[clang] [llvm] [RISCV] Add Qualcomm uC Xqcisim (Simulation Hint) extension (PR #128833)

[Jessica Clarke via cfe-commits]

jrtc27 wrote:

Is this the kind of thing we have agreed to take in LLVM? If it's "simulation hint" instructions, does that not by definition mean that it's not an extension present in real hardware?

https://github.com/llvm/llvm-project/pull/128833