Example #1
0
/// MO is an operand of SU's instruction that defines a physical register. Add
/// data dependencies from SU to any uses of the physical register.
void ScheduleDAGInstrs::addPhysRegDataDeps(SUnit *SU, unsigned OperIdx) {
  const MachineOperand &MO = SU->getInstr()->getOperand(OperIdx);
  assert(MO.isDef() && "expect physreg def");

  // Ask the target if address-backscheduling is desirable, and if so how much.
  const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>();

  for (MCRegAliasIterator Alias(MO.getReg(), TRI, true);
       Alias.isValid(); ++Alias) {
    if (!Uses.contains(*Alias))
      continue;
    std::vector<PhysRegSUOper> &UseList = Uses[*Alias];
    for (unsigned i = 0, e = UseList.size(); i != e; ++i) {
      SUnit *UseSU = UseList[i].SU;
      if (UseSU == SU)
        continue;

      SDep dep(SU, SDep::Data, 1, *Alias);

      // Adjust the dependence latency using operand def/use information,
      // then allow the target to perform its own adjustments.
      int UseOp = UseList[i].OpIdx;
      MachineInstr *RegUse = UseOp < 0 ? 0 : UseSU->getInstr();
      dep.setLatency(
        SchedModel.computeOperandLatency(SU->getInstr(), OperIdx,
                                         RegUse, UseOp, /*FindMin=*/false));
      dep.setMinLatency(
        SchedModel.computeOperandLatency(SU->getInstr(), OperIdx,
                                         RegUse, UseOp, /*FindMin=*/true));

      ST.adjustSchedDependency(SU, UseSU, dep);
      UseSU->addPred(dep);
    }
  }
}
Example #2
0
/// addVRegDefDeps - Add register output and data dependencies from this SUnit
/// to instructions that occur later in the same scheduling region if they read
/// from or write to the virtual register defined at OperIdx.
///
/// TODO: Hoist loop induction variable increments. This has to be
/// reevaluated. Generally, IV scheduling should be done before coalescing.
void ScheduleDAGInstrs::addVRegDefDeps(SUnit *SU, unsigned OperIdx) {
  const MachineInstr *MI = SU->getInstr();
  unsigned Reg = MI->getOperand(OperIdx).getReg();

  // Singly defined vregs do not have output/anti dependencies.
  // The current operand is a def, so we have at least one.
  // Check here if there are any others...
  if (MRI.hasOneDef(Reg))
    return;

  // Add output dependence to the next nearest def of this vreg.
  //
  // Unless this definition is dead, the output dependence should be
  // transitively redundant with antidependencies from this definition's
  // uses. We're conservative for now until we have a way to guarantee the uses
  // are not eliminated sometime during scheduling. The output dependence edge
  // is also useful if output latency exceeds def-use latency.
  VReg2SUnitMap::iterator DefI = VRegDefs.find(Reg);
  if (DefI == VRegDefs.end())
    VRegDefs.insert(VReg2SUnit(Reg, SU));
  else {
    SUnit *DefSU = DefI->SU;
    if (DefSU != SU && DefSU != &ExitSU) {
      unsigned OutLatency = TII->getOutputLatency(InstrItins, MI, OperIdx,
                                                  DefSU->getInstr());
      DefSU->addPred(SDep(SU, SDep::Output, OutLatency, Reg));
    }
    DefI->SU = SU;
  }
}
Example #3
0
/// EmitSchedule - Emit the machine code in scheduled order.
MachineBasicBlock *ScheduleDAGSDNodes::EmitSchedule() {
  DenseMap<SDValue, unsigned> VRBaseMap;
  DenseMap<SUnit*, unsigned> CopyVRBaseMap;
  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
    SUnit *SU = Sequence[i];
    if (!SU) {
      // Null SUnit* is a noop.
      EmitNoop();
      continue;
    }

    // For pre-regalloc scheduling, create instructions corresponding to the
    // SDNode and any flagged SDNodes and append them to the block.
    if (!SU->getNode()) {
      // Emit a copy.
      EmitPhysRegCopy(SU, CopyVRBaseMap);
      continue;
    }

    SmallVector<SDNode *, 4> FlaggedNodes;
    for (SDNode *N = SU->getNode()->getFlaggedNode(); N;
         N = N->getFlaggedNode())
      FlaggedNodes.push_back(N);
    while (!FlaggedNodes.empty()) {
      EmitNode(FlaggedNodes.back(), SU->OrigNode != SU, SU->isCloned,VRBaseMap);
      FlaggedNodes.pop_back();
    }
    EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned, VRBaseMap);
  }

  return BB;
}
Example #4
0
/// ComputeHeight - Calculate the maximal path from the node to the entry.
///
void SUnit::ComputeHeight() {
  SmallVector<SUnit*, 8> WorkList;
  WorkList.push_back(this);
  do {
    SUnit *Cur = WorkList.back();

    bool Done = true;
    unsigned MaxSuccHeight = 0;
    for (SUnit::const_succ_iterator I = Cur->Succs.begin(),
         E = Cur->Succs.end(); I != E; ++I) {
      SUnit *SuccSU = I->getSUnit();
      if (SuccSU->isHeightCurrent)
        MaxSuccHeight = std::max(MaxSuccHeight,
                                 SuccSU->Height + I->getLatency());
      else {
        Done = false;
        WorkList.push_back(SuccSU);
      }
    }

    if (Done) {
      WorkList.pop_back();
      if (MaxSuccHeight != Cur->Height) {
        Cur->setHeightDirty();
        Cur->Height = MaxSuccHeight;
      }
      Cur->isHeightCurrent = true;
    }
  } while (!WorkList.empty());
}
Example #5
0
/// ComputeDepth - Calculate the maximal path from the node to the exit.
///
void SUnit::ComputeDepth() {
  SmallVector<SUnit*, 8> WorkList;
  WorkList.push_back(this);
  do {
    SUnit *Cur = WorkList.back();

    bool Done = true;
    unsigned MaxPredDepth = 0;
    for (SUnit::const_pred_iterator I = Cur->Preds.begin(),
         E = Cur->Preds.end(); I != E; ++I) {
      SUnit *PredSU = I->getSUnit();
      if (PredSU->isDepthCurrent)
        MaxPredDepth = std::max(MaxPredDepth,
                                PredSU->Depth + I->getLatency());
      else {
        Done = false;
        WorkList.push_back(PredSU);
      }
    }

