[flang-commits] [flang] [flang][OpenMP] Switch SOURCE/SINK to use modifier infrastructure (PR #217644)

[Caroline Newcombe via flang-commits]

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cenewcombe wrote:

I think doacross.f90 could benefit from a few more semantic tests around these changes, e.g. (the first two within an `ordered(n)` nest):
```
!ERROR: Iteration vector must be specified with SINK dependence type
!$omp ordered doacross(sink)

!ERROR: Iteration vector may not be specified with SOURCE dependence type
!$omp ordered doacross(source: i)

!ERROR: 'dependence-type' modifier cannot occur multiple times
!ERROR: 'dependence-type' should be the last modifier
!$omp ordered doacross(sink, sink: i, j)
```

https://github.com/llvm/llvm-project/pull/217644