On Tue, Feb 15, 2022 at 11:26:12AM +0100, Tobias Burnus wrote:
> As found by Marcel, the 'depend' clause was differently handled in
> 'omp depobj(...) depend(...)' and in 'omp task depend(...)'.
>
> The problem was that for a scalar pointer, depobj depended
> on the pointer address - while task depended on the pointer-target address.
>
> If one now combines depobj and direct var dependency, the dependency
> is on different addresses, such that the dependency is not honored.
> Marcel's example is testsuite/libgomp.fortran/depend-4.f90.
> (Thanks for the report!)
>
>
> I think in the real world, the problem is not that big as most
> code either uses depobj or a variable and does not mix them. Likewise,
> using the address of a temporary variable (cf. below) will also usually
> work in terms of dependency.
>
>
> The attached patch does:
> - depend clause (as used by task etc):
> For scalar allocatable/pointer, add another dereference
>
> - For depobj (which handles the depend clause by itself)
> - Fix array(element) handling by coping the depend-clause.
> Before the result was 'D.123 = var; depobj = &D.123;'
> which is really not intended.
> - Several issues related to optional and allocatable/pointer.
>
> OK for mainline? Does backporting to GCC 11 make sense?
Ok. Dunno about backporting, perhaps later.
Jakub
