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llvm-6502/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
Chandler Carruth 8677f2ff9a [Modules] Remove potential ODR violations by sinking the DEBUG_TYPE 
define below all header includes in the lib/CodeGen/... tree. While the
current modules implementation doesn't check for this kind of ODR
violation yet, it is likely to grow support for it in the future. It
also removes one layer of macro pollution across all the included
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206837 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-22 02:02:50 +00:00

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//===----- ScheduleDAGFast.cpp - Fast poor list scheduler -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements a fast scheduler.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "InstrEmitter.h"
#include "ScheduleDAGSDNodes.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
#define DEBUG_TYPE "pre-RA-sched"
STATISTIC(NumUnfolds, "Number of nodes unfolded");
STATISTIC(NumDups, "Number of duplicated nodes");
STATISTIC(NumPRCopies, "Number of physical copies");
static RegisterScheduler
fastDAGScheduler("fast", "Fast suboptimal list scheduling",
createFastDAGScheduler);
static RegisterScheduler
linearizeDAGScheduler("linearize", "Linearize DAG, no scheduling",
createDAGLinearizer);
namespace {
/// FastPriorityQueue - A degenerate priority queue that considers
/// all nodes to have the same priority.
///
struct FastPriorityQueue {
SmallVector<SUnit *, 16> Queue;
bool empty() const { return Queue.empty(); }
void push(SUnit *U) {
Queue.push_back(U);
}
SUnit *pop() {
if (empty()) return nullptr;
SUnit *V = Queue.back();
Queue.pop_back();
return V;
}
};
//===----------------------------------------------------------------------===//
/// ScheduleDAGFast - The actual "fast" list scheduler implementation.
///
class ScheduleDAGFast : public ScheduleDAGSDNodes {
private:
/// AvailableQueue - The priority queue to use for the available SUnits.
FastPriorityQueue AvailableQueue;
/// LiveRegDefs - A set of physical registers and their definition
/// that are "live". These nodes must be scheduled before any other nodes that
/// modifies the registers can be scheduled.
unsigned NumLiveRegs;
std::vector<SUnit*> LiveRegDefs;
std::vector<unsigned> LiveRegCycles;
public:
ScheduleDAGFast(MachineFunction &mf)
: ScheduleDAGSDNodes(mf) {}
void Schedule() override;
/// AddPred - adds a predecessor edge to SUnit SU.
/// This returns true if this is a new predecessor.
void AddPred(SUnit *SU, const SDep &D) {
SU->addPred(D);
}
/// RemovePred - removes a predecessor edge from SUnit SU.
/// This returns true if an edge was removed.
void RemovePred(SUnit *SU, const SDep &D) {
SU->removePred(D);
}
private:
void ReleasePred(SUnit *SU, SDep *PredEdge);
void ReleasePredecessors(SUnit *SU, unsigned CurCycle);
void ScheduleNodeBottomUp(SUnit*, unsigned);
SUnit *CopyAndMoveSuccessors(SUnit*);
void InsertCopiesAndMoveSuccs(SUnit*, unsigned,
const TargetRegisterClass*,
const TargetRegisterClass*,
SmallVectorImpl<SUnit*>&);
bool DelayForLiveRegsBottomUp(SUnit*, SmallVectorImpl<unsigned>&);
void ListScheduleBottomUp();
/// forceUnitLatencies - The fast scheduler doesn't care about real latencies.
bool forceUnitLatencies() const override { return true; }
};
} // end anonymous namespace
/// Schedule - Schedule the DAG using list scheduling.
void ScheduleDAGFast::Schedule() {
DEBUG(dbgs() << "********** List Scheduling **********\n");
NumLiveRegs = 0;
LiveRegDefs.resize(TRI->getNumRegs(), nullptr);
LiveRegCycles.resize(TRI->getNumRegs(), 0);
// Build the scheduling graph.
BuildSchedGraph(nullptr);
DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su)
SUnits[su].dumpAll(this));
// Execute the actual scheduling loop.
