[llvm] [RISCV] Reverse (add x, (zext c)) back to (select c, (add x, 1), x) (PR #87236)

[Luke Lau via llvm-commits]

lukel97 wrote:

Thanks for pointing that out, seems better to try and fix foldSelectWithIdentityConstant. Will take a look

https://github.com/llvm/llvm-project/pull/87236