burrListDAGScheduler("list-burr",
"Bottom-up register reduction list scheduling",
createBURRListDAGScheduler);
-static RegisterScheduler
- tdrListrDAGScheduler("list-tdrr",
- "Top-down register reduction list scheduling",
- createTDRRListDAGScheduler);
static RegisterScheduler
sourceListDAGScheduler("source",
"Similar to list-burr but schedules in source "
"which tries to balance ILP and register pressure",
createILPListDAGScheduler);
-static cl::opt<bool> EnableSchedCycles(
- "enable-sched-cycles",
- cl::desc("Enable cycle-level precision during preRA scheduling"),
- cl::init(false), cl::Hidden);
+static cl::opt<bool> DisableSchedCycles(
+ "disable-sched-cycles", cl::Hidden, cl::init(false),
+ cl::desc("Disable cycle-level precision during preRA scheduling"));
+
+// Temporary sched=list-ilp flags until the heuristics are robust.
+// Some options are also available under sched=list-hybrid.
+static cl::opt<bool> DisableSchedRegPressure(
+ "disable-sched-reg-pressure", cl::Hidden, cl::init(false),
+ cl::desc("Disable regpressure priority in sched=list-ilp"));
+static cl::opt<bool> DisableSchedLiveUses(
+ "disable-sched-live-uses", cl::Hidden, cl::init(true),
+ cl::desc("Disable live use priority in sched=list-ilp"));
+static cl::opt<bool> DisableSchedVRegCycle(
+ "disable-sched-vrcycle", cl::Hidden, cl::init(false),
+ cl::desc("Disable virtual register cycle interference checks"));
+static cl::opt<bool> DisableSchedPhysRegJoin(
+ "disable-sched-physreg-join", cl::Hidden, cl::init(false),
+ cl::desc("Disable physreg def-use affinity"));
+static cl::opt<bool> DisableSchedStalls(
+ "disable-sched-stalls", cl::Hidden, cl::init(true),
+ cl::desc("Disable no-stall priority in sched=list-ilp"));
+static cl::opt<bool> DisableSchedCriticalPath(
+ "disable-sched-critical-path", cl::Hidden, cl::init(false),
+ cl::desc("Disable critical path priority in sched=list-ilp"));
+static cl::opt<bool> DisableSchedHeight(
+ "disable-sched-height", cl::Hidden, cl::init(false),
+ cl::desc("Disable scheduled-height priority in sched=list-ilp"));
+static cl::opt<bool> Disable2AddrHack(
+ "disable-2addr-hack", cl::Hidden, cl::init(true),
+ cl::desc("Disable scheduler's two-address hack"));
+
+static cl::opt<int> MaxReorderWindow(
+ "max-sched-reorder", cl::Hidden, cl::init(6),
+ cl::desc("Number of instructions to allow ahead of the critical path "
+ "in sched=list-ilp"));
+
+static cl::opt<unsigned> AvgIPC(
+ "sched-avg-ipc", cl::Hidden, cl::init(1),
+ cl::desc("Average inst/cycle whan no target itinerary exists."));
namespace {
//===----------------------------------------------------------------------===//
///
class ScheduleDAGRRList : public ScheduleDAGSDNodes {
private:
- /// isBottomUp - This is true if the scheduling problem is bottom-up, false if
- /// it is top-down.
- bool isBottomUp;
-
/// NeedLatency - True if the scheduler will make use of latency information.
///
bool NeedLatency;
/// MinAvailableCycle - Cycle of the soonest available instruction.
unsigned MinAvailableCycle;
+ /// IssueCount - Count instructions issued in this cycle
+ /// Currently valid only for bottom-up scheduling.
+ unsigned IssueCount;
+
/// 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.
/// and similar queries.
ScheduleDAGTopologicalSort Topo;
+ // Hack to keep track of the inverse of FindCallSeqStart without more crazy
+ // DAG crawling.
+ DenseMap<SUnit*, SUnit*> CallSeqEndForStart;
+
public:
ScheduleDAGRRList(MachineFunction &mf, bool needlatency,
SchedulingPriorityQueue *availqueue,
CodeGenOpt::Level OptLevel)
- : ScheduleDAGSDNodes(mf), isBottomUp(availqueue->isBottomUp()),
+ : ScheduleDAGSDNodes(mf),
NeedLatency(needlatency), AvailableQueue(availqueue), CurCycle(0),
Topo(SUnits) {
const TargetMachine &tm = mf.getTarget();
- if (EnableSchedCycles && OptLevel != CodeGenOpt::None)
- HazardRec = tm.getInstrInfo()->CreateTargetHazardRecognizer(&tm, this);
- else
+ if (DisableSchedCycles || !NeedLatency)
HazardRec = new ScheduleHazardRecognizer();
+ else
+ HazardRec = tm.getInstrInfo()->CreateTargetHazardRecognizer(&tm, this);
}
~ScheduleDAGRRList() {
void Schedule();
+ ScheduleHazardRecognizer *getHazardRec() { return HazardRec; }
+
/// IsReachable - Checks if SU is reachable from TargetSU.
bool IsReachable(const SUnit *SU, const SUnit *TargetSU) {
return Topo.IsReachable(SU, TargetSU);
private:
bool isReady(SUnit *SU) {
- return !EnableSchedCycles || !AvailableQueue->hasReadyFilter() ||
+ return DisableSchedCycles || !AvailableQueue->hasReadyFilter() ||
AvailableQueue->isReady(SU);
}
void ReleasePred(SUnit *SU, const SDep *PredEdge);
void ReleasePredecessors(SUnit *SU);
- void ReleaseSucc(SUnit *SU, const SDep *SuccEdge);
- void ReleaseSuccessors(SUnit *SU);
void ReleasePending();
void AdvanceToCycle(unsigned NextCycle);
void AdvancePastStalls(SUnit *SU);
SUnit *PickNodeToScheduleBottomUp();
void ListScheduleBottomUp();
- void ScheduleNodeTopDown(SUnit*);
- void ListScheduleTopDown();
-
-
/// CreateNewSUnit - Creates a new SUnit and returns a pointer to it.
/// Updates the topological ordering if required.
SUnit *CreateNewSUnit(SDNode *N) {
unsigned NumSUnits = SUnits.size();
- SUnit *NewNode = NewSUnit(N);
+ SUnit *NewNode = newSUnit(N);
// Update the topological ordering.
if (NewNode->NodeNum >= NumSUnits)
Topo.InitDAGTopologicalSorting();
return NewNode;
}
- /// ForceUnitLatencies - Register-pressure-reducing scheduling doesn't
+ /// forceUnitLatencies - Register-pressure-reducing scheduling doesn't
/// need actual latency information but the hybrid scheduler does.
- bool ForceUnitLatencies() const {
+ bool forceUnitLatencies() const {
return !NeedLatency;
}
};
} // end anonymous namespace
+/// GetCostForDef - Looks up the register class and cost for a given definition.
+/// Typically this just means looking up the representative register class,
+/// but for untyped values (MVT::Untyped) it means inspecting the node's
+/// opcode to determine what register class is being generated.
+static void GetCostForDef(const ScheduleDAGSDNodes::RegDefIter &RegDefPos,
+ const TargetLowering *TLI,
+ const TargetInstrInfo *TII,
+ const TargetRegisterInfo *TRI,
+ unsigned &RegClass, unsigned &Cost,
+ const MachineFunction &MF) {
+ EVT VT = RegDefPos.GetValue();
+
+ // Special handling for untyped values. These values can only come from
+ // the expansion of custom DAG-to-DAG patterns.
+ if (VT == MVT::Untyped) {
+ const SDNode *Node = RegDefPos.GetNode();
+ unsigned Opcode = Node->getMachineOpcode();
+
+ if (Opcode == TargetOpcode::REG_SEQUENCE) {
+ unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue();
+ const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx);
+ RegClass = RC->getID();
+ Cost = 1;
+ return;
+ }
+
+ unsigned Idx = RegDefPos.GetIdx();
+ const MCInstrDesc Desc = TII->get(Opcode);
+ const TargetRegisterClass *RC = TII->getRegClass(Desc, Idx, TRI, MF);
+ RegClass = RC->getID();
+ // FIXME: Cost arbitrarily set to 1 because there doesn't seem to be a
+ // better way to determine it.
+ Cost = 1;
+ } else {
+ RegClass = TLI->getRepRegClassFor(VT)->getID();
+ Cost = TLI->getRepRegClassCostFor(VT);
+ }
+}
/// Schedule - Schedule the DAG using list scheduling.
void ScheduleDAGRRList::Schedule() {
<< " '" << BB->getName() << "' **********\n");
CurCycle = 0;
- MinAvailableCycle = EnableSchedCycles ? UINT_MAX : 0;
+ IssueCount = 0;
+ MinAvailableCycle = DisableSchedCycles ? 0 : UINT_MAX;
NumLiveRegs = 0;
- LiveRegDefs.resize(TRI->getNumRegs(), NULL);
- LiveRegGens.resize(TRI->getNumRegs(), NULL);
+ // Allocate slots for each physical register, plus one for a special register
+ // to track the virtual resource of a calling sequence.
+ LiveRegDefs.resize(TRI->getNumRegs() + 1, NULL);
+ LiveRegGens.resize(TRI->getNumRegs() + 1, NULL);
+ CallSeqEndForStart.clear();
// Build the scheduling graph.
BuildSchedGraph(NULL);
HazardRec->Reset();
- // Execute the actual scheduling loop Top-Down or Bottom-Up as appropriate.
- if (isBottomUp)
- ListScheduleBottomUp();
- else
- ListScheduleTopDown();
+ // Execute the actual scheduling loop.
+ ListScheduleBottomUp();
AvailableQueue->releaseState();
+
+ DEBUG({
+ dbgs() << "*** Final schedule ***\n";
+ dumpSchedule();
+ dbgs() << '\n';
+ });
}
//===----------------------------------------------------------------------===//
#endif
--PredSU->NumSuccsLeft;
- if (!ForceUnitLatencies()) {
+ if (!forceUnitLatencies()) {
// Updating predecessor's height. This is now the cycle when the
// predecessor can be scheduled without causing a pipeline stall.
PredSU->setHeightToAtLeast(SU->getHeight() + PredEdge->getLatency());
if (Height < MinAvailableCycle)
MinAvailableCycle = Height;
- if (isReady(SU)) {
+ if (isReady(PredSU)) {
AvailableQueue->push(PredSU);
}
// CapturePred and others may have left the node in the pending queue, avoid
}
}
+/// IsChainDependent - Test if Outer is reachable from Inner through
+/// chain dependencies.
+static bool IsChainDependent(SDNode *Outer, SDNode *Inner,
+ unsigned NestLevel,
+ const TargetInstrInfo *TII) {
+ SDNode *N = Outer;
+ for (;;) {
+ if (N == Inner)
+ return true;
+ // For a TokenFactor, examine each operand. There may be multiple ways
+ // to get to the CALLSEQ_BEGIN, but we need to find the path with the
+ // most nesting in order to ensure that we find the corresponding match.
+ if (N->getOpcode() == ISD::TokenFactor) {
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
+ if (IsChainDependent(N->getOperand(i).getNode(), Inner, NestLevel, TII))
+ return true;
+ return false;
+ }
+ // Check for a lowered CALLSEQ_BEGIN or CALLSEQ_END.
+ if (N->isMachineOpcode()) {
+ if (N->getMachineOpcode() ==
+ (unsigned)TII->getCallFrameDestroyOpcode()) {
+ ++NestLevel;
+ } else if (N->getMachineOpcode() ==
+ (unsigned)TII->getCallFrameSetupOpcode()) {
+ if (NestLevel == 0)
+ return false;
+ --NestLevel;
+ }
+ }
+ // Otherwise, find the chain and continue climbing.
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
+ if (N->getOperand(i).getValueType() == MVT::Other) {
+ N = N->getOperand(i).getNode();
+ goto found_chain_operand;
+ }
+ return false;
+ found_chain_operand:;
+ if (N->getOpcode() == ISD::EntryToken)
+ return false;
+ }
+}
+
+/// FindCallSeqStart - Starting from the (lowered) CALLSEQ_END node, locate
+/// the corresponding (lowered) CALLSEQ_BEGIN node.
+///
+/// NestLevel and MaxNested are used in recursion to indcate the current level
+/// of nesting of CALLSEQ_BEGIN and CALLSEQ_END pairs, as well as the maximum
+/// level seen so far.
+///
+/// TODO: It would be better to give CALLSEQ_END an explicit operand to point
+/// to the corresponding CALLSEQ_BEGIN to avoid needing to search for it.
+static SDNode *
+FindCallSeqStart(SDNode *N, unsigned &NestLevel, unsigned &MaxNest,
+ const TargetInstrInfo *TII) {
+ for (;;) {
+ // For a TokenFactor, examine each operand. There may be multiple ways
+ // to get to the CALLSEQ_BEGIN, but we need to find the path with the
+ // most nesting in order to ensure that we find the corresponding match.
+ if (N->getOpcode() == ISD::TokenFactor) {
+ SDNode *Best = 0;
+ unsigned BestMaxNest = MaxNest;
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+ unsigned MyNestLevel = NestLevel;
+ unsigned MyMaxNest = MaxNest;
+ if (SDNode *New = FindCallSeqStart(N->getOperand(i).getNode(),
+ MyNestLevel, MyMaxNest, TII))
+ if (!Best || (MyMaxNest > BestMaxNest)) {
+ Best = New;
+ BestMaxNest = MyMaxNest;
+ }
+ }
+ assert(Best);
+ MaxNest = BestMaxNest;
+ return Best;
+ }
+ // Check for a lowered CALLSEQ_BEGIN or CALLSEQ_END.
