[llvm] [LangRef] Add a description of the semantics of call signatures. (PR #136189)

[Nikita Popov via llvm-commits]

nikic wrote:

@joker-eph This updates LangRef to reflect current LLVM semantics. I understand that *you* think these semantics are not desirable, but LangRef should still reflect the current semantics.

I can see how a reasonable person might disagree on the best way to handle the problem of mismatched function signatures, but as the issue discussion explains in detail, the current design is intentional, so calling this a "bug" is disingenuous. It is not the case that someone just forgot to implement a verifier check -- the lack of a verifier check is deliberate.

If we wanted to make any change away from the current semantics, it would have to go through an RFC (unless it's just a cosmetic change in textual IR, without impact on the IR model itself -- but you didn't like that either).

https://github.com/llvm/llvm-project/pull/136189