Re: [RFC] fortran: restore array indexing for all descriptor arrays [PR102043]

[Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>]

On 2 July 2022 14:47:01 CEST, Mikael Morin <morin-mikael@orange.fr> wrote:
>Le 02/07/2022 à 13:18, Thomas Koenig a écrit :
>> 
>> One thought: If we have to bite the bullet and break the ABI, why not go
>> all the way and use the C descriptors in ISO_Fortran_binding.h as
>> gfortran's native format?
>> 
>As far as I know, CFI descriptors are mutually exclusive with
>non-negative array indexes.
>
>CFI descriptors' base_addr field points to the first element in
>descriptor indexing order, so they can be indexed negatively and we
>can’t safely use array indexing with them.
>
>With an additional offset field it would be possible though (with a
>different semantics for the base_addr field).  Or we just keep the
>different semantics of the base_addr field and assume that there is an
>implicit offset with value sum(extent * max(-sm, 0)).
>
>Anyway, this is the long-delayed array descriptor reform, right?  Any

I think so, yes.

>one remembers how far we are from it?

We have a wiki page with notes IIRC.