[compiler-rt] [llvm] [X86][BF16] Add libcall for F80 -> BF16 (PR #109116)

[Benjamin Kramer via llvm-commits]

https://github.com/d0k commented:

If GCC already has the method people will eventually end up linking with libgcc and run into calling convention differences. Why are they different?

https://github.com/llvm/llvm-project/pull/109116