    if (Done) {
      WorkList.pop_back();
      if (MaxPredDepth != Cur->Depth) {
        Cur->setDepthDirty();
        Cur->Depth = MaxPredDepth;
      }
      Cur->isDepthCurrent = true;
    }
  } while (!WorkList.empty());
}
Example #6
0
/// addPred - This adds the specified edge as a pred of the current node if
/// not already.  It also adds the current node as a successor of the
/// specified node.
void SUnit::addPred(const SDep &D) {
  // If this node already has this depenence, don't add a redundant one.
  for (unsigned i = 0, e = (unsigned)Preds.size(); i != e; ++i)
    if (Preds[i] == D)
      return;
  // Now add a corresponding succ to N.
  SDep P = D;
  P.setSUnit(this);
  SUnit *N = D.getSUnit();
  // Update the bookkeeping.
  if (D.getKind() == SDep::Data) {
    ++NumPreds;
    ++N->NumSuccs;
  }
  if (!N->isScheduled)
    ++NumPredsLeft;
  if (!isScheduled)
    ++N->NumSuccsLeft;
  Preds.push_back(D);
  N->Succs.push_back(P);
  if (P.getLatency() != 0) {
    this->setDepthDirty();
    N->setHeightDirty();
  }
}
Example #7
0
/// removePred - This removes the specified edge as a pred of the current
/// node if it exists.  It also removes the current node as a successor of
/// the specified node.
void SUnit::removePred(const SDep &D) {
  // Find the matching predecessor.
  for (SmallVector<SDep, 4>::iterator I = Preds.begin(), E = Preds.end();
       I != E; ++I)
    if (*I == D) {
      bool FoundSucc = false;
      // Find the corresponding successor in N.
      SDep P = D;
      P.setSUnit(this);
      SUnit *N = D.getSUnit();
      for (SmallVector<SDep, 4>::iterator II = N->Succs.begin(),
             EE = N->Succs.end(); II != EE; ++II)
        if (*II == P) {
          FoundSucc = true;
          N->Succs.erase(II);
          break;
        }
      assert(FoundSucc && "Mismatching preds / succs lists!");
      Preds.erase(I);
      // Update the bookkeeping.
      if (P.getKind() == SDep::Data) {
        --NumPreds;
        --N->NumSuccs;
      }
      if (!N->isScheduled)
        --NumPredsLeft;
      if (!isScheduled)
        --N->NumSuccsLeft;
      if (P.getLatency() != 0) {
        this->setDepthDirty();
        N->setHeightDirty();
      }
      return;
    }
}
Example #8
0
/// addPred - This adds the specified edge as a pred of the current node if
/// not already.  It also adds the current node as a successor of the
/// specified node.
bool SUnit::addPred(const SDep &D) {
  // If this node already has this depenence, don't add a redundant one.
  for (SmallVector<SDep, 4>::const_iterator I = Preds.begin(), E = Preds.end();
       I != E; ++I)
    if (*I == D)
      return false;
  // Now add a corresponding succ to N.
  SDep P = D;
  P.setSUnit(this);
  SUnit *N = D.getSUnit();
  // Update the bookkeeping.
  if (D.getKind() == SDep::Data) {
    assert(NumPreds < UINT_MAX && "NumPreds will overflow!");
    assert(N->NumSuccs < UINT_MAX && "NumSuccs will overflow!");
    ++NumPreds;
    ++N->NumSuccs;
  }
  if (!N->isScheduled) {
    assert(NumPredsLeft < UINT_MAX && "NumPredsLeft will overflow!");
    ++NumPredsLeft;
  }
  if (!isScheduled) {
    assert(N->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
    ++N->NumSuccsLeft;
  }
  Preds.push_back(D);
  N->Succs.push_back(P);
  if (P.getLatency() != 0) {
    this->setDepthDirty();
    N->setHeightDirty();
  }
  return true;
}
/// Select a bundle for the current cycle. The selected instructions are
/// put into bundle in the correct issue order. If no instruction can be
/// issued, false is returned.
bool PatmosLatencyQueue::selectBundle(std::vector<SUnit*> &Bundle)
{
  if (AvailableQueue.empty()) return false;

  // Find best bundle:
  // - Ensure that instructions that MUST be scheduled go into the bundle.
  // - find best pair of available programs, e.g. two stores with exclusive
  //   predicates and highest ILP/.., but only if at least one of those instr.
  //   has high priority.
  // - find best instructions that fit into the bundle with highest ILP/..
  //
  // Instructions are built up into a bundle in Bundle. Instructions are removed
  // from AvailableQueue in scheduled() once the instruction is actually picked.

  unsigned CurrWidth = 0;
  // If the bundle is not empty, we should calculate the initial width
  assert(Bundle.empty());

  std::vector<bool> Selected;
  Selected.resize(AvailableQueue.size());

  // Make sure that all instructions with ScheduleLow flag go into the bundle.
  for (unsigned i = 0; i < AvailableQueue.size() && CurrWidth < IssueWidth; i++)
  {
    SUnit *SU = AvailableQueue[i];
    if (!SU->isScheduleLow) break;

    if (addToBundle(Bundle, SU, CurrWidth)) {
      Selected[i] = true;
    }
  }

  // Check if any of the highest <IssueWidth> instructions can be
  // scheduled only with a single other instruction in this queue, or if there
  // is any instruction in the queue that can only be scheduled with the highest
  // ones. Pick them in any case



  // TODO magic goes here..



  // Try to fill up the bundle with instructions from the queue by best effort
  for (unsigned i = 0; i < AvailableQueue.size() && CurrWidth < IssueWidth; i++)
  {
    if (Selected[i]) continue;
    SUnit *SU = AvailableQueue[i];

    // check the width. ignore the width for the first instruction to allow
    // ALUl even when bundling is disabled.
    unsigned width = PII.getIssueWidth(SU->getInstr());
    if (!Bundle.empty() && CurrWidth + width > IssueWidth) continue;

    addToBundle(Bundle, SU, CurrWidth);
  }

  return true;
}
void LatencyPriorityQueue::dump(ScheduleDAG *DAG) const {
    LatencyPriorityQueue q = *this;
    while (!q.empty()) {
        SUnit *su = q.pop();
        dbgs() << "Height " << su->getHeight() << ": ";
        su->dump(DAG);
    }
}
Example #11
0
/// MO is an operand of SU's instruction that defines a physical register. Add
/// data dependencies from SU to any uses of the physical register.
void ScheduleDAGInstrs::addPhysRegDataDeps(SUnit *SU, unsigned OperIdx) {
  const MachineOperand &MO = SU->getInstr()->getOperand(OperIdx);
  assert(MO.isDef() && "expect physreg def");

