[flang-commits] [flang] [llvm] [Frontend][OpenMP] Follow compound construct clause restrictions (PR #107853)

[Sergio Afonso via flang-commits]

skatrak wrote:

I see, I imagined your concern could be related to the future auto-generated OMP.td. The problem is that the current approach is actually not having frontend-specific checks for this specifically, but rather omitting clauses from the `allowedClauses` property. As reference, see these cases prior to this PR:
- No `OMPC_Copyin` because of the `target` leaf: `OMP_TargetParallel`, `OMP_TargetParallelDoSimd`, `OMP_TargetParallelFor`, `OMP_TargetParallelForSimd`, `OMP_TargetTeamsDistributeParallelFor`, `OMP_TargetTeamsDistributeParallelForSimd`.
- No `OMPC_Ordered` because of the `distribute` leaf: `OMP_DistributeParallelDoSimd`, `OMP_DistributeParallelFor`, `OMP_DistributeParallelForSimd`, `OMP_TargetTeamsDistribute`, `OMP_TargetTeamsDistributeParallelFor`, `OMP_TargetTeamsDistributeParallelForSimd`, `OMP_TargetTeamsDistributeSimd`, `OMP_TeamsDistributeParallelDoSimd`, `OMP_TeamsDistributeParallelFor`, `OMP_TeamsDistributeParallelForSimd`, `OMP_TeamsDistributeSimd`.

This PR just completes these checks, since there were fewer exceptions missing than exceptions handled. If these checks need to be migrated to frontend checks because of the limited information available from these JSON files, I'm not against that. I just think that's a separate PR, what do you think?

https://github.com/llvm/llvm-project/pull/107853