[llvm] [AArch64][SVE] Fold ADD+CNTB to INCB and DECB (PR #118280)

[Ricardo Jesus via llvm-commits]

rj-jesus wrote:

> Looks good to me. Although it does remind me to revisit the add/sub vscale work to see if there's a better way to capture all the requirements but using less patterns. The need to handle 64-bit and 32-bit separately still irks me.

Thanks very much! Please let me know if I can help with refactoring these patterns - they do look a bit clunky!

https://github.com/llvm/llvm-project/pull/118280