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

[via llvm-commits]

workingjubilee 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

Of all calls for... what? All function calls that are hypothetically possible at runtime? Used for what purpose? Based on what conditions? What are we assuming is linked and therefore imposing on frontends that they must guarantee is linked?

Can we have some way of marking the ones that aren't actually going to, and should not, get spontaneously lowered to?

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