/// Compute an ILP metric for all nodes in the subDAG reachable via depth-first
/// search from this root.
void ScheduleDAGILP::computeILP(const SUnit *Root) {
if (!IsBottomUp)
llvm_unreachable("Top-down ILP metric is unimplemnted");
SchedDAGReverseDFS DFS;
// Mark a node visited by validating it.
ILPValues[Root->NodeNum] = initILP(Root);
DFS.follow(Root);
for (;;) {
// Traverse the leftmost path as far as possible.
while (DFS.getPred() != DFS.getPredEnd()) {
const SUnit *PredSU = DFS.getPred()->getSUnit();
DFS.advance();
// If the pred is already valid, skip it.
if (ILPValues[PredSU->NodeNum].isValid())
continue;
ILPValues[PredSU->NodeNum] = initILP(PredSU);
DFS.follow(PredSU);
}
// Visit the top of the stack in postorder and backtrack.
unsigned PredCount = ILPValues[DFS.getCurr()->NodeNum].InstrCount;
DFS.backtrack();
if (DFS.isComplete())
break;
// Add the recently finished predecessor's bottom-up descendent count.
ILPValues[DFS.getCurr()->NodeNum].InstrCount += PredCount;
}
}
/// Compute an ILP metric for all nodes in the subDAG reachable via depth-first
/// search from this root.
void SchedDFSResult::compute(ArrayRef<SUnit *> Roots) {
if (!IsBottomUp)
llvm_unreachable("Top-down ILP metric is unimplemnted");
SchedDFSImpl Impl(*this);
for (ArrayRef<const SUnit*>::const_iterator
RootI = Roots.begin(), RootE = Roots.end(); RootI != RootE; ++RootI) {
SchedDAGReverseDFS DFS;
Impl.visitPreorder(*RootI);
DFS.follow(*RootI);
for (;;) {
// Traverse the leftmost path as far as possible.
while (DFS.getPred() != DFS.getPredEnd()) {
const SDep &PredDep = *DFS.getPred();
DFS.advance();
// If the pred is already valid, skip it. We may preorder visit a node
// with InstrCount==0 more than once, but it won't affect heuristics
// because we don't care about cross edges to leaf copies.
if (Impl.isVisited(PredDep.getSUnit())) {
Impl.visitCross(PredDep, DFS.getCurr());
continue;
}
Impl.visitPreorder(PredDep.getSUnit());
DFS.follow(PredDep.getSUnit());
}
// Visit the top of the stack in postorder and backtrack.
const SUnit *Child = DFS.getCurr();
const SDep *PredDep = DFS.backtrack();
Impl.visitPostorder(Child, PredDep, PredDep ? DFS.getCurr() : 0);
if (DFS.isComplete())
break;
}
}
Impl.finalize();
}