ListScheduleBottomUp();
}
//===----------------------------------------------------------------------===//
// Bottom-Up Scheduling
//===----------------------------------------------------------------------===//
/// ReleasePred - Decrement the NumSuccsLeft count of a predecessor. Add it to
/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGFast::ReleasePred(SUnit *SU, SDep *PredEdge) {
SUnit *PredSU = PredEdge->getSUnit();
#ifndef NDEBUG
if (PredSU->NumSuccsLeft == 0) {
dbgs() << "*** Scheduling failed! ***\n";
PredSU->dump(this);
dbgs() << " has been released too many times!\n";
llvm_unreachable(nullptr);
}
#endif
--PredSU->NumSuccsLeft;
// If all the node's successors are scheduled, this node is ready
// to be scheduled. Ignore the special EntrySU node.
if (PredSU->NumSuccsLeft == 0 && PredSU != &EntrySU) {
PredSU->isAvailable = true;
AvailableQueue.push(PredSU);
}
}
void ScheduleDAGFast::ReleasePredecessors(SUnit *SU, unsigned CurCycle) {
// Bottom up: release predecessors
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
ReleasePred(SU, &*I);
if (I->isAssignedRegDep()) {
// This is a physical register dependency and it's impossible or
// expensive to copy the register. Make sure nothing that can
// clobber the register is scheduled between the predecessor and
// this node.
if (!LiveRegDefs[I->getReg()]) {
++NumLiveRegs;
LiveRegDefs[I->getReg()] = I->getSUnit();
LiveRegCycles[I->getReg()] = CurCycle;
}
}
}
}
/// 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.
void ScheduleDAGFast::ScheduleNodeBottomUp(SUnit *SU, unsigned CurCycle) {
DEBUG(dbgs() << "*** Scheduling [" << CurCycle << "]: ");
DEBUG(SU->dump(this));
assert(CurCycle >= SU->getHeight() && "Node scheduled below its height!");
SU->setHeightToAtLeast(CurCycle);
Sequence.push_back(SU);
ReleasePredecessors(SU, CurCycle);
// Release all the implicit physical register defs that are live.
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isAssignedRegDep()) {
if (LiveRegCycles[I->getReg()] == I->getSUnit()->getHeight()) {
assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
assert(LiveRegDefs[I->getReg()] == SU &&
"Physical register dependency violated?");
--NumLiveRegs;
LiveRegDefs[I->getReg()] = nullptr;
LiveRegCycles[I->getReg()] = 0;
}
}
}
SU->isScheduled = true;
}
/// CopyAndMoveSuccessors - Clone the specified node and move its scheduled
/// successors to the newly created node.
SUnit *ScheduleDAGFast::CopyAndMoveSuccessors(SUnit *SU) {
if (SU->getNode()->getGluedNode())
return nullptr;
SDNode *N = SU->getNode();
if (!N)
return nullptr;
SUnit *NewSU;
bool TryUnfold = false;
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
EVT VT = N->getValueType(i);
if (VT == MVT::Glue)
return nullptr;
else if (VT == MVT::Other)
TryUnfold = true;
}
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
const SDValue &Op = N->getOperand(i);
EVT VT = Op.getNode()->getValueType(Op.getResNo());
if (VT == MVT::Glue)
return nullptr;
}
if (TryUnfold) {
SmallVector<SDNode*, 2> NewNodes;
if (!TII->unfoldMemoryOperand(*DAG, N, NewNodes))
return nullptr;
DEBUG(dbgs() << "Unfolding SU # " << SU->NodeNum << "\n");
assert(NewNodes.size() == 2 && "Expected a load folding node!");
N = NewNodes[1];
SDNode *LoadNode = NewNodes[0];
unsigned NumVals = N->getNumValues();
unsigned OldNumVals = SU->getNode()->getNumValues();
for (unsigned i = 0; i != NumVals; ++i)
DAG->ReplaceAllUsesOfValueWith(SDValue(SU->getNode(), i), SDValue(N, i));
DAG->ReplaceAllUsesOfValueWith(SDValue(SU->getNode(), OldNumVals-1),
SDValue(LoadNode, 1));
SUnit *NewSU = newSUnit(N);
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NewSU->NodeNum);
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 (MCID.isCommutable())
NewSU->isCommutable = true;
// LoadNode may already exist. This can happen when there is another
// load from the same location and producing the same type of value
// but it has different alignment or volatileness.
