is two-address so
- // it will clobber OpSU. Try to commute it if possible.
- bool DoCommute = true;
- for (unsigned j = 1, e = SU->Node->getNumOperands(); j != e; ++j) {
- OpN = SU->Node->getOperand(j).Val;
- OpSU = SUnitMap[OpN];
- if (OpSU && OperandSeen.count(OpSU) == 1) {
- DoCommute = false;
- break;
+ if (!SU || !SU->Node) continue;
+ if (SU->isCommutable) {
+ unsigned Opc = SU->Node->getMachineOpcode();
+ const TargetInstrDesc &TID = TII->get(Opc);
+ unsigned NumRes = TID.getNumDefs();
+ unsigned NumOps = TID.getNumOperands() - NumRes;
+ for (unsigned j = 0; j != NumOps; ++j) {
+ if (TID.getOperandConstraint(j+NumRes, TOI::TIED_TO) == -1)
+ continue;
+
+ SDNode *OpN = SU->Node->getOperand(j).getNode();
+ SUnit *OpSU = isPassiveNode(OpN) ? NULL : &SUnits[OpN->getNodeId()];
+ if (OpSU && OperandSeen.count(OpSU) == 1) {
+ // Ok, so SU is not the last use of OpSU, but SU is two-address so
+ // it will clobber OpSU. Try to commute SU if no other source operands
+ // are live below.
+ bool DoCommute = true;
+ for (unsigned k = 0; k < NumOps; ++k) {
+ if (k != j) {
+ OpN = SU->Node->getOperand(k).getNode();
+ OpSU = isPassiveNode(OpN) ? NULL : &SUnits[OpN->getNodeId()];
+ if (OpSU && OperandSeen.count(OpSU) == 1) {
+ DoCommute = false;
+ break;
+ }
+ }
}
+ if (DoCommute)
+ CommuteSet.insert(SU->Node);
}
- if (DoCommute)
- CommuteSet.insert(SU->Node);
+
+ // Only look at the first use&def node for now.
+ break;
}
}
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
- if (!I->second)
- OperandSeen.insert(I->first);
+ if (!I->isCtrl)
+ OperandSeen.insert(I->Dep->OrigNode);
}
}
}
// Bottom-Up Scheduling
//===----------------------------------------------------------------------===//
-static const TargetRegisterClass *getRegClass(SUnit *SU,
- const TargetInstrInfo *TII,
- const MRegisterInfo *MRI,
- SSARegMap *RegMap) {
- if (SU->Node->isTargetOpcode()) {
- unsigned Opc = SU->Node->getTargetOpcode();
- const TargetInstrDescriptor &II = TII->get(Opc);
- return MRI->getRegClass(II.OpInfo->RegClass);
- } else {
- assert(SU->Node->getOpcode() == ISD::CopyFromReg);
- unsigned SrcReg = cast<RegisterSDNode>(SU->Node->getOperand(1))->getReg();
- if (MRegisterInfo::isVirtualRegister(SrcReg))
- return RegMap->getRegClass(SrcReg);
- else {
- for (MRegisterInfo::regclass_iterator I = MRI->regclass_begin(),
- E = MRI->regclass_end(); I != E; ++I)
- if ((*I)->hasType(SU->Node->getValueType(0)) &&
- (*I)->contains(SrcReg))
- return *I;
- assert(false && "Couldn't find register class for reg copy!");
- }
- return NULL;
- }
-}
-
-static unsigned getNumResults(SUnit *SU) {
- unsigned NumResults = 0;
- for (unsigned i = 0, e = SU->Node->getNumValues(); i != e; ++i) {
- MVT::ValueType VT = SU->Node->getValueType(i);
- if (VT != MVT::Other && VT != MVT::Flag)
- NumResults++;
- }
- return NumResults;
-}
-
/// ReleasePred - Decrement the NumSuccsLeft count of a predecessor. Add it to
-/// the Available queue is the count reaches zero. Also update its cycle bound.
+/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGRRList::ReleasePred(SUnit *PredSU, bool isChain,
unsigned CurCycle) {
// FIXME: the distance between two nodes is not always == the predecessor's
// interrupt model (drain vs. freeze).
PredSU->CycleBound = std::max(PredSU->CycleBound, CurCycle + PredSU->Latency);
- if (!isChain)
- PredSU->NumSuccsLeft--;
- else
- PredSU->NumChainSuccsLeft--;
+ --PredSU->NumSuccsLeft;
#ifndef NDEBUG
- if (PredSU->NumSuccsLeft < 0 || PredSU->NumChainSuccsLeft < 0) {
- std::cerr << "*** List scheduling failed! ***\n";
+ if (PredSU->NumSuccsLeft < 0) {
+ cerr << "*** List scheduling failed! ***\n";
PredSU->dump(&DAG);
- std::cerr << " has been released too many times!\n";
+ cerr << " has been released too many times!\n";
assert(0);
}
#endif
- if ((PredSU->NumSuccsLeft + PredSU->NumChainSuccsLeft) == 0) {
- // EntryToken has to go last! Special case it here.
- if (PredSU->Node->getOpcode() != ISD::EntryToken) {
- PredSU->isAvailable = true;
- AvailableQueue->push(PredSU);
- }
+ if (PredSU->NumSuccsLeft == 0) {
+ PredSU->isAvailable = true;
+ AvailableQueue->push(PredSU);
}
}
/// count of its predecessors. If a predecessor pending count is zero, add it to
/// the Available queue.
void ScheduleDAGRRList::ScheduleNodeBottomUp(SUnit *SU, unsigned CurCycle) {
- DEBUG(std::cerr << "*** Scheduling [" << CurCycle << "]: ");
+ DOUT << "*** Scheduling [" << CurCycle << "]: ";
DEBUG(SU->dump(&DAG));
SU->Cycle = CurCycle;
AvailableQueue->ScheduledNode(SU);
- Sequence.push_back(SU);
// Bottom up: release predecessors
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
- I != E; ++I)
- ReleasePred(I->first, I->second, CurCycle);
+ I != E; ++I) {
+ ReleasePred(I->Dep, I->isCtrl, CurCycle);
+ if (I->Cost < 0) {
+ // This is a physical register dependency and it's impossible or
+ // expensive to copy the register. Make sure nothing that can
+ // clobber the register is scheduled between the predecessor and
+ // this node.
+ if (!LiveRegDefs[I->Reg]) {
+ ++NumLiveRegs;
+ LiveRegDefs[I->Reg] = I->Dep;
+ LiveRegCycles[I->Reg] = CurCycle;
+ }
+ }
+ }
+
+ // Release all the implicit physical register defs that are live.
+ for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ if (I->Cost < 0) {
+ if (LiveRegCycles[I->Reg] == I->Dep->Cycle) {
+ assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
+ assert(LiveRegDefs[I->Reg] == SU &&
+ "Physical register dependency violated?");
+ --NumLiveRegs;
+ LiveRegDefs[I->Reg] = NULL;
+ LiveRegCycles[I->Reg] = 0;
+ }
+ }
+ }
+
SU->isScheduled = true;
}
-/// isReady - True if node's lower cycle bound is less or equal to the current
-/// scheduling cycle. Always true if all nodes have uniform latency 1.
-static inline bool isReady(SUnit *SU, unsigned CurCycle) {
- return SU->CycleBound <= CurCycle;
+/// CapturePred - This does the opposite of ReleasePred. Since SU is being
+/// unscheduled, incrcease the succ left count of its predecessors. Remove
+/// them from AvailableQueue if necessary.
+void ScheduleDAGRRList::CapturePred(SUnit *PredSU, SUnit *SU, bool isChain) {
+ unsigned CycleBound = 0;
+ for (SUnit::succ_iterator I = PredSU->Succs.begin(), E = PredSU->Succs.end();
+ I != E; ++I) {
+ if (I->Dep == SU)
+ continue;
+ CycleBound = std::max(CycleBound,
+ I->Dep->Cycle + PredSU->Latency);
+ }
+
+ if (PredSU->isAvailable) {
+ PredSU->isAvailable = false;
+ if (!PredSU->isPending)
+ AvailableQueue->remove(PredSU);
+ }
+
+ PredSU->CycleBound = CycleBound;
+ ++PredSU->NumSuccsLeft;
+}
+
+/// UnscheduleNodeBottomUp - Remove the node from the schedule, update its and
+/// its predecessor states to reflect the change.
+void ScheduleDAGRRList::UnscheduleNodeBottomUp(SUnit *SU) {
+ DOUT << "*** Unscheduling [" << SU->Cycle << "]: ";
+ DEBUG(SU->dump(&DAG));
+
+ AvailableQueue->UnscheduledNode(SU);
+
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ CapturePred(I->Dep, SU, I->isCtrl);
+ if (I->Cost < 0 && SU->Cycle == LiveRegCycles[I->Reg]) {
+ assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
+ assert(LiveRegDefs[I->Reg] == I->Dep &&
+ "Physical register dependency violated?");
+ --NumLiveRegs;
+ LiveRegDefs[I->Reg] = NULL;
+ LiveRegCycles[I->Reg] = 0;
+ }
+ }
+
+ for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ if (I->Cost < 0) {
+ if (!LiveRegDefs[I->Reg]) {
+ LiveRegDefs[I->Reg] = SU;
+ ++NumLiveRegs;
+ }
+ if (I->Dep->Cycle < LiveRegCycles[I->Reg])
+ LiveRegCycles[I->Reg] = I->Dep->Cycle;
+ }
+ }
+
+ SU->Cycle = 0;
+ SU->isScheduled = false;
+ SU->isAvailable = true;
+ AvailableQueue->push(SU);
+}
+
+/// IsReachable - Checks if SU is reachable from TargetSU.
+bool ScheduleDAGRRList::IsReachable(const SUnit *SU, const SUnit *TargetSU) {
+ // 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;
+}
+
+/// Allocate - assign the topological index to the node n.
