[llvm] RFC: Argpromotion of externally visible functions (PR #87731)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

I mean, some callers might not be compiled with ThinLTO enabled, e.g. written in assembly, or another language.  Or might just take the address of the function.  Or the symbol might be exported from a shared library.  So in general, inlining isn't reliable no matter what you do.

If this code were running as part of ThinLTO, instead of a pass running before ThinLTO, you could possibly detect those cases; the linker knows whether a symbol has external references.

https://github.com/llvm/llvm-project/pull/87731