Re: [PATCH] openmp, fortran: Check that event handles passed to detach clauses are not arrays [PR104131]

[Jakub Jelinek <jakub@redhat.com>]

On Mon, Feb 28, 2022 at 04:54:24PM +0100, Mikael Morin wrote:
> Le 28/02/2022 à 15:27, Kwok Cheung Yeung a écrit :
> > On 28/02/2022 2:07 pm, Jakub Jelinek wrote:
> (...)
> > > Don't we usually test instead || (*expr)->rank != 0 when testing for
> > > scalars?
> > > 
> (...)
> > 
> > So (*expr)->rank is 0 here even with an array. I'm not sure why - is
> > rank updated later, or did we forget to call something on the event
> > handle expression?
> > 
> > Testing against n->sym->as for an array check has been used elsewhere in
> > openmp.cc, to prevent reductions against arrays in OpenACC in
> > resolve_omp_clauses.
> > 
> I can’t tell what openmp requires; it depends on your needs.
> 
> Checking sym->as captures array variables which may include scalar
> expressions (arr(10) is a scalar expression even if arr is an array
> variable), while checking expr->rank only capture array expression,
> including scalar variable with array subcomponent (scal%array_comp(:) is an
> array expression, even if scal is a scalar variable).
> 
> gfc_resolve_expr, through gfc_expression_rank takes care of properly setting
> expr->rank.
> If the check is done at resolution stage (somewhere in resolve_omp_clauses I
> guess?), the rank should be set.
> 
> I hope it helps.

It is true that the spots I saw in fortran/openmp.cc that test rank look
like:
        if (!gfc_resolve_expr (el->expr)
            || el->expr->ts.type != BT_INTEGER || el->expr->rank != 0)
etc., so probably !gfc_resolve_expr call is missing.

	Jakub