+inline void ScheduleDAGRRList::Allocate(int n, int index) {
+ Node2Index[n] = index;
+ Index2Node[index] = n;
+}
+
+/// InitDAGTopologicalSorting - create the initial topological
+/// ordering from the DAG to be scheduled.
+
+/// 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.
+void ScheduleDAGRRList::InitDAGTopologicalSorting() {
+ unsigned DAGSize = SUnits.size();
+ std::vector<SUnit*> WorkList;
+ WorkList.reserve(DAGSize);
+
+ Index2Node.resize(DAGSize);
+ Node2Index.resize(DAGSize);
+
+ // Initialize the data structures.
+ for (unsigned i = 0, e = DAGSize; i != e; ++i) {
+ SUnit *SU = &SUnits[i];
+ 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();
+ Allocate(SU->NodeNum, --Id);
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ SUnit *SU = I->Dep;
+ if (!--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);
+
+#ifndef NDEBUG
+ // Check correctness of the ordering
+ for (unsigned i = 0, e = DAGSize; i != e; ++i) {
+ SUnit *SU = &SUnits[i];
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ assert(Node2Index[SU->NodeNum] > Node2Index[I->Dep->NodeNum] &&
+ "Wrong topological sorting");
+ }
+ }
+#endif
+}
+
+/// AddPred - adds an edge from SUnit X to SUnit Y.
+/// Updates the topological ordering if required.
+bool ScheduleDAGRRList::AddPred(SUnit *Y, SUnit *X, bool isCtrl, bool isSpecial,
+ unsigned PhyReg, int Cost) {
+ 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);
+ }
+ // Now really insert the edge.
+ return Y->addPred(X, isCtrl, isSpecial, PhyReg, Cost);
}
+/// RemovePred - This removes the specified node N from the predecessors of
+/// the current node M. Updates the topological ordering if required.
+bool ScheduleDAGRRList::RemovePred(SUnit *M, SUnit *N,
+ bool isCtrl, bool isSpecial) {
+ // InitDAGTopologicalSorting();
+ return M->removePred(N, isCtrl, isSpecial);
+}
+
+/// DFS - Make a DFS traversal to mark all nodes reachable from SU and mark
+/// all nodes affected by the edge insertion. These nodes will later get new
+/// topological indexes by means of the Shift method.
+void ScheduleDAGRRList::DFS(const SUnit *SU, int UpperBound, bool& HasLoop) {
+ std::vector<const SUnit*> WorkList;
+ WorkList.reserve(SUnits.size());
+
+ WorkList.push_back(SU);
+ while (!WorkList.empty()) {
+ SU = WorkList.back();
+ WorkList.pop_back();
+ Visited.set(SU->NodeNum);
+ for (int I = SU->Succs.size()-1; I >= 0; --I) {
+ int s = SU->Succs[I].Dep->NodeNum;
+ 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(SU->Succs[I].Dep);
+ }
+ }
+ }
+}
+
+/// Shift - Renumber the nodes so that the topological ordering is
+/// preserved.
+void ScheduleDAGRRList::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 j = 0; j < L.size(); ++j) {
+ Allocate(L[j], i - shift);
+ i = i + 1;
+ }
+}
+
+
+/// WillCreateCycle - Returns true if adding an edge from SU to TargetSU will
+/// create a cycle.
+bool ScheduleDAGRRList::WillCreateCycle(SUnit *SU, SUnit *TargetSU) {
+ if (IsReachable(TargetSU, SU))
+ return true;
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I)
+ if (I->Cost < 0 && IsReachable(TargetSU, I->Dep))
+ return true;
+ return false;
+}
+
+/// BacktrackBottomUp - Backtrack scheduling to a previous cycle specified in
+/// BTCycle in order to schedule a specific node. Returns the last unscheduled
+/// SUnit. Also returns if a successor is unscheduled in the process.
+void ScheduleDAGRRList::BacktrackBottomUp(SUnit *SU, unsigned BtCycle,
+ unsigned &CurCycle) {
+ SUnit *OldSU = NULL;
+ while (CurCycle > BtCycle) {
+ OldSU = Sequence.back();
+ Sequence.pop_back();
+ if (SU->isSucc(OldSU))
+ // Don't try to remove SU from AvailableQueue.
+ SU->isAvailable = false;
+ UnscheduleNodeBottomUp(OldSU);
+ --CurCycle;
+ }
+
+
+ if (SU->isSucc(OldSU)) {
+ assert(false && "Something is wrong!");
+ abort();
+ }
+
+ ++NumBacktracks;
+}
+
+/// CopyAndMoveSuccessors - Clone the specified node and move its scheduled
+/// successors to the newly created node.
+SUnit *ScheduleDAGRRList::CopyAndMoveSuccessors(SUnit *SU) {
+ if (SU->FlaggedNodes.size())
+ return NULL;
+
+ SDNode *N = SU->Node;
+ if (!N)
+ return NULL;
+
+ SUnit *NewSU;
+ bool TryUnfold = false;
+ for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
+ MVT VT = N->getValueType(i);
+ if (VT == MVT::Flag)
+ return NULL;
+ else if (VT == MVT::Other)
+ TryUnfold = true;
+ }
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+ const SDValue &Op = N->getOperand(i);
+ MVT VT = Op.getNode()->getValueType(Op.getResNo());
+ if (VT == MVT::Flag)
+ return NULL;
+ }
+
+ if (TryUnfold) {
+ SmallVector<SDNode*, 2> NewNodes;
+ if (!TII->unfoldMemoryOperand(DAG, N, NewNodes))
+ return NULL;
+
+ DOUT << "Unfolding SU # " << SU->NodeNum << "\n";
+ assert(NewNodes.size() == 2 && "Expected a load folding node!");
+
+ N = NewNodes[1];
+ SDNode *LoadNode = NewNodes[0];
+ unsigned NumVals = N->getNumValues();
+ unsigned OldNumVals = SU->Node->getNumValues();
+ for (unsigned i = 0; i != NumVals; ++i)
+ DAG.ReplaceAllUsesOfValueWith(SDValue(SU->Node, i), SDValue(N, i));
+ DAG.ReplaceAllUsesOfValueWith(SDValue(SU->Node, OldNumVals-1),
+ SDValue(LoadNode, 1));
+
+ SUnit *NewSU = CreateNewSUnit(N);
+ assert(N->getNodeId() == -1 && "Node already inserted!");
+ N->setNodeId(NewSU->NodeNum);
+
+ const TargetInstrDesc &TID = TII->get(N->getMachineOpcode());
+ for (unsigned i = 0; i != TID.getNumOperands(); ++i) {
+ if (TID.getOperandConstraint(i, TOI::TIED_TO) != -1) {
+ NewSU->isTwoAddress = true;
+ break;
+ }
+ }
+ if (TID.isCommutable())
+ NewSU->isCommutable = true;
+ // FIXME: Calculate height / depth and propagate the changes?
+ NewSU->Depth = SU->Depth;
+ NewSU->Height = SU->Height;
+ ComputeLatency(NewSU);
+
+ // LoadNode may already exist. This can happen when there is another
+ // load from the same location and producing the same type of value
+ // but it has different alignment or volatileness.
+ bool isNewLoad = true;
+ SUnit *LoadSU;
+ if (LoadNode->getNodeId() != -1) {
+ LoadSU = &SUnits[LoadNode->getNodeId()];
+ isNewLoad = false;
+ } else {
+ LoadSU = CreateNewSUnit(LoadNode);
+ LoadNode->setNodeId(LoadSU->NodeNum);
+
+ LoadSU->Depth = SU->Depth;
+ LoadSU->Height = SU->Height;
+ ComputeLatency(LoadSU);
+ }
+
+ SUnit *ChainPred = NULL;
+ SmallVector<SDep, 4> ChainSuccs;
+ SmallVector<SDep, 4> LoadPreds;
+ SmallVector<SDep, 4> NodePreds;
+ SmallVector<SDep, 4> NodeSuccs;
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl)
+ ChainPred = I->Dep;
+ else if (I->Dep->Node && I->Dep->Node->isOperandOf(LoadNode))
+ LoadPreds.push_back(SDep(I->Dep, I->Reg, I->Cost, false, false));
+ else
+ NodePreds.push_back(SDep(I->Dep, I->Reg, I->Cost, false, false));
+ }
+ for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ if (I->isCtrl)
+ ChainSuccs.push_back(SDep(I->Dep, I->Reg, I->Cost,
+ I->isCtrl, I->isSpecial));
+ else
+ NodeSuccs.push_back(SDep(I->Dep, I->Reg, I->Cost,
+ I->isCtrl, I->isSpecial));
+ }
+
+ if (ChainPred) {
+ RemovePred(SU, ChainPred, true, false);
+ if (isNewLoad)
+ AddPred(LoadSU, ChainPred, true, false);
+ }
+ for (unsigned i = 0, e = LoadPreds.size(); i != e; ++i) {
+ SDep *Pred = &LoadPreds[i];
+ RemovePred(SU, Pred->Dep, Pred->isCtrl, Pred->isSpecial);
+ if (isNewLoad) {
+ AddPred(LoadSU, Pred->Dep, Pred->isCtrl, Pred->isSpecial,
+ Pred->Reg, Pred->Cost);
+ }
+ }
+ for (unsigned i = 0, e = NodePreds.size(); i != e; ++i) {
+ SDep *Pred = &NodePreds[i];
+ RemovePred(SU, Pred->Dep, Pred->isCtrl, Pred->isSpecial);
+ AddPred(NewSU, Pred->Dep, Pred->isCtrl, Pred->isSpecial,
+ Pred->Reg, Pred->Cost);
+ }
+ for (unsigned i = 0, e = NodeSuccs.size(); i != e; ++i) {
+ SDep *Succ = &NodeSuccs[i];
+ RemovePred(Succ->Dep, SU, Succ->isCtrl, Succ->isSpecial);
+ AddPred(Succ->Dep, NewSU, Succ->isCtrl, Succ->isSpecial,
+ Succ->Reg, Succ->Cost);
+ }
+ for (unsigned i = 0, e = ChainSuccs.size(); i != e; ++i) {
+ SDep *Succ = &ChainSuccs[i];
+ RemovePred(Succ->Dep, SU, Succ->isCtrl, Succ->isSpecial);
+ if (isNewLoad) {
+ AddPred(Succ->Dep, LoadSU, Succ->isCtrl, Succ->isSpecial,
+ Succ->Reg, Succ->Cost);
+ }
+ }
+ if (isNewLoad) {
+ AddPred(NewSU, LoadSU, false, false);
+ }
+
+ if (isNewLoad)
+ AvailableQueue->addNode(LoadSU);
+ AvailableQueue->addNode(NewSU);
+
+ ++NumUnfolds;
+
+ if (NewSU->NumSuccsLeft == 0) {
+ NewSU->isAvailable = true;
+ return NewSU;
+ }
+ SU = NewSU;
+ }
+
+ DOUT << "Duplicating SU # " << SU->NodeNum << "\n";
+ NewSU = CreateClone(SU);
+
+ // New SUnit has the exact same predecessors.
