[llvm] [Transforms][Utils] Add LoopSplit for iteration-space loop splitting (PR #217232)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

Thanks for the latest updates, a few more comments inline.

One thing I noticed is that there seems to be some overlap with `llvm/include/llvm/Transforms/Utils/LoopConstrainer.h` used by IRCE.

Apologies if this was already discussed previously, but I think it would be worth at least calling out what the plan is going forward in the PR description, hopefully removing the duplication soon

https://github.com/llvm/llvm-project/pull/217232