void ScheduleDAGSDNodes::
EmitPhysRegCopy(SUnit *SU, DenseMap<SUnit*, unsigned> &VRBaseMap,
MachineBasicBlock::iterator InsertPos) {
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl()) continue; // ignore chain preds
if (I->getSUnit()->CopyDstRC) {
// Copy to physical register.
DenseMap<SUnit*, unsigned>::iterator VRI = VRBaseMap.find(I->getSUnit());
assert(VRI != VRBaseMap.end() && "Node emitted out of order - late");
// Find the destination physical register.
unsigned Reg = 0;
for (SUnit::const_succ_iterator II = SU->Succs.begin(),
EE = SU->Succs.end(); II != EE; ++II) {
if (II->isCtrl()) continue; // ignore chain preds
if (II->getReg()) {
Reg = II->getReg();
break;
}
}
BuildMI(*BB, InsertPos, DebugLoc(), TII->get(TargetOpcode::COPY), Reg)
.addReg(VRI->second);
} else {
// Copy from physical register.
assert(I->getReg() && "Unknown physical register!");
unsigned VRBase = MRI.createVirtualRegister(SU->CopyDstRC);
bool isNew = VRBaseMap.insert(std::make_pair(SU, VRBase)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
BuildMI(*BB, InsertPos, DebugLoc(), TII->get(TargetOpcode::COPY), VRBase)
.addReg(I->getReg());
}
break;
}
}
/// This function assumes that "downward" from SU there exist
/// tail/leaf of already constructed DAG. It iterates downward and
/// checks whether SU can be aliasing any node dominated
/// by it.
static void adjustChainDeps(AliasAnalysis *AA, const MachineFrameInfo *MFI,
SUnit *SU, SUnit *ExitSU, std::set<SUnit *> &CheckList,
unsigned LatencyToLoad) {
if (!SU)
return;
SmallPtrSet<const SUnit*, 16> Visited;
unsigned Depth = 0;
for (std::set<SUnit *>::iterator I = CheckList.begin(), IE = CheckList.end();
I != IE; ++I) {
if (SU == *I)
continue;
if (MIsNeedChainEdge(AA, MFI, SU->getInstr(), (*I)->getInstr())) {
unsigned Latency = ((*I)->getInstr()->mayLoad()) ? LatencyToLoad : 0;
(*I)->addPred(SDep(SU, SDep::Order, Latency, /*Reg=*/0,
/*isNormalMemory=*/true));
}
// Now go through all the chain successors and iterate from them.
// Keep track of visited nodes.
for (SUnit::const_succ_iterator J = (*I)->Succs.begin(),
JE = (*I)->Succs.end(); J != JE; ++J)
if (J->isCtrl())
iterateChainSucc (AA, MFI, SU, J->getSUnit(),
ExitSU, &Depth, Visited);
}
}
static unsigned numberCtrlDepsInSU(SUnit *SU) {
unsigned NumberDeps = 0;
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I)
if (I->isCtrl())
NumberDeps++;
return NumberDeps;
}
/// Check if scheduling of this SU is possible
/// in the current packet.
/// It is _not_ precise (statefull), it is more like
/// another heuristic. Many corner cases are figured
/// empirically.
bool VLIWResourceModel::isResourceAvailable(SUnit *SU) {
if (!SU || !SU->getInstr())
return false;
// First see if the pipeline could receive this instruction
// in the current cycle.
switch (SU->getInstr()->getOpcode()) {
default:
if (!ResourcesModel->canReserveResources(*SU->getInstr()))
return false;
case TargetOpcode::EXTRACT_SUBREG:
case TargetOpcode::INSERT_SUBREG:
case TargetOpcode::SUBREG_TO_REG:
case TargetOpcode::REG_SEQUENCE:
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::COPY:
case TargetOpcode::INLINEASM:
break;
}
MachineFunction &MF = *SU->getInstr()->getParent()->getParent();
auto &QII = *MF.getSubtarget<HexagonSubtarget>().getInstrInfo();
// Now see if there are no other dependencies to instructions already
// in the packet.
for (unsigned i = 0, e = Packet.size(); i != e; ++i) {
if (Packet[i]->Succs.size() == 0)
continue;
// Enable .cur formation.
if (QII.mayBeCurLoad(*Packet[i]->getInstr()))
continue;
for (SUnit::const_succ_iterator I = Packet[i]->Succs.begin(),
E = Packet[i]->Succs.end(); I != E; ++I) {
// Since we do not add pseudos to packets, might as well
// ignore order dependencies.
if (I->isCtrl())
continue;
if (I->getSUnit() == SU)
return false;
}
}
return true;
}
unsigned ResourcePriorityQueue::numberRCValSuccInSU(SUnit *SU,
unsigned RCId) {
unsigned NumberDeps = 0;
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isCtrl())
continue;
SUnit *SuccSU = I->getSUnit();
const SDNode *ScegN = SuccSU->getNode();
if (!ScegN)
continue;
// If value is passed to CopyToReg, it is probably
// live outside BB.
switch (ScegN->getOpcode()) {
default:
break;
case ISD::TokenFactor:
break;
case ISD::CopyFromReg:
break;
case ISD::CopyToReg:
NumberDeps++;
break;
case ISD::INLINEASM:
break;
}
if (!ScegN->isMachineOpcode())
continue;
for (unsigned i = 0, e = ScegN->getNumOperands(); i != e; ++i) {
const SDValue &Op = ScegN->getOperand(i);
MVT VT = Op.getNode()->getSimpleValueType(Op.getResNo());
if (TLI->isTypeLegal(VT)
&& (TLI->getRegClassFor(VT)->getID() == RCId)) {
NumberDeps++;
break;
}
}
}
return NumberDeps;
}
/// This recursive function iterates over chain deps of SUb looking for
/// "latest" node that needs a chain edge to SUa.
static unsigned
iterateChainSucc(AliasAnalysis *AA, const MachineFrameInfo *MFI,
SUnit *SUa, SUnit *SUb, SUnit *ExitSU, unsigned *Depth,
SmallPtrSet<const SUnit*, 16> &Visited) {
if (!SUa || !SUb || SUb == ExitSU)
return *Depth;
// Remember visited nodes.
if (!Visited.insert(SUb))
return *Depth;
// If there is _some_ dependency already in place, do not
// descend any further.
