[llvm] [VPlan] Dispatch to multiple exit blocks via middle blocks. (PR #112138)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

> Should the block diagram of https://llvm.org/docs/Vectorizers.html#epilogue-vectorization be updated?

Added a brief section with a diagram of the VPlan for loops with early exits, thanks

https://github.com/llvm/llvm-project/pull/112138