[clang] [llvm] [RISCV] Add generic CPUs for profiles (PR #84877)

[Alex Bradbury via llvm-commits]

asb wrote:

> > I don't know if we need S-mode profile CPUs.
> 
> I lean towards not supporting them since the S extensions don't do anything in the compiler except preprocessor defines and ELF attributes, but maybe we should put it on the agenda for the sync meeting this week.

My initial feeling is it probably wouldn't hurt to have them, but it's not clear who would use them in practice. Build systems for userspace code presumably wouldn't do so, and I'd have thought kernels would typically want more control (as they wouldn't want the compiler to make use of floating point or vectors freely). But I could be wrong on that, so I'd love to hear from others with more experience on that. e.g. @petrhosek

https://github.com/llvm/llvm-project/pull/84877