When unfolding a load during scheduling, the new operator node has

a data dependency on the load node, so it really needs a
data-dependence edge to the load node, even if the load previously
existed.

And add a few comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67554 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-03-23 20:20:43 +00:00
parent 3e744c8bc4
commit fa9afef7ea

View File

@ -410,6 +410,7 @@ SUnit *ScheduleDAGRRList::CopyAndMoveSuccessors(SUnit *SU) {
NewSU->isCommutable = true;
ComputeLatency(NewSU);
// Record all the edges to and from the old SU, by category.
SmallVector<SDep, 4> ChainPreds;
SmallVector<SDep, 4> ChainSuccs;
SmallVector<SDep, 4> LoadPreds;
@ -433,6 +434,7 @@ SUnit *ScheduleDAGRRList::CopyAndMoveSuccessors(SUnit *SU) {
NodeSuccs.push_back(*I);
}
// Now assign edges to the newly-created nodes.
for (unsigned i = 0, e = ChainPreds.size(); i != e; ++i) {
const SDep &Pred = ChainPreds[i];
RemovePred(SU, Pred);
@ -468,9 +470,10 @@ SUnit *ScheduleDAGRRList::CopyAndMoveSuccessors(SUnit *SU) {
AddPred(SuccDep, D);
}
}
if (isNewLoad) {
AddPred(NewSU, SDep(LoadSU, SDep::Order, LoadSU->Latency));
}
// Add a data dependency to reflect that NewSU reads the value defined
// by LoadSU.
AddPred(NewSU, SDep(LoadSU, SDep::Data, LoadSU->Latency));
if (isNewLoad)
AvailableQueue->addNode(LoadSU);