[llvm] [VectorCombine] Fold Deinterleave/Interleave Pairs (PR #211022)

[Benjamin Maxwell via llvm-commits]

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MacDue wrote:

Yeah, I'm not sure about this one :sweat_smile: I think the first stage is mostly generic across instruction types, so I'm not sure the visitor would really help there. It could maybe help with the widening step, but I think it might be a little more complex than the current approach (but maybe not, idk :smile:).  

https://github.com/llvm/llvm-project/pull/211022