+ if (N->isMachineOpcode()) {
+ if (N->getMachineOpcode() ==
+ (unsigned)TII->getCallFrameDestroyOpcode()) {
+ ++NestLevel;
+ MaxNest = std::max(MaxNest, NestLevel);
+ } else if (N->getMachineOpcode() ==
+ (unsigned)TII->getCallFrameSetupOpcode()) {
+ assert(NestLevel != 0);
+ --NestLevel;
+ if (NestLevel == 0)
+ return N;
+ }
+ }
+ // Otherwise, find the chain and continue climbing.
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
+ if (N->getOperand(i).getValueType() == MVT::Other) {
+ N = N->getOperand(i).getNode();
+ goto found_chain_operand;
+ }
+ return 0;
+ found_chain_operand:;
+ if (N->getOpcode() == ISD::EntryToken)
+ return 0;
+ }
+}
+
/// Call ReleasePred for each predecessor, then update register live def/gen.
/// Always update LiveRegDefs for a register dependence even if the current SU
/// also defines the register. This effectively create one large live range
}
}
}
+
+ // If we're scheduling a lowered CALLSEQ_END, find the corresponding
+ // CALLSEQ_BEGIN. Inject an artificial physical register dependence between
+ // these nodes, to prevent other calls from being interscheduled with them.
+ unsigned CallResource = TRI->getNumRegs();
+ if (!LiveRegDefs[CallResource])
+ for (SDNode *Node = SU->getNode(); Node; Node = Node->getGluedNode())
+ if (Node->isMachineOpcode() &&
+ Node->getMachineOpcode() == (unsigned)TII->getCallFrameDestroyOpcode()) {
+ unsigned NestLevel = 0;
+ unsigned MaxNest = 0;
+ SDNode *N = FindCallSeqStart(Node, NestLevel, MaxNest, TII);
+
+ SUnit *Def = &SUnits[N->getNodeId()];
+ CallSeqEndForStart[Def] = SU;
+
+ ++NumLiveRegs;
+ LiveRegDefs[CallResource] = Def;
+ LiveRegGens[CallResource] = SU;
+ break;
+ }
}
/// Check to see if any of the pending instructions are ready to issue. If
/// so, add them to the available queue.
void ScheduleDAGRRList::ReleasePending() {
- assert(!EnableSchedCycles && "requires --enable-sched-cycles" );
+ if (DisableSchedCycles) {
+ assert(PendingQueue.empty() && "pending instrs not allowed in this mode");
+ return;
+ }
// If the available queue is empty, it is safe to reset MinAvailableCycle.
if (AvailableQueue->empty())
// Check to see if any of the pending instructions are ready to issue. If
// so, add them to the available queue.
for (unsigned i = 0, e = PendingQueue.size(); i != e; ++i) {
- unsigned ReadyCycle =
- isBottomUp ? PendingQueue[i]->getHeight() : PendingQueue[i]->getDepth();
+ unsigned ReadyCycle = PendingQueue[i]->getHeight();
if (ReadyCycle < MinAvailableCycle)
MinAvailableCycle = ReadyCycle;
if (NextCycle <= CurCycle)
return;
+ IssueCount = 0;
AvailableQueue->setCurCycle(NextCycle);
- if (HazardRec->getMaxLookAhead() == 0) {
+ if (!HazardRec->isEnabled()) {
// Bypass lots of virtual calls in case of long latency.
CurCycle = NextCycle;
}
else {
for (; CurCycle != NextCycle; ++CurCycle) {
- if (isBottomUp)
- HazardRec->RecedeCycle();
- else
- HazardRec->AdvanceCycle();
+ HazardRec->RecedeCycle();
}
}
// FIXME: Instead of visiting the pending Q each time, set a dirty flag on the
/// Move the scheduler state forward until the specified node's dependents are
/// ready and can be scheduled with no resource conflicts.
void ScheduleDAGRRList::AdvancePastStalls(SUnit *SU) {
- if (!EnableSchedCycles)
+ if (DisableSchedCycles)
return;
- unsigned ReadyCycle = isBottomUp ? SU->getHeight() : SU->getDepth();
+ // FIXME: Nodes such as CopyFromReg probably should not advance the current
+ // cycle. Otherwise, we can wrongly mask real stalls. If the non-machine node
+ // has predecessors the cycle will be advanced when they are scheduled.
+ // But given the crude nature of modeling latency though such nodes, we
+ // currently need to treat these nodes like real instructions.
+ // if (!SU->getNode() || !SU->getNode()->isMachineOpcode()) return;
+
+ unsigned ReadyCycle = SU->getHeight();
// Bump CurCycle to account for latency. We assume the latency of other
// available instructions may be hidden by the stall (not a full pipe stall).
// Calls are scheduled in their preceding cycle, so don't conflict with
// hazards from instructions after the call. EmitNode will reset the
// scoreboard state before emitting the call.
- if (isBottomUp && SU->isCall)
+ if (SU->isCall)
return;
// FIXME: For resource conflicts in very long non-pipelined stages, we
int Stalls = 0;
while (true) {
ScheduleHazardRecognizer::HazardType HT =
- HazardRec->getHazardType(SU, isBottomUp ? -Stalls : Stalls);
+ HazardRec->getHazardType(SU, -Stalls);
if (HT == ScheduleHazardRecognizer::NoHazard)
break;
/// Record this SUnit in the HazardRecognizer.
/// Does not update CurCycle.
void ScheduleDAGRRList::EmitNode(SUnit *SU) {
- if (!EnableSchedCycles || HazardRec->getMaxLookAhead() == 0)
+ if (!HazardRec->isEnabled())
return;
// Check for phys reg copy.
HazardRec->Reset();
return;
}
- if (isBottomUp && SU->isCall) {
+ if (SU->isCall) {
// Calls are scheduled with their preceding instructions. For bottom-up
// scheduling, clear the pipeline state before emitting.
HazardRec->Reset();
}
HazardRec->EmitInstruction(SU);
-
- if (!isBottomUp && SU->isCall) {
- HazardRec->Reset();
- }
}
+static void resetVRegCycle(SUnit *SU);
+
/// ScheduleNodeBottomUp - Add the node to the schedule. Decrement the pending
/// count of its predecessors. If a predecessor pending count is zero, add it to
/// the Available queue.
#ifndef NDEBUG
if (CurCycle < SU->getHeight())
- DEBUG(dbgs() << " Height [" << SU->getHeight() << "] pipeline stall!\n");
+ DEBUG(dbgs() << " Height [" << SU->getHeight()
+ << "] pipeline stall!\n");
#endif
// FIXME: Do not modify node height. It may interfere with
// backtracking. Instead add a "ready cycle" to SUnit. Before scheduling the
- // node it's ready cycle can aid heuristics, and after scheduling it can
+ // node its ready cycle can aid heuristics, and after scheduling it can
// indicate the scheduled cycle.
SU->setHeightToAtLeast(CurCycle);
Sequence.push_back(SU);
- AvailableQueue->ScheduledNode(SU);
+ AvailableQueue->scheduledNode(SU);
+
+ // If HazardRec is disabled, and each inst counts as one cycle, then
+ // advance CurCycle before ReleasePredecessors to avoid useless pushes to
+ // PendingQueue for schedulers that implement HasReadyFilter.
+ if (!HazardRec->isEnabled() && AvgIPC < 2)
+ AdvanceToCycle(CurCycle + 1);
// Update liveness of predecessors before successors to avoid treating a
// two-address node as a live range def.
LiveRegGens[I->getReg()] = NULL;
}
}
+ // Release the special call resource dependence, if this is the beginning
+ // of a call.
+ unsigned CallResource = TRI->getNumRegs();
+ if (LiveRegDefs[CallResource] == SU)
+ for (const SDNode *SUNode = SU->getNode(); SUNode;
+ SUNode = SUNode->getGluedNode()) {
+ if (SUNode->isMachineOpcode() &&
+ SUNode->getMachineOpcode() == (unsigned)TII->getCallFrameSetupOpcode()) {
+ assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
+ --NumLiveRegs;
+ LiveRegDefs[CallResource] = NULL;
+ LiveRegGens[CallResource] = NULL;
+ }
+ }
+
+ resetVRegCycle(SU);
SU->isScheduled = true;
// (1) No available instructions
// (2) All pipelines full, so available instructions must have hazards.
//
- // If SchedCycles is disabled, count each inst as one cycle.
- if (!EnableSchedCycles ||
- AvailableQueue->empty() || HazardRec->atIssueLimit())
- AdvanceToCycle(CurCycle + 1);
+ // If HazardRec is disabled, the cycle was pre-advanced before calling
+ // ReleasePredecessors. In that case, IssueCount should remain 0.
+ //
+ // Check AvailableQueue after ReleasePredecessors in case of zero latency.
+ if (HazardRec->isEnabled() || AvgIPC > 1) {
+ if (SU->getNode() && SU->getNode()->isMachineOpcode())
+ ++IssueCount;
+ if ((HazardRec->isEnabled() && HazardRec->atIssueLimit())
+ || (!HazardRec->isEnabled() && IssueCount == AvgIPC))
+ AdvanceToCycle(CurCycle + 1);
+ }
}
/// CapturePred - This does the opposite of ReleasePred. Since SU is being
}
}
+ // Reclaim the special call resource dependence, if this is the beginning
+ // of a call.
+ unsigned CallResource = TRI->getNumRegs();
+ for (const SDNode *SUNode = SU->getNode(); SUNode;
+ SUNode = SUNode->getGluedNode()) {
+ if (SUNode->isMachineOpcode() &&
+ SUNode->getMachineOpcode() == (unsigned)TII->getCallFrameSetupOpcode()) {
+ ++NumLiveRegs;
+ LiveRegDefs[CallResource] = SU;
+ LiveRegGens[CallResource] = CallSeqEndForStart[SU];
+ }
+ }
+
+ // Release the special call resource dependence, if this is the end
+ // of a call.
+ if (LiveRegGens[CallResource] == SU)
+ for (const SDNode *SUNode = SU->getNode(); SUNode;
+ SUNode = SUNode->getGluedNode()) {
+ if (SUNode->isMachineOpcode() &&
+ SUNode->getMachineOpcode() == (unsigned)TII->getCallFrameDestroyOpcode()) {
+ assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
+ --NumLiveRegs;
+ LiveRegDefs[CallResource] = NULL;
+ LiveRegGens[CallResource] = NULL;
+ }
+ }
+
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isAssignedRegDep()) {
+ if (!LiveRegDefs[I->getReg()])
+ ++NumLiveRegs;
// This becomes the nearest def. Note that an earlier def may still be
// pending if this is a two-address node.
LiveRegDefs[I->getReg()] = SU;
- if (!LiveRegDefs[I->getReg()]) {
- ++NumLiveRegs;
- }
if (LiveRegGens[I->getReg()] == NULL ||
I->getSUnit()->getHeight() < LiveRegGens[I->getReg()]->getHeight())
LiveRegGens[I->getReg()] = I->getSUnit();
SU->setHeightDirty();
SU->isScheduled = false;
SU->isAvailable = true;
- if (EnableSchedCycles && AvailableQueue->hasReadyFilter()) {
+ if (!DisableSchedCycles && AvailableQueue->hasReadyFilter()) {
// Don't make available until backtracking is complete.
SU->isPending = true;
PendingQueue.push_back(SU);
else {
AvailableQueue->push(SU);
}
- AvailableQueue->UnscheduledNode(SU);
+ AvailableQueue->unscheduledNode(SU);
}
/// After backtracking, the hazard checker needs to be restored to a state
-/// corresponding the the current cycle.
+/// corresponding the current cycle.
void ScheduleDAGRRList::RestoreHazardCheckerBottomUp() {
HazardRec->Reset();
RestoreHazardCheckerBottomUp();
- if (EnableSchedCycles)
- ReleasePending();
+ ReleasePending();
++NumBacktracks;
}
if (!TII->unfoldMemoryOperand(*DAG, N, NewNodes))
return NULL;
+ // unfolding an x86 DEC64m operation results in store, dec, load which
+ // can't be handled here so quit
+ if (NewNodes.size() == 3)
+ return NULL;
+
DEBUG(dbgs() << "Unfolding SU #" << SU->NodeNum << "\n");
assert(NewNodes.size() == 2 && "Expected a load folding node!");
} else {
LoadSU = CreateNewSUnit(LoadNode);
LoadNode->setNodeId(LoadSU->NodeNum);
- ComputeLatency(LoadSU);
+
+ InitNumRegDefsLeft(LoadSU);
+ computeLatency(LoadSU);
}
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) {
+ const MCInstrDesc &MCID = TII->get(N->getMachineOpcode());
+ for (unsigned i = 0; i != MCID.getNumOperands(); ++i) {
+ if (MCID.getOperandConstraint(i, MCOI::TIED_TO) != -1) {
NewSU->isTwoAddress = true;
break;
}
}
- if (TID.isCommutable())
+ if (MCID.isCommutable())
NewSU->isCommutable = true;
- ComputeLatency(NewSU);
+
+ InitNumRegDefsLeft(NewSU);
+ computeLatency(NewSU);
// Record all the edges to and from the old SU, by category.
SmallVector<SDep, 4> ChainPreds;
RemovePred(SuccDep, D);
D.setSUnit(NewSU);
AddPred(SuccDep, D);
+ // Balance register pressure.
+ if (AvailableQueue->tracksRegPressure() && SuccDep->isScheduled
+ && !D.isCtrl() && NewSU->NumRegDefsLeft > 0)
+ --NewSU->NumRegDefsLeft;
}
for (unsigned i = 0, e = ChainSuccs.size(); i != e; ++i) {
SDep D = ChainSuccs[i];
AddPred(SuccSU, D);
DelDeps.push_back(std::make_pair(SuccSU, *I));
}
+ else {
+ // Avoid scheduling the def-side copy before other successors. Otherwise
+ // we could introduce another physreg interference on the copy and
+ // continue inserting copies indefinitely.
