[clang] [llvm] [RISCV] Assembler support for XRivosVizip (PR #127694)

[Philip Reames via cfe-commits]

preames wrote:

> I am kind of confused now. So the situation here is that RVIOS has already implemented these vendor extensions in cores and RVIOS is also trying to make these extensions official RVI standards, right?

You're confusing two things.  We (Rivos) have defined a set of custom vendor extensions - this patch is the first in that sub-series.  We are *also and separately* proposing a subset of instructions for consideration at RVI for eventual standardization.  As an example of how these are different, see XRivosVisni in the linked repo.  That's a vendor extension which relates to gaps identified in RVV, but for which we're not currently proposing an extension at RVI. 

https://github.com/llvm/llvm-project/pull/127694