[llvm] [verify][swift] Allow passing swifterror to phi instructions (PR #138598)

[Nikita Popov via llvm-commits]

https://github.com/nikic requested changes to this pull request.

If you are allowing phi nodes, you need to allow selects as well. This should also result in a LangRef change.

But this really needs confirmation from someone familiar with swifterror that this is safe. I think that used to be @TNorthover, but I'm not sure who it is now. @fhahn Do you know who should review swifterror stuff?

https://github.com/llvm/llvm-project/pull/138598