[PATCH] D62392: [DAGCombine][ARM] (sub Carry, X) -> (addcarry (sub 0, X), 0, Carry) fold

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D62392#1525650 <https://reviews.llvm.org/D62392#1525650>, @efriedma wrote:

> If you don't want to continue working on this, that's okay, I think.


I'm just really unfamiliar with `carry`-nodes (and with ARM),
so it is not obvious to me what needs fixing, and in what way,
if there are no existing tests that regress due to my change.

In D62392#1525650 <https://reviews.llvm.org/D62392#1525650>, @efriedma wrote:

> D62450 <https://reviews.llvm.org/D62450> looks like it's the more interesting fix.


These two are intertwined.
D62450 <https://reviews.llvm.org/D62450> folds constant from `setcc` into parent `addcarry`/`subcarry`.
But without this patch there is no `addcarry`/`subcarry`...


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62392/new/

https://reviews.llvm.org/D62392