[llvm] [LAA] strip dead code, simplify logic (NFC) (PR #92119)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

This looks reasonable to me, but is it really NFC? I would expect this to allow determining the stride in more cases that previously failed that check?

https://github.com/llvm/llvm-project/pull/92119