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

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

FYI, `trunc X to i1` will be canonicalized into `(X & 1) == 0`.
godbolt: https://godbolt.org/z/cMv6K8qKd


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