+ SDep D(CopyFromSU, SDep::Order, /*Latency=*/0,
+ /*Reg=*/0, /*isNormalMemory=*/false,
+ /*isMustAlias=*/false, /*isArtificial=*/true);
+ AddPred(SuccSU, D);
+ }
}
for (unsigned i = 0, e = DelDeps.size(); i != e; ++i)
RemovePred(DelDeps[i].first, DelDeps[i].second);
/// FIXME: Move to SelectionDAG?
static EVT 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) {
+ const MCInstrDesc &MCID = TII->get(N->getMachineOpcode());
+ assert(MCID.ImplicitDefs && "Physical reg def must be in implicit def list!");
+ unsigned NumRes = MCID.getNumDefs();
+ for (const uint16_t *ImpDef = MCID.getImplicitDefs(); *ImpDef; ++ImpDef) {
if (Reg == *ImpDef)
break;
++NumRes;
SmallSet<unsigned, 4> &RegAdded,
SmallVector<unsigned, 4> &LRegs,
const TargetRegisterInfo *TRI) {
- for (const unsigned *AliasI = TRI->getOverlaps(Reg); *AliasI; ++AliasI) {
+ for (MCRegAliasIterator AliasI(Reg, TRI, true); AliasI.isValid(); ++AliasI) {
// Check if Ref is live.
- if (!LiveRegDefs[Reg]) continue;
+ if (!LiveRegDefs[*AliasI]) continue;
// Allow multiple uses of the same def.
- if (LiveRegDefs[Reg] == SU) continue;
+ if (LiveRegDefs[*AliasI] == SU) continue;
// Add Reg to the set of interfering live regs.
- if (RegAdded.insert(Reg))
- LRegs.push_back(Reg);
+ if (RegAdded.insert(*AliasI)) {
+ LRegs.push_back(*AliasI);
+ }
+ }
+}
+
+/// CheckForLiveRegDefMasked - Check for any live physregs that are clobbered
+/// by RegMask, and add them to LRegs.
+static void CheckForLiveRegDefMasked(SUnit *SU, const uint32_t *RegMask,
+ std::vector<SUnit*> &LiveRegDefs,
+ SmallSet<unsigned, 4> &RegAdded,
+ SmallVector<unsigned, 4> &LRegs) {
+ // Look at all live registers. Skip Reg0 and the special CallResource.
+ for (unsigned i = 1, e = LiveRegDefs.size()-1; i != e; ++i) {
+ if (!LiveRegDefs[i]) continue;
+ if (LiveRegDefs[i] == SU) continue;
+ if (!MachineOperand::clobbersPhysReg(RegMask, i)) continue;
+ if (RegAdded.insert(i))
+ LRegs.push_back(i);
}
}
+/// getNodeRegMask - Returns the register mask attached to an SDNode, if any.
+static const uint32_t *getNodeRegMask(const SDNode *N) {
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
+ if (const RegisterMaskSDNode *Op =
+ dyn_cast<RegisterMaskSDNode>(N->getOperand(i).getNode()))
+ return Op->getRegMask();
+ return NULL;
+}
+
/// 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
++i; // Skip the ID value.
if (InlineAsm::isRegDefKind(Flags) ||
- InlineAsm::isRegDefEarlyClobberKind(Flags)) {
+ InlineAsm::isRegDefEarlyClobberKind(Flags) ||
+ InlineAsm::isClobberKind(Flags)) {
// Check for def of register or earlyclobber register.
for (; NumVals; --NumVals, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
if (!Node->isMachineOpcode())
continue;
- const TargetInstrDesc &TID = TII->get(Node->getMachineOpcode());
- if (!TID.ImplicitDefs)
+ // If we're in the middle of scheduling a call, don't begin scheduling
+ // another call. Also, don't allow any physical registers to be live across
+ // the call.
+ if (Node->getMachineOpcode() == (unsigned)TII->getCallFrameDestroyOpcode()) {
+ // Check the special calling-sequence resource.
+ unsigned CallResource = TRI->getNumRegs();
+ if (LiveRegDefs[CallResource]) {
+ SDNode *Gen = LiveRegGens[CallResource]->getNode();
+ while (SDNode *Glued = Gen->getGluedNode())
+ Gen = Glued;
+ if (!IsChainDependent(Gen, Node, 0, TII) && RegAdded.insert(CallResource))
+ LRegs.push_back(CallResource);
+ }
+ }
+ if (const uint32_t *RegMask = getNodeRegMask(Node))
+ CheckForLiveRegDefMasked(SU, RegMask, LiveRegDefs, RegAdded, LRegs);
+
+ const MCInstrDesc &MCID = TII->get(Node->getMachineOpcode());
+ if (!MCID.ImplicitDefs)
continue;
- for (const unsigned *Reg = TID.ImplicitDefs; *Reg; ++Reg)
+ for (const uint16_t *Reg = MCID.getImplicitDefs(); *Reg; ++Reg)
CheckForLiveRegDef(SU, *Reg, LiveRegDefs, RegAdded, LRegs, TRI);
}
TRI->getMinimalPhysRegClass(Reg, VT);
const TargetRegisterClass *DestRC = TRI->getCrossCopyRegClass(RC);
- // If cross copy register class is null, then it must be possible copy
- // the value directly. Do not try duplicate the def.
+ // If cross copy register class is the same as RC, then it must be possible
+ // copy the value directly. Do not try duplicate the def.
+ // If cross copy register class is not the same as RC, then it's possible to
+ // copy the value but it require cross register class copies and it is
+ // expensive.
+ // If cross copy register class is null, then it's not possible to copy
+ // the value at all.
SUnit *NewDef = 0;
- if (DestRC)
+ if (DestRC != RC) {
NewDef = CopyAndMoveSuccessors(LRDef);
- else
- DestRC = RC;
+ if (!DestRC && !NewDef)
+ report_fatal_error("Can't handle live physical register dependency!");
+ }
if (!NewDef) {
// Issue copies, these can be expensive cross register class copies.
SmallVector<SUnit*, 2> Copies;
// priority. If it is not ready put it back. Schedule the node.
Sequence.reserve(SUnits.size());
while (!AvailableQueue->empty()) {
- DEBUG(dbgs() << "\n*** Examining Available\n";
+ DEBUG(dbgs() << "\nExamining Available:\n";
AvailableQueue->dump(this));
// Pick the best node to schedule taking all constraints into
std::reverse(Sequence.begin(), Sequence.end());
#ifndef NDEBUG
- VerifySchedule(isBottomUp);
+ VerifyScheduledSequence(/*isBottomUp=*/true);
#endif
}
//===----------------------------------------------------------------------===//
-// Top-Down Scheduling
+// RegReductionPriorityQueue Definition
//===----------------------------------------------------------------------===//
+//
+// This is a SchedulingPriorityQueue that schedules using Sethi Ullman numbers
+// to reduce register pressure.
+//
+namespace {
+class RegReductionPQBase;
-/// ReleaseSucc - Decrement the NumPredsLeft count of a successor. Add it to
-/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
-void ScheduleDAGRRList::ReleaseSucc(SUnit *SU, const SDep *SuccEdge) {
- SUnit *SuccSU = SuccEdge->getSUnit();
+struct queue_sort : public std::binary_function<SUnit*, SUnit*, bool> {
+ bool isReady(SUnit* SU, unsigned CurCycle) const { return true; }
+};
#ifndef NDEBUG
- if (SuccSU->NumPredsLeft == 0) {
- dbgs() << "*** Scheduling failed! ***\n";
- SuccSU->dump(this);
- dbgs() << " has been released too many times!\n";
- llvm_unreachable(0);
- }
-#endif
- --SuccSU->NumPredsLeft;
+template<class SF>
+struct reverse_sort : public queue_sort {
+ SF &SortFunc;
+ reverse_sort(SF &sf) : SortFunc(sf) {}
+ reverse_sort(const reverse_sort &RHS) : SortFunc(RHS.SortFunc) {}
- // If all the node's predecessors are scheduled, this node is ready
- // to be scheduled. Ignore the special ExitSU node.
- if (SuccSU->NumPredsLeft == 0 && SuccSU != &ExitSU) {
- SuccSU->isAvailable = true;
- AvailableQueue->push(SuccSU);
+ bool operator()(SUnit* left, SUnit* right) const {
+ // reverse left/right rather than simply !SortFunc(left, right)
+ // to expose different paths in the comparison logic.
+ return SortFunc(right, left);
}
-}
+};
+#endif // NDEBUG
+
+/// bu_ls_rr_sort - Priority function for bottom up register pressure
+// reduction scheduler.
+struct bu_ls_rr_sort : public queue_sort {
+ enum {
+ IsBottomUp = true,
+ HasReadyFilter = false
+ };
-void ScheduleDAGRRList::ReleaseSuccessors(SUnit *SU) {
- // Top down: release successors
- for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
- I != E; ++I) {
- assert(!I->isAssignedRegDep() &&
- "The list-tdrr scheduler doesn't yet support physreg dependencies!");
+ RegReductionPQBase *SPQ;
+ bu_ls_rr_sort(RegReductionPQBase *spq) : SPQ(spq) {}
+ bu_ls_rr_sort(const bu_ls_rr_sort &RHS) : SPQ(RHS.SPQ) {}
- ReleaseSucc(SU, &*I);
- }
-}
+ bool operator()(SUnit* left, SUnit* right) const;
+};
-/// ScheduleNodeTopDown - Add the node to the schedule. Decrement the pending
-/// count of its successors. If a successor pending count is zero, add it to
-/// the Available queue.
-void ScheduleDAGRRList::ScheduleNodeTopDown(SUnit *SU) {
- DEBUG(dbgs() << "*** Scheduling [" << CurCycle << "]: ");
- DEBUG(SU->dump(this));
+// src_ls_rr_sort - Priority function for source order scheduler.
+struct src_ls_rr_sort : public queue_sort {
+ enum {
+ IsBottomUp = true,
+ HasReadyFilter = false
+ };
- assert(CurCycle >= SU->getDepth() && "Node scheduled above its depth!");
- SU->setDepthToAtLeast(CurCycle);
- Sequence.push_back(SU);
+ RegReductionPQBase *SPQ;
+ src_ls_rr_sort(RegReductionPQBase *spq)
+ : SPQ(spq) {}
+ src_ls_rr_sort(const src_ls_rr_sort &RHS)
+ : SPQ(RHS.SPQ) {}
- ReleaseSuccessors(SU);
- SU->isScheduled = true;
- AvailableQueue->ScheduledNode(SU);
-}
+ bool operator()(SUnit* left, SUnit* right) const;
+};
-/// ListScheduleTopDown - The main loop of list scheduling for top-down
-/// schedulers.
-void ScheduleDAGRRList::ListScheduleTopDown() {
- AvailableQueue->setCurCycle(CurCycle);
+// hybrid_ls_rr_sort - Priority function for hybrid scheduler.
+struct hybrid_ls_rr_sort : public queue_sort {
+ enum {
+ IsBottomUp = true,
+ HasReadyFilter = false
+ };
+
+ RegReductionPQBase *SPQ;
+ hybrid_ls_rr_sort(RegReductionPQBase *spq)
+ : SPQ(spq) {}
+ hybrid_ls_rr_sort(const hybrid_ls_rr_sort &RHS)
+ : SPQ(RHS.SPQ) {}
+
+ bool isReady(SUnit *SU, unsigned CurCycle) const;
+
+ bool operator()(SUnit* left, SUnit* right) const;
+};
+
+// ilp_ls_rr_sort - Priority function for ILP (instruction level parallelism)
+// scheduler.
+struct ilp_ls_rr_sort : public queue_sort {
+ enum {
+ IsBottomUp = true,
+ HasReadyFilter = false
+ };
+
+ RegReductionPQBase *SPQ;
+ ilp_ls_rr_sort(RegReductionPQBase *spq)
+ : SPQ(spq) {}
+ ilp_ls_rr_sort(const ilp_ls_rr_sort &RHS)
+ : SPQ(RHS.SPQ) {}
- // Release any successors of the special Entry node.
- ReleaseSuccessors(&EntrySU);
+ bool isReady(SUnit *SU, unsigned CurCycle) const;
- // 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.empty()) {
- AvailableQueue->push(&SUnits[i]);
- SUnits[i].isAvailable = true;
+ bool operator()(SUnit* left, SUnit* right) const;
+};
+
+class RegReductionPQBase : public SchedulingPriorityQueue {
+protected:
+ std::vector<SUnit*> Queue;
+ unsigned CurQueueId;
+ bool TracksRegPressure;
+ bool SrcOrder;
+
+ // SUnits - The SUnits for the current graph.
+ std::vector<SUnit> *SUnits;
+
+ MachineFunction &MF;
+ const TargetInstrInfo *TII;
+ const TargetRegisterInfo *TRI;
+ const TargetLowering *TLI;
+ ScheduleDAGRRList *scheduleDAG;
+
+ // SethiUllmanNumbers - The SethiUllman number for each node.
+ std::vector<unsigned> SethiUllmanNumbers;
+
+ /// RegPressure - Tracking current reg pressure per register class.
+ ///
+ std::vector<unsigned> RegPressure;
+
+ /// RegLimit - Tracking the number of allocatable registers per register
+ /// class.
