[llvm] [VPlan] Expand affine AddRecs to VPInstructions (PR #209921)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

I might be missing something, but I think currently all AddRecs are for loops outside the scope of VPlan, and they need to be expanded in the scope of the loop attached to the AddRec, not the vector loop?

I don't think we can do anything other than expanding them via VPExpandSCEVRecipe, as it may require inserting instructions in loops outside the scope of VPlan, like https://github.com/llvm/llvm-project/pull/210013?

https://github.com/llvm/llvm-project/pull/209921