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I)
+ if (!I->isSpecial) {
+ AddPred(NewSU, I->Dep, I->isCtrl, false, I->Reg, I->Cost);
+ NewSU->Depth = std::max(NewSU->Depth, I->Dep->Depth+1);
+ }
+
+ // Only copy scheduled successors. Cut them from old node's successor
+ // list and move them over.
+ SmallVector<std::pair<SUnit*, bool>, 4> DelDeps;
+ for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ if (I->isSpecial)
+ continue;
+ if (I->Dep->isScheduled) {
+ NewSU->Height = std::max(NewSU->Height, I->Dep->Height+1);
+ AddPred(I->Dep, NewSU, I->isCtrl, false, I->Reg, I->Cost);
+ DelDeps.push_back(std::make_pair(I->Dep, I->isCtrl));
+ }
+ }
+ for (unsigned i = 0, e = DelDeps.size(); i != e; ++i) {
+ SUnit *Succ = DelDeps[i].first;
+ bool isCtrl = DelDeps[i].second;
+ RemovePred(Succ, SU, isCtrl, false);
+ }
+
+ AvailableQueue->updateNode(SU);
+ AvailableQueue->addNode(NewSU);
+
+ ++NumDups;
+ return NewSU;
+}
+
+/// InsertCCCopiesAndMoveSuccs - Insert expensive cross register class copies
+/// and move all scheduled successors of the given SUnit to the last copy.
+void ScheduleDAGRRList::InsertCCCopiesAndMoveSuccs(SUnit *SU, unsigned Reg,
+ const TargetRegisterClass *DestRC,
+ const TargetRegisterClass *SrcRC,
+ SmallVector<SUnit*, 2> &Copies) {
+ SUnit *CopyFromSU = CreateNewSUnit(NULL);
+ CopyFromSU->CopySrcRC = SrcRC;
+ CopyFromSU->CopyDstRC = DestRC;
+ CopyFromSU->Depth = SU->Depth;
+ CopyFromSU->Height = SU->Height;
+
+ SUnit *CopyToSU = CreateNewSUnit(NULL);
+ CopyToSU->CopySrcRC = DestRC;
+ CopyToSU->CopyDstRC = SrcRC;
+
+ // Only copy scheduled successors. Cut them from old node's successor
+ // list and move them over.
+ SmallVector<std::pair<SUnit*, bool>, 4> DelDeps;
+ for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ if (I->isSpecial)
+ continue;
+ if (I->Dep->isScheduled) {
+ CopyToSU->Height = std::max(CopyToSU->Height, I->Dep->Height+1);
+ AddPred(I->Dep, CopyToSU, I->isCtrl, false, I->Reg, I->Cost);
+ DelDeps.push_back(std::make_pair(I->Dep, I->isCtrl));
+ }
+ }
+ for (unsigned i = 0, e = DelDeps.size(); i != e; ++i) {
+ SUnit *Succ = DelDeps[i].first;
+ bool isCtrl = DelDeps[i].second;
+ RemovePred(Succ, SU, isCtrl, false);
+ }
+
+ AddPred(CopyFromSU, SU, false, false, Reg, -1);
+ AddPred(CopyToSU, CopyFromSU, false, false, Reg, 1);
+
+ AvailableQueue->updateNode(SU);
+ AvailableQueue->addNode(CopyFromSU);
+ AvailableQueue->addNode(CopyToSU);
+ Copies.push_back(CopyFromSU);
+ Copies.push_back(CopyToSU);
+
+ ++NumCCCopies;
+}
+
+/// getPhysicalRegisterVT - Returns the ValueType of the physical register
+/// definition of the specified node.
+/// FIXME: Move to SelectionDAG?
+static MVT getPhysicalRegisterVT(SDNode *N, unsigned Reg,
+ const TargetInstrInfo *TII) {
+ const TargetInstrDesc &TID = TII->get(N->getMachineOpcode());
+ assert(TID.ImplicitDefs && "Physical reg def must be in implicit def list!");
+ unsigned NumRes = TID.getNumDefs();
+ for (const unsigned *ImpDef = TID.getImplicitDefs(); *ImpDef; ++ImpDef) {
+ if (Reg == *ImpDef)
+ break;
+ ++NumRes;
+ }
+ return N->getValueType(NumRes);
+}
+
+/// DelayForLiveRegsBottomUp - Returns true if it is necessary to delay
+/// scheduling of the given node to satisfy live physical register dependencies.
+/// If the specific node is the last one that's available to schedule, do
+/// whatever is necessary (i.e. backtracking or cloning) to make it possible.
+bool ScheduleDAGRRList::DelayForLiveRegsBottomUp(SUnit *SU,
+ SmallVector<unsigned, 4> &LRegs){
+ if (NumLiveRegs == 0)
+ return false;
+
+ SmallSet<unsigned, 4> RegAdded;
+ // If this node would clobber any "live" register, then it's not ready.
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->Cost < 0) {
+ unsigned Reg = I->Reg;
+ if (LiveRegDefs[Reg] && LiveRegDefs[Reg] != I->Dep) {
+ if (RegAdded.insert(Reg))
+ LRegs.push_back(Reg);
+ }
+ for (const unsigned *Alias = TRI->getAliasSet(Reg);
+ *Alias; ++Alias)
+ if (LiveRegDefs[*Alias] && LiveRegDefs[*Alias] != I->Dep) {
+ if (RegAdded.insert(*Alias))
+ LRegs.push_back(*Alias);
+ }
+ }
+ }
+
+ for (unsigned i = 0, e = SU->FlaggedNodes.size()+1; i != e; ++i) {
+ SDNode *Node = (i == 0) ? SU->Node : SU->FlaggedNodes[i-1];
+ if (!Node || !Node->isMachineOpcode())
+ continue;
+ const TargetInstrDesc &TID = TII->get(Node->getMachineOpcode());
+ if (!TID.ImplicitDefs)
+ continue;
+ for (const unsigned *Reg = TID.ImplicitDefs; *Reg; ++Reg) {
+ if (LiveRegDefs[*Reg] && LiveRegDefs[*Reg] != SU) {
+ if (RegAdded.insert(*Reg))
+ LRegs.push_back(*Reg);
+ }
+ for (const unsigned *Alias = TRI->getAliasSet(*Reg);
+ *Alias; ++Alias)
+ if (LiveRegDefs[*Alias] && LiveRegDefs[*Alias] != SU) {
+ if (RegAdded.insert(*Alias))
+ LRegs.push_back(*Alias);
+ }
+ }
+ }
+ return !LRegs.empty();
+}
+
+
/// ListScheduleBottomUp - The main loop of list scheduling for bottom-up
/// schedulers.
void ScheduleDAGRRList::ListScheduleBottomUp() {
unsigned CurCycle = 0;
// Add root to Available queue.
- AvailableQueue->push(SUnitMap[DAG.getRoot().Val]);
+ if (!SUnits.empty()) {
+ SUnit *RootSU = &SUnits[DAG.getRoot().getNode()->getNodeId()];
+ assert(RootSU->Succs.empty() && "Graph root shouldn't have successors!");
+ RootSU->isAvailable = true;
+ AvailableQueue->push(RootSU);
+ }
// While Available queue is not empty, grab the node with the highest
- // priority. If it is not ready put it back. Schedule the node.
- std::vector<SUnit*> NotReady;
- SUnit *CurNode = NULL;
+ // priority. If it is not ready put it back. Schedule the node.
+ SmallVector<SUnit*, 4> NotReady;
+ DenseMap<SUnit*, SmallVector<unsigned, 4> > LRegsMap;
+ Sequence.reserve(SUnits.size());
while (!AvailableQueue->empty()) {
- SUnit *CurNode = AvailableQueue->pop();
- while (CurNode && !isReady(CurNode, CurCycle)) {
- NotReady.push_back(CurNode);
- CurNode = AvailableQueue->pop();
+ bool Delayed = false;
+ LRegsMap.clear();
+ SUnit *CurSU = AvailableQueue->pop();
+ while (CurSU) {
+ if (CurSU->CycleBound <= CurCycle) {
+ SmallVector<unsigned, 4> LRegs;
+ if (!DelayForLiveRegsBottomUp(CurSU, LRegs))
+ break;
+ Delayed = true;
+ LRegsMap.insert(std::make_pair(CurSU, LRegs));
+ }
+
+ CurSU->isPending = true; // This SU is not in AvailableQueue right now.
+ NotReady.push_back(CurSU);
+ CurSU = AvailableQueue->pop();
}
-
+
+ // All candidates are delayed due to live physical reg dependencies.
+ // Try backtracking, code duplication, or inserting cross class copies
+ // to resolve it.
+ if (Delayed && !CurSU) {
+ for (unsigned i = 0, e = NotReady.size(); i != e; ++i) {
+ SUnit *TrySU = NotReady[i];
+ SmallVector<unsigned, 4> &LRegs = LRegsMap[TrySU];
+
+ // Try unscheduling up to the point where it's safe to schedule
+ // this node.
