[llvm] [VPlan] Add transform to replace VPWidenCanonicalIV with wide IV. (PR #194267)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

> Also, the issue with the cost-based transform is that it cannot be guaranteed to fixup things for https://github.com/llvm/llvm-project/pull/191219.

I'm not 100% sure how this is related. This seems independent of deciding whether to generate a wide IV or materialize from canonical IV?

https://github.com/llvm/llvm-project/pull/194267