[llvm] [RISCV] Combine vmv.s.x to vmv.v.i if VL is known > 0 (PR #67155)

[Philip Reames via llvm-commits]

preames wrote:

I don't think this is going to be profitable.  An LI is going to be much cheaper than a VL toggle.  

https://github.com/llvm/llvm-project/pull/67155