+ unsigned LiveCycle = CurCycle;
+ for (unsigned j = 0, ee = LRegs.size(); j != ee; ++j) {
+ unsigned Reg = LRegs[j];
+ unsigned LCycle = LiveRegCycles[Reg];
+ LiveCycle = std::min(LiveCycle, LCycle);
+ }
+ SUnit *OldSU = Sequence[LiveCycle];
+ if (!WillCreateCycle(TrySU, OldSU)) {
+ BacktrackBottomUp(TrySU, LiveCycle, CurCycle);
+ // Force the current node to be scheduled before the node that
+ // requires the physical reg dep.
+ if (OldSU->isAvailable) {
+ OldSU->isAvailable = false;
+ AvailableQueue->remove(OldSU);
+ }
+ AddPred(TrySU, OldSU, true, true);
+ // If one or more successors has been unscheduled, then the current
+ // node is no longer avaialable. Schedule a successor that's now
+ // available instead.
+ if (!TrySU->isAvailable)
+ CurSU = AvailableQueue->pop();
+ else {
+ CurSU = TrySU;
+ TrySU->isPending = false;
+ NotReady.erase(NotReady.begin()+i);
+ }
+ break;
+ }
+ }
+
+ if (!CurSU) {
+ // Can't backtrack. Try duplicating the nodes that produces these
+ // "expensive to copy" values to break the dependency. In case even
+ // that doesn't work, insert cross class copies.
+ SUnit *TrySU = NotReady[0];
+ SmallVector<unsigned, 4> &LRegs = LRegsMap[TrySU];
+ assert(LRegs.size() == 1 && "Can't handle this yet!");
+ unsigned Reg = LRegs[0];
+ SUnit *LRDef = LiveRegDefs[Reg];
+ SUnit *NewDef = CopyAndMoveSuccessors(LRDef);
+ if (!NewDef) {
+ // Issue expensive cross register class copies.
+ MVT VT = getPhysicalRegisterVT(LRDef->Node, Reg, TII);
+ const TargetRegisterClass *RC =
+ TRI->getPhysicalRegisterRegClass(Reg, VT);
+ const TargetRegisterClass *DestRC = TRI->getCrossCopyRegClass(RC);
+ if (!DestRC) {
+ assert(false && "Don't know how to copy this physical register!");
+ abort();
+ }
+ SmallVector<SUnit*, 2> Copies;
+ InsertCCCopiesAndMoveSuccs(LRDef, Reg, DestRC, RC, Copies);
+ DOUT << "Adding an edge from SU # " << TrySU->NodeNum
+ << " to SU #" << Copies.front()->NodeNum << "\n";
+ AddPred(TrySU, Copies.front(), true, true);
+ NewDef = Copies.back();
+ }
+
+ DOUT << "Adding an edge from SU # " << NewDef->NodeNum
+ << " to SU #" << TrySU->NodeNum << "\n";
+ LiveRegDefs[Reg] = NewDef;
+ AddPred(NewDef, TrySU, true, true);
+ TrySU->isAvailable = false;
+ CurSU = NewDef;
+ }
+
+ if (!CurSU) {
+ assert(false && "Unable to resolve live physical register dependencies!");
+ abort();
+ }
+ }
+
// Add the nodes that aren't ready back onto the available list.
- AvailableQueue->push_all(NotReady);
+ for (unsigned i = 0, e = NotReady.size(); i != e; ++i) {
+ NotReady[i]->isPending = false;
+ // May no longer be available due to backtracking.
+ if (NotReady[i]->isAvailable)
+ AvailableQueue->push(NotReady[i]);
+ }
NotReady.clear();
- if (CurNode != NULL)
- ScheduleNodeBottomUp(CurNode, CurCycle);
- CurCycle++;
- }
-
- // Add entry node last
- if (DAG.getEntryNode().Val != DAG.getRoot().Val) {
- SUnit *Entry = SUnitMap[DAG.getEntryNode().Val];
- Sequence.push_back(Entry);
+ if (!CurSU)
+ Sequence.push_back(0);
+ else {
+ ScheduleNodeBottomUp(CurSU, CurCycle);
+ Sequence.push_back(CurSU);
+ }
+ ++CurCycle;
}
// Reverse the order if it is bottom up.
#ifndef NDEBUG
// Verify that all SUnits were scheduled.
bool AnyNotSched = false;
+ unsigned DeadNodes = 0;
+ unsigned Noops = 0;
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
- if (SUnits[i].NumSuccsLeft != 0 || SUnits[i].NumChainSuccsLeft != 0) {
+ if (!SUnits[i].isScheduled) {
+ if (SUnits[i].NumPreds == 0 && SUnits[i].NumSuccs == 0) {
+ ++DeadNodes;
+ continue;
+ }
if (!AnyNotSched)
- std::cerr << "*** List scheduling failed! ***\n";
+ cerr << "*** List scheduling failed! ***\n";
SUnits[i].dump(&DAG);
- std::cerr << "has not been scheduled!\n";
+ cerr << "has not been scheduled!\n";
+ AnyNotSched = true;
+ }
+ if (SUnits[i].NumSuccsLeft != 0) {
+ if (!AnyNotSched)
+ cerr << "*** List scheduling failed! ***\n";
+ SUnits[i].dump(&DAG);
+ cerr << "has successors left!\n";
AnyNotSched = true;
}
}
+ for (unsigned i = 0, e = Sequence.size(); i != e; ++i)
+ if (!Sequence[i])
+ ++Noops;
assert(!AnyNotSched);
+ assert(Sequence.size() + DeadNodes - Noops == SUnits.size() &&
+ "The number of nodes scheduled doesn't match the expected number!");
#endif
}
//===----------------------------------------------------------------------===//
/// ReleaseSucc - Decrement the NumPredsLeft count of a successor. Add it to
-/// the PendingQueue if the count reaches zero.
+/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGRRList::ReleaseSucc(SUnit *SuccSU, bool isChain,
unsigned CurCycle) {
// FIXME: the distance between two nodes is not always == the predecessor's
// interrupt model (drain vs. freeze).
SuccSU->CycleBound = std::max(SuccSU->CycleBound, CurCycle + SuccSU->Latency);
- if (!isChain)
- SuccSU->NumPredsLeft--;
- else
- SuccSU->NumChainPredsLeft--;
+ --SuccSU->NumPredsLeft;
#ifndef NDEBUG
- if (SuccSU->NumPredsLeft < 0 || SuccSU->NumChainPredsLeft < 0) {
- std::cerr << "*** List scheduling failed! ***\n";
+ if (SuccSU->NumPredsLeft < 0) {
+ cerr << "*** List scheduling failed! ***\n";
SuccSU->dump(&DAG);
- std::cerr << " has been released too many times!\n";
+ cerr << " has been released too many times!\n";
assert(0);
}
#endif
- if ((SuccSU->NumPredsLeft + SuccSU->NumChainPredsLeft) == 0) {
+ if (SuccSU->NumPredsLeft == 0) {
SuccSU->isAvailable = true;
AvailableQueue->push(SuccSU);
}
/// count of its successors. If a successor pending count is zero, add it to
/// the Available queue.
void ScheduleDAGRRList::ScheduleNodeTopDown(SUnit *SU, unsigned CurCycle) {
- DEBUG(std::cerr << "*** Scheduling [" << CurCycle << "]: ");
+ DOUT << "*** Scheduling [" << CurCycle << "]: ";
DEBUG(SU->dump(&DAG));
SU->Cycle = CurCycle;
AvailableQueue->ScheduledNode(SU);
- Sequence.push_back(SU);
// Top down: release successors
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I)
- ReleaseSucc(I->first, I->second, CurCycle);
+ ReleaseSucc(I->Dep, I->isCtrl, CurCycle);
SU->isScheduled = true;
}
+/// ListScheduleTopDown - The main loop of list scheduling for top-down
+/// schedulers.
void ScheduleDAGRRList::ListScheduleTopDown() {
unsigned CurCycle = 0;
- SUnit *Entry = SUnitMap[DAG.getEntryNode().Val];
// All leaves to Available queue.
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
// It is available if it has no predecessors.
- if (SUnits[i].Preds.size() == 0 && &SUnits[i] != Entry) {
+ if (SUnits[i].Preds.empty()) {
AvailableQueue->push(&SUnits[i]);
SUnits[i].isAvailable = true;
}
}
- // Emit the entry node first.
- ScheduleNodeTopDown(Entry, CurCycle);
- CurCycle++;
-
// While Available queue is not empty, grab the node with the highest
- // priority. If it is not ready put it back. Schedule the node.
+ // priority. If it is not ready put it back. Schedule the node.
std::vector<SUnit*> NotReady;
- SUnit *CurNode = NULL;
+ Sequence.reserve(SUnits.size());
while (!AvailableQueue->empty()) {
- SUnit *CurNode = AvailableQueue->pop();
- while (CurNode && !isReady(CurNode, CurCycle)) {
- NotReady.push_back(CurNode);
- CurNode = AvailableQueue->pop();
+ SUnit *CurSU = AvailableQueue->pop();
+ while (CurSU && CurSU->CycleBound > CurCycle) {
+ NotReady.push_back(CurSU);
+ CurSU = AvailableQueue->pop();
}
// Add the nodes that aren't ready back onto the available list.
