[llvm] [InstCombine][RISCV] Convert VPIntrinsics with splat operands to splats (PR #65706)

[Luke Lau via llvm-commits]

lukel97 wrote:

> Thank you very much for your review on this. You were very helpful in improving this patch and I learned a lot about a space I was not too familiar with previously.

No problem, I learnt lots about UB too :)

https://github.com/llvm/llvm-project/pull/65706