+ std::vector<unsigned> RegLimit;
+
+public:
+ RegReductionPQBase(MachineFunction &mf,
+ bool hasReadyFilter,
+ bool tracksrp,
+ bool srcorder,
+ const TargetInstrInfo *tii,
+ const TargetRegisterInfo *tri,
+ const TargetLowering *tli)
+ : SchedulingPriorityQueue(hasReadyFilter),
+ CurQueueId(0), TracksRegPressure(tracksrp), SrcOrder(srcorder),
+ MF(mf), TII(tii), TRI(tri), TLI(tli), scheduleDAG(NULL) {
+ if (TracksRegPressure) {
+ unsigned NumRC = TRI->getNumRegClasses();
+ RegLimit.resize(NumRC);
+ RegPressure.resize(NumRC);
+ std::fill(RegLimit.begin(), RegLimit.end(), 0);
+ std::fill(RegPressure.begin(), RegPressure.end(), 0);
+ for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
+ E = TRI->regclass_end(); I != E; ++I)
+ RegLimit[(*I)->getID()] = tri->getRegPressureLimit(*I, MF);
}
}
- // While Available queue is not empty, grab the node with the highest
- // priority. If it is not ready put it back. Schedule the node.
- Sequence.reserve(SUnits.size());
- while (!AvailableQueue->empty()) {
- SUnit *CurSU = AvailableQueue->pop();
+ void setScheduleDAG(ScheduleDAGRRList *scheduleDag) {
+ scheduleDAG = scheduleDag;
+ }
- if (CurSU)
- ScheduleNodeTopDown(CurSU);
- ++CurCycle;
- AvailableQueue->setCurCycle(CurCycle);
+ ScheduleHazardRecognizer* getHazardRec() {
+ return scheduleDAG->getHazardRec();
}
-#ifndef NDEBUG
- VerifySchedule(isBottomUp);
-#endif
-}
+ void initNodes(std::vector<SUnit> &sunits);
+ void addNode(const SUnit *SU);
-//===----------------------------------------------------------------------===//
-// RegReductionPriorityQueue Implementation
-//===----------------------------------------------------------------------===//
-//
-// This is a SchedulingPriorityQueue that schedules using Sethi Ullman numbers
-// to reduce register pressure.
-//
-namespace {
- template<class SF>
- class RegReductionPriorityQueue;
+ void updateNode(const SUnit *SU);
- struct queue_sort : public std::binary_function<SUnit*, SUnit*, bool> {
- bool isReady(SUnit* SU, unsigned CurCycle) const { return true; }
- };
+ void releaseState() {
+ SUnits = 0;
+ SethiUllmanNumbers.clear();
+ std::fill(RegPressure.begin(), RegPressure.end(), 0);
+ }
- /// bu_ls_rr_sort - Priority function for bottom up register pressure
- // reduction scheduler.
- struct bu_ls_rr_sort : public queue_sort {
- enum {
- IsBottomUp = true,
- HasReadyFilter = false
- };
+ unsigned getNodePriority(const SUnit *SU) const;
- RegReductionPriorityQueue<bu_ls_rr_sort> *SPQ;
- bu_ls_rr_sort(RegReductionPriorityQueue<bu_ls_rr_sort> *spq) : SPQ(spq) {}
- bu_ls_rr_sort(const bu_ls_rr_sort &RHS) : SPQ(RHS.SPQ) {}
+ unsigned getNodeOrdering(const SUnit *SU) const {
+ if (!SU->getNode()) return 0;
- bool operator()(const SUnit* left, const SUnit* right) const;
- };
+ return scheduleDAG->DAG->GetOrdering(SU->getNode());
+ }
- // td_ls_rr_sort - Priority function for top down register pressure reduction
- // scheduler.
- struct td_ls_rr_sort : public queue_sort {
- enum {
- IsBottomUp = false,
- HasReadyFilter = false
- };
+ bool empty() const { return Queue.empty(); }
- RegReductionPriorityQueue<td_ls_rr_sort> *SPQ;
- td_ls_rr_sort(RegReductionPriorityQueue<td_ls_rr_sort> *spq) : SPQ(spq) {}
- td_ls_rr_sort(const td_ls_rr_sort &RHS) : SPQ(RHS.SPQ) {}
+ void push(SUnit *U) {
+ assert(!U->NodeQueueId && "Node in the queue already");
+ U->NodeQueueId = ++CurQueueId;
+ Queue.push_back(U);
+ }
- bool operator()(const SUnit* left, const SUnit* right) const;
- };
+ void remove(SUnit *SU) {
+ assert(!Queue.empty() && "Queue is empty!");
+ assert(SU->NodeQueueId != 0 && "Not in queue!");
+ std::vector<SUnit *>::iterator I = std::find(Queue.begin(), Queue.end(),
+ SU);
+ if (I != prior(Queue.end()))
+ std::swap(*I, Queue.back());
+ Queue.pop_back();
+ SU->NodeQueueId = 0;
+ }
- // src_ls_rr_sort - Priority function for source order scheduler.
- struct src_ls_rr_sort : public queue_sort {
- enum {
- IsBottomUp = true,
- HasReadyFilter = false
- };
+ bool tracksRegPressure() const { return TracksRegPressure; }
- RegReductionPriorityQueue<src_ls_rr_sort> *SPQ;
- src_ls_rr_sort(RegReductionPriorityQueue<src_ls_rr_sort> *spq)
- : SPQ(spq) {}
- src_ls_rr_sort(const src_ls_rr_sort &RHS)
- : SPQ(RHS.SPQ) {}
+ void dumpRegPressure() const;
- bool operator()(const SUnit* left, const SUnit* right) const;
- };
+ bool HighRegPressure(const SUnit *SU) const;
- // hybrid_ls_rr_sort - Priority function for hybrid scheduler.
- struct hybrid_ls_rr_sort : public queue_sort {
- enum {
- IsBottomUp = true,
- HasReadyFilter = false
- };
+ bool MayReduceRegPressure(SUnit *SU) const;
- RegReductionPriorityQueue<hybrid_ls_rr_sort> *SPQ;
- hybrid_ls_rr_sort(RegReductionPriorityQueue<hybrid_ls_rr_sort> *spq)
- : SPQ(spq) {}
- hybrid_ls_rr_sort(const hybrid_ls_rr_sort &RHS)
- : SPQ(RHS.SPQ) {}
+ int RegPressureDiff(SUnit *SU, unsigned &LiveUses) const;
- bool operator()(const SUnit* left, const SUnit* right) const;
- };
+ void scheduledNode(SUnit *SU);
+
+ void unscheduledNode(SUnit *SU);
- // ilp_ls_rr_sort - Priority function for ILP (instruction level parallelism)
- // scheduler.
- struct ilp_ls_rr_sort : public queue_sort {
- enum {
- IsBottomUp = true,
- HasReadyFilter = true
- };
+protected:
+ bool canClobber(const SUnit *SU, const SUnit *Op);
+ void AddPseudoTwoAddrDeps();
+ void PrescheduleNodesWithMultipleUses();
+ void CalculateSethiUllmanNumbers();
+};
- RegReductionPriorityQueue<ilp_ls_rr_sort> *SPQ;
- ilp_ls_rr_sort(RegReductionPriorityQueue<ilp_ls_rr_sort> *spq)
- : SPQ(spq) {}
- ilp_ls_rr_sort(const ilp_ls_rr_sort &RHS)
- : SPQ(RHS.SPQ) {}
+template<class SF>
+static SUnit *popFromQueueImpl(std::vector<SUnit*> &Q, SF &Picker) {
+ std::vector<SUnit *>::iterator Best = Q.begin();
+ for (std::vector<SUnit *>::iterator I = llvm::next(Q.begin()),
+ E = Q.end(); I != E; ++I)
+ if (Picker(*Best, *I))
+ Best = I;
+ SUnit *V = *Best;
+ if (Best != prior(Q.end()))
+ std::swap(*Best, Q.back());
+ Q.pop_back();
+ return V;
+}
- bool isReady(SUnit *SU, unsigned CurCycle) const;
+template<class SF>
+SUnit *popFromQueue(std::vector<SUnit*> &Q, SF &Picker, ScheduleDAG *DAG) {
+#ifndef NDEBUG
+ if (DAG->StressSched) {
+ reverse_sort<SF> RPicker(Picker);
+ return popFromQueueImpl(Q, RPicker);
+ }
+#endif
+ (void)DAG;
+ return popFromQueueImpl(Q, Picker);
+}
- bool operator()(const SUnit* left, const SUnit* right) const;
- };
-} // end anonymous namespace
+template<class SF>
+class RegReductionPriorityQueue : public RegReductionPQBase {
+ SF Picker;
+
+public:
+ RegReductionPriorityQueue(MachineFunction &mf,
+ bool tracksrp,
+ bool srcorder,
+ const TargetInstrInfo *tii,
+ const TargetRegisterInfo *tri,
+ const TargetLowering *tli)
+ : RegReductionPQBase(mf, SF::HasReadyFilter, tracksrp, srcorder,
+ tii, tri, tli),
+ Picker(this) {}
+
+ bool isBottomUp() const { return SF::IsBottomUp; }
+
+ bool isReady(SUnit *U) const {
+ return Picker.HasReadyFilter && Picker.isReady(U, getCurCycle());
+ }
+
+ SUnit *pop() {
+ if (Queue.empty()) return NULL;
+
+ SUnit *V = popFromQueue(Queue, Picker, scheduleDAG);
+ V->NodeQueueId = 0;
+ return V;
+ }
+
+ void dump(ScheduleDAG *DAG) const {
+ // Emulate pop() without clobbering NodeQueueIds.
+ std::vector<SUnit*> DumpQueue = Queue;
+ SF DumpPicker = Picker;
+ while (!DumpQueue.empty()) {
+ SUnit *SU = popFromQueue(DumpQueue, DumpPicker, scheduleDAG);
+ dbgs() << "Height " << SU->getHeight() << ": ";
+ SU->dump(DAG);
+ }
+ }
+};
+
+typedef RegReductionPriorityQueue<bu_ls_rr_sort>
+BURegReductionPriorityQueue;
+
+typedef RegReductionPriorityQueue<src_ls_rr_sort>
+SrcRegReductionPriorityQueue;
+
+typedef RegReductionPriorityQueue<hybrid_ls_rr_sort>
+HybridBURRPriorityQueue;
+
+typedef RegReductionPriorityQueue<ilp_ls_rr_sort>
+ILPBURRPriorityQueue;
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// Static Node Priority for Register Pressure Reduction
+//===----------------------------------------------------------------------===//
+
+// Check for special nodes that bypass scheduling heuristics.
+// Currently this pushes TokenFactor nodes down, but may be used for other
+// pseudo-ops as well.
+//
+// Return -1 to schedule right above left, 1 for left above right.
+// Return 0 if no bias exists.
+static int checkSpecialNodes(const SUnit *left, const SUnit *right) {
+ bool LSchedLow = left->isScheduleLow;
+ bool RSchedLow = right->isScheduleLow;
+ if (LSchedLow != RSchedLow)
+ return LSchedLow < RSchedLow ? 1 : -1;
+ return 0;
+}
/// CalcNodeSethiUllmanNumber - Compute Sethi Ullman number.
/// Smaller number is the higher priority.
return SethiUllmanNumber;
}
-namespace {
- template<class SF>
- class RegReductionPriorityQueue : public SchedulingPriorityQueue {
- static SUnit *popFromQueue(std::vector<SUnit*> &Q, SF &Picker) {
- std::vector<SUnit *>::iterator Best = Q.begin();
- for (std::vector<SUnit *>::iterator I = llvm::next(Q.begin()),
- E = Q.end(); I != E; ++I)
- if (Picker(*Best, *I))
- Best = I;
- SUnit *V = *Best;
- if (Best != prior(Q.end()))
- std::swap(*Best, Q.back());
- Q.pop_back();
- return V;
- }
-
- std::vector<SUnit*> Queue;
- SF Picker;
- unsigned CurQueueId;
- bool TracksRegPressure;
-
- protected:
- // SUnits - The SUnits for the current graph.
- std::vector<SUnit> *SUnits;
-
- MachineFunction &MF;
- const TargetInstrInfo *TII;
- const TargetRegisterInfo *TRI;
- const TargetLowering *TLI;
- ScheduleDAGRRList *scheduleDAG;
-
- // SethiUllmanNumbers - The SethiUllman number for each node.
- std::vector<unsigned> SethiUllmanNumbers;
-
- /// RegPressure - Tracking current reg pressure per register class.
- ///
- std::vector<unsigned> RegPressure;
-
- /// RegLimit - Tracking the number of allocatable registers per register
- /// class.
- std::vector<unsigned> RegLimit;
-
- public:
- RegReductionPriorityQueue(MachineFunction &mf,
- bool tracksrp,
- const TargetInstrInfo *tii,
- const TargetRegisterInfo *tri,
- const TargetLowering *tli)
- : SchedulingPriorityQueue(SF::HasReadyFilter), Picker(this),
- CurQueueId(0), TracksRegPressure(tracksrp),
- MF(mf), TII(tii), TRI(tri), TLI(tli), scheduleDAG(NULL) {
- if (TracksRegPressure) {
- unsigned NumRC = TRI->getNumRegClasses();
- RegLimit.resize(NumRC);
- RegPressure.resize(NumRC);
- std::fill(RegLimit.begin(), RegLimit.end(), 0);
- std::fill(RegPressure.begin(), RegPressure.end(), 0);
- for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
- E = TRI->regclass_end(); I != E; ++I)
- RegLimit[(*I)->getID()] = tli->getRegPressureLimit(*I, MF);
- }
- }
+/// CalculateSethiUllmanNumbers - Calculate Sethi-Ullman numbers of all
+/// scheduling units.
+void RegReductionPQBase::CalculateSethiUllmanNumbers() {
+ SethiUllmanNumbers.assign(SUnits->size(), 0);
- bool isBottomUp() const { return SF::IsBottomUp; }
+ for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
+ CalcNodeSethiUllmanNumber(&(*SUnits)[i], SethiUllmanNumbers);
+}
- void initNodes(std::vector<SUnit> &sunits) {
- SUnits = &sunits;
- // Add pseudo dependency edges for two-address nodes.
- AddPseudoTwoAddrDeps();
- // Reroute edges to nodes with multiple uses.
- PrescheduleNodesWithMultipleUses();
- // Calculate node priorities.