AvailableQueue->push_all(NotReady);
NotReady.clear();
- if (CurNode != NULL)
- ScheduleNodeTopDown(CurNode, CurCycle);
- CurCycle++;
+ if (!CurSU)
+ Sequence.push_back(0);
+ else {
+ ScheduleNodeTopDown(CurSU, CurCycle);
+ Sequence.push_back(CurSU);
+ }
+ ++CurCycle;
}
#ifndef NDEBUG
// Verify that all SUnits were scheduled.
bool AnyNotSched = false;
+ unsigned DeadNodes = 0;
+ unsigned Noops = 0;
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
if (!SUnits[i].isScheduled) {
+ if (SUnits[i].NumPreds == 0 && SUnits[i].NumSuccs == 0) {
+ ++DeadNodes;
+ continue;
+ }
if (!AnyNotSched)
- std::cerr << "*** List scheduling failed! ***\n";
+ cerr << "*** List scheduling failed! ***\n";
SUnits[i].dump(&DAG);
- std::cerr << "has not been scheduled!\n";
+ cerr << "has not been scheduled!\n";
+ AnyNotSched = true;
+ }
+ if (SUnits[i].NumPredsLeft != 0) {
+ if (!AnyNotSched)
+ cerr << "*** List scheduling failed! ***\n";
+ SUnits[i].dump(&DAG);
+ cerr << "has predecessors left!\n";
AnyNotSched = true;
}
}
+ for (unsigned i = 0, e = Sequence.size(); i != e; ++i)
+ if (!Sequence[i])
+ ++Noops;
assert(!AnyNotSched);
+ assert(Sequence.size() + DeadNodes - Noops == SUnits.size() &&
+ "The number of nodes scheduled doesn't match the expected number!");
#endif
}
bool operator()(const SUnit* left, const SUnit* right) const;
};
+ struct bu_ls_rr_fast_sort : public std::binary_function<SUnit*, SUnit*, bool>{
+ RegReductionPriorityQueue<bu_ls_rr_fast_sort> *SPQ;
+ bu_ls_rr_fast_sort(RegReductionPriorityQueue<bu_ls_rr_fast_sort> *spq)
+ : SPQ(spq) {}
+ bu_ls_rr_fast_sort(const bu_ls_rr_fast_sort &RHS) : SPQ(RHS.SPQ) {}
+
+ bool operator()(const SUnit* left, const SUnit* right) const;
+ };
+
struct td_ls_rr_sort : public std::binary_function<SUnit*, SUnit*, bool> {
RegReductionPriorityQueue<td_ls_rr_sort> *SPQ;
td_ls_rr_sort(RegReductionPriorityQueue<td_ls_rr_sort> *spq) : SPQ(spq) {}
};
} // end anonymous namespace
+static inline bool isCopyFromLiveIn(const SUnit *SU) {
+ SDNode *N = SU->Node;
+ return N && N->getOpcode() == ISD::CopyFromReg &&
+ N->getOperand(N->getNumOperands()-1).getValueType() != MVT::Flag;
+}
+
+/// CalcNodeBUSethiUllmanNumber - Compute Sethi Ullman number for bottom up
+/// scheduling. Smaller number is the higher priority.
+static unsigned
+CalcNodeBUSethiUllmanNumber(const SUnit *SU, std::vector<unsigned> &SUNumbers) {
+ unsigned &SethiUllmanNumber = SUNumbers[SU->NodeNum];
+ if (SethiUllmanNumber != 0)
+ return SethiUllmanNumber;
+
+ unsigned Extra = 0;
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl) continue; // ignore chain preds
+ SUnit *PredSU = I->Dep;
+ unsigned PredSethiUllman = CalcNodeBUSethiUllmanNumber(PredSU, SUNumbers);
+ if (PredSethiUllman > SethiUllmanNumber) {
+ SethiUllmanNumber = PredSethiUllman;
+ Extra = 0;
+ } else if (PredSethiUllman == SethiUllmanNumber && !I->isCtrl)
+ ++Extra;
+ }
+
+ SethiUllmanNumber += Extra;
+
+ if (SethiUllmanNumber == 0)
+ SethiUllmanNumber = 1;
+
+ return SethiUllmanNumber;
+}
+
+/// CalcNodeTDSethiUllmanNumber - Compute Sethi Ullman number for top down
+/// scheduling. Smaller number is the higher priority.
+static unsigned
+CalcNodeTDSethiUllmanNumber(const SUnit *SU, std::vector<unsigned> &SUNumbers) {
+ unsigned &SethiUllmanNumber = SUNumbers[SU->NodeNum];
+ if (SethiUllmanNumber != 0)
+ return SethiUllmanNumber;
+
+ unsigned Opc = SU->Node ? SU->Node->getOpcode() : 0;
+ if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
+ SethiUllmanNumber = 0xffff;
+ else if (SU->NumSuccsLeft == 0)
+ // If SU does not have a use, i.e. it doesn't produce a value that would
+ // be consumed (e.g. store), then it terminates a chain of computation.
+ // Give it a small SethiUllman number so it will be scheduled right before
+ // its predecessors that it doesn't lengthen their live ranges.
+ SethiUllmanNumber = 0;
+ else if (SU->NumPredsLeft == 0 &&
+ (Opc != ISD::CopyFromReg || isCopyFromLiveIn(SU)))
+ SethiUllmanNumber = 0xffff;
+ else {
+ int Extra = 0;
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl) continue; // ignore chain preds
+ SUnit *PredSU = I->Dep;
+ unsigned PredSethiUllman = CalcNodeTDSethiUllmanNumber(PredSU, SUNumbers);
+ if (PredSethiUllman > SethiUllmanNumber) {
+ SethiUllmanNumber = PredSethiUllman;
+ Extra = 0;
+ } else if (PredSethiUllman == SethiUllmanNumber && !I->isCtrl)
+ ++Extra;
+ }
+
+ SethiUllmanNumber += Extra;
+ }
+
+ return SethiUllmanNumber;
+}
+
+
namespace {
template<class SF>
class VISIBILITY_HIDDEN RegReductionPriorityQueue
: public SchedulingPriorityQueue {
- std::priority_queue<SUnit*, std::vector<SUnit*>, SF> Queue;
+ PriorityQueue<SUnit*, std::vector<SUnit*>, SF> Queue;
+ unsigned currentQueueId;
public:
RegReductionPriorityQueue() :
- Queue(SF(this)) {}
+ Queue(SF(this)), currentQueueId(0) {}
- virtual void initNodes(std::vector<SUnit> &sunits) {}
- virtual void releaseState() {}
+ virtual void initNodes(std::vector<SUnit> &sunits) = 0;
+
+ virtual void addNode(const SUnit *SU) = 0;
+
+ virtual void updateNode(const SUnit *SU) = 0;
+
+ virtual void releaseState() = 0;
- virtual int getSethiUllmanNumber(unsigned NodeNum) const {
- return 0;
- }
+ virtual unsigned getNodePriority(const SUnit *SU) const = 0;
+ unsigned size() const { return Queue.size(); }
+
bool empty() const { return Queue.empty(); }
void push(SUnit *U) {
+ assert(!U->NodeQueueId && "Node in the queue already");
+ U->NodeQueueId = ++currentQueueId;
Queue.push(U);
}
+
void push_all(const std::vector<SUnit *> &Nodes) {
for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
- Queue.push(Nodes[i]);
+ push(Nodes[i]);
}
SUnit *pop() {
if (empty()) return NULL;
SUnit *V = Queue.top();
Queue.pop();
+ V->NodeQueueId = 0;
return V;
}
+
+ void remove(SUnit *SU) {
+ assert(!Queue.empty() && "Queue is empty!");
+ assert(SU->NodeQueueId != 0 && "Not in queue!");
+ Queue.erase_one(SU);
+ SU->NodeQueueId = 0;
+ }
};
- template<class SF>
class VISIBILITY_HIDDEN BURegReductionPriorityQueue
- : public RegReductionPriorityQueue<SF> {
+ : public RegReductionPriorityQueue<bu_ls_rr_sort> {
// SUnits - The SUnits for the current graph.
- const std::vector<SUnit> *SUnits;
+ std::vector<SUnit> *SUnits;
// SethiUllmanNumbers - The SethiUllman number for each node.
- std::vector<int> SethiUllmanNumbers;
+ std::vector<unsigned> SethiUllmanNumbers;
+
+ const TargetInstrInfo *TII;
+ const TargetRegisterInfo *TRI;
+ ScheduleDAGRRList *scheduleDAG;
public:
- BURegReductionPriorityQueue() {}
+ explicit BURegReductionPriorityQueue(const TargetInstrInfo *tii,
+ const TargetRegisterInfo *tri)
+ : TII(tii), TRI(tri), scheduleDAG(NULL) {}
void initNodes(std::vector<SUnit> &sunits) {
SUnits = &sunits;
// Add pseudo dependency edges for two-address nodes.
AddPseudoTwoAddrDeps();
// Calculate node priorities.
- CalculatePriorities();
+ CalculateSethiUllmanNumbers();
+ }
+
+ void addNode(const SUnit *SU) {
+ unsigned SUSize = SethiUllmanNumbers.size();
+ if (SUnits->size() > SUSize)
+ SethiUllmanNumbers.resize(SUSize*2, 0);
+ CalcNodeBUSethiUllmanNumber(SU, SethiUllmanNumbers);
+ }
+
+ void updateNode(const SUnit *SU) {
+ SethiUllmanNumbers[SU->NodeNum] = 0;
+ CalcNodeBUSethiUllmanNumber(SU, SethiUllmanNumbers);
}
void releaseState() {
SethiUllmanNumbers.clear();
}
- int getSethiUllmanNumber(unsigned NodeNum) const {
- assert(NodeNum < SethiUllmanNumbers.size());
- return SethiUllmanNumbers[NodeNum];
+ unsigned getNodePriority(const SUnit *SU) const {
+ assert(SU->NodeNum < SethiUllmanNumbers.size());
+ unsigned Opc = SU->Node ? SU->Node->getOpcode() : 0;
+ if (Opc == ISD::CopyFromReg && !isCopyFromLiveIn(SU))
+ // CopyFromReg should be close to its def because it restricts
+ // allocation choices. But if it is a livein then perhaps we want it
+ // closer to its uses so it can be coalesced.
+ return 0xffff;
+ else if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
+ // CopyToReg should be close to its uses to facilitate coalescing and
+ // avoid spilling.
