[clang] [FMV][AArch64][clang] Emit fmv-features metadata in LLVM IR. (PR #118544)

[Alexandros Lamprineas via cfe-commits]

labrinea wrote:

Thanks for looking into this Andrew. There's one thing I would like to clarify here. Jon expressed the opinion that in your example the command line should determine the highest priority version (i8mm+fcma), which isn't what https://github.com/ARM-software/acle/pull/370 suggests. That said, this PR is still need after the amendment to ACLE. Personally I don't have a strong opinion which way to go. I am open to discuss.

https://github.com/llvm/llvm-project/pull/118544