[Bug libgomp/59337] New: surprising OMP error message

[Bug libgomp/59337] New: surprising OMP error message

[Joost.VandeVondele at mat dot ethz.ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337

            Bug ID: 59337
           Summary: surprising OMP error message
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgomp
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Joost.VandeVondele at mat dot ethz.ch
                CC: jakub at gcc dot gnu.org

> cat test.f90 
!$OMP ATOMIC
i=-i
END

> gfortran -fopenmp test.f90 
test.f90:2.2:

i=-i
  1
Error: !$OMP ATOMIC assignment operator must be +, *, -, /, .AND., .OR., .EQV.
or .NEQV. at (1)


The caret is pointing at a '-', and the error message is saying it must be one.
It appear that the proper way to write this is 

!$OMP ATOMIC
i=0-i
END

but that is not so obvious from the error messsage. Maybe it could be worded as
'... must be one of the binary operators '

[Bug libgomp/59337] surprising OMP error message

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I wonder why atomic negate isn't possible - from a QOI perspective treating
it as 0 - i would be obvious, no?

[Bug libgomp/59337] surprising OMP error message

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The standard doesn't allow it, and given the parsing complexities of the
atomics creating extensions there is IMHO undesirable, especially when it will
unlikely work with other compilers.

Because the standard explicitly lists the operators that can be used, I'd just
do s/must be /must be binary / in the message.

[Bug libgomp/59337] surprising OMP error message

[Joost.VandeVondele at mat dot ethz.ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337

Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Joost.VandeVondele at mat dot ethz
                   |                            |.ch

--- Comment #3 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> ---
(In reply to Jakub Jelinek from comment #2)
> creating extensions there is IMHO undesirable, especially when it
> will unlikely work with other compilers.

I agree with that, the compilers I tested all rejected this. I think it is a
flaw in the standard.

[Bug libgomp/59337] surprising OMP error message

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Mon Dec 16 15:33:42 2013
New Revision: 206017

URL: http://gcc.gnu.org/viewcvs?rev=206017&root=gcc&view=rev
Log:
    PR libgomp/59337
    * openmp.c (resolve_omp_atomic): Adjust error message.

    * gfortran.dg/gomp/pr59337.f90: New test.

Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/openmp.c
    trunk/gcc/testsuite/ChangeLog

[Bug libgomp/59337] surprising OMP error message

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Just use
!$OMP ATOMIC
i=i*-1
if you want to negate.