[llvm] [RISCV] Allow non-power-of-2 vectors for VLS code generation (PR #97010)

[Philip Reames via llvm-commits]

preames wrote:

> I'm focusing my comment on the codegen changes to understand the merits of this approach over alternatives.

Can I ask that you rebase this?  I've now landed a couple of pragmatic improvements for the current lowering without the additional value types, and I'm curious to see what remaining difference we have here.  

https://github.com/llvm/llvm-project/pull/97010