bool isNewLoad = true;
SUnit *LoadSU;
if (LoadNode->getNodeId() != -1) {
LoadSU = &SUnits[LoadNode->getNodeId()];
isNewLoad = false;
} else {
LoadSU = newSUnit(LoadNode);
LoadNode->setNodeId(LoadSU->NodeNum);
}
SDep ChainPred;
SmallVector<SDep, 4> ChainSuccs;
SmallVector<SDep, 4> LoadPreds;
SmallVector<SDep, 4> NodePreds;
SmallVector<SDep, 4> NodeSuccs;
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl())
ChainPred = *I;
else if (I->getSUnit()->getNode() &&
I->getSUnit()->getNode()->isOperandOf(LoadNode))
LoadPreds.push_back(*I);
else
NodePreds.push_back(*I);
}
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isCtrl())
ChainSuccs.push_back(*I);
else
NodeSuccs.push_back(*I);
}
if (ChainPred.getSUnit()) {
RemovePred(SU, ChainPred);
if (isNewLoad)
AddPred(LoadSU, ChainPred);
}
for (unsigned i = 0, e = LoadPreds.size(); i != e; ++i) {
const SDep &Pred = LoadPreds[i];
RemovePred(SU, Pred);
if (isNewLoad) {
AddPred(LoadSU, Pred);
}
}
for (unsigned i = 0, e = NodePreds.size(); i != e; ++i) {
const SDep &Pred = NodePreds[i];
RemovePred(SU, Pred);
AddPred(NewSU, Pred);
}
for (unsigned i = 0, e = NodeSuccs.size(); i != e; ++i) {
SDep D = NodeSuccs[i];
SUnit *SuccDep = D.getSUnit();
D.setSUnit(SU);
RemovePred(SuccDep, D);
D.setSUnit(NewSU);
AddPred(SuccDep, D);
}
for (unsigned i = 0, e = ChainSuccs.size(); i != e; ++i) {
SDep D = ChainSuccs[i];
SUnit *SuccDep = D.getSUnit();
D.setSUnit(SU);
RemovePred(SuccDep, D);
if (isNewLoad) {
D.setSUnit(LoadSU);
AddPred(SuccDep, D);
}
}
if (isNewLoad) {
SDep D(LoadSU, SDep::Barrier);
D.setLatency(LoadSU->Latency);
AddPred(NewSU, D);
}
++NumUnfolds;
if (NewSU->NumSuccsLeft == 0) {
NewSU->isAvailable = true;
return NewSU;
}
SU = NewSU;
}
DEBUG(dbgs() << "Duplicating SU # " << SU->NodeNum << "\n");
NewSU = Clone(SU);
// New SUnit has the exact same predecessors.
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I)
if (!I->isArtificial())
AddPred(NewSU, *I);
// Only copy scheduled successors. Cut them from old node's successor
// list and move them over.
SmallVector<std::pair<SUnit *, SDep>, 4> DelDeps;
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isArtificial())
continue;
SUnit *SuccSU = I->getSUnit();
if (SuccSU->isScheduled) {
SDep D = *I;
D.setSUnit(NewSU);
AddPred(SuccSU, D);
D.setSUnit(SU);
DelDeps.push_back(std::make_pair(SuccSU, D));
}
}
for (unsigned i = 0, e = DelDeps.size(); i != e; ++i)
RemovePred(DelDeps[i].first, DelDeps[i].second);
++NumDups;
return NewSU;
}
/// InsertCopiesAndMoveSuccs - Insert register copies and move all
/// scheduled successors of the given SUnit to the last copy.
void ScheduleDAGFast::InsertCopiesAndMoveSuccs(SUnit *SU, unsigned Reg,
const TargetRegisterClass *DestRC,
const TargetRegisterClass *SrcRC,
SmallVectorImpl<SUnit*> &Copies) {
SUnit *CopyFromSU = newSUnit(static_cast<SDNode *>(nullptr));
CopyFromSU->CopySrcRC = SrcRC;
CopyFromSU->CopyDstRC = DestRC;
SUnit *CopyToSU = newSUnit(static_cast<SDNode *>(nullptr));
CopyToSU->CopySrcRC = DestRC;
CopyToSU->CopyDstRC = SrcRC;
// Only copy scheduled successors. Cut them from old node's successor
// list and move them over.