- CalculateSethiUllmanNumbers();
- }
+void RegReductionPQBase::addNode(const SUnit *SU) {
+ unsigned SUSize = SethiUllmanNumbers.size();
+ if (SUnits->size() > SUSize)
+ SethiUllmanNumbers.resize(SUSize*2, 0);
+ CalcNodeSethiUllmanNumber(SU, SethiUllmanNumbers);
+}
- void addNode(const SUnit *SU) {
- unsigned SUSize = SethiUllmanNumbers.size();
- if (SUnits->size() > SUSize)
- SethiUllmanNumbers.resize(SUSize*2, 0);
- CalcNodeSethiUllmanNumber(SU, SethiUllmanNumbers);
- }
+void RegReductionPQBase::updateNode(const SUnit *SU) {
+ SethiUllmanNumbers[SU->NodeNum] = 0;
+ CalcNodeSethiUllmanNumber(SU, SethiUllmanNumbers);
+}
- void updateNode(const SUnit *SU) {
- SethiUllmanNumbers[SU->NodeNum] = 0;
- CalcNodeSethiUllmanNumber(SU, SethiUllmanNumbers);
- }
+// Lower priority means schedule further down. For bottom-up scheduling, lower
+// priority SUs are scheduled before higher priority SUs.
+unsigned RegReductionPQBase::getNodePriority(const SUnit *SU) const {
+ assert(SU->NodeNum < SethiUllmanNumbers.size());
+ unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0;
+ if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
+ // CopyToReg should be close to its uses to facilitate coalescing and
+ // avoid spilling.
+ return 0;
+ if (Opc == TargetOpcode::EXTRACT_SUBREG ||
+ Opc == TargetOpcode::SUBREG_TO_REG ||
+ Opc == TargetOpcode::INSERT_SUBREG)
+ // EXTRACT_SUBREG, INSERT_SUBREG, and SUBREG_TO_REG nodes should be
+ // close to their uses to facilitate coalescing.
+ return 0;
+ if (SU->NumSuccs == 0 && SU->NumPreds != 0)
+ // If SU does not have a register 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;
+ if (SU->NumPreds == 0 && SU->NumSuccs != 0)
+ // If SU does not have a register def, schedule it close to its uses
+ // because it does not lengthen any live ranges.
+ return 0;
+#if 1
+ return SethiUllmanNumbers[SU->NodeNum];
+#else
+ unsigned Priority = SethiUllmanNumbers[SU->NodeNum];
+ if (SU->isCallOp) {
+ // FIXME: This assumes all of the defs are used as call operands.
+ int NP = (int)Priority - SU->getNode()->getNumValues();
+ return (NP > 0) ? NP : 0;
+ }
+ return Priority;
+#endif
+}
- void releaseState() {
- SUnits = 0;
- SethiUllmanNumbers.clear();
- std::fill(RegPressure.begin(), RegPressure.end(), 0);
- }
+//===----------------------------------------------------------------------===//
+// Register Pressure Tracking
+//===----------------------------------------------------------------------===//
+
+void RegReductionPQBase::dumpRegPressure() const {
+ for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
+ E = TRI->regclass_end(); I != E; ++I) {
+ const TargetRegisterClass *RC = *I;
+ unsigned Id = RC->getID();
+ unsigned RP = RegPressure[Id];
+ if (!RP) continue;
+ DEBUG(dbgs() << RC->getName() << ": " << RP << " / " << RegLimit[Id]
+ << '\n');
+ }
+}
+
+bool RegReductionPQBase::HighRegPressure(const SUnit *SU) const {
+ if (!TLI)
+ return false;
- unsigned getNodePriority(const SUnit *SU) const {
- assert(SU->NodeNum < SethiUllmanNumbers.size());
- unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0;
- if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
- // CopyToReg should be close to its uses to facilitate coalescing and
- // avoid spilling.
- return 0;
- if (Opc == TargetOpcode::EXTRACT_SUBREG ||
- Opc == TargetOpcode::SUBREG_TO_REG ||
- Opc == TargetOpcode::INSERT_SUBREG)
- // EXTRACT_SUBREG, INSERT_SUBREG, and SUBREG_TO_REG nodes should be
- // close to their uses to facilitate coalescing.
- return 0;
- if (SU->NumSuccs == 0 && SU->NumPreds != 0)
- // If SU does not have a register 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;
- if (SU->NumPreds == 0 && SU->NumSuccs != 0)
- // If SU does not have a register def, schedule it close to its uses
- // because it does not lengthen any live ranges.
- return 0;
- return SethiUllmanNumbers[SU->NodeNum];
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl())
+ continue;
+ SUnit *PredSU = I->getSUnit();
+ // NumRegDefsLeft is zero when enough uses of this node have been scheduled
+ // to cover the number of registers defined (they are all live).
+ if (PredSU->NumRegDefsLeft == 0) {
+ continue;
}
+ for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
+ RegDefPos.IsValid(); RegDefPos.Advance()) {
+ unsigned RCId, Cost;
+ GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost, MF);
- unsigned getNodeOrdering(const SUnit *SU) const {
- return scheduleDAG->DAG->GetOrdering(SU->getNode());
+ if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
+ return true;
}
+ }
+ return false;
+}
- bool empty() const { return Queue.empty(); }
+bool RegReductionPQBase::MayReduceRegPressure(SUnit *SU) const {
+ const SDNode *N = SU->getNode();
- bool isReady(SUnit *U) const {
- return Picker.HasReadyFilter && Picker.isReady(U, getCurCycle());
- }
+ if (!N->isMachineOpcode() || !SU->NumSuccs)
+ return false;
+
+ unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
+ for (unsigned i = 0; i != NumDefs; ++i) {
+ EVT VT = N->getValueType(i);
+ if (!N->hasAnyUseOfValue(i))
+ continue;
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ if (RegPressure[RCId] >= RegLimit[RCId])
+ return true;
+ }
+ return false;
+}
- void push(SUnit *U) {
- assert(!U->NodeQueueId && "Node in the queue already");
- U->NodeQueueId = ++CurQueueId;
- Queue.push_back(U);
+// Compute the register pressure contribution by this instruction by count up
+// for uses that are not live and down for defs. Only count register classes
+// that are already under high pressure. As a side effect, compute the number of
+// uses of registers that are already live.
+//
+// FIXME: This encompasses the logic in HighRegPressure and MayReduceRegPressure
+// so could probably be factored.
+int RegReductionPQBase::RegPressureDiff(SUnit *SU, unsigned &LiveUses) const {
+ LiveUses = 0;
+ int PDiff = 0;
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl())
+ continue;
+ SUnit *PredSU = I->getSUnit();
+ // NumRegDefsLeft is zero when enough uses of this node have been scheduled
+ // to cover the number of registers defined (they are all live).
+ if (PredSU->NumRegDefsLeft == 0) {
+ if (PredSU->getNode()->isMachineOpcode())
+ ++LiveUses;
+ continue;
}
+ for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
+ RegDefPos.IsValid(); RegDefPos.Advance()) {
+ EVT VT = RegDefPos.GetValue();
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ if (RegPressure[RCId] >= RegLimit[RCId])
+ ++PDiff;
+ }
+ }
+ const SDNode *N = SU->getNode();
- SUnit *pop() {
- if (Queue.empty()) return NULL;
+ if (!N || !N->isMachineOpcode() || !SU->NumSuccs)
+ return PDiff;
- SUnit *V = popFromQueue(Queue, Picker);
- V->NodeQueueId = 0;
- return V;
- }
+ unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
+ for (unsigned i = 0; i != NumDefs; ++i) {
+ EVT VT = N->getValueType(i);
+ if (!N->hasAnyUseOfValue(i))
+ continue;
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ if (RegPressure[RCId] >= RegLimit[RCId])
+ --PDiff;
+ }
+ return PDiff;
+}
- void remove(SUnit *SU) {
- assert(!Queue.empty() && "Queue is empty!");
- assert(SU->NodeQueueId != 0 && "Not in queue!");
- std::vector<SUnit *>::iterator I = std::find(Queue.begin(), Queue.end(),
- SU);
- if (I != prior(Queue.end()))
- std::swap(*I, Queue.back());
- Queue.pop_back();
- SU->NodeQueueId = 0;
- }
+void RegReductionPQBase::scheduledNode(SUnit *SU) {
+ if (!TracksRegPressure)
+ return;
- bool HighRegPressure(const SUnit *SU) const {
- if (!TLI)
- return false;
+ if (!SU->getNode())
+ return;
- for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
- I != E; ++I) {
- if (I->isCtrl())
- continue;
- SUnit *PredSU = I->getSUnit();
- const SDNode *PN = PredSU->getNode();
- if (!PN->isMachineOpcode()) {
- if (PN->getOpcode() == ISD::CopyFromReg) {
- EVT VT = PN->getValueType(0);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- unsigned Cost = TLI->getRepRegClassCostFor(VT);
- if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
- return true;
- }
- continue;
- }
- unsigned POpc = PN->getMachineOpcode();
- if (POpc == TargetOpcode::IMPLICIT_DEF)
- continue;
- if (POpc == TargetOpcode::EXTRACT_SUBREG) {
- EVT VT = PN->getOperand(0).getValueType();
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- unsigned Cost = TLI->getRepRegClassCostFor(VT);
- // Check if this increases register pressure of the specific register
- // class to the point where it would cause spills.
- if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
- return true;
- continue;
- } else if (POpc == TargetOpcode::INSERT_SUBREG ||
- POpc == TargetOpcode::SUBREG_TO_REG) {
- EVT VT = PN->getValueType(0);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- unsigned Cost = TLI->getRepRegClassCostFor(VT);
- // Check if this increases register pressure of the specific register
- // class to the point where it would cause spills.
- if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
- return true;
- continue;
- }
- unsigned NumDefs = TII->get(PN->getMachineOpcode()).getNumDefs();
- for (unsigned i = 0; i != NumDefs; ++i) {
- EVT VT = PN->getValueType(i);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- if (RegPressure[RCId] >= RegLimit[RCId])
- return true; // Reg pressure already high.
- unsigned Cost = TLI->getRepRegClassCostFor(VT);
- if (!PN->hasAnyUseOfValue(i))
- continue;
- // Check if this increases register pressure of the specific register
- // class to the point where it would cause spills.
- if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
- return true;
- }
- }
-
- return false;
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl())
+ continue;
+ SUnit *PredSU = I->getSUnit();
+ // NumRegDefsLeft is zero when enough uses of this node have been scheduled
+ // to cover the number of registers defined (they are all live).
+ if (PredSU->NumRegDefsLeft == 0) {
+ continue;
}
+ // FIXME: The ScheduleDAG currently loses information about which of a
+ // node's values is consumed by each dependence. Consequently, if the node
+ // defines multiple register classes, we don't know which to pressurize
+ // here. Instead the following loop consumes the register defs in an
+ // arbitrary order. At least it handles the common case of clustered loads
+ // to the same class. For precise liveness, each SDep needs to indicate the
+ // result number. But that tightly couples the ScheduleDAG with the
+ // SelectionDAG making updates tricky. A simpler hack would be to attach a
+ // value type or register class to SDep.
+ //
+ // The most important aspect of register tracking is balancing the increase
+ // here with the reduction further below. Note that this SU may use multiple
+ // defs in PredSU. The can't be determined here, but we've already
+ // compensated by reducing NumRegDefsLeft in PredSU during
+ // ScheduleDAGSDNodes::AddSchedEdges.
+ --PredSU->NumRegDefsLeft;
+ unsigned SkipRegDefs = PredSU->NumRegDefsLeft;
+ for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
+ RegDefPos.IsValid(); RegDefPos.Advance(), --SkipRegDefs) {
+ if (SkipRegDefs)
+ continue;
- void ScheduledNode(SUnit *SU) {
- if (!TracksRegPressure)
- return;
-
- const SDNode *N = SU->getNode();
- if (!N->isMachineOpcode()) {
- if (N->getOpcode() != ISD::CopyToReg)
- return;
- } else {
- unsigned Opc = N->getMachineOpcode();
- if (Opc == TargetOpcode::EXTRACT_SUBREG ||
- Opc == TargetOpcode::INSERT_SUBREG ||
- Opc == TargetOpcode::SUBREG_TO_REG ||
- Opc == TargetOpcode::REG_SEQUENCE ||
- Opc == TargetOpcode::IMPLICIT_DEF)
- return;
- }
+ unsigned RCId, Cost;
+ GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost, MF);
+ RegPressure[RCId] += Cost;
+ break;
+ }
+ }
- for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
- I != E; ++I) {
- if (I->isCtrl())
- continue;
- SUnit *PredSU = I->getSUnit();
- if (PredSU->NumSuccsLeft != PredSU->NumSuccs)
- continue;
- const SDNode *PN = PredSU->getNode();
- if (!PN->isMachineOpcode()) {
- if (PN->getOpcode() == ISD::CopyFromReg) {
- EVT VT = PN->getValueType(0);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- }
- continue;
- }
- unsigned POpc = PN->getMachineOpcode();
- if (POpc == TargetOpcode::IMPLICIT_DEF)
- continue;
- if (POpc == TargetOpcode::EXTRACT_SUBREG) {
- EVT VT = PN->getOperand(0).getValueType();
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- continue;
- } else if (POpc == TargetOpcode::INSERT_SUBREG ||
- POpc == TargetOpcode::SUBREG_TO_REG) {
- EVT VT = PN->getValueType(0);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- continue;
- }
- unsigned NumDefs = TII->get(PN->getMachineOpcode()).getNumDefs();
- for (unsigned i = 0; i != NumDefs; ++i) {
- EVT VT = PN->getValueType(i);
- if (!PN->hasAnyUseOfValue(i))
- continue;
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- }
- }
+ // We should have this assert, but there may be dead SDNodes that never
+ // materialize as SUnits, so they don't appear to generate liveness.
