[llvm] [VPlan] Remove loop region in optimizeForVFAndUF. (PR #108378)

[Florian Hahn via llvm-commits]

fhahn wrote:

It turns out that tracking the blocks to delete in VPlan directly would help to simply other transforms as well (https://github.com/llvm/llvm-project/pull/106748 in particular) so I put up https://github.com/llvm/llvm-project/pull/120918

https://github.com/llvm/llvm-project/pull/108378