SmallVector<std::pair<SUnit *, SDep>, 4> DelDeps;
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isArtificial())
continue;
SUnit *SuccSU = I->getSUnit();
if (SuccSU->isScheduled) {
SDep D = *I;
D.setSUnit(CopyToSU);
AddPred(SuccSU, D);
DelDeps.push_back(std::make_pair(SuccSU, *I));
}
}
for (unsigned i = 0, e = DelDeps.size(); i != e; ++i) {
RemovePred(DelDeps[i].first, DelDeps[i].second);
}
SDep FromDep(SU, SDep::Data, Reg);
FromDep.setLatency(SU->Latency);
AddPred(CopyFromSU, FromDep);
SDep ToDep(CopyFromSU, SDep::Data, 0);
ToDep.setLatency(CopyFromSU->Latency);
AddPred(CopyToSU, ToDep);
Copies.push_back(CopyFromSU);
Copies.push_back(CopyToSU);
++NumPRCopies;
}
/// getPhysicalRegisterVT - Returns the ValueType of the physical register
/// definition of the specified node.
/// FIXME: Move to SelectionDAG?
static EVT getPhysicalRegisterVT(SDNode *N, unsigned Reg,
const TargetInstrInfo *TII) {
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;
}
return N->getValueType(NumRes);
}
/// CheckForLiveRegDef - Return true and update live register vector if the
/// specified register def of the specified SUnit clobbers any "live" registers.
static bool CheckForLiveRegDef(SUnit *SU, unsigned Reg,
std::vector<SUnit*> &LiveRegDefs,
SmallSet<unsigned, 4> &RegAdded,
SmallVectorImpl<unsigned> &LRegs,
const TargetRegisterInfo *TRI) {
bool Added = false;
for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
if (LiveRegDefs[*AI] && LiveRegDefs[*AI] != SU) {
if (RegAdded.insert(*AI)) {
LRegs.push_back(*AI);
Added = true;
}
}
}
return Added;
}
/// DelayForLiveRegsBottomUp - Returns true if it is necessary to delay
/// scheduling of the given node to satisfy live physical register dependencies.
/// If the specific node is the last one that's available to schedule, do
/// whatever is necessary (i.e. backtracking or cloning) to make it possible.
bool ScheduleDAGFast::DelayForLiveRegsBottomUp(SUnit *SU,
SmallVectorImpl<unsigned> &LRegs){
if (NumLiveRegs == 0)
return false;
SmallSet<unsigned, 4> RegAdded;
// If this node would clobber any "live" register, then it's not ready.
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
if (I->isAssignedRegDep()) {
CheckForLiveRegDef(I->getSUnit(), I->getReg(), LiveRegDefs,
RegAdded, LRegs, TRI);
}
}
for (SDNode *Node = SU->getNode(); Node; Node = Node->getGluedNode()) {
if (Node->getOpcode() == ISD::INLINEASM) {
// Inline asm can clobber physical defs.
unsigned NumOps = Node->getNumOperands();
if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue)
--NumOps; // Ignore the glue operand.
for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) {
unsigned Flags =
cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue();
unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
++i; // Skip the ID value.
if (InlineAsm::isRegDefKind(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 (TargetRegisterInfo::isPhysicalRegister(Reg))
CheckForLiveRegDef(SU, Reg, LiveRegDefs, RegAdded, LRegs, TRI);
}
} else
i += NumVals;
}
continue;
}
if (!Node->isMachineOpcode())
continue;
const MCInstrDesc &MCID = TII->get(Node->getMachineOpcode());
if (!MCID.ImplicitDefs)
continue;
for (const uint16_t *Reg = MCID.getImplicitDefs(); *Reg; ++Reg) {
CheckForLiveRegDef(SU, *Reg, LiveRegDefs, RegAdded, LRegs, TRI);
}
}
return !LRegs.empty();
}
/// ListScheduleBottomUp - The main loop of list scheduling for bottom-up
/// schedulers.
void ScheduleDAGFast::ListScheduleBottomUp() {
unsigned CurCycle = 0;
// Release any predecessors of the special Exit node.
ReleasePredecessors(&ExitSU, CurCycle);
// Add root to Available queue.
if (!SUnits.empty()) {
SUnit *RootSU = &SUnits[DAG->getRoot().getNode()->getNodeId()];
assert(RootSU->Succs.empty() && "Graph root shouldn't have successors!");
RootSU->isAvailable = true;
AvailableQueue.push(RootSU);
}
// While Available queue is not empty, grab the node with the highest
// priority. If it is not ready put it back. Schedule the node.
