[llvm] [VectorCombine] Fold interleave and widen chained operations (PR #224005)

[Gaëtan Bossu via llvm-commits]

gbossu wrote:

I'll try to have a look later today as well, but let me ask a stupid question before that :)

I expected the code change to be quite minimal if we are to match multiple `deinterleave` instructions instead of a single one, but it seems that most of the code has changed. Is there something that made the original code fundamentally hard to extend?

https://github.com/llvm/llvm-project/pull/224005