+ return 0;
+ else if (Opc == TargetInstrInfo::EXTRACT_SUBREG ||
+ Opc == TargetInstrInfo::INSERT_SUBREG)
+ // EXTRACT_SUBREG / INSERT_SUBREG should be close to its use to
+ // facilitate coalescing.
+ return 0;
+ else if (SU->NumSuccs == 0)
+ // If SU does not have a use, i.e. it doesn't produce a value that would
+ // be consumed (e.g. store), then it terminates a chain of computation.
+ // Give it a large SethiUllman number so it will be scheduled right
+ // before its predecessors that it doesn't lengthen their live ranges.
+ return 0xffff;
+ else if (SU->NumPreds == 0)
+ // If SU does not have a def, schedule it close to its uses because it
+ // does not lengthen any live ranges.
+ return 0;
+ else
+ return SethiUllmanNumbers[SU->NodeNum];
+ }
+
+ void setScheduleDAG(ScheduleDAGRRList *scheduleDag) {
+ scheduleDAG = scheduleDag;
}
private:
+ bool canClobber(const SUnit *SU, const SUnit *Op);
void AddPseudoTwoAddrDeps();
- void CalculatePriorities();
- int CalcNodePriority(const SUnit *SU);
+ void CalculateSethiUllmanNumbers();
};
- template<class SF>
- class TDRegReductionPriorityQueue : public RegReductionPriorityQueue<SF> {
+ class VISIBILITY_HIDDEN BURegReductionFastPriorityQueue
+ : public RegReductionPriorityQueue<bu_ls_rr_fast_sort> {
// SUnits - The SUnits for the current graph.
const std::vector<SUnit> *SUnits;
// SethiUllmanNumbers - The SethiUllman number for each node.
- std::vector<int> SethiUllmanNumbers;
+ std::vector<unsigned> SethiUllmanNumbers;
+ public:
+ explicit BURegReductionFastPriorityQueue() {}
+
+ void initNodes(std::vector<SUnit> &sunits) {
+ SUnits = &sunits;
+ // Calculate node priorities.
+ CalculateSethiUllmanNumbers();
+ }
+
+ void addNode(const SUnit *SU) {
+ unsigned SUSize = SethiUllmanNumbers.size();
+ if (SUnits->size() > SUSize)
+ SethiUllmanNumbers.resize(SUSize*2, 0);
+ CalcNodeBUSethiUllmanNumber(SU, SethiUllmanNumbers);
+ }
+
+ void updateNode(const SUnit *SU) {
+ SethiUllmanNumbers[SU->NodeNum] = 0;
+ CalcNodeBUSethiUllmanNumber(SU, SethiUllmanNumbers);
+ }
+
+ void releaseState() {
+ SUnits = 0;
+ SethiUllmanNumbers.clear();
+ }
+
+ unsigned getNodePriority(const SUnit *SU) const {
+ return SethiUllmanNumbers[SU->NodeNum];
+ }
+
+ private:
+ void CalculateSethiUllmanNumbers();
+ };
+
+
+ class VISIBILITY_HIDDEN TDRegReductionPriorityQueue
+ : public RegReductionPriorityQueue<td_ls_rr_sort> {
+ // SUnits - The SUnits for the current graph.
+ const std::vector<SUnit> *SUnits;
+
+ // SethiUllmanNumbers - The SethiUllman number for each node.
+ std::vector<unsigned> SethiUllmanNumbers;
public:
TDRegReductionPriorityQueue() {}
void initNodes(std::vector<SUnit> &sunits) {
SUnits = &sunits;
// Calculate node priorities.
- CalculatePriorities();
+ CalculateSethiUllmanNumbers();
+ }
+
+ void addNode(const SUnit *SU) {
+ unsigned SUSize = SethiUllmanNumbers.size();
+ if (SUnits->size() > SUSize)
+ SethiUllmanNumbers.resize(SUSize*2, 0);
+ CalcNodeTDSethiUllmanNumber(SU, SethiUllmanNumbers);
+ }
+
+ void updateNode(const SUnit *SU) {
+ SethiUllmanNumbers[SU->NodeNum] = 0;
+ CalcNodeTDSethiUllmanNumber(SU, SethiUllmanNumbers);
}
void releaseState() {
SethiUllmanNumbers.clear();
}
- int getSethiUllmanNumber(unsigned NodeNum) const {
- assert(NodeNum < SethiUllmanNumbers.size());
- return SethiUllmanNumbers[NodeNum];
+ unsigned getNodePriority(const SUnit *SU) const {
+ assert(SU->NodeNum < SethiUllmanNumbers.size());
+ return SethiUllmanNumbers[SU->NodeNum];
}
private:
- void CalculatePriorities();
- int CalcNodePriority(const SUnit *SU);
+ void CalculateSethiUllmanNumbers();
};
}
-static bool isFloater(const SUnit *SU) {
- if (SU->Node->isTargetOpcode()) {
- if (SU->NumPreds == 0)
- return true;
- if (SU->NumPreds == 1) {
- for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
- I != E; ++I) {
- if (I->second) continue;
-
- SUnit *PredSU = I->first;
- unsigned Opc = PredSU->Node->getOpcode();
- if (Opc != ISD::EntryToken && Opc != ISD::TokenFactor &&
- Opc != ISD::CopyFromReg && Opc != ISD::CopyToReg)
- return false;
- }
- return true;
- }
+/// closestSucc - Returns the scheduled cycle of the successor which is
+/// closet to the current cycle.
+static unsigned closestSucc(const SUnit *SU) {
+ unsigned MaxCycle = 0;
+ for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ unsigned Cycle = I->Dep->Cycle;
+ // If there are bunch of CopyToRegs stacked up, they should be considered
+ // to be at the same position.
+ if (I->Dep->Node && I->Dep->Node->getOpcode() == ISD::CopyToReg)
+ Cycle = closestSucc(I->Dep)+1;
+ if (Cycle > MaxCycle)
+ MaxCycle = Cycle;
}
- return false;
+ return MaxCycle;
}
-static bool isSimpleFloaterUse(const SUnit *SU) {
- unsigned NumOps = 0;
+/// calcMaxScratches - Returns an cost estimate of the worse case requirement
+/// for scratch registers. Live-in operands and live-out results don't count
+/// since they are "fixed".
+static unsigned calcMaxScratches(const SUnit *SU) {
+ unsigned Scratches = 0;
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
- if (I->second) continue;
- if (++NumOps > 1)
- return false;
- if (!isFloater(I->first))
- return false;
+ if (I->isCtrl) continue; // ignore chain preds
+ if (!I->Dep->Node || I->Dep->Node->getOpcode() != ISD::CopyFromReg)
+ Scratches++;
}
- return true;
+ for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
+ I != E; ++I) {
+ if (I->isCtrl) continue; // ignore chain succs
+ if (!I->Dep->Node || I->Dep->Node->getOpcode() != ISD::CopyToReg)
+ Scratches += 10;
+ }
+ return Scratches;
}
// Bottom up
bool bu_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
- unsigned LeftNum = left->NodeNum;
- unsigned RightNum = right->NodeNum;
- bool LIsTarget = left->Node->isTargetOpcode();
- bool RIsTarget = right->Node->isTargetOpcode();
- int LPriority = SPQ->getSethiUllmanNumber(LeftNum);
- int RPriority = SPQ->getSethiUllmanNumber(RightNum);
- int LBonus = 0;
- int RBonus = 0;
-
- // Schedule floaters (e.g. load from some constant address) and those nodes
- // with a single predecessor each first. They maintain / reduce register
- // pressure.
- if (isFloater(left) || isSimpleFloaterUse(left))
- LBonus += 2;
- if (isFloater(right) || isSimpleFloaterUse(right))
- RBonus += 2;
+ unsigned LPriority = SPQ->getNodePriority(left);
+ unsigned RPriority = SPQ->getNodePriority(right);
+ if (LPriority != RPriority)
+ return LPriority > RPriority;
+
+ // Try schedule def + use closer when Sethi-Ullman numbers are the same.
+ // e.g.
+ // t1 = op t2, c1
+ // t3 = op t4, c2
+ //
+ // and the following instructions are both ready.
+ // t2 = op c3
+ // t4 = op c4
+ //
+ // Then schedule t2 = op first.
+ // i.e.
+ // t4 = op c4
+ // t2 = op c3
+ // t1 = op t2, c1
+ // t3 = op t4, c2
+ //
+ // This creates more short live intervals.
+ unsigned LDist = closestSucc(left);
+ unsigned RDist = closestSucc(right);
+ if (LDist != RDist)
+ return LDist < RDist;
+
+ // Intuitively, it's good to push down instructions whose results are
+ // liveout so their long live ranges won't conflict with other values
+ // which are needed inside the BB. Further prioritize liveout instructions
+ // by the number of operands which are calculated within the BB.
+ unsigned LScratch = calcMaxScratches(left);
+ unsigned RScratch = calcMaxScratches(right);
+ if (LScratch != RScratch)
+ return LScratch > RScratch;
+
+ if (left->Height != right->Height)
+ return left->Height > right->Height;
+
+ if (left->Depth != right->Depth)
+ return left->Depth < right->Depth;
- // Special tie breaker: if two nodes share a operand, the one that use it
- // as a def&use operand is preferred.
