[PATCH] D29872: Do not legalize large add with addc/adde, introduce addcarry and do it with uaddo/addcarry

[Amaury SECHET via Phabricator via llvm-commits]

deadalnix added a comment.

> It'll be great to also eliminate ADDC/ADDE/SUBC/SUBE, instead of adding an alternative method. Oh...and, SETCCE. Will probably need a new variant of that as well?

Yes I think that where we want to go with this, but proceeding incrementally seems to make more sense. My plan was to get the new stuff up, move in tree backend to use it, and then deprecate it/remove it. SETCCE is also on my radar.

> The FIXME for x86 seems pretty distasteful...

Yes I was very unhappy with that solution and was hopping for some advice on how to do this better. I'll try your solution and see how it goes. Do you see the setcarry as a generic ISD or as a X86 specific one ?


https://reviews.llvm.org/D29872