[llvm] Widen rt stride loads (PR #162336)

[Mikhail Gudim via llvm-commits]

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mgudim wrote:

Technically should be possible, but then the following checks probably won't pass. If they pass it means that essentially we did have and `add`, it was just expressed differently. I can't come up with a good example though right now.

https://github.com/llvm/llvm-project/pull/162336