SmallVector<SUnit*, 4> NotReady;
DenseMap<SUnit*, SmallVector<unsigned, 4> > LRegsMap;
Sequence.reserve(SUnits.size());
while (!AvailableQueue.empty()) {
bool Delayed = false;
LRegsMap.clear();
SUnit *CurSU = AvailableQueue.pop();
while (CurSU) {
SmallVector<unsigned, 4> LRegs;
if (!DelayForLiveRegsBottomUp(CurSU, LRegs))
break;
Delayed = true;
LRegsMap.insert(std::make_pair(CurSU, LRegs));
CurSU->isPending = true; // This SU is not in AvailableQueue right now.
NotReady.push_back(CurSU);
CurSU = AvailableQueue.pop();
}
// All candidates are delayed due to live physical reg dependencies.
// Try code duplication or inserting cross class copies
// to resolve it.
if (Delayed && !CurSU) {
if (!CurSU) {
// Try duplicating the nodes that produces these
// "expensive to copy" values to break the dependency. In case even
// that doesn't work, insert cross class copies.
SUnit *TrySU = NotReady[0];
SmallVectorImpl<unsigned> &LRegs = LRegsMap[TrySU];
assert(LRegs.size() == 1 && "Can't handle this yet!");
unsigned Reg = LRegs[0];
SUnit *LRDef = LiveRegDefs[Reg];
EVT VT = getPhysicalRegisterVT(LRDef->getNode(), Reg, TII);
const TargetRegisterClass *RC =
TRI->getMinimalPhysRegClass(Reg, VT);
const TargetRegisterClass *DestRC = TRI->getCrossCopyRegClass(RC);
// 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 = nullptr;
if (DestRC != RC) {
NewDef = CopyAndMoveSuccessors(LRDef);
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;
InsertCopiesAndMoveSuccs(LRDef, Reg, DestRC, RC, Copies);
DEBUG(dbgs() << "Adding an edge from SU # " << TrySU->NodeNum
<< " to SU #" << Copies.front()->NodeNum << "\n");
AddPred(TrySU, SDep(Copies.front(), SDep::Artificial));
NewDef = Copies.back();
}
DEBUG(dbgs() << "Adding an edge from SU # " << NewDef->NodeNum
<< " to SU #" << TrySU->NodeNum << "\n");
LiveRegDefs[Reg] = NewDef;
AddPred(NewDef, SDep(TrySU, SDep::Artificial));
TrySU->isAvailable = false;
CurSU = NewDef;
}
if (!CurSU) {
llvm_unreachable("Unable to resolve live physical register dependencies!");
}
}
// Add the nodes that aren't ready back onto the available list.
for (unsigned i = 0, e = NotReady.size(); i != e; ++i) {
NotReady[i]->isPending = false;
// May no longer be available due to backtracking.
if (NotReady[i]->isAvailable)
AvailableQueue.push(NotReady[i]);
}
NotReady.clear();
if (CurSU)
ScheduleNodeBottomUp(CurSU, CurCycle);
++CurCycle;
}
// Reverse the order since it is bottom up.
std::reverse(Sequence.begin(), Sequence.end());
#ifndef NDEBUG
VerifyScheduledSequence(/*isBottomUp=*/true);
#endif
}
namespace {
//===----------------------------------------------------------------------===//
// ScheduleDAGLinearize - No scheduling scheduler, it simply linearize the
// DAG in topological order.
// IMPORTANT: this may not work for targets with phyreg dependency.
//
class ScheduleDAGLinearize : public ScheduleDAGSDNodes {
public:
ScheduleDAGLinearize(MachineFunction &mf) : ScheduleDAGSDNodes(mf) {}
void Schedule() override;
MachineBasicBlock *
EmitSchedule(MachineBasicBlock::iterator &InsertPos) override;
private:
std::vector<SDNode*> Sequence;
DenseMap<SDNode*, SDNode*> GluedMap; // Cache glue to its user
void ScheduleNode(SDNode *N);
};
} // end anonymous namespace
void ScheduleDAGLinearize::ScheduleNode(SDNode *N) {
if (N->getNodeId() != 0)
llvm_unreachable(nullptr);
if (!N->isMachineOpcode() &&
(N->getOpcode() == ISD::EntryToken || isPassiveNode(N)))
// These nodes do not need to be translated into MIs.
return;
DEBUG(dbgs() << "\n*** Scheduling: ");
DEBUG(N->dump(DAG));
Sequence.push_back(N);
unsigned NumOps = N->getNumOperands();
if (unsigned NumLeft = NumOps) {
SDNode *GluedOpN = nullptr;
do {
const SDValue &Op = N->getOperand(NumLeft-1);
SDNode *OpN = Op.getNode();
if (NumLeft == NumOps && Op.getValueType() == MVT::Glue) {
// Schedule glue operand right above N.
