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

[Mikael Morin <morin-mikael@orange.fr>]

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.