[llvm] [VPlan] Make simplifyRecipe more like InstCombine (PR #212968)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon approved this pull request.

I think this LGTM, thanks. Kindly wait 48h before landing, in case Florian has any further comments?

https://github.com/llvm/llvm-project/pull/212968