+ //assert(SU->NumRegDefsLeft == 0 && "not all regdefs have scheduled uses");
+ int SkipRegDefs = (int)SU->NumRegDefsLeft;
+ for (ScheduleDAGSDNodes::RegDefIter RegDefPos(SU, scheduleDAG);
+ RegDefPos.IsValid(); RegDefPos.Advance(), --SkipRegDefs) {
+ if (SkipRegDefs > 0)
+ continue;
+ unsigned RCId, Cost;
+ GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost, MF);
+ if (RegPressure[RCId] < Cost) {
+ // Register pressure tracking is imprecise. This can happen. But we try
+ // hard not to let it happen because it likely results in poor scheduling.
+ DEBUG(dbgs() << " SU(" << SU->NodeNum << ") has too many regdefs\n");
+ RegPressure[RCId] = 0;
+ }
+ else {
+ RegPressure[RCId] -= Cost;
+ }
+ }
+ dumpRegPressure();
+}
- // Check for isMachineOpcode() as PrescheduleNodesWithMultipleUses()
- // may transfer data dependencies to CopyToReg.
- if (SU->NumSuccs && N->isMachineOpcode()) {
- unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
- for (unsigned i = 0; i != NumDefs; ++i) {
- EVT VT = N->getValueType(i);
- if (!N->hasAnyUseOfValue(i))
- continue;
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- if (RegPressure[RCId] < TLI->getRepRegClassCostFor(VT))
- // Register pressure tracking is imprecise. This can happen.
- RegPressure[RCId] = 0;
- else
- RegPressure[RCId] -= TLI->getRepRegClassCostFor(VT);
- }
- }
+void RegReductionPQBase::unscheduledNode(SUnit *SU) {
+ if (!TracksRegPressure)
+ return;
- dumpRegPressure();
- }
-
- void UnscheduledNode(SUnit *SU) {
- if (!TracksRegPressure)
- return;
-
- const SDNode *N = SU->getNode();
- if (!N->isMachineOpcode()) {
- if (N->getOpcode() != ISD::CopyToReg)
- return;
- } else {
- unsigned Opc = N->getMachineOpcode();
- if (Opc == TargetOpcode::EXTRACT_SUBREG ||
- Opc == TargetOpcode::INSERT_SUBREG ||
- Opc == TargetOpcode::SUBREG_TO_REG ||
- Opc == TargetOpcode::REG_SEQUENCE ||
- Opc == TargetOpcode::IMPLICIT_DEF)
- return;
- }
+ const SDNode *N = SU->getNode();
+ if (!N) return;
- for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
- I != E; ++I) {
- if (I->isCtrl())
- continue;
- SUnit *PredSU = I->getSUnit();
- if (PredSU->NumSuccsLeft != PredSU->NumSuccs)
- continue;
- const SDNode *PN = PredSU->getNode();
- if (!PN->isMachineOpcode()) {
- if (PN->getOpcode() == ISD::CopyFromReg) {
- EVT VT = PN->getValueType(0);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- }
- continue;
- }
- unsigned POpc = PN->getMachineOpcode();
- if (POpc == TargetOpcode::IMPLICIT_DEF)
- continue;
- if (POpc == TargetOpcode::EXTRACT_SUBREG) {
- EVT VT = PN->getOperand(0).getValueType();
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- continue;
- } else if (POpc == TargetOpcode::INSERT_SUBREG ||
- POpc == TargetOpcode::SUBREG_TO_REG) {
- EVT VT = PN->getValueType(0);
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- continue;
- }
- unsigned NumDefs = TII->get(PN->getMachineOpcode()).getNumDefs();
- for (unsigned i = 0; i != NumDefs; ++i) {
- EVT VT = PN->getValueType(i);
- if (!PN->hasAnyUseOfValue(i))
- continue;
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- if (RegPressure[RCId] < TLI->getRepRegClassCostFor(VT))
- // Register pressure tracking is imprecise. This can happen.
- RegPressure[RCId] = 0;
- else
- RegPressure[RCId] -= TLI->getRepRegClassCostFor(VT);
- }
- }
+ if (!N->isMachineOpcode()) {
+ if (N->getOpcode() != ISD::CopyToReg)
+ return;
+ } else {
+ unsigned Opc = N->getMachineOpcode();
+ if (Opc == TargetOpcode::EXTRACT_SUBREG ||
+ Opc == TargetOpcode::INSERT_SUBREG ||
+ Opc == TargetOpcode::SUBREG_TO_REG ||
+ Opc == TargetOpcode::REG_SEQUENCE ||
+ Opc == TargetOpcode::IMPLICIT_DEF)
+ return;
+ }
- // Check for isMachineOpcode() as PrescheduleNodesWithMultipleUses()
- // may transfer data dependencies to CopyToReg.
- if (SU->NumSuccs && N->isMachineOpcode()) {
- unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
- for (unsigned i = NumDefs, e = N->getNumValues(); i != e; ++i) {
- EVT VT = N->getValueType(i);
- if (VT == MVT::Glue || VT == MVT::Other)
- continue;
- if (!N->hasAnyUseOfValue(i))
- continue;
- unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
- RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
- }
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl())
+ continue;
+ SUnit *PredSU = I->getSUnit();
+ // NumSuccsLeft counts all deps. Don't compare it with NumSuccs which only
+ // counts data deps.
+ if (PredSU->NumSuccsLeft != PredSU->Succs.size())
+ continue;
+ const SDNode *PN = PredSU->getNode();
+ if (!PN->isMachineOpcode()) {
+ if (PN->getOpcode() == ISD::CopyFromReg) {
+ EVT VT = PN->getValueType(0);
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
}
-
- dumpRegPressure();
+ continue;
}
-
- void setScheduleDAG(ScheduleDAGRRList *scheduleDag) {
- scheduleDAG = scheduleDag;
+ unsigned POpc = PN->getMachineOpcode();
+ if (POpc == TargetOpcode::IMPLICIT_DEF)
+ continue;
+ if (POpc == TargetOpcode::EXTRACT_SUBREG ||
+ POpc == TargetOpcode::INSERT_SUBREG ||
+ POpc == TargetOpcode::SUBREG_TO_REG) {
+ EVT VT = PN->getValueType(0);
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
+ continue;
}
-
- void dumpRegPressure() const {
- for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
- E = TRI->regclass_end(); I != E; ++I) {
- const TargetRegisterClass *RC = *I;
- unsigned Id = RC->getID();
- unsigned RP = RegPressure[Id];
- if (!RP) continue;
- DEBUG(dbgs() << RC->getName() << ": " << RP << " / " << RegLimit[Id]
- << '\n');
- }
+ unsigned NumDefs = TII->get(PN->getMachineOpcode()).getNumDefs();
+ for (unsigned i = 0; i != NumDefs; ++i) {
+ EVT VT = PN->getValueType(i);
+ if (!PN->hasAnyUseOfValue(i))
+ continue;
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ if (RegPressure[RCId] < TLI->getRepRegClassCostFor(VT))
+ // Register pressure tracking is imprecise. This can happen.
+ RegPressure[RCId] = 0;
+ else
+ RegPressure[RCId] -= TLI->getRepRegClassCostFor(VT);
}
+ }
- void dump(ScheduleDAG *DAG) const {
- // Emulate pop() without clobbering NodeQueueIds.
- std::vector<SUnit*> DumpQueue = Queue;
- SF DumpPicker = Picker;
- while (!DumpQueue.empty()) {
- SUnit *SU = popFromQueue(DumpQueue, DumpPicker);
- if (isBottomUp())
- dbgs() << "Height " << SU->getHeight() << ": ";
- else
- dbgs() << "Depth " << SU->getDepth() << ": ";
- SU->dump(DAG);
- }
+ // Check for isMachineOpcode() as PrescheduleNodesWithMultipleUses()
+ // may transfer data dependencies to CopyToReg.
+ if (SU->NumSuccs && N->isMachineOpcode()) {
+ unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
+ for (unsigned i = NumDefs, e = N->getNumValues(); i != e; ++i) {
+ EVT VT = N->getValueType(i);
+ if (VT == MVT::Glue || VT == MVT::Other)
+ continue;
+ if (!N->hasAnyUseOfValue(i))
+ continue;
+ unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
+ RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
}
+ }
- protected:
- bool canClobber(const SUnit *SU, const SUnit *Op);
- void AddPseudoTwoAddrDeps();
- void PrescheduleNodesWithMultipleUses();
- void CalculateSethiUllmanNumbers();
- };
-
- typedef RegReductionPriorityQueue<bu_ls_rr_sort>
- BURegReductionPriorityQueue;
-
- typedef RegReductionPriorityQueue<td_ls_rr_sort>
- TDRegReductionPriorityQueue;
-
- typedef RegReductionPriorityQueue<src_ls_rr_sort>
- SrcRegReductionPriorityQueue;
-
- typedef RegReductionPriorityQueue<hybrid_ls_rr_sort>
- HybridBURRPriorityQueue;
-
- typedef RegReductionPriorityQueue<ilp_ls_rr_sort>
- ILPBURRPriorityQueue;
+ dumpRegPressure();
}
+//===----------------------------------------------------------------------===//
+// Dynamic Node Priority for Register Pressure Reduction
+//===----------------------------------------------------------------------===//
+
/// closestSucc - Returns the scheduled cycle of the successor which is
/// closest to the current cycle.
static unsigned closestSucc(const SUnit *SU) {
return Scratches;
}
-/// hasOnlyLiveOutUse - Return true if SU has a single value successor that is a
+/// hasOnlyLiveInOpers - Return true if SU has only value predecessors that are
+/// CopyFromReg from a virtual register.
+static bool hasOnlyLiveInOpers(const SUnit *SU) {
+ bool RetVal = false;
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl()) continue;
+ const SUnit *PredSU = I->getSUnit();
+ if (PredSU->getNode() &&
+ PredSU->getNode()->getOpcode() == ISD::CopyFromReg) {
+ unsigned Reg =
+ cast<RegisterSDNode>(PredSU->getNode()->getOperand(1))->getReg();
+ if (TargetRegisterInfo::isVirtualRegister(Reg)) {
+ RetVal = true;
+ continue;
+ }
+ }
+ return false;
+ }
+ return RetVal;
+}
+
+/// hasOnlyLiveOutUses - Return true if SU has only value successors that are
/// CopyToReg to a virtual register. This SU def is probably a liveout and
/// it has no other use. It should be scheduled closer to the terminator.
static bool hasOnlyLiveOutUses(const SUnit *SU) {
return RetVal;
}
-/// UnitsSharePred - Return true if the two scheduling units share a common
-/// data predecessor.
-static bool UnitsSharePred(const SUnit *left, const SUnit *right) {
- SmallSet<const SUnit*, 4> Preds;
- for (SUnit::const_pred_iterator I = left->Preds.begin(),E = left->Preds.end();
+// Set isVRegCycle for a node with only live in opers and live out uses. Also
+// set isVRegCycle for its CopyFromReg operands.
+//
+// This is only relevant for single-block loops, in which case the VRegCycle
+// node is likely an induction variable in which the operand and target virtual
+// registers should be coalesced (e.g. pre/post increment values). Setting the
+// isVRegCycle flag helps the scheduler prioritize other uses of the same
+// CopyFromReg so that this node becomes the virtual register "kill". This
+// avoids interference between the values live in and out of the block and
+// eliminates a copy inside the loop.
+static void initVRegCycle(SUnit *SU) {
+ if (DisableSchedVRegCycle)
+ return;
+
+ if (!hasOnlyLiveInOpers(SU) || !hasOnlyLiveOutUses(SU))
+ return;
+
+ DEBUG(dbgs() << "VRegCycle: SU(" << SU->NodeNum << ")\n");
+
+ SU->isVRegCycle = true;
+
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ if (I->isCtrl()) continue;
+ I->getSUnit()->isVRegCycle = true;
+ }
+}
+
+// After scheduling the definition of a VRegCycle, clear the isVRegCycle flag of
+// CopyFromReg operands. We should no longer penalize other uses of this VReg.
+static void resetVRegCycle(SUnit *SU) {
+ if (!SU->isVRegCycle)
+ return;
+
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl()) continue; // ignore chain preds
- Preds.insert(I->getSUnit());
+ SUnit *PredSU = I->getSUnit();
+ if (PredSU->isVRegCycle) {
+ assert(PredSU->getNode()->getOpcode() == ISD::CopyFromReg &&
+ "VRegCycle def must be CopyFromReg");
+ I->getSUnit()->isVRegCycle = 0;
+ }
}
- for (SUnit::const_pred_iterator I = right->Preds.begin(),E = right->Preds.end();
+}
+
+// Return true if this SUnit uses a CopyFromReg node marked as a VRegCycle. This
+// means a node that defines the VRegCycle has not been scheduled yet.
+static bool hasVRegCycleUse(const SUnit *SU) {
+ // If this SU also defines the VReg, don't hoist it as a "use".
+ if (SU->isVRegCycle)
+ return false;
+
+ for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl()) continue; // ignore chain preds
- if (Preds.count(I->getSUnit()))
+ if (I->getSUnit()->isVRegCycle &&
+ I->getSUnit()->getNode()->getOpcode() == ISD::CopyFromReg) {
+ DEBUG(dbgs() << " VReg cycle use: SU (" << SU->NodeNum << ")\n");
return true;
+ }
}
return false;
}
-template <typename RRSort>
-static bool BURRSort(const SUnit *left, const SUnit *right,
- const RegReductionPriorityQueue<RRSort> *SPQ) {
+// Check for either a dependence (latency) or resource (hazard) stall.
+//
+// Note: The ScheduleHazardRecognizer interface requires a non-const SU.
