[PATCH] D91267: [ARM] Remove copies from low overhead phi inductions.

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

Yeah this might look a little strange. This was really written for a following patch (D91358 <https://reviews.llvm.org/D91358>), where it was more about trying to create the new instructions without copies, than trying to specifically remove them. We do still need to remove those before the phi, but it seems to make sense to do that all together as we are already needing to check here. I was trying to get as much stuff out of the way as I could beforehand that other patch to simplify it.

I'm not sure about doing it in general. We are replacing a phi that accepts many registers with one that only accepts 1. We are being very careful here that it is OK to do that, but in general that might not always be true.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D91267/new/

https://reviews.llvm.org/D91267