  // Ask the target if address-backscheduling is desirable, and if so how much.
  const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>();
  unsigned SpecialAddressLatency = ST.getSpecialAddressLatency();
  unsigned DataLatency = SU->Latency;

  for (MCRegAliasIterator Alias(MO.getReg(), TRI, true);
       Alias.isValid(); ++Alias) {
    if (!Uses.contains(*Alias))
      continue;
    std::vector<PhysRegSUOper> &UseList = Uses[*Alias];
    for (unsigned i = 0, e = UseList.size(); i != e; ++i) {
      SUnit *UseSU = UseList[i].SU;
      if (UseSU == SU)
        continue;
      MachineInstr *UseMI = UseSU->getInstr();
      int UseOp = UseList[i].OpIdx;
      unsigned LDataLatency = DataLatency;
      // Optionally add in a special extra latency for nodes that
      // feed addresses.
      // TODO: Perhaps we should get rid of
      // SpecialAddressLatency and just move this into
      // adjustSchedDependency for the targets that care about it.
      if (SpecialAddressLatency != 0 && !UnitLatencies &&
          UseSU != &ExitSU) {
        const MCInstrDesc &UseMCID = UseMI->getDesc();
        int RegUseIndex = UseMI->findRegisterUseOperandIdx(*Alias);
        assert(RegUseIndex >= 0 && "UseMI doesn't use register!");
        if (RegUseIndex >= 0 &&
            (UseMI->mayLoad() || UseMI->mayStore()) &&
            (unsigned)RegUseIndex < UseMCID.getNumOperands() &&
            UseMCID.OpInfo[RegUseIndex].isLookupPtrRegClass())
          LDataLatency += SpecialAddressLatency;
      }
      // Adjust the dependence latency using operand def/use
      // information (if any), and then allow the target to
      // perform its own adjustments.
      SDep dep(SU, SDep::Data, LDataLatency, *Alias);
      if (!UnitLatencies) {
        unsigned Latency =
          TII->computeOperandLatency(InstrItins, SU->getInstr(), OperIdx,
                                     (UseOp < 0 ? 0 : UseMI), UseOp);
        dep.setLatency(Latency);
        unsigned MinLatency =
          TII->computeOperandLatency(InstrItins, SU->getInstr(), OperIdx,
                                     (UseOp < 0 ? 0 : UseMI), UseOp,
                                     /*FindMin=*/true);
        dep.setMinLatency(MinLatency);

        ST.adjustSchedDependency(SU, UseSU, dep);
      }
      UseSU->addPred(dep);
    }
  }
}
Example #12
0
// Check if a call and subsequent A2_tfrpi instructions should maintain
// scheduling affinity. We are looking for the TFRI to be consumed in
// the next instruction. This should help reduce the instances of
// double register pairs being allocated and scheduled before a call
// when not used until after the call. This situation is exacerbated
// by the fact that we allocate the pair from the callee saves list,
// leading to excess spills and restores.
bool HexagonCallMutation::shouldTFRICallBind(const HexagonInstrInfo &HII,
      const SUnit &Inst1, const SUnit &Inst2) const {
  if (Inst1.getInstr()->getOpcode() != Hexagon::A2_tfrpi)
    return false;

  // TypeXTYPE are 64 bit operations.
  if (HII.getType(Inst2.getInstr()) == HexagonII::TypeXTYPE)
    return true;
  return false;
}
Example #13
0
SUnit* R600SchedStrategy::pickNode(bool &IsTopNode) {
  SUnit *SU = 0;
  IsTopNode = true;
  NextInstKind = IDOther;

  // check if we might want to switch current clause type
  bool AllowSwitchToAlu = (CurInstKind == IDOther) ||
      (CurEmitted > InstKindLimit[CurInstKind]) ||
      (Available[CurInstKind]->empty());
  bool AllowSwitchFromAlu = (CurEmitted > InstKindLimit[CurInstKind]) &&
      (!Available[IDFetch]->empty() || !Available[IDOther]->empty());

  if ((AllowSwitchToAlu && CurInstKind != IDAlu) ||
      (!AllowSwitchFromAlu && CurInstKind == IDAlu)) {
    // try to pick ALU
    SU = pickAlu();
    if (SU) {
      if (CurEmitted >  InstKindLimit[IDAlu])
        CurEmitted = 0;
      NextInstKind = IDAlu;
    }
  }

  if (!SU) {
    // try to pick FETCH
    SU = pickOther(IDFetch);
    if (SU)
      NextInstKind = IDFetch;
  }

  // try to pick other
  if (!SU) {
    SU = pickOther(IDOther);
    if (SU)
      NextInstKind = IDOther;
  }

  DEBUG(
      if (SU) {
        dbgs() << "picked node: ";
        SU->dump(DAG);
      } else {
        dbgs() << "NO NODE ";
        for (int i = 0; i < IDLast; ++i) {
          Available[i]->dump();
          Pending[i]->dump();
        }
        for (unsigned i = 0; i < DAG->SUnits.size(); i++) {
          const SUnit &S = DAG->SUnits[i];
          if (!S.isScheduled)
            S.dump(DAG);
        }
      }
  );
Example #14
0
/// addPred - This adds the specified edge as a pred of the current node if
/// not already.  It also adds the current node as a successor of the
/// specified node.
bool SUnit::addPred(const SDep &D) {
  // If this node already has this depenence, don't add a redundant one.
  for (SmallVector<SDep, 4>::iterator I = Preds.begin(), E = Preds.end();
       I != E; ++I) {
    if (I->overlaps(D)) {
      // Extend the latency if needed. Equivalent to removePred(I) + addPred(D).
      if (I->getLatency() < D.getLatency()) {
        SUnit *PredSU = I->getSUnit();
        // Find the corresponding successor in N.
        SDep ForwardD = *I;
        ForwardD.setSUnit(this);
        for (SmallVector<SDep, 4>::iterator II = PredSU->Succs.begin(),
               EE = PredSU->Succs.end(); II != EE; ++II) {
          if (*II == ForwardD) {
            II->setLatency(D.getLatency());
            break;
          }
        }
        I->setLatency(D.getLatency());
      }
      return false;
    }
  }
  // Now add a corresponding succ to N.
  SDep P = D;
  P.setSUnit(this);
  SUnit *N = D.getSUnit();
  // Update the bookkeeping.
  if (D.getKind() == SDep::Data) {
    assert(NumPreds < UINT_MAX && "NumPreds will overflow!");
    assert(N->NumSuccs < UINT_MAX && "NumSuccs will overflow!");
    ++NumPreds;
    ++N->NumSuccs;
  }
  if (!N->isScheduled) {
    assert(NumPredsLeft < UINT_MAX && "NumPredsLeft will overflow!");
    ++NumPredsLeft;
  }
  if (!isScheduled) {
    assert(N->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
    ++N->NumSuccsLeft;
  }
  Preds.push_back(D);
  N->Succs.push_back(P);
  if (P.getLatency() != 0) {
    this->setDepthDirty();
    N->setHeightDirty();
  }
  return true;
}
Example #15
0
/// MO is an operand of SU's instruction that defines a physical register. Add
/// data dependencies from SU to any uses of the physical register.
void ScheduleDAGInstrs::addPhysRegDataDeps(SUnit *SU,
                                           const MachineOperand &MO) {
  assert(MO.isDef() && "expect physreg def");

