[llvm] [RISCV] Use software guarded branch for indirect jump table branch. (PR #66762)

[Yeting Kuo via llvm-commits]

yetingk wrote:

> The GPRJALR register class used by BRIND (the non-guarded form) doesn't seem to exclude X7.

Thank you for finding the bug. I should exclude x7 for non-guarded branch.

> Has there been an assembly syntax defined for the SW guarded branch?

I think the answer is No.

https://github.com/llvm/llvm-project/pull/66762