[llvm] [RISCV] and x (sub 0, y) -> andn x y (PR #129253)

[Jay Foad via llvm-commits]

jayfoad wrote:

> and x (sub 0, y) -> andn x y

This seems completely wrong since they calculate different results. Perhaps you meant "and x (sub **-1**, y) -> andn x y"??

https://github.com/llvm/llvm-project/pull/129253