  // Ask the target if address-backscheduling is desirable, and if so how much.
  const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>();
  unsigned SpecialAddressLatency = ST.getSpecialAddressLatency();
  unsigned DataLatency = SU->Latency;

  for (const unsigned *Alias = TRI->getOverlaps(MO.getReg()); *Alias; ++Alias) {
    if (!Uses.contains(*Alias))
      continue;
    std::vector<SUnit*> &UseList = Uses[*Alias];
    for (unsigned i = 0, e = UseList.size(); i != e; ++i) {
      SUnit *UseSU = UseList[i];
      if (UseSU == SU)
        continue;
      unsigned LDataLatency = DataLatency;
      // Optionally add in a special extra latency for nodes that
      // feed addresses.
      // TODO: Perhaps we should get rid of
      // SpecialAddressLatency and just move this into
      // adjustSchedDependency for the targets that care about it.
      if (SpecialAddressLatency != 0 && !UnitLatencies &&
          UseSU != &ExitSU) {
        MachineInstr *UseMI = UseSU->getInstr();
        const MCInstrDesc &UseMCID = UseMI->getDesc();
        int RegUseIndex = UseMI->findRegisterUseOperandIdx(*Alias);
        assert(RegUseIndex >= 0 && "UseMI doesn't use register!");
        if (RegUseIndex >= 0 &&
            (UseMI->mayLoad() || UseMI->mayStore()) &&
            (unsigned)RegUseIndex < UseMCID.getNumOperands() &&
            UseMCID.OpInfo[RegUseIndex].isLookupPtrRegClass())
          LDataLatency += SpecialAddressLatency;
      }
      // Adjust the dependence latency using operand def/use
      // information (if any), and then allow the target to
      // perform its own adjustments.
      const SDep& dep = SDep(SU, SDep::Data, LDataLatency, *Alias);
      if (!UnitLatencies) {
        ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep));
        ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep));
      }
      UseSU->addPred(dep);
    }
  }
}
uint32_t CommandCargoTransMsg::execute(){
	
	cerr<<"execute CommandCargoTransMsg"<<endl;

	Processable *tproc = _processor->getLocalProcssable(_toShipId);
	if (!tproc)
		return COMMAND_FINAL;
	SUnit* unit = tproc->isUnit();
	if (!unit)
		return COMMAND_FINAL;

	if(!itemlist[_itemType])
		return COMMAND_FINAL;
	unit->getsubable()->getCargoBay()->AddReturn(itemlist[_itemType],_quan);
	
	return COMMAND_FINAL;
}
Example #17
0
// EmitSchedule - Emit the machine code in scheduled order.
MachineBasicBlock *ScheduleDAGInstrs::EmitSchedule() {
  // For MachineInstr-based scheduling, we're rescheduling the instructions in
  // the block, so start by removing them from the block.
  while (Begin != InsertPos) {
    MachineBasicBlock::iterator I = Begin;
    ++Begin;
    BB->remove(I);
  }

  // First reinsert any remaining debug_values; these are either constants,
  // or refer to live-in registers.  The beginning of the block is the right
  // place for the latter.  The former might reasonably be placed elsewhere
  // using some kind of ordering algorithm, but right now it doesn't matter.
  for (int i = DbgValueVec.size()-1; i>=0; --i)
    if (DbgValueVec[i])
      BB->insert(InsertPos, DbgValueVec[i]);

  // Then re-insert them according to the given schedule.
  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
    SUnit *SU = Sequence[i];
    if (!SU) {
      // Null SUnit* is a noop.
      EmitNoop();
      continue;
    }

    BB->insert(InsertPos, SU->getInstr());
    for (unsigned i = 0, e = SU->DbgInstrList.size() ; i < e ; ++i)
      BB->insert(InsertPos, SU->DbgInstrList[i]);
  }

  // Update the Begin iterator, as the first instruction in the block
  // may have been scheduled later.
  if (!DbgValueVec.empty()) {
    for (int i = DbgValueVec.size()-1; i>=0; --i)
      if (DbgValueVec[i]!=0) {
        Begin = DbgValueVec[DbgValueVec.size()-1];
        break;
      }
  } else if (!Sequence.empty())
    Begin = Sequence[0]->getInstr();

