[llvm] [LAA] Prepare to handle diff type sizes (NFC) (PR #122318)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> It may be good to lift the restriction for each use separately, as this will make it easier to track down potential regressions

Done; this patch is now an NFC.

https://github.com/llvm/llvm-project/pull/122318