[llvm] [DAG] Add legalization handling for AVGCEIL/AVGFLOOR nodes (PR #92096)

[Jay Foad via llvm-commits]

https://github.com/jayfoad commented:

No objection from me. The logic looks good. But I don't feel I know enough about any of the affected targets to approve it.

https://github.com/llvm/llvm-project/pull/92096