  DbgValueVec.clear();
  return BB;
}
/// Change the latency between the two SUnits.
void HexagonSubtarget::changeLatency(SUnit *Src, SmallVector<SDep, 4> &Deps,
      SUnit *Dst, unsigned Lat) const {
  MachineInstr &SrcI = *Src->getInstr();
  for (auto &I : Deps) {
    if (I.getSUnit() != Dst)
      continue;
    I.setLatency(Lat);
    SUnit *UpdateDst = I.getSUnit();
    updateLatency(SrcI, *UpdateDst->getInstr(), I);
    // Update the latency of opposite edge too.
    for (auto &PI : UpdateDst->Preds) {
      if (PI.getSUnit() != Src || !PI.isAssignedRegDep())
        continue;
      PI.setLatency(Lat);
      updateLatency(SrcI, *UpdateDst->getInstr(), PI);
    }
  }
}
Example #19
0
/// removePred - This removes the specified edge as a pred of the current
/// node if it exists.  It also removes the current node as a successor of
/// the specified node.
void SUnit::removePred(const SDep &D) {
  // Find the matching predecessor.
  for (SmallVector<SDep, 4>::iterator I = Preds.begin(), E = Preds.end();
       I != E; ++I)
    if (*I == D) {
      // Find the corresponding successor in N.
      SDep P = D;
      P.setSUnit(this);
      SUnit *N = D.getSUnit();
      SmallVectorImpl<SDep>::iterator Succ = std::find(N->Succs.begin(),
                                                       N->Succs.end(), P);
      assert(Succ != N->Succs.end() && "Mismatching preds / succs lists!");
      N->Succs.erase(Succ);
      Preds.erase(I);
      // Update the bookkeeping.
      if (P.getKind() == SDep::Data) {
        assert(NumPreds > 0 && "NumPreds will underflow!");
        assert(N->NumSuccs > 0 && "NumSuccs will underflow!");
        --NumPreds;
        --N->NumSuccs;
      }
      if (!N->isScheduled) {
        if (D.isWeak())
          --WeakPredsLeft;
        else {
          assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!");
          --NumPredsLeft;
        }
      }
      if (!isScheduled) {
        if (D.isWeak())
          --N->WeakSuccsLeft;
        else {
          assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!");
          --N->NumSuccsLeft;
        }
      }
      if (P.getLatency() != 0) {
        this->setDepthDirty();
        N->setHeightDirty();
      }
      return;
    }
}
Example #20
0
/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
/// critical path.
static SDep *CriticalPathStep(SUnit *SU) {
  SDep *Next = 0;
  unsigned NextDepth = 0;
  // Find the predecessor edge with the greatest depth.
  for (SUnit::pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
       P != PE; ++P) {
    SUnit *PredSU = P->getSUnit();
    unsigned PredLatency = P->getLatency();
    unsigned PredTotalLatency = PredSU->getDepth() + PredLatency;
    // In the case of a latency tie, prefer an anti-dependency edge over
    // other types of edges.
    if (NextDepth < PredTotalLatency ||
        (NextDepth == PredTotalLatency && P->getKind() == SDep::Anti)) {
      NextDepth = PredTotalLatency;
      Next = &*P;
    }
  }
  return Next;
}
unsigned
ResourcePriorityQueue::numberRCValPredInSU(SUnit *SU, unsigned RCId) {
    unsigned NumberDeps = 0;
    for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
            I != E; ++I) {
        if (I->isCtrl())
            continue;

        SUnit *PredSU = I->getSUnit();
        const SDNode *ScegN = PredSU->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:
            NumberDeps++;
            break;
        case ISD::CopyToReg:
            break;
        case ISD::INLINEASM:
            break;
        }
        if (!ScegN->isMachineOpcode())
            continue;

        for (unsigned i = 0, e = ScegN->getNumValues(); i != e; ++i) {
            MVT VT = ScegN->getSimpleValueType(i);
            if (TLI->isTypeLegal(VT)
                    && (TLI->getRegClassFor(VT)->getID() == RCId)) {
                NumberDeps++;
                break;
            }
        }
    }
    return NumberDeps;
}
  void apply(ScheduleDAGInstrs *DAGInstrs) override {
    ScheduleDAGMI *DAG = static_cast<ScheduleDAGMI*>(DAGInstrs);

    SUnit *SUa = nullptr;
    // Search for two consequent memory operations and link them
    // to prevent scheduler from moving them apart.
    // In DAG pre-process SUnits are in the original order of
    // the instructions before scheduling.
    for (SUnit &SU : DAG->SUnits) {
      MachineInstr &MI2 = *SU.getInstr();
      if (!MI2.mayLoad() && !MI2.mayStore()) {
        SUa = nullptr;
        continue;
      }
      if (!SUa) {
        SUa = &SU;
        continue;
      }

      MachineInstr &MI1 = *SUa->getInstr();
      if ((TII->isVMEM(MI1) && TII->isVMEM(MI2)) ||
          (TII->isFLAT(MI1) && TII->isFLAT(MI2)) ||
          (TII->isSMRD(MI1) && TII->isSMRD(MI2)) ||
          (TII->isDS(MI1)   && TII->isDS(MI2))) {
        SU.addPredBarrier(SUa);

        for (const SDep &SI : SU.Preds) {
          if (SI.getSUnit() != SUa)
            SUa->addPred(SDep(SI.getSUnit(), SDep::Artificial));
        }

        if (&SU != &DAG->ExitSU) {
          for (const SDep &SI : SUa->Succs) {
            if (SI.getSUnit() != &SU)
              SI.getSUnit()->addPred(SDep(&SU, SDep::Artificial));
          }
        }
      }

      SUa = &SU;
    }
  }
Example #23
0
/// ReleaseSucc - Decrement the NumPredsLeft count of a successor. Add it to
/// the PendingQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGList::ReleaseSucc(SUnit *SU, const SDep &D) {
  SUnit *SuccSU = D.getSUnit();

#ifndef NDEBUG
  if (SuccSU->NumPredsLeft == 0) {
    errs() << "*** Scheduling failed! ***\n";
    SuccSU->dump(this);
    errs() << " has been released too many times!\n";
    llvm_unreachable(0);
  }
#endif
  --SuccSU->NumPredsLeft;

  SuccSU->setDepthToAtLeast(SU->getDepth() + D.getLatency());
  
  // 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)
    PendingQueue.push_back(SuccSU);
}
Example #24
0
/// Create an SUnit for each real instruction, numbered in top-down toplological
/// order. The instruction order A < B, implies that no edge exists from B to A.
///
/// Map each real instruction to its SUnit.
///
/// After initSUnits, the SUnits vector cannot be resized and the scheduler may
/// hang onto SUnit pointers. We may relax this in the future by using SUnit IDs
/// instead of pointers.
///
/// MachineScheduler relies on initSUnits numbering the nodes by their order in
/// the original instruction list.
void ScheduleDAGInstrs::initSUnits() {
  // We'll be allocating one SUnit for each real instruction in the region,
  // which is contained within a basic block.
  SUnits.reserve(BB->size());

  for (MachineBasicBlock::iterator I = RegionBegin; I != RegionEnd; ++I) {
    MachineInstr *MI = I;
    if (MI->isDebugValue())
      continue;

    SUnit *SU = newSUnit(MI);
    MISUnitMap[MI] = SU;

    SU->isCall = MI->isCall();
    SU->isCommutable = MI->isCommutable();

    // Assign the Latency field of SU using target-provided information.
    SU->Latency = SchedModel.computeInstrLatency(SU->getInstr());
  }
}
/// Go back one cycle and update availability queue.
void PatmosLatencyQueue::recedeCycle(unsigned CurrCycle)
{
  unsigned avail = 0;
  for (unsigned i = 0; i < PendingQueue.size() - avail; i++) {
    SUnit *SU = PendingQueue[i];

    if (SU->getHeight() <= CurrCycle) {
      // remove the instruction from pending
      avail++;
      PendingQueue[i] = *(PendingQueue.end() - avail);
      // revisit the moved instruction
      i--;

