[llvm] [RFC][LV] VPlan-based cost model (PR #67647)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon commented:

General idea seems sound, but this needs tests to convince me that LV behavior doesn't change with VPlan-based costing.

https://github.com/llvm/llvm-project/pull/67647