[llvm] [LoopInterchange] Add an option to prioritize vectorization (PR #131988)

[Michael Kruse via llvm-commits]

Meinersbur wrote:

@sjoerdmeijer Each cost concern can also return "the order is optimal as-is; if it was in a different order I would suggest to change it". Lets say, vectorization prefers to swap, but cache analysis wants to keep. Since we are in a loop that only finishes until a fixpoint is reached, we would alternate between vectorization wants to swap, then cache analysis swaps back, tham vectorization wants to swap again, .... .

https://github.com/llvm/llvm-project/pull/131988