      // Make the instruction available
      AvailableQueue.push_back(SU);
      std::inplace_merge(AvailableQueue.begin(), AvailableQueue.end() - 1,
                         AvailableQueue.end(), Cmp);
    }
  }

  PendingQueue.resize(PendingQueue.size() - avail);
}
Example #26
0
void ScheduleDAGSDNodes::dumpNode(const SUnit &SU) const {
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  dumpNodeName(SU);
  dbgs() << ": ";

  if (!SU.getNode()) {
    dbgs() << "PHYS REG COPY\n";
    return;
  }

  SU.getNode()->dump(DAG);
  dbgs() << "\n";
  SmallVector<SDNode *, 4> GluedNodes;
  for (SDNode *N = SU.getNode()->getGluedNode(); N; N = N->getGluedNode())
    GluedNodes.push_back(N);
  while (!GluedNodes.empty()) {
    dbgs() << "    ";
    GluedNodes.back()->dump(DAG);
    dbgs() << "\n";
    GluedNodes.pop_back();
  }
#endif
}
Example #27
0
/// releaseSucc - Decrement the NumPredsLeft count of a successor. Add it to
/// the PendingQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGVLIW::releaseSucc(SUnit *SU, const SDep &D) {
    SUnit *SuccSU = D.getSUnit();

#ifndef NDEBUG
    if (SuccSU->NumPredsLeft == 0) {
        dbgs() << "*** Scheduling failed! ***\n";
        SuccSU->dump(this);
        dbgs() << " has been released too many times!\n";
        llvm_unreachable(nullptr);
    }
#endif
    assert(!D.isWeak() && "unexpected artificial DAG edge");

    --SuccSU->NumPredsLeft;

    SuccSU->setDepthToAtLeast(SU->getDepth() + D.getLatency());

    // 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) {
        PendingQueue.push_back(SuccSU);
    }
}
unsigned ResourcePriorityQueue::numberRCValSuccInSU(SUnit *SU,
                                                    unsigned RCId) {
  unsigned NumberDeps = 0;
  for (const SDep &Succ : SU->Succs) {
    if (Succ.isCtrl())
      continue;

    SUnit *SuccSU = Succ.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;
}
void PatmosLatencyQueue::dump()
{
  dbgs() << "PendingQueue:";
  for (unsigned i = 0; i < PendingQueue.size(); i++) {
    SUnit *SU = PendingQueue[i];
    if (i > 0) dbgs() << ",";
    dbgs() << " SU(" << SU->NodeNum << "): Height " << SU->getHeight()
           << " Depth " << SU->getDepth()
           << " Tree: " << Cmp.DFSResult->getSubtreeID(SU) << " @"
           << Cmp.DFSResult->getSubtreeLevel(Cmp.DFSResult->getSubtreeID(SU));
    if (SU->isScheduleLow) dbgs() << " low ";
  }
  dbgs() << "\nAvailableQueue:";
  for (unsigned i = 0; i < AvailableQueue.size(); i++) {
    SUnit *SU = AvailableQueue[i];
    if (i > 0) dbgs() << ",";
    dbgs() << " SU(" << SU->NodeNum << ") Height " << SU->getHeight()
           << " Depth " << SU->getDepth()
           << " ILP: " << Cmp.DFSResult->getILP(SU);
    if (SU->isScheduleLow) dbgs() << " low ";
  }
  dbgs() << "\n";
}
Example #30
0
void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) {
  // We'll be allocating one SUnit for each instruction, plus one for
  // the region exit node.
  SUnits.reserve(BB->size());

  // We build scheduling units by walking a block's instruction list from bottom
  // to top.

  // Remember where a generic side-effecting instruction is as we procede.
  SUnit *BarrierChain = 0, *AliasChain = 0;

  // Memory references to specific known memory locations are tracked
  // so that they can be given more precise dependencies. We track
  // separately the known memory locations that may alias and those
  // that are known not to alias
  std::map<const Value *, SUnit *> AliasMemDefs, NonAliasMemDefs;
  std::map<const Value *, std::vector<SUnit *> > AliasMemUses, NonAliasMemUses;

  // Keep track of dangling debug references to registers.
  std::vector<std::pair<MachineInstr*, unsigned> >
    DanglingDebugValue(TRI->getNumRegs(),
    std::make_pair(static_cast<MachineInstr*>(0), 0));

  // Check to see if the scheduler cares about latencies.
  bool UnitLatencies = ForceUnitLatencies();

  // Ask the target if address-backscheduling is desirable, and if so how much.
  const TargetSubtarget &ST = TM.getSubtarget<TargetSubtarget>();
  unsigned SpecialAddressLatency = ST.getSpecialAddressLatency();

  // Remove any stale debug info; sometimes BuildSchedGraph is called again
  // without emitting the info from the previous call.
  DbgValueVec.clear();

  // Model data dependencies between instructions being scheduled and the
  // ExitSU.
  AddSchedBarrierDeps();

  // Walk the list of instructions, from bottom moving up.
  for (MachineBasicBlock::iterator MII = InsertPos, MIE = Begin;
       MII != MIE; --MII) {
    MachineInstr *MI = prior(MII);
    // DBG_VALUE does not have SUnit's built, so just remember these for later
    // reinsertion.
    if (MI->isDebugValue()) {
      if (MI->getNumOperands()==3 && MI->getOperand(0).isReg() &&
          MI->getOperand(0).getReg())
        DanglingDebugValue[MI->getOperand(0).getReg()] =
             std::make_pair(MI, DbgValueVec.size());
      DbgValueVec.push_back(MI);
      continue;
    }
    const TargetInstrDesc &TID = MI->getDesc();
    assert(!TID.isTerminator() && !MI->isLabel() &&
           "Cannot schedule terminators or labels!");
    // Create the SUnit for this MI.
    SUnit *SU = NewSUnit(MI);
    SU->isCall = TID.isCall();
    SU->isCommutable = TID.isCommutable();

    // Assign the Latency field of SU using target-provided information.
    if (UnitLatencies)
      SU->Latency = 1;
    else
      ComputeLatency(SU);