+static bool BUHasStall(SUnit *SU, int Height, RegReductionPQBase *SPQ) {
+ if ((int)SPQ->getCurCycle() < Height) return true;
+ if (SPQ->getHazardRec()->getHazardType(SU, 0)
+ != ScheduleHazardRecognizer::NoHazard)
+ return true;
+ return false;
+}
+
+// Return -1 if left has higher priority, 1 if right has higher priority.
+// Return 0 if latency-based priority is equivalent.
+static int BUCompareLatency(SUnit *left, SUnit *right, bool checkPref,
+ RegReductionPQBase *SPQ) {
+ // Scheduling an instruction that uses a VReg whose postincrement has not yet
+ // been scheduled will induce a copy. Model this as an extra cycle of latency.
+ int LPenalty = hasVRegCycleUse(left) ? 1 : 0;
+ int RPenalty = hasVRegCycleUse(right) ? 1 : 0;
+ int LHeight = (int)left->getHeight() + LPenalty;
+ int RHeight = (int)right->getHeight() + RPenalty;
+
+ bool LStall = (!checkPref || left->SchedulingPref == Sched::ILP) &&
+ BUHasStall(left, LHeight, SPQ);
+ bool RStall = (!checkPref || right->SchedulingPref == Sched::ILP) &&
+ BUHasStall(right, RHeight, SPQ);
+
+ // If scheduling one of the node will cause a pipeline stall, delay it.
+ // If scheduling either one of the node will cause a pipeline stall, sort
+ // them according to their height.
+ if (LStall) {
+ if (!RStall)
+ return 1;
+ if (LHeight != RHeight)
+ return LHeight > RHeight ? 1 : -1;
+ } else if (RStall)
+ return -1;
+
+ // If either node is scheduling for latency, sort them by height/depth
+ // and latency.
+ if (!checkPref || (left->SchedulingPref == Sched::ILP ||
+ right->SchedulingPref == Sched::ILP)) {
+ // If neither instruction stalls (!LStall && !RStall) and HazardRecognizer
+ // is enabled, grouping instructions by cycle, then its height is already
+ // covered so only its depth matters. We also reach this point if both stall
+ // but have the same height.
+ if (!SPQ->getHazardRec()->isEnabled()) {
+ if (LHeight != RHeight)
+ return LHeight > RHeight ? 1 : -1;
+ }
+ int LDepth = left->getDepth() - LPenalty;
+ int RDepth = right->getDepth() - RPenalty;
+ if (LDepth != RDepth) {
+ DEBUG(dbgs() << " Comparing latency of SU (" << left->NodeNum
+ << ") depth " << LDepth << " vs SU (" << right->NodeNum
+ << ") depth " << RDepth << "\n");
+ return LDepth < RDepth ? 1 : -1;
+ }
+ if (left->Latency != right->Latency)
+ return left->Latency > right->Latency ? 1 : -1;
+ }
+ return 0;
+}
+
+static bool BURRSort(SUnit *left, SUnit *right, RegReductionPQBase *SPQ) {
+ // Schedule physical register definitions close to their use. This is
+ // motivated by microarchitectures that can fuse cmp+jump macro-ops. But as
+ // long as shortening physreg live ranges is generally good, we can defer
+ // creating a subtarget hook.
+ if (!DisableSchedPhysRegJoin) {
+ bool LHasPhysReg = left->hasPhysRegDefs;
+ bool RHasPhysReg = right->hasPhysRegDefs;
+ if (LHasPhysReg != RHasPhysReg) {
+ #ifndef NDEBUG
+ const char *const PhysRegMsg[] = {" has no physreg"," defines a physreg"};
+ #endif
+ DEBUG(dbgs() << " SU (" << left->NodeNum << ") "
+ << PhysRegMsg[LHasPhysReg] << " SU(" << right->NodeNum << ") "
+ << PhysRegMsg[RHasPhysReg] << "\n");
+ return LHasPhysReg < RHasPhysReg;
+ }
+ }
+
+ // Prioritize by Sethi-Ulmann number and push CopyToReg nodes down.
unsigned LPriority = SPQ->getNodePriority(left);
unsigned RPriority = SPQ->getNodePriority(right);
+
+ // Be really careful about hoisting call operands above previous calls.
+ // Only allows it if it would reduce register pressure.
+ if (left->isCall && right->isCallOp) {
+ unsigned RNumVals = right->getNode()->getNumValues();
+ RPriority = (RPriority > RNumVals) ? (RPriority - RNumVals) : 0;
+ }
+ if (right->isCall && left->isCallOp) {
+ unsigned LNumVals = left->getNode()->getNumValues();
+ LPriority = (LPriority > LNumVals) ? (LPriority - LNumVals) : 0;
+ }
+
if (LPriority != RPriority)
return LPriority > RPriority;
+ // One or both of the nodes are calls and their sethi-ullman numbers are the
+ // same, then keep source order.
+ if (left->isCall || right->isCall) {
+ unsigned LOrder = SPQ->getNodeOrdering(left);
+ unsigned ROrder = SPQ->getNodeOrdering(right);
+
+ // Prefer an ordering where the lower the non-zero order number, the higher
+ // the preference.
+ if ((LOrder || ROrder) && LOrder != ROrder)
+ return LOrder != 0 && (LOrder < ROrder || ROrder == 0);
+ }
+
// Try schedule def + use closer when Sethi-Ullman numbers are the same.
// e.g.
// t1 = op t2, c1
if (LScratch != RScratch)
return LScratch > RScratch;
- // Note: with a bottom-up ready filter, the height check may be redundant.
- if (left->getHeight() != right->getHeight())
- return left->getHeight() > right->getHeight();
+ // Comparing latency against a call makes little sense unless the node
+ // is register pressure-neutral.
+ if ((left->isCall && RPriority > 0) || (right->isCall && LPriority > 0))
+ return (left->NodeQueueId > right->NodeQueueId);
- if (left->getDepth() != right->getDepth())
- return left->getDepth() < right->getDepth();
+ // Do not compare latencies when one or both of the nodes are calls.
+ if (!DisableSchedCycles &&
+ !(left->isCall || right->isCall)) {
+ int result = BUCompareLatency(left, right, false /*checkPref*/, SPQ);
+ if (result != 0)
+ return result > 0;
+ }
+ else {
+ if (left->getHeight() != right->getHeight())
+ return left->getHeight() > right->getHeight();
+
+ if (left->getDepth() != right->getDepth())
+ return left->getDepth() < right->getDepth();
+ }
assert(left->NodeQueueId && right->NodeQueueId &&
"NodeQueueId cannot be zero");
}
// Bottom up
-bool bu_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
+bool bu_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
+ if (int res = checkSpecialNodes(left, right))
+ return res > 0;
+
return BURRSort(left, right, SPQ);
}
// Source order, otherwise bottom up.
-bool src_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
+bool src_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
+ if (int res = checkSpecialNodes(left, right))
+ return res > 0;
+
unsigned LOrder = SPQ->getNodeOrdering(left);
unsigned ROrder = SPQ->getNodeOrdering(right);
return BURRSort(left, right, SPQ);
}
-bool hybrid_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const{
+// If the time between now and when the instruction will be ready can cover
+// the spill code, then avoid adding it to the ready queue. This gives long
+// stalls highest priority and allows hoisting across calls. It should also
+// speed up processing the available queue.
+bool hybrid_ls_rr_sort::isReady(SUnit *SU, unsigned CurCycle) const {
+ static const unsigned ReadyDelay = 3;
+
+ if (SPQ->MayReduceRegPressure(SU)) return true;
+
+ if (SU->getHeight() > (CurCycle + ReadyDelay)) return false;
+
+ if (SPQ->getHazardRec()->getHazardType(SU, -ReadyDelay)
+ != ScheduleHazardRecognizer::NoHazard)
+ return false;
+
+ return true;
+}
+
+// Return true if right should be scheduled with higher priority than left.
+bool hybrid_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
+ if (int res = checkSpecialNodes(left, right))
+ return res > 0;
+
if (left->isCall || right->isCall)
// No way to compute latency of calls.
return BURRSort(left, right, SPQ);
bool RHigh = SPQ->HighRegPressure(right);
// Avoid causing spills. If register pressure is high, schedule for
// register pressure reduction.
- if (LHigh && !RHigh)
+ if (LHigh && !RHigh) {
+ DEBUG(dbgs() << " pressure SU(" << left->NodeNum << ") > SU("
+ << right->NodeNum << ")\n");
return true;
- else if (!LHigh && RHigh)
+ }
+ else if (!LHigh && RHigh) {
+ DEBUG(dbgs() << " pressure SU(" << right->NodeNum << ") > SU("
+ << left->NodeNum << ")\n");
return false;
- else if (!LHigh && !RHigh) {
- // If the two nodes share an operand and one of them has a single
- // use that is a live out copy, favor the one that is live out. Otherwise
- // it will be difficult to eliminate the copy if the instruction is a
- // loop induction variable update. e.g.
- // BB:
- // sub r1, r3, #1
- // str r0, [r2, r3]
- // mov r3, r1
- // cmp
- // bne BB
- bool SharePred = UnitsSharePred(left, right);
- // FIXME: Only adjust if BB is a loop back edge.
- // FIXME: What's the cost of a copy?
- int LBonus = (SharePred && hasOnlyLiveOutUses(left)) ? 1 : 0;
- int RBonus = (SharePred && hasOnlyLiveOutUses(right)) ? 1 : 0;
- int LHeight = (int)left->getHeight() - LBonus;
- int RHeight = (int)right->getHeight() - RBonus;
-
- // Low register pressure situation, schedule for latency if possible.
- bool LStall = left->SchedulingPref == Sched::Latency &&
- (int)SPQ->getCurCycle() < LHeight;
- bool RStall = right->SchedulingPref == Sched::Latency &&
- (int)SPQ->getCurCycle() < RHeight;
- // If scheduling one of the node will cause a pipeline stall, delay it.
- // If scheduling either one of the node will cause a pipeline stall, sort
- // them according to their height.
- if (LStall) {
- if (!RStall)
- return true;
- if (LHeight != RHeight)
- return LHeight > RHeight;
- } else if (RStall)
- return false;
-
- // If either node is scheduling for latency, sort them by height
- // and latency.
- if (left->SchedulingPref == Sched::Latency ||
- right->SchedulingPref == Sched::Latency) {
- if (LHeight != RHeight)
- return LHeight > RHeight;
- if (left->Latency != right->Latency)
- return left->Latency > right->Latency;
- }
}
-
+ if (!LHigh && !RHigh) {
+ int result = BUCompareLatency(left, right, true /*checkPref*/, SPQ);
+ if (result != 0)
+ return result > 0;
+ }
return BURRSort(left, right, SPQ);
}
// Schedule as many instructions in each cycle as possible. So don't make an
// instruction available unless it is ready in the current cycle.
bool ilp_ls_rr_sort::isReady(SUnit *SU, unsigned CurCycle) const {
- return SU->getHeight() <= CurCycle;
+ if (SU->getHeight() > CurCycle) return false;
+
+ if (SPQ->getHazardRec()->getHazardType(SU, 0)
+ != ScheduleHazardRecognizer::NoHazard)
+ return false;
+
+ return true;
}
-bool ilp_ls_rr_sort::operator()(const SUnit *left,
- const SUnit *right) const {
+static bool canEnableCoalescing(SUnit *SU) {
+ unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0;
+ if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
+ // CopyToReg should be close to its uses to facilitate coalescing and
+ // avoid spilling.
+ return true;
+
+ if (Opc == TargetOpcode::EXTRACT_SUBREG ||
+ Opc == TargetOpcode::SUBREG_TO_REG ||
+ Opc == TargetOpcode::INSERT_SUBREG)
+ // EXTRACT_SUBREG, INSERT_SUBREG, and SUBREG_TO_REG nodes should be
+ // close to their uses to facilitate coalescing.
+ return true;
+
+ if (SU->NumPreds == 0 && SU->NumSuccs != 0)
+ // If SU does not have a register def, schedule it close to its uses
+ // because it does not lengthen any live ranges.
+ return true;
+
+ return false;
+}
+
+// list-ilp is currently an experimental scheduler that allows various
+// heuristics to be enabled prior to the normal register reduction logic.
+bool ilp_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
+ if (int res = checkSpecialNodes(left, right))
+ return res > 0;
+
if (left->isCall || right->isCall)
// No way to compute latency of calls.
return BURRSort(left, right, SPQ);
- bool LHigh = SPQ->HighRegPressure(left);
- bool RHigh = SPQ->HighRegPressure(right);
- // Avoid causing spills. If register pressure is high, schedule for
- // register pressure reduction.
- if (LHigh && !RHigh)
- return true;
- else if (!LHigh && RHigh)
- return false;
- else if (!LHigh && !RHigh) {
- // Low register pressure situation, schedule to maximize instruction level
- // parallelism.
