Ejemplo n.º 1
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());
}
Ejemplo n.º 2
0
/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
/// critical path.
static const SDep *CriticalPathStep(const SUnit *SU) {
  const SDep *Next = 0;
  unsigned NextDepth = 0;
  // Find the predecessor edge with the greatest depth.
  for (SUnit::const_pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
       P != PE; ++P) {
    const 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;
}