[llvm] [DAG] canCreateUndefOrPoison - add handling for ADD/SUB overflow nodes (PR #146322)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM. I don't think having explicit test coverage for everything in this list is particularly useful.

https://github.com/llvm/llvm-project/pull/146322