[clang] [llvm] [RISCV] Add processor definition for SpacemiT-X60 (PR #94564)

[Philip Reames via cfe-commits]

preames wrote:

> Will this core have active support on the LLVM side?

I can't speak for the vendor, but I'll say that I'm interested in having this supported upstream.  This looks to be a reasonable rva22 dev board w/V1.0, and having in tree support seems worthwhile.  I've ordered one of these myself, and plan on using it for ongoing RISC-V vector development.  

https://github.com/llvm/llvm-project/pull/94564