[PATCH] D60125: [ScheduleDAGRRList] Recompute topological ordering on demand.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp:1488
+  if (!Interferences.empty())
+    Topo.fixOrder();
   // All candidates are delayed due to live physical reg dependencies.
----------------
fhahn wrote:
> efriedma wrote:
> > Where exactly do we query the topological order relative to this call to fixOrder()?  Do we need to fixOrder() inside the loop?
> We only query it in the loop below (WillCreateCycle call). In case we add new predecessors, we also exit the loop. And we only enter the loop, if there are some interferences. Maybe it's worth adding a comment here?
Probably worth adding a comment, yes.

By the way, how frequently do we hit this case in practice?


Repository:
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  https://reviews.llvm.org/D60125/new/

https://reviews.llvm.org/D60125