[flang] [llvm] [mlir] [flang][OpenMP] Enable tiling (PR #143715)

[Kareem Ergawy via llvm-commits]

https://github.com/ergawy commented:

Took another look this time trying to understand the approach on a higher level. I have one concern/question. It seems like we are "hiding" the `tile` directive too early in the pipeline (i.e. during PFT to the `omp` dialect); both for the combined and the standalone cases. I would have expected to model `tile` as a separate op in the dialect and handle mapping combined and standalone versions later in the compiler. In the standalone case, for instance, we conflate the `loop` and `tile` directives in one op which overloads `omp.loop` with more semantics than it is intended to carry.

To me, the `tile` is similar to `simd` in the sense that it is a loop wrapper op that controls division of the loop nests' iterations. So I would have expected both to have similar modelling (i.e. a separate op that impelements the `LoopWrapperInterface`).

You probably have good reason not to what I suggested so just asking for my understanding.

https://github.com/llvm/llvm-project/pull/143715