[PATCH] D31081: [ARM] ScheduleDAGRRList::DelayForLiveRegsBottomUp must consider OptionalDefs

[A. Skrobov via Phabricator via llvm-commits]

tyomitch added a comment.

> This needs a much better comment explaining why this is necessary

Done.

> I spent a little time experimenting with multiclassing the Thumb1 instructions to avoid optional defs;
>  it seems like it's viable, and it's substantially simpler in some ways, but it would take a lot of time to finish.

Yes, that's my own understanding, too.


https://reviews.llvm.org/D31081