[PATCH] D125372: [SCEVExpander] Expand umin_seq using freeze

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

Hello.

(This is part of my ~6 months backlog
in which i was not really around,
so i'm commenting on these things
as i stumble into them.)

While it is good that this helps optimizations,
there is one thing that is not mentioned at all here: round-tripping.
SCEV does not recognize this new canonical expansion back as `umin_seq`,
which means subsequent SCEV usages will have less insight into the IR.

I think, this is salvageable, but given that we model `freeze` as a `SCEVUnkown`,
the solution will be controversial. Will post patch soon.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125372/new/

https://reviews.llvm.org/D125372