- if (LIsTarget && RIsTarget) {
- if (left->isTwoAddress && !right->isTwoAddress) {
- SDNode *DUNode = left->Node->getOperand(0).Val;
- if (DUNode->isOperand(right->Node))
- LBonus += 2;
- }
- if (!left->isTwoAddress && right->isTwoAddress) {
- SDNode *DUNode = right->Node->getOperand(0).Val;
- if (DUNode->isOperand(left->Node))
- RBonus += 2;
- }
- }
+ if (left->CycleBound != right->CycleBound)
+ return left->CycleBound > right->CycleBound;
- if (LPriority+LBonus < RPriority+RBonus)
- return true;
- else if (LPriority+LBonus == RPriority+RBonus)
- if (left->Height > right->Height)
- return true;
- else if (left->Height == right->Height)
- if (left->Depth < right->Depth)
- return true;
- else if (left->Depth == right->Depth)
- if (left->CycleBound > right->CycleBound)
- return true;
- return false;
+ assert(left->NodeQueueId && right->NodeQueueId &&
+ "NodeQueueId cannot be zero");
+ return (left->NodeQueueId > right->NodeQueueId);
}
-static inline bool isCopyFromLiveIn(const SUnit *SU) {
- SDNode *N = SU->Node;
- return N->getOpcode() == ISD::CopyFromReg &&
- N->getOperand(N->getNumOperands()-1).getValueType() != MVT::Flag;
+bool
+bu_ls_rr_fast_sort::operator()(const SUnit *left, const SUnit *right) const {
+ unsigned LPriority = SPQ->getNodePriority(left);
+ unsigned RPriority = SPQ->getNodePriority(right);
+ if (LPriority != RPriority)
+ return LPriority > RPriority;
+ assert(left->NodeQueueId && right->NodeQueueId &&
+ "NodeQueueId cannot be zero");
+ return (left->NodeQueueId > right->NodeQueueId);
}
-// FIXME: This is probably too slow!
-static void isReachable(SUnit *SU, SUnit *TargetSU,
- std::set<SUnit *> &Visited, bool &Reached) {
- if (Reached) return;
- if (SU == TargetSU) {
- Reached = true;
- return;
+bool
+BURegReductionPriorityQueue::canClobber(const SUnit *SU, const SUnit *Op) {
+ if (SU->isTwoAddress) {
+ unsigned Opc = SU->Node->getMachineOpcode();
+ const TargetInstrDesc &TID = TII->get(Opc);
+ unsigned NumRes = TID.getNumDefs();
+ unsigned NumOps = TID.getNumOperands() - NumRes;
+ for (unsigned i = 0; i != NumOps; ++i) {
+ if (TID.getOperandConstraint(i+NumRes, TOI::TIED_TO) != -1) {
+ SDNode *DU = SU->Node->getOperand(i).getNode();
+ if (DU->getNodeId() != -1 &&
+ Op->OrigNode == &(*SUnits)[DU->getNodeId()])
+ return true;
+ }
+ }
}
- if (!Visited.insert(SU).second) return;
-
- for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end(); I != E;
- ++I)
- isReachable(I->first, TargetSU, Visited, Reached);
+ return false;
}
-static bool isReachable(SUnit *SU, SUnit *TargetSU) {
- std::set<SUnit *> Visited;
- bool Reached = false;
- isReachable(SU, TargetSU, Visited, Reached);
- return Reached;
-}
-static SUnit *getDefUsePredecessor(SUnit *SU) {
- SDNode *DU = SU->Node->getOperand(0).Val;
- for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+/// hasCopyToRegUse - Return true if SU has a value successor that is a
+/// CopyToReg node.
+static bool hasCopyToRegUse(const SUnit *SU) {
+ for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
- if (I->second) continue; // ignore chain preds
- SUnit *PredSU = I->first;
- if (PredSU->Node == DU)
- return PredSU;
+ if (I->isCtrl) continue;
+ const SUnit *SuccSU = I->Dep;
+ if (SuccSU->Node && SuccSU->Node->getOpcode() == ISD::CopyToReg)
+ return true;
}
-
- // Must be flagged.
- return NULL;
+ return false;
}
-static bool canClobber(SUnit *SU, SUnit *Op) {
- if (SU->isTwoAddress)
- return Op == getDefUsePredecessor(SU);
+/// canClobberPhysRegDefs - True if SU would clobber one of SuccSU's
+/// physical register defs.
+static bool canClobberPhysRegDefs(const SUnit *SuccSU, const SUnit *SU,
+ const TargetInstrInfo *TII,
+ const TargetRegisterInfo *TRI) {
+ SDNode *N = SuccSU->Node;
+ unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
+ const unsigned *ImpDefs = TII->get(N->getMachineOpcode()).getImplicitDefs();
+ assert(ImpDefs && "Caller should check hasPhysRegDefs");
+ const unsigned *SUImpDefs =
+ TII->get(SU->Node->getMachineOpcode()).getImplicitDefs();
+ if (!SUImpDefs)
+ return false;
+ for (unsigned i = NumDefs, e = N->getNumValues(); i != e; ++i) {
+ MVT VT = N->getValueType(i);
+ if (VT == MVT::Flag || VT == MVT::Other)
+ continue;
+ if (!N->hasAnyUseOfValue(i))
+ continue;
+ unsigned Reg = ImpDefs[i - NumDefs];
+ for (;*SUImpDefs; ++SUImpDefs) {
+ unsigned SUReg = *SUImpDefs;
+ if (TRI->regsOverlap(Reg, SUReg))
+ return true;
+ }
+ }
return false;
}
/// AddPseudoTwoAddrDeps - If two nodes share an operand and one of them uses
/// it as a def&use operand. Add a pseudo control edge from it to the other
/// node (if it won't create a cycle) so the two-address one will be scheduled
-/// first (lower in the schedule).
-template<class SF>
-void BURegReductionPriorityQueue<SF>::AddPseudoTwoAddrDeps() {
+/// first (lower in the schedule). If both nodes are two-address, favor the
+/// one that has a CopyToReg use (more likely to be a loop induction update).
+/// If both are two-address, but one is commutable while the other is not
+/// commutable, favor the one that's not commutable.
+void BURegReductionPriorityQueue::AddPseudoTwoAddrDeps() {
for (unsigned i = 0, e = SUnits->size(); i != e; ++i) {
- SUnit *SU = (SUnit *)&((*SUnits)[i]);
+ SUnit *SU = &(*SUnits)[i];
+ if (!SU->isTwoAddress)
+ continue;
+
SDNode *Node = SU->Node;
- if (!Node->isTargetOpcode())
+ if (!Node || !Node->isMachineOpcode() || SU->FlaggedNodes.size() > 0)
continue;
- if (SU->isTwoAddress) {
- SUnit *DUSU = getDefUsePredecessor(SU);
- if (!DUSU) continue;
-
- for (SUnit::succ_iterator I = DUSU->Succs.begin(), E = DUSU->Succs.end();
- I != E; ++I) {
- if (I->second) continue;
- SUnit *SuccSU = I->first;
- if (SuccSU != SU &&
- (!canClobber(SuccSU, DUSU) ||
- (!SU->isCommutable && SuccSU->isCommutable))){
- if (SuccSU->Depth == SU->Depth && !isReachable(SuccSU, SU)) {
- DEBUG(std::cerr << "Adding an edge from SU # " << SU->NodeNum
- << " to SU #" << SuccSU->NodeNum << "\n");
- if (SU->addPred(SuccSU, true))
- SU->NumChainPredsLeft++;
- if (SuccSU->addSucc(SU, true))
- SuccSU->NumChainSuccsLeft++;
+ unsigned Opc = Node->getMachineOpcode();
+ const TargetInstrDesc &TID = TII->get(Opc);
+ unsigned NumRes = TID.getNumDefs();
+ unsigned NumOps = TID.getNumOperands() - NumRes;
+ for (unsigned j = 0; j != NumOps; ++j) {
+ if (TID.getOperandConstraint(j+NumRes, TOI::TIED_TO) != -1) {
+ SDNode *DU = SU->Node->getOperand(j).getNode();
+ if (DU->getNodeId() == -1)
+ continue;
+ const SUnit *DUSU = &(*SUnits)[DU->getNodeId()];
+ if (!DUSU) continue;
+ for (SUnit::const_succ_iterator I = DUSU->Succs.begin(),
+ E = DUSU->Succs.end(); I != E; ++I) {
+ if (I->isCtrl) continue;
+ SUnit *SuccSU = I->Dep;
+ if (SuccSU == SU)
+ continue;
+ // Be conservative. Ignore if nodes aren't at roughly the same
+ // depth and height.
+ if (SuccSU->Height < SU->Height && (SU->Height - SuccSU->Height) > 1)
+ continue;
+ if (!SuccSU->Node || !SuccSU->Node->isMachineOpcode())
+ continue;
+ // Don't constrain nodes with physical register defs if the
+ // predecessor can clobber them.
+ if (SuccSU->hasPhysRegDefs) {
+ if (canClobberPhysRegDefs(SuccSU, SU, TII, TRI))
+ continue;
+ }
+ // Don't constraint extract_subreg / insert_subreg these may be
+ // coalesced away. We don't them close to their uses.
+ unsigned SuccOpc = SuccSU->Node->getMachineOpcode();
+ if (SuccOpc == TargetInstrInfo::EXTRACT_SUBREG ||
+ SuccOpc == TargetInstrInfo::INSERT_SUBREG)
+ continue;
+ if ((!canClobber(SuccSU, DUSU) ||
+ (hasCopyToRegUse(SU) && !hasCopyToRegUse(SuccSU)) ||
+ (!SU->isCommutable && SuccSU->isCommutable)) &&
+ !scheduleDAG->IsReachable(SuccSU, SU)) {
+ DOUT << "Adding an edge from SU # " << SU->NodeNum
+ << " to SU #" << SuccSU->NodeNum << "\n";
+ scheduleDAG->AddPred(SU, SuccSU, true, true);
}
}
}
}
}
-/// CalcNodePriority - Priority is the Sethi Ullman number.
-/// Smaller number is the higher priority.
-template<class SF>
-int BURegReductionPriorityQueue<SF>::CalcNodePriority(const SUnit *SU) {
- int &SethiUllmanNumber = SethiUllmanNumbers[SU->NodeNum];
- if (SethiUllmanNumber != 0)
- return SethiUllmanNumber;
-
- unsigned Opc = SU->Node->getOpcode();
- if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
- SethiUllmanNumber = INT_MAX - 10;
- else if (SU->NumSuccsLeft == 0)
- // If SU does not have a use, i.e. it doesn't produce a value that would
- // be consumed (e.g. store), then it terminates a chain of computation.