// TODO: Need to make sure that if that dependency got eliminated or ignored
// for any reason in the future, we would not violate DAG topology.
// Currently it does not happen, but makes an implicit assumption about
// future implementation.
//
// Independently, if we encounter node that is some sort of global
// object (like a call) we already have full set of dependencies to it
// and we can stop descending.
if (SUa->isSucc(SUb) ||
isGlobalMemoryObject(AA, SUb->getInstr()))
return *Depth;
// If we do need an edge, or we have exceeded depth budget,
// add that edge to the predecessors chain of SUb,
// and stop descending.
if (*Depth > 200 ||
MIsNeedChainEdge(AA, MFI, SUa->getInstr(), SUb->getInstr())) {
SUb->addPred(SDep(SUa, SDep::Order, /*Latency=*/0, /*Reg=*/0,
/*isNormalMemory=*/true));
return *Depth;
}
// Track current depth.
(*Depth)++;
// Iterate over chain dependencies only.
for (SUnit::const_succ_iterator I = SUb->Succs.begin(), E = SUb->Succs.end();
I != E; ++I)
if (I->isCtrl())
iterateChainSucc (AA, MFI, SUa, I->getSUnit(), ExitSU, Depth, Visited);
return *Depth;
}
/// Check if scheduling of this SU is possible
/// in the current packet.
bool ResourcePriorityQueue::isResourceAvailable(SUnit *SU) {
if (!SU || !SU->getNode())
return false;
// If this is a compound instruction,
// it is likely to be a call. Do not delay it.
if (SU->getNode()->getGluedNode())
return true;
// First see if the pipeline could receive this instruction
// in the current cycle.
if (SU->getNode()->isMachineOpcode())
switch (SU->getNode()->getMachineOpcode()) {
default:
if (!ResourcesModel->canReserveResources(&TII->get(
SU->getNode()->getMachineOpcode())))
return false;
case TargetOpcode::EXTRACT_SUBREG:
case TargetOpcode::INSERT_SUBREG:
case TargetOpcode::SUBREG_TO_REG:
case TargetOpcode::REG_SEQUENCE:
case TargetOpcode::IMPLICIT_DEF:
break;
}
// Now see if there are no other dependencies
// to instructions alredy in the packet.
for (unsigned i = 0, e = Packet.size(); i != e; ++i)
for (SUnit::const_succ_iterator I = Packet[i]->Succs.begin(),
E = Packet[i]->Succs.end(); I != E; ++I) {
// Since we do not add pseudos to packets, might as well
// ignor order deps.
if (I->isCtrl())
continue;
if (I->getSUnit() == SU)
return false;
}
return true;
}
/// Main resource tracking point.
void ResourcePriorityQueue::scheduledNode(SUnit *SU) {
// Use NULL entry as an event marker to reset
// the DFA state.
if (!SU) {
ResourcesModel->clearResources();
Packet.clear();
return;
}
const SDNode *ScegN = SU->getNode();
// Update reg pressure tracking.
// First update current node.
if (ScegN->isMachineOpcode()) {
// Estimate generated regs.
for (unsigned i = 0, e = ScegN->getNumValues(); i != e; ++i) {
MVT VT = ScegN->getSimpleValueType(i);
if (TLI->isTypeLegal(VT)) {
const TargetRegisterClass *RC = TLI->getRegClassFor(VT);
if (RC)
RegPressure[RC->getID()] += numberRCValSuccInSU(SU, RC->getID());
}
}
// Estimate killed regs.
for (unsigned i = 0, e = ScegN->getNumOperands(); i != e; ++i) {
const SDValue &Op = ScegN->getOperand(i);
MVT VT = Op.getNode()->getSimpleValueType(Op.getResNo());
if (TLI->isTypeLegal(VT)) {
const TargetRegisterClass *RC = TLI->getRegClassFor(VT);
if (RC) {
if (RegPressure[RC->getID()] >
(numberRCValPredInSU(SU, RC->getID())))
RegPressure[RC->getID()] -= numberRCValPredInSU(SU, RC->getID());
else RegPressure[RC->getID()] = 0;
}
}
}
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl() || (I->getSUnit()->NumRegDefsLeft == 0))
continue;
--I->getSUnit()->NumRegDefsLeft;
}
}
// Reserve resources for this SU.
reserveResources(SU);
// Adjust number of parallel live ranges.
// Heuristic is simple - node with no data successors reduces
// number of live ranges. All others, increase it.
unsigned NumberNonControlDeps = 0;
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
adjustPriorityOfUnscheduledPreds(I->getSUnit());
if (!I->isCtrl())
NumberNonControlDeps++;
}
if (!NumberNonControlDeps) {
if (ParallelLiveRanges >= SU->NumPreds)
ParallelLiveRanges -= SU->NumPreds;
else
ParallelLiveRanges = 0;
}
else
ParallelLiveRanges += SU->NumRegDefsLeft;
// Track parallel live chains.
HorizontalVerticalBalance += (SU->Succs.size() - numberCtrlDepsInSU(SU));
HorizontalVerticalBalance -= (SU->Preds.size() - numberCtrlPredInSU(SU));
}