[llvm] [InstCombine] Avoid DeMorgan's on occasion (PR #109215)

[Nikita Popov via llvm-commits]

nikic wrote:

Landed https://github.com/llvm/llvm-project/commit/f1ff3a279f3320d8e0d4abbc1a8357bb51de25a2 to hopefully save the next person some time.

https://github.com/llvm/llvm-project/pull/109215