- // Give it a small SethiUllman number so it will be scheduled right before its
- // predecessors that it doesn't lengthen their live ranges.
- SethiUllmanNumber = INT_MIN + 10;
- // FIXME: remove this else if? It seems to reduce register spills but often
- // ends up increasing runtime. Need to investigate.
- else if (SU->NumPredsLeft == 0 &&
- (Opc != ISD::CopyFromReg || isCopyFromLiveIn(SU)))
- SethiUllmanNumber = INT_MAX - 10;
- else {
- int Extra = 0;
- for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
- I != E; ++I) {
- if (I->second) continue; // ignore chain preds
- SUnit *PredSU = I->first;
- int PredSethiUllman = CalcNodePriority(PredSU);
- if (PredSethiUllman > SethiUllmanNumber) {
- SethiUllmanNumber = PredSethiUllman;
- Extra = 0;
- } else if (PredSethiUllman == SethiUllmanNumber && !I->second)
- Extra++;
- }
-
- SethiUllmanNumber += Extra;
- }
+/// CalculateSethiUllmanNumbers - Calculate Sethi-Ullman numbers of all
+/// scheduling units.
+void BURegReductionPriorityQueue::CalculateSethiUllmanNumbers() {
+ SethiUllmanNumbers.assign(SUnits->size(), 0);
- return SethiUllmanNumber;
+ for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
+ CalcNodeBUSethiUllmanNumber(&(*SUnits)[i], SethiUllmanNumbers);
}
-
-/// CalculatePriorities - Calculate priorities of all scheduling units.
-template<class SF>
-void BURegReductionPriorityQueue<SF>::CalculatePriorities() {
+void BURegReductionFastPriorityQueue::CalculateSethiUllmanNumbers() {
SethiUllmanNumbers.assign(SUnits->size(), 0);
for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
- CalcNodePriority(&(*SUnits)[i]);
+ CalcNodeBUSethiUllmanNumber(&(*SUnits)[i], SethiUllmanNumbers);
}
-static unsigned SumOfUnscheduledPredsOfSuccs(const SUnit *SU) {
+/// LimitedSumOfUnscheduledPredsOfSuccs - Compute the sum of the unscheduled
+/// predecessors of the successors of the SUnit SU. Stop when the provided
+/// limit is exceeded.
+static unsigned LimitedSumOfUnscheduledPredsOfSuccs(const SUnit *SU,
+ unsigned Limit) {
unsigned Sum = 0;
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
- SUnit *SuccSU = I->first;
+ const SUnit *SuccSU = I->Dep;
for (SUnit::const_pred_iterator II = SuccSU->Preds.begin(),
EE = SuccSU->Preds.end(); II != EE; ++II) {
- SUnit *PredSU = II->first;
+ SUnit *PredSU = II->Dep;
if (!PredSU->isScheduled)
- Sum++;
+ if (++Sum > Limit)
+ return Sum;
}
}
-
return Sum;
}
// Top down
bool td_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
- unsigned LeftNum = left->NodeNum;
- unsigned RightNum = right->NodeNum;
- int LPriority = SPQ->getSethiUllmanNumber(LeftNum);
- int RPriority = SPQ->getSethiUllmanNumber(RightNum);
- bool LIsTarget = left->Node->isTargetOpcode();
- bool RIsTarget = right->Node->isTargetOpcode();
+ unsigned LPriority = SPQ->getNodePriority(left);
+ unsigned RPriority = SPQ->getNodePriority(right);
+ bool LIsTarget = left->Node && left->Node->isMachineOpcode();
+ bool RIsTarget = right->Node && right->Node->isMachineOpcode();
bool LIsFloater = LIsTarget && left->NumPreds == 0;
bool RIsFloater = RIsTarget && right->NumPreds == 0;
- unsigned LBonus = (SumOfUnscheduledPredsOfSuccs(left) == 1) ? 2 : 0;
- unsigned RBonus = (SumOfUnscheduledPredsOfSuccs(right) == 1) ? 2 : 0;
+ unsigned LBonus = (LimitedSumOfUnscheduledPredsOfSuccs(left,1) == 1) ? 2 : 0;
+ unsigned RBonus = (LimitedSumOfUnscheduledPredsOfSuccs(right,1) == 1) ? 2 : 0;
if (left->NumSuccs == 0 && right->NumSuccs != 0)
return false;
else if (left->NumSuccs != 0 && right->NumSuccs == 0)
return true;
- // Special tie breaker: if two nodes share a operand, the one that use it
- // as a def&use operand is preferred.
- if (LIsTarget && RIsTarget) {
- if (left->isTwoAddress && !right->isTwoAddress) {
- SDNode *DUNode = left->Node->getOperand(0).Val;
- if (DUNode->isOperand(right->Node))
- RBonus += 2;
- }
- if (!left->isTwoAddress && right->isTwoAddress) {
- SDNode *DUNode = right->Node->getOperand(0).Val;
- if (DUNode->isOperand(left->Node))
- LBonus += 2;
- }
- }
if (LIsFloater)
LBonus -= 2;
if (RIsFloater)
if (right->NumSuccs == 1)
RBonus += 2;
- if (LPriority+LBonus < RPriority+RBonus)
- return true;
- else if (LPriority == RPriority)
- if (left->Depth < right->Depth)
- return true;
- else if (left->Depth == right->Depth)
- if (left->NumSuccsLeft > right->NumSuccsLeft)
- return true;
- else if (left->NumSuccsLeft == right->NumSuccsLeft)
- if (left->CycleBound > right->CycleBound)
- return true;
- return false;
-}
+ if (LPriority+LBonus != RPriority+RBonus)
+ return LPriority+LBonus < RPriority+RBonus;
-/// CalcNodePriority - Priority is the Sethi Ullman number.
-/// Smaller number is the higher priority.
-template<class SF>
-int TDRegReductionPriorityQueue<SF>::CalcNodePriority(const SUnit *SU) {
- int &SethiUllmanNumber = SethiUllmanNumbers[SU->NodeNum];
- if (SethiUllmanNumber != 0)
- return SethiUllmanNumber;
+ if (left->Depth != right->Depth)
+ return left->Depth < right->Depth;
- unsigned Opc = SU->Node->getOpcode();
- if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
- SethiUllmanNumber = INT_MAX - 10;
- else if (SU->NumSuccsLeft == 0)
- // If SU does not have a use, i.e. it doesn't produce a value that would
- // be consumed (e.g. store), then it terminates a chain of computation.
- // Give it a small SethiUllman number so it will be scheduled right before its
- // predecessors that it doesn't lengthen their live ranges.
- SethiUllmanNumber = INT_MIN + 10;
- else if (SU->NumPredsLeft == 0 &&
- (Opc != ISD::CopyFromReg || isCopyFromLiveIn(SU)))
- SethiUllmanNumber = 1;
- else {
- int Extra = 0;
- for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
- I != E; ++I) {
- if (I->second) continue; // ignore chain preds
- SUnit *PredSU = I->first;
- int PredSethiUllman = CalcNodePriority(PredSU);
- if (PredSethiUllman > SethiUllmanNumber) {
- SethiUllmanNumber = PredSethiUllman;
- Extra = 0;
- } else if (PredSethiUllman == SethiUllmanNumber && !I->second)
- Extra++;
- }
+ if (left->NumSuccsLeft != right->NumSuccsLeft)
+ return left->NumSuccsLeft > right->NumSuccsLeft;
- SethiUllmanNumber += Extra;
- }
-
- return SethiUllmanNumber;
+ if (left->CycleBound != right->CycleBound)
+ return left->CycleBound > right->CycleBound;
+
+ assert(left->NodeQueueId && right->NodeQueueId &&
+ "NodeQueueId cannot be zero");
+ return (left->NodeQueueId > right->NodeQueueId);
}
-/// CalculatePriorities - Calculate priorities of all scheduling units.
-template<class SF>
-void TDRegReductionPriorityQueue<SF>::CalculatePriorities() {
+/// CalculateSethiUllmanNumbers - Calculate Sethi-Ullman numbers of all
+/// scheduling units.
+void TDRegReductionPriorityQueue::CalculateSethiUllmanNumbers() {
SethiUllmanNumbers.assign(SUnits->size(), 0);
for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
- CalcNodePriority(&(*SUnits)[i]);
+ CalcNodeTDSethiUllmanNumber(&(*SUnits)[i], SethiUllmanNumbers);
}
//===----------------------------------------------------------------------===//
llvm::ScheduleDAG* llvm::createBURRListDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
- MachineBasicBlock *BB) {
- return new ScheduleDAGRRList(*DAG, BB, DAG->getTarget(), true,
- new BURegReductionPriorityQueue<bu_ls_rr_sort>());
+ MachineBasicBlock *BB,
+ bool Fast) {
+ if (Fast)
+ return new ScheduleDAGRRList(*DAG, BB, DAG->getTarget(), true, true,
+ new BURegReductionFastPriorityQueue());
+
+ const TargetInstrInfo *TII = DAG->getTarget().getInstrInfo();
+ const TargetRegisterInfo *TRI = DAG->getTarget().getRegisterInfo();
+
+ BURegReductionPriorityQueue *PQ = new BURegReductionPriorityQueue(TII, TRI);
+
+ ScheduleDAGRRList *SD =
+ new ScheduleDAGRRList(*DAG, BB, DAG->getTarget(),true,false, PQ);
+ PQ->setScheduleDAG(SD);
+ return SD;
}
llvm::ScheduleDAG* llvm::createTDRRListDAGScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
- MachineBasicBlock *BB) {
- return new ScheduleDAGRRList(*DAG, BB, DAG->getTarget(), false,
- new TDRegReductionPriorityQueue<td_ls_rr_sort>());
+ MachineBasicBlock *BB,
+ bool Fast) {
+ return new ScheduleDAGRRList(*DAG, BB, DAG->getTarget(), false, Fast,
+ new TDRegReductionPriorityQueue());
}
-
projects / oota-llvm.git / blobdiff