[llvm] [RISCV] AIFoundry.org ET extensions for RISCV (PR #174571)

[Sam Elliott via llvm-commits]

lenary wrote:

To slightly follow on from Craig's comments:
- Please ensure that you have had a vendor prefix assigned and used for all instructions and csrs. These are assigned through coordination here: https://github.com/riscv-non-isa/riscv-toolchain-conventions/blob/main/src/toolchain-conventions.adoc#list-of-vendor-prefixes 
- We cannot really review this without documentation for the instructions. Is this the right docs? https://github.com/aifoundry-org/et-man/blob/main/ET%20Programmer's%20Reference%20Manual.pdf - if not, can you please point us at the right documentation.




https://github.com/llvm/llvm-project/pull/174571