    // Add register-based dependencies (data, anti, and output).
    for (unsigned j = 0, n = MI->getNumOperands(); j != n; ++j) {
      const MachineOperand &MO = MI->getOperand(j);
      if (!MO.isReg()) continue;
      unsigned Reg = MO.getReg();
      if (Reg == 0) continue;

      assert(TRI->isPhysicalRegister(Reg) && "Virtual register encountered!");

      if (MO.isDef() && DanglingDebugValue[Reg].first!=0) {
        SU->DbgInstrList.push_back(DanglingDebugValue[Reg].first);
        DbgValueVec[DanglingDebugValue[Reg].second] = 0;
        DanglingDebugValue[Reg] = std::make_pair((MachineInstr*)0, 0);
      }

      std::vector<SUnit *> &UseList = Uses[Reg];
      std::vector<SUnit *> &DefList = Defs[Reg];
      // Optionally add output and anti dependencies. For anti
      // dependencies we use a latency of 0 because for a multi-issue
      // target we want to allow the defining instruction to issue
      // in the same cycle as the using instruction.
      // TODO: Using a latency of 1 here for output dependencies assumes
      //       there's no cost for reusing registers.
      SDep::Kind Kind = MO.isUse() ? SDep::Anti : SDep::Output;
      unsigned AOLatency = (Kind == SDep::Anti) ? 0 : 1;
      for (unsigned i = 0, e = DefList.size(); i != e; ++i) {
        SUnit *DefSU = DefList[i];
        if (DefSU == &ExitSU)
          continue;
        if (DefSU != SU &&
            (Kind != SDep::Output || !MO.isDead() ||
             !DefSU->getInstr()->registerDefIsDead(Reg)))
          DefSU->addPred(SDep(SU, Kind, AOLatency, /*Reg=*/Reg));
      }
      for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
        std::vector<SUnit *> &DefList = Defs[*Alias];
        for (unsigned i = 0, e = DefList.size(); i != e; ++i) {
          SUnit *DefSU = DefList[i];
          if (DefSU == &ExitSU)
            continue;
          if (DefSU != SU &&
              (Kind != SDep::Output || !MO.isDead() ||
               !DefSU->getInstr()->registerDefIsDead(*Alias)))
            DefSU->addPred(SDep(SU, Kind, AOLatency, /*Reg=*/ *Alias));
        }
      }

      if (MO.isDef()) {
        // Add any data dependencies.
        unsigned DataLatency = SU->Latency;
        for (unsigned i = 0, e = UseList.size(); i != e; ++i) {
          SUnit *UseSU = UseList[i];
          if (UseSU == SU)
            continue;
          unsigned LDataLatency = DataLatency;
          // Optionally add in a special extra latency for nodes that
          // feed addresses.
          // TODO: Do this for register aliases too.
          // TODO: Perhaps we should get rid of
          // SpecialAddressLatency and just move this into
          // adjustSchedDependency for the targets that care about it.
          if (SpecialAddressLatency != 0 && !UnitLatencies &&
              UseSU != &ExitSU) {
            MachineInstr *UseMI = UseSU->getInstr();
            const TargetInstrDesc &UseTID = UseMI->getDesc();
            int RegUseIndex = UseMI->findRegisterUseOperandIdx(Reg);
            assert(RegUseIndex >= 0 && "UseMI doesn's use register!");
            if (RegUseIndex >= 0 &&
                (UseTID.mayLoad() || UseTID.mayStore()) &&
                (unsigned)RegUseIndex < UseTID.getNumOperands() &&
                UseTID.OpInfo[RegUseIndex].isLookupPtrRegClass())
              LDataLatency += SpecialAddressLatency;
          }
          // Adjust the dependence latency using operand def/use
          // information (if any), and then allow the target to
          // perform its own adjustments.
          const SDep& dep = SDep(SU, SDep::Data, LDataLatency, Reg);
          if (!UnitLatencies) {
            ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep));
            ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep));
          }
          UseSU->addPred(dep);
        }
        for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
          std::vector<SUnit *> &UseList = Uses[*Alias];
          for (unsigned i = 0, e = UseList.size(); i != e; ++i) {
            SUnit *UseSU = UseList[i];
            if (UseSU == SU)
              continue;
            const SDep& dep = SDep(SU, SDep::Data, DataLatency, *Alias);
            if (!UnitLatencies) {
              ComputeOperandLatency(SU, UseSU, const_cast<SDep &>(dep));
              ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep));
            }
            UseSU->addPred(dep);
          }
        }

        // If a def is going to wrap back around to the top of the loop,
        // backschedule it.
        if (!UnitLatencies && DefList.empty()) {
          LoopDependencies::LoopDeps::iterator I = LoopRegs.Deps.find(Reg);
          if (I != LoopRegs.Deps.end()) {
            const MachineOperand *UseMO = I->second.first;
            unsigned Count = I->second.second;
            const MachineInstr *UseMI = UseMO->getParent();
            unsigned UseMOIdx = UseMO - &UseMI->getOperand(0);
            const TargetInstrDesc &UseTID = UseMI->getDesc();
            // TODO: If we knew the total depth of the region here, we could
            // handle the case where the whole loop is inside the region but
            // is large enough that the isScheduleHigh trick isn't needed.
            if (UseMOIdx < UseTID.getNumOperands()) {
              // Currently, we only support scheduling regions consisting of
              // single basic blocks. Check to see if the instruction is in
              // the same region by checking to see if it has the same parent.
              if (UseMI->getParent() != MI->getParent()) {
                unsigned Latency = SU->Latency;
                if (UseTID.OpInfo[UseMOIdx].isLookupPtrRegClass())
                  Latency += SpecialAddressLatency;
                // This is a wild guess as to the portion of the latency which
                // will be overlapped by work done outside the current
                // scheduling region.
                Latency -= std::min(Latency, Count);
                // Add the artificial edge.
                ExitSU.addPred(SDep(SU, SDep::Order, Latency,
                                    /*Reg=*/0, /*isNormalMemory=*/false,
                                    /*isMustAlias=*/false,
                                    /*isArtificial=*/true));
              } else if (SpecialAddressLatency > 0 &&
                         UseTID.OpInfo[UseMOIdx].isLookupPtrRegClass()) {
                // The entire loop body is within the current scheduling region
                // and the latency of this operation is assumed to be greater
                // than the latency of the loop.
                // TODO: Recursively mark data-edge predecessors as
                //       isScheduleHigh too.
                SU->isScheduleHigh = true;
              }
            }
            LoopRegs.Deps.erase(I);
          }
        }

        UseList.clear();
        if (!MO.isDead())
          DefList.clear();
        DefList.push_back(SU);
      } else {
        UseList.push_back(SU);
      }
    }

