[llvm] [InstCombine] fold `(a == c && b != c) || (a != c && b == c))` to `(a == c) == (b != c)` (PR #94915)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM

Note that there is a conjugate pattern with or and and swapped: https://alive2.llvm.org/ce/z/mRhkK2 Would be good to handle it in a followup as well.

https://github.com/llvm/llvm-project/pull/94915