[llvm] [LLVM] Slay undead copysign code (PR #111269)

[Ralf Jung via llvm-commits]

RalfJung wrote:

> Regardless of the usage, I think these should still be recorded in RuntimeLibcalls. Ideally it would be a complete database of all calls for the system, not just used

It would be good to know which functions LLVM might actually use so that frontends have a chance of ensuring they are all provided. And it would be good for that list to be as short as possible so that frontends don't spend effort trying to provide some functions that LLVM will not actually use.

https://github.com/llvm/llvm-project/pull/111269