    // Add chain dependencies.
    // Chain dependencies used to enforce memory order should have
    // latency of 0 (except for true dependency of Store followed by
    // aliased Load... we estimate that with a single cycle of latency
    // assuming the hardware will bypass)
    // Note that isStoreToStackSlot and isLoadFromStackSLot are not usable
    // after stack slots are lowered to actual addresses.
    // TODO: Use an AliasAnalysis and do real alias-analysis queries, and
    // produce more precise dependence information.
#define STORE_LOAD_LATENCY 1
    unsigned TrueMemOrderLatency = 0;
    if (TID.isCall() || MI->hasUnmodeledSideEffects() ||
        (MI->hasVolatileMemoryRef() && 
         (!TID.mayLoad() || !MI->isInvariantLoad(AA)))) {
      // Be conservative with these and add dependencies on all memory
      // references, even those that are known to not alias.
      for (std::map<const Value *, SUnit *>::iterator I = 
             NonAliasMemDefs.begin(), E = NonAliasMemDefs.end(); I != E; ++I) {
        I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
      }
      for (std::map<const Value *, std::vector<SUnit *> >::iterator I =
             NonAliasMemUses.begin(), E = NonAliasMemUses.end(); I != E; ++I) {
        for (unsigned i = 0, e = I->second.size(); i != e; ++i)
          I->second[i]->addPred(SDep(SU, SDep::Order, TrueMemOrderLatency));
      }
      NonAliasMemDefs.clear();
      NonAliasMemUses.clear();
      // Add SU to the barrier chain.
      if (BarrierChain)
        BarrierChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
      BarrierChain = SU;

      // fall-through
    new_alias_chain:
      // Chain all possibly aliasing memory references though SU.
      if (AliasChain)
        AliasChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
      AliasChain = SU;
      for (unsigned k = 0, m = PendingLoads.size(); k != m; ++k)
        PendingLoads[k]->addPred(SDep(SU, SDep::Order, TrueMemOrderLatency));
      for (std::map<const Value *, SUnit *>::iterator I = AliasMemDefs.begin(),
           E = AliasMemDefs.end(); I != E; ++I) {
        I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
      }
      for (std::map<const Value *, std::vector<SUnit *> >::iterator I =
           AliasMemUses.begin(), E = AliasMemUses.end(); I != E; ++I) {
        for (unsigned i = 0, e = I->second.size(); i != e; ++i)
          I->second[i]->addPred(SDep(SU, SDep::Order, TrueMemOrderLatency));
      }
      PendingLoads.clear();
      AliasMemDefs.clear();
      AliasMemUses.clear();
    } else if (TID.mayStore()) {
      bool MayAlias = true;
      TrueMemOrderLatency = STORE_LOAD_LATENCY;
      if (const Value *V = getUnderlyingObjectForInstr(MI, MFI, MayAlias)) {
        // A store to a specific PseudoSourceValue. Add precise dependencies.
        // Record the def in MemDefs, first adding a dep if there is
        // an existing def.
        std::map<const Value *, SUnit *>::iterator I = 
          ((MayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V));
        std::map<const Value *, SUnit *>::iterator IE = 
          ((MayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end());
        if (I != IE) {
          I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0, /*Reg=*/0,
                                  /*isNormalMemory=*/true));
          I->second = SU;
        } else {
          if (MayAlias)
            AliasMemDefs[V] = SU;
          else
            NonAliasMemDefs[V] = SU;
        }
        // Handle the uses in MemUses, if there are any.
        std::map<const Value *, std::vector<SUnit *> >::iterator J =
          ((MayAlias) ? AliasMemUses.find(V) : NonAliasMemUses.find(V));
        std::map<const Value *, std::vector<SUnit *> >::iterator JE =
          ((MayAlias) ? AliasMemUses.end() : NonAliasMemUses.end());
        if (J != JE) {
          for (unsigned i = 0, e = J->second.size(); i != e; ++i)
            J->second[i]->addPred(SDep(SU, SDep::Order, TrueMemOrderLatency,
                                       /*Reg=*/0, /*isNormalMemory=*/true));
          J->second.clear();
        }
        if (MayAlias) {
          // Add dependencies from all the PendingLoads, i.e. loads
          // with no underlying object.
          for (unsigned k = 0, m = PendingLoads.size(); k != m; ++k)
            PendingLoads[k]->addPred(SDep(SU, SDep::Order, TrueMemOrderLatency));
          // Add dependence on alias chain, if needed.
          if (AliasChain)
            AliasChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
        }
        // Add dependence on barrier chain, if needed.
        if (BarrierChain)
          BarrierChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
      } else {
        // Treat all other stores conservatively.
        goto new_alias_chain;
      }

      if (!ExitSU.isPred(SU))
        // Push store's up a bit to avoid them getting in between cmp
        // and branches.
        ExitSU.addPred(SDep(SU, SDep::Order, 0,
                            /*Reg=*/0, /*isNormalMemory=*/false,
                            /*isMustAlias=*/false,
                            /*isArtificial=*/true));
    } else if (TID.mayLoad()) {
      bool MayAlias = true;
      TrueMemOrderLatency = 0;
      if (MI->isInvariantLoad(AA)) {
        // Invariant load, no chain dependencies needed!
      } else {
        if (const Value *V = 
            getUnderlyingObjectForInstr(MI, MFI, MayAlias)) {
          // A load from a specific PseudoSourceValue. Add precise dependencies.
          std::map<const Value *, SUnit *>::iterator I = 
            ((MayAlias) ? AliasMemDefs.find(V) : NonAliasMemDefs.find(V));
          std::map<const Value *, SUnit *>::iterator IE = 
            ((MayAlias) ? AliasMemDefs.end() : NonAliasMemDefs.end());
          if (I != IE)
            I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0, /*Reg=*/0,
                                    /*isNormalMemory=*/true));
          if (MayAlias)
            AliasMemUses[V].push_back(SU);
          else 
            NonAliasMemUses[V].push_back(SU);
        } else {
          // A load with no underlying object. Depend on all
          // potentially aliasing stores.
          for (std::map<const Value *, SUnit *>::iterator I = 
                 AliasMemDefs.begin(), E = AliasMemDefs.end(); I != E; ++I)
            I->second->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
          
          PendingLoads.push_back(SU);
          MayAlias = true;
        }
        
        // Add dependencies on alias and barrier chains, if needed.
        if (MayAlias && AliasChain)
          AliasChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
        if (BarrierChain)
          BarrierChain->addPred(SDep(SU, SDep::Order, /*Latency=*/0));
      } 
    }
  }

  for (int i = 0, e = TRI->getNumRegs(); i != e; ++i) {
    Defs[i].clear();
    Uses[i].clear();
  }
  PendingLoads.clear();
}