[llvm] [VPlan] Optz WidenGEP with single-scalar operands (PR #166740)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> if all operands are single scalar, we should be able to handle this in narrowToSingleScalar, and remove the special handling in the recipe altogether?

This is currently not possible, as narrowToSingleScalars' users check is too weak.

https://github.com/llvm/llvm-project/pull/166740