[llvm-branch-commits] [flang] [mlir] [mlir][omp] Improve canonloop/iv naming (PR #159773)

[Michael Kruse via llvm-branch-commits]

Meinersbur wrote:

> The reduction and privatisation declaration operations have multiple regions.

They are "[IsolatedFromAbove](https://mlir.llvm.org/docs/Traits/#isolatedfromabove)" though, meaning each indivually have they separated namespace.

This also meant that I previously misunderstool the "IsolatedFromAbove" trait, which I though was about the operation itself, not its region argument. I found out by trying to create a naming conflict of variable names in different region arguments. They do not conflict, so no reason to append an `_r<idx>` suffix. I did not find a operation with multiple region arguments in either the LLVMIR nor OpenMP dialects. There is one in FIR: `fir.if`. I added a test into flang as well to use it.

https://github.com/llvm/llvm-project/pull/159773