[llvm] [CVP]: Fold `icmp eq X, C` to `trunc X to i1` if C=2k+1 and X in [2k, 2k+1] (PR #83829)

[via llvm-commits]

YanWQ-monad wrote:

> > With this fold, RISC-V can eliminate two instructions, while ARM can eliminate one instruction on the hot path.
> 
> Could you please provide the godbolt link?

Sure, the link is https://godbolt.org/z/xMTbP94Yn.

https://github.com/llvm/llvm-project/pull/83829