[llvm] [RISCV] Decompose single source shuffles (without exact VLEN) (PR #126108)

[Philip Reames via llvm-commits]

preames wrote:

> I'll likely have to step away shortly so if you can look at the revert that would be great - thank you.

Reverted - tests were fine, but had to manually resolve a conflict with a later patch.  

> I'll file that bug with collated information on how to reproduce.

Look forward to it.  I took a skim through the code and don't see an obvious problem, so will need a reproducer to identity the mistake.

https://github.com/llvm/llvm-project/pull/126108