[llvm] [PGO] Do not promote an indirect call over a known set of targets (PR #222518)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

I'm not sure this is actually profitable in general.

The compiler could infer information about call targets, but in practice the only pass I'm aware of that would actually do indirect call promotion here is ICP (`pgo-icall-prom`). If there's a heavily biased callee, I would think that ICP+inlining would still be profitable performance wise. If the code size here is that important, maybe we change the behavior of ICP in the presence of `minsize`/`optsize` as right now I believe it does the same thing regardless of code size preferences.

https://github.com/llvm/llvm-project/pull/222518