- if (left->NumPreds > right->NumPreds)
- return false;
- else if (left->NumPreds < right->NumPreds)
- return false;
+ unsigned LLiveUses = 0, RLiveUses = 0;
+ int LPDiff = 0, RPDiff = 0;
+ if (!DisableSchedRegPressure || !DisableSchedLiveUses) {
+ LPDiff = SPQ->RegPressureDiff(left, LLiveUses);
+ RPDiff = SPQ->RegPressureDiff(right, RLiveUses);
+ }
+ if (!DisableSchedRegPressure && LPDiff != RPDiff) {
+ DEBUG(dbgs() << "RegPressureDiff SU(" << left->NodeNum << "): " << LPDiff
+ << " != SU(" << right->NodeNum << "): " << RPDiff << "\n");
+ return LPDiff > RPDiff;
+ }
+
+ if (!DisableSchedRegPressure && (LPDiff > 0 || RPDiff > 0)) {
+ bool LReduce = canEnableCoalescing(left);
+ bool RReduce = canEnableCoalescing(right);
+ if (LReduce && !RReduce) return false;
+ if (RReduce && !LReduce) return true;
+ }
+
+ if (!DisableSchedLiveUses && (LLiveUses != RLiveUses)) {
+ DEBUG(dbgs() << "Live uses SU(" << left->NodeNum << "): " << LLiveUses
+ << " != SU(" << right->NodeNum << "): " << RLiveUses << "\n");
+ return LLiveUses < RLiveUses;
+ }
+
+ if (!DisableSchedStalls) {
+ bool LStall = BUHasStall(left, left->getHeight(), SPQ);
+ bool RStall = BUHasStall(right, right->getHeight(), SPQ);
+ if (LStall != RStall)
+ return left->getHeight() > right->getHeight();
+ }
+
+ if (!DisableSchedCriticalPath) {
+ int spread = (int)left->getDepth() - (int)right->getDepth();
+ if (std::abs(spread) > MaxReorderWindow) {
+ DEBUG(dbgs() << "Depth of SU(" << left->NodeNum << "): "
+ << left->getDepth() << " != SU(" << right->NodeNum << "): "
+ << right->getDepth() << "\n");
+ return left->getDepth() < right->getDepth();
+ }
+ }
+
+ if (!DisableSchedHeight && left->getHeight() != right->getHeight()) {
+ int spread = (int)left->getHeight() - (int)right->getHeight();
+ if (std::abs(spread) > MaxReorderWindow)
+ return left->getHeight() > right->getHeight();
}
return BURRSort(left, right, SPQ);
}
-template<class SF>
-bool
-RegReductionPriorityQueue<SF>::canClobber(const SUnit *SU, const SUnit *Op) {
+void RegReductionPQBase::initNodes(std::vector<SUnit> &sunits) {
+ SUnits = &sunits;
+ // Add pseudo dependency edges for two-address nodes.
+ if (!Disable2AddrHack)
+ AddPseudoTwoAddrDeps();
+ // Reroute edges to nodes with multiple uses.
+ if (!TracksRegPressure && !SrcOrder)
+ PrescheduleNodesWithMultipleUses();
+ // Calculate node priorities.
+ CalculateSethiUllmanNumbers();
+
+ // For single block loops, mark nodes that look like canonical IV increments.
+ if (scheduleDAG->BB->isSuccessor(scheduleDAG->BB)) {
+ for (unsigned i = 0, e = sunits.size(); i != e; ++i) {
+ initVRegCycle(&sunits[i]);
+ }
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// Preschedule for Register Pressure
+//===----------------------------------------------------------------------===//
+
+bool RegReductionPQBase::canClobber(const SUnit *SU, const SUnit *Op) {
if (SU->isTwoAddress) {
unsigned Opc = SU->getNode()->getMachineOpcode();
- const TargetInstrDesc &TID = TII->get(Opc);
- unsigned NumRes = TID.getNumDefs();
- unsigned NumOps = TID.getNumOperands() - NumRes;
+ const MCInstrDesc &MCID = TII->get(Opc);
+ unsigned NumRes = MCID.getNumDefs();
+ unsigned NumOps = MCID.getNumOperands() - NumRes;
for (unsigned i = 0; i != NumOps; ++i) {
- if (TID.getOperandConstraint(i+NumRes, TOI::TIED_TO) != -1) {
+ if (MCID.getOperandConstraint(i+NumRes, MCOI::TIED_TO) != -1) {
SDNode *DU = SU->getNode()->getOperand(i).getNode();
if (DU->getNodeId() != -1 &&
Op->OrigNode == &(*SUnits)[DU->getNodeId()])
return false;
}
+/// canClobberReachingPhysRegUse - True if SU would clobber one of it's
+/// successor's explicit physregs whose definition can reach DepSU.
+/// i.e. DepSU should not be scheduled above SU.
+static bool canClobberReachingPhysRegUse(const SUnit *DepSU, const SUnit *SU,
+ ScheduleDAGRRList *scheduleDAG,
+ const TargetInstrInfo *TII,
+ const TargetRegisterInfo *TRI) {
+ const uint16_t *ImpDefs
+ = TII->get(SU->getNode()->getMachineOpcode()).getImplicitDefs();
+ const uint32_t *RegMask = getNodeRegMask(SU->getNode());
+ if(!ImpDefs && !RegMask)
+ return false;
+
+ for (SUnit::const_succ_iterator SI = SU->Succs.begin(), SE = SU->Succs.end();
+ SI != SE; ++SI) {
+ SUnit *SuccSU = SI->getSUnit();
+ for (SUnit::const_pred_iterator PI = SuccSU->Preds.begin(),
+ PE = SuccSU->Preds.end(); PI != PE; ++PI) {
+ if (!PI->isAssignedRegDep())
+ continue;
+
+ if (RegMask && MachineOperand::clobbersPhysReg(RegMask, PI->getReg()) &&
+ scheduleDAG->IsReachable(DepSU, PI->getSUnit()))
+ return true;
+
+ if (ImpDefs)
+ for (const uint16_t *ImpDef = ImpDefs; *ImpDef; ++ImpDef)
+ // Return true if SU clobbers this physical register use and the
+ // definition of the register reaches from DepSU. IsReachable queries
+ // a topological forward sort of the DAG (following the successors).
+ if (TRI->regsOverlap(*ImpDef, PI->getReg()) &&
+ scheduleDAG->IsReachable(DepSU, PI->getSUnit()))
+ return true;
+ }
+ }
+ return false;
+}
+
/// canClobberPhysRegDefs - True if SU would clobber one of SuccSU's
/// physical register defs.
static bool canClobberPhysRegDefs(const SUnit *SuccSU, const SUnit *SU,
const TargetRegisterInfo *TRI) {
SDNode *N = SuccSU->getNode();
unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
- const unsigned *ImpDefs = TII->get(N->getMachineOpcode()).getImplicitDefs();
+ const uint16_t *ImpDefs = TII->get(N->getMachineOpcode()).getImplicitDefs();
assert(ImpDefs && "Caller should check hasPhysRegDefs");
for (const SDNode *SUNode = SU->getNode(); SUNode;
SUNode = SUNode->getGluedNode()) {
if (!SUNode->isMachineOpcode())
continue;
- const unsigned *SUImpDefs =
+ const uint16_t *SUImpDefs =
TII->get(SUNode->getMachineOpcode()).getImplicitDefs();
- if (!SUImpDefs)
- return false;
+ const uint32_t *SURegMask = getNodeRegMask(SUNode);
+ if (!SUImpDefs && !SURegMask)
+ continue;
for (unsigned i = NumDefs, e = N->getNumValues(); i != e; ++i) {
EVT VT = N->getValueType(i);
if (VT == MVT::Glue || VT == MVT::Other)
if (!N->hasAnyUseOfValue(i))
continue;
unsigned Reg = ImpDefs[i - NumDefs];
+ if (SURegMask && MachineOperand::clobbersPhysReg(SURegMask, Reg))
+ return true;
+ if (!SUImpDefs)
+ continue;
for (;*SUImpDefs; ++SUImpDefs) {
unsigned SUReg = *SUImpDefs;
if (TRI->regsOverlap(Reg, SUReg))
/// after N, which shortens the U->N live range, reducing
/// register pressure.
///
-template<class SF>
-void RegReductionPriorityQueue<SF>::PrescheduleNodesWithMultipleUses() {
+void RegReductionPQBase::PrescheduleNodesWithMultipleUses() {
// Visit all the nodes in topological order, working top-down.
for (unsigned i = 0, e = SUnits->size(); i != e; ++i) {
SUnit *SU = &(*SUnits)[i];
if (PredSU->NumSuccs == 1)
continue;
// Avoid prescheduling to copies from virtual registers, which don't behave
- // like other nodes from the perspective of scheduling // heuristics.
+ // like other nodes from the perspective of scheduling heuristics.
if (SDNode *N = SU->getNode())
if (N->getOpcode() == ISD::CopyFromReg &&
TargetRegisterInfo::isVirtualRegister
/// 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.
-template<class SF>
-void RegReductionPriorityQueue<SF>::AddPseudoTwoAddrDeps() {
+void RegReductionPQBase::AddPseudoTwoAddrDeps() {
for (unsigned i = 0, e = SUnits->size(); i != e; ++i) {
SUnit *SU = &(*SUnits)[i];
if (!SU->isTwoAddress)
bool isLiveOut = hasOnlyLiveOutUses(SU);
unsigned Opc = Node->getMachineOpcode();
- const TargetInstrDesc &TID = TII->get(Opc);
- unsigned NumRes = TID.getNumDefs();
- unsigned NumOps = TID.getNumOperands() - NumRes;
+ const MCInstrDesc &MCID = TII->get(Opc);
+ unsigned NumRes = MCID.getNumDefs();
+ unsigned NumOps = MCID.getNumOperands() - NumRes;
for (unsigned j = 0; j != NumOps; ++j) {
- if (TID.getOperandConstraint(j+NumRes, TOI::TIED_TO) == -1)
+ if (MCID.getOperandConstraint(j+NumRes, MCOI::TIED_TO) == -1)
continue;
SDNode *DU = SU->getNode()->getOperand(j).getNode();
if (DU->getNodeId() == -1)
SuccOpc == TargetOpcode::INSERT_SUBREG ||
SuccOpc == TargetOpcode::SUBREG_TO_REG)
continue;
- if ((!canClobber(SuccSU, DUSU) ||
+ if (!canClobberReachingPhysRegUse(SuccSU, SU, scheduleDAG, TII, TRI) &&
+ (!canClobber(SuccSU, DUSU) ||
(isLiveOut && !hasOnlyLiveOutUses(SuccSU)) ||
(!SU->isCommutable && SuccSU->isCommutable)) &&
!scheduleDAG->IsReachable(SuccSU, SU)) {
}
}
-/// CalculateSethiUllmanNumbers - Calculate Sethi-Ullman numbers of all
-/// scheduling units.
-template<class SF>
-void RegReductionPriorityQueue<SF>::CalculateSethiUllmanNumbers() {
- SethiUllmanNumbers.assign(SUnits->size(), 0);
-
- for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
- CalcNodeSethiUllmanNumber(&(*SUnits)[i], SethiUllmanNumbers);
-}
-
-/// 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) {
- const SUnit *SuccSU = I->getSUnit();
- for (SUnit::const_pred_iterator II = SuccSU->Preds.begin(),
- EE = SuccSU->Preds.end(); II != EE; ++II) {
- SUnit *PredSU = II->getSUnit();
- if (!PredSU->isScheduled)
- if (++Sum > Limit)
- return Sum;
- }
- }
- return Sum;
-}
-
-
-// Top down
-bool td_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
- unsigned LPriority = SPQ->getNodePriority(left);
- unsigned RPriority = SPQ->getNodePriority(right);
- bool LIsTarget = left->getNode() && left->getNode()->isMachineOpcode();
- bool RIsTarget = right->getNode() && right->getNode()->isMachineOpcode();
- bool LIsFloater = LIsTarget && left->NumPreds == 0;
- bool RIsFloater = RIsTarget && right->NumPreds == 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;
-
- if (LIsFloater)
- LBonus -= 2;
- if (RIsFloater)
- RBonus -= 2;
- if (left->NumSuccs == 1)
- LBonus += 2;
- if (right->NumSuccs == 1)
- RBonus += 2;
-
- if (LPriority+LBonus != RPriority+RBonus)
- return LPriority+LBonus < RPriority+RBonus;
-
- if (left->getDepth() != right->getDepth())
- return left->getDepth() < right->getDepth();
-
- if (left->NumSuccsLeft != right->NumSuccsLeft)
- return left->NumSuccsLeft > right->NumSuccsLeft;
-
- assert(left->NodeQueueId && right->NodeQueueId &&
- "NodeQueueId cannot be zero");
- return (left->NodeQueueId > right->NodeQueueId);
-}
-
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
BURegReductionPriorityQueue *PQ =
- new BURegReductionPriorityQueue(*IS->MF, false, TII, TRI, 0);
- ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, false, PQ, OptLevel);
- PQ->setScheduleDAG(SD);
- return SD;
-}
-
-llvm::ScheduleDAGSDNodes *
-llvm::createTDRRListDAGScheduler(SelectionDAGISel *IS,
- CodeGenOpt::Level OptLevel) {
- const TargetMachine &TM = IS->TM;
- const TargetInstrInfo *TII = TM.getInstrInfo();
- const TargetRegisterInfo *TRI = TM.getRegisterInfo();
-
- TDRegReductionPriorityQueue *PQ =
- new TDRegReductionPriorityQueue(*IS->MF, false, TII, TRI, 0);
+ new BURegReductionPriorityQueue(*IS->MF, false, false, TII, TRI, 0);
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, false, PQ, OptLevel);
PQ->setScheduleDAG(SD);
return SD;
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
SrcRegReductionPriorityQueue *PQ =
- new SrcRegReductionPriorityQueue(*IS->MF, false, TII, TRI, 0);
+ new SrcRegReductionPriorityQueue(*IS->MF, false, true, TII, TRI, 0);
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, false, PQ, OptLevel);
PQ->setScheduleDAG(SD);
return SD;
const TargetLowering *TLI = &IS->getTargetLowering();
HybridBURRPriorityQueue *PQ =
- new HybridBURRPriorityQueue(*IS->MF, true, TII, TRI, TLI);
+ new HybridBURRPriorityQueue(*IS->MF, true, false, TII, TRI, TLI);
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, true, PQ, OptLevel);
PQ->setScheduleDAG(SD);
const TargetLowering *TLI = &IS->getTargetLowering();
ILPBURRPriorityQueue *PQ =
- new ILPBURRPriorityQueue(*IS->MF, true, TII, TRI, TLI);
+ new ILPBURRPriorityQueue(*IS->MF, true, false, TII, TRI, TLI);
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, true, PQ, OptLevel);
PQ->setScheduleDAG(SD);
return SD;
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