[llvm] [SLP][NFC] Redesign schedule bundle, separate from schedule data, NFC (PR #131625)

[Gaëtan Bossu via llvm-commits]

https://github.com/gbossu commented:

I'm currently looking into the SLPVectorizer to add support for more "re-vectorization" and I saw this patch pop up so I thought I'd have a quick look at it. I'm completely new to the SLP code base, so feel free to ignore my comments. I just thought it might help me get a better understanding if I look at pull requests. 😄 

As a vectorizer newbie, one thing which I feel would make the code easier to understand is to modularize, even just slightly. Do you maybe have some plans to make the SLPVectorizer act more like a driver, and move components like cost modelling or scheduling into separate files?

https://github.com/llvm/llvm-project/pull/131625