[PATCH] D149651: [UnreachableBlockElim] Don't remove LCSSA phi nodes

[Jay Foad via Phabricator via llvm-commits]

foad added a comment.

> SDISel's constant branch folding can fold away self-loops, which doesn't result in any dead blocks, but
> rather an incorrect phi input.  Add code to UnreachableMachineBlockElim to get rid of these entries.

This description from r54432 is pretty unclear to me. It sounds like maybe it was using UnreachableBlockElim to fix MIR that was broken by a previous pass? Anyway reverting does not appear to cause any failures of that sort.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149651/new/

https://reviews.llvm.org/D149651