GluedOpN = OpN;
assert(OpN->getNodeId() != 0 && "Glue operand not ready?");
OpN->setNodeId(0);
ScheduleNode(OpN);
continue;
}
if (OpN == GluedOpN)
// Glue operand is already scheduled.
continue;
DenseMap<SDNode*, SDNode*>::iterator DI = GluedMap.find(OpN);
if (DI != GluedMap.end() && DI->second != N)
// Users of glues are counted against the glued users.
OpN = DI->second;
unsigned Degree = OpN->getNodeId();
assert(Degree > 0 && "Predecessor over-released!");
OpN->setNodeId(--Degree);
if (Degree == 0)
ScheduleNode(OpN);
} while (--NumLeft);
}
}
/// findGluedUser - Find the representative use of a glue value by walking
/// the use chain.
static SDNode *findGluedUser(SDNode *N) {
while (SDNode *Glued = N->getGluedUser())
N = Glued;
return N;
}
void ScheduleDAGLinearize::Schedule() {
DEBUG(dbgs() << "********** DAG Linearization **********\n");
SmallVector<SDNode*, 8> Glues;
unsigned DAGSize = 0;
for (SelectionDAG::allnodes_iterator I = DAG->allnodes_begin(),
E = DAG->allnodes_end(); I != E; ++I) {
SDNode *N = I;
// Use node id to record degree.
unsigned Degree = N->use_size();
N->setNodeId(Degree);
unsigned NumVals = N->getNumValues();
if (NumVals && N->getValueType(NumVals-1) == MVT::Glue &&
N->hasAnyUseOfValue(NumVals-1)) {
SDNode *User = findGluedUser(N);
if (User) {
Glues.push_back(N);
GluedMap.insert(std::make_pair(N, User));
}
}
if (N->isMachineOpcode() ||
(N->getOpcode() != ISD::EntryToken && !isPassiveNode(N)))
++DAGSize;
}
for (unsigned i = 0, e = Glues.size(); i != e; ++i) {
SDNode *Glue = Glues[i];
SDNode *GUser = GluedMap[Glue];
unsigned Degree = Glue->getNodeId();
unsigned UDegree = GUser->getNodeId();
// Glue user must be scheduled together with the glue operand. So other
// users of the glue operand must be treated as its users.
SDNode *ImmGUser = Glue->getGluedUser();
for (SDNode::use_iterator ui = Glue->use_begin(), ue = Glue->use_end();
ui != ue; ++ui)
if (*ui == ImmGUser)
--Degree;
GUser->setNodeId(UDegree + Degree);
Glue->setNodeId(1);
}
Sequence.reserve(DAGSize);
ScheduleNode(DAG->getRoot().getNode());
}
MachineBasicBlock*
ScheduleDAGLinearize::EmitSchedule(MachineBasicBlock::iterator &InsertPos) {
InstrEmitter Emitter(BB, InsertPos);
DenseMap<SDValue, unsigned> VRBaseMap;
DEBUG({
dbgs() << "\n*** Final schedule ***\n";
});
// FIXME: Handle dbg_values.
unsigned NumNodes = Sequence.size();
for (unsigned i = 0; i != NumNodes; ++i) {
SDNode *N = Sequence[NumNodes-i-1];
DEBUG(N->dump(DAG));
Emitter.EmitNode(N, false, false, VRBaseMap);
}
DEBUG(dbgs() << '\n');
InsertPos = Emitter.getInsertPos();
return Emitter.getBlock();
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
llvm::ScheduleDAGSDNodes *
llvm::createFastDAGScheduler(SelectionDAGISel *IS, CodeGenOpt::Level) {
return new ScheduleDAGFast(*IS->MF);
}
llvm::ScheduleDAGSDNodes *
llvm::createDAGLinearizer(SelectionDAGISel *IS, CodeGenOpt::Level) {
return new ScheduleDAGLinearize(*IS->MF);
}
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