[Bug debug/85748] dbg, gfortran: Erroneous watch of matrix rows as formal arguments using assumed shape

[eberhard.fr...@th-nuernberg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85748

Eberhard Franz <eberhard.fr...@th-nuernberg.de> changed:

   What|Removed |Added

 CC||eberhard.franz@th-nuernberg
   ||.de

--- Comment #1 from Eberhard Franz <eberhard.fr...@th-nuernberg.de> ---
Created attachment 44117
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44117=edit
Fortran sample program

[Bug debug/85748] New: dbg, gfortran: Erroneous watch of matrix rows as formal arguments using assumed shape

[eberhard.fr...@th-nuernberg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85748

Bug ID: 85748
   Summary: dbg, gfortran: Erroneous watch of matrix rows as
formal arguments using assumed shape
   Product: gcc
   Version: 8.1.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: debug
  Assignee: unassigned at gcc dot gnu.org
  Reporter: eberhard.fr...@th-nuernberg.de
  Target Milestone: ---

The newer versions of gdb have greatly simplified watching of Fortran arrays.
No longer *((real_8 *)y)@2 or similiar when one wants to watch arrays passed by
assumed shape to a subprogram. Just type the name of the array ... Thank you
very much for it!

But I believe there is a bug in watching arrays in a special case. This special
case occurs when you pass the row of a matrix (e.g. A(3, :)) to a subprogram
using assumed shape. The subprogram handles such vectors absolutely correctly,
but the vectors are displayed incorrectly using print in gdb. Obviously one
will see the first element of the row followed by wrong elements.

This error doesn't occur when one uses explict shape passing the matrix row.

I wrote a little sample program in order to demonstrate this behaviour and
attached it.