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* [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array
@ 2014-11-18 16:37 paul.k.romano at gmail dot com
2014-11-24 7:10 ` [Bug fortran/63938] " Joost.VandeVondele at mat dot ethz.ch
` (6 more replies)
0 siblings, 7 replies; 8+ messages in thread
From: paul.k.romano at gmail dot com @ 2014-11-18 16:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
Bug ID: 63938
Summary: OpenMP atomic update does not protect access to
automatic array
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: paul.k.romano at gmail dot com
It appears that performing !$omp atomic update on an automatic array does not
protect access to the array. As an example, consider the following program:
program atomic
integer :: i, x(1)
x(1) = 0
!$omp parallel do
do i = 1, 1000
!$omp atomic
x(1) = x(1) + 1
end do
!$omp end parallel do
print *, x
end program atomic
Compiling and running this program should result in the value 1000. Instead, it
results in an unpredictable value for x, indicating there is a race condition.
If you change x to a scalar or an allocatable array, it works fine and reports
the value 1000. Equivalent code in C does not produce a race condition. The
code gives the correct value when compiled with the Intel fortran compiler.
Information on my build of gcc:
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --disable-multilib
Thread model: posix
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
@ 2014-11-24 7:10 ` Joost.VandeVondele at mat dot ethz.ch
2014-11-24 10:39 ` jakub at gcc dot gnu.org
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Joost.VandeVondele at mat dot ethz.ch @ 2014-11-24 7:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2014-11-24
CC| |Joost.VandeVondele at mat dot ethz
| |.ch
Ever confirmed|0 |1
Known to fail| |4.7.2, 4.8.3, 4.9.2, 5.0
--- Comment #1 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> ---
confirmed to affect all open branches, and at all optimization levels.
It is triggered by the fact that the array index is a constant, i.e.
this fails:
!$omp atomic
x(1) = x(1) + 1
this works:
!$omp atomic
x(j) = x(j) + 1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
2014-11-24 7:10 ` [Bug fortran/63938] " Joost.VandeVondele at mat dot ethz.ch
@ 2014-11-24 10:39 ` jakub at gcc dot gnu.org
2014-11-24 10:39 ` jakub at gcc dot gnu.org
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-11-24 10:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.8.4
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
2014-11-24 7:10 ` [Bug fortran/63938] " Joost.VandeVondele at mat dot ethz.ch
2014-11-24 10:39 ` jakub at gcc dot gnu.org
@ 2014-11-24 10:39 ` jakub at gcc dot gnu.org
2014-11-24 23:09 ` jakub at gcc dot gnu.org
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-11-24 10:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 34088
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34088&action=edit
gcc5-pr63938.patch
Untested fix.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
` (2 preceding siblings ...)
2014-11-24 10:39 ` jakub at gcc dot gnu.org
@ 2014-11-24 23:09 ` jakub at gcc dot gnu.org
2014-11-28 13:37 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-11-24 23:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Mon Nov 24 23:08:26 2014
New Revision: 218031
URL: https://gcc.gnu.org/viewcvs?rev=218031&root=gcc&view=rev
Log:
PR fortran/63938
* trans-openmp.c (gfc_trans_omp_atomic): Make sure lhsaddr is
simple enough for goa_lhs_expr_p.
* libgomp.fortran/pr63938-1.f90: New test.
* libgomp.fortran/pr63938-2.f90: New test.
Added:
trunk/libgomp/testsuite/libgomp.fortran/pr63938-1.f90
trunk/libgomp/testsuite/libgomp.fortran/pr63938-2.f90
Modified:
trunk/gcc/fortran/ChangeLog
trunk/gcc/fortran/trans-openmp.c
trunk/libgomp/ChangeLog
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
` (3 preceding siblings ...)
2014-11-24 23:09 ` jakub at gcc dot gnu.org
@ 2014-11-28 13:37 ` jakub at gcc dot gnu.org
2014-11-28 17:05 ` jakub at gcc dot gnu.org
2014-11-28 17:11 ` jakub at gcc dot gnu.org
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-11-28 13:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Nov 28 13:36:36 2014
New Revision: 218153
URL: https://gcc.gnu.org/viewcvs?rev=218153&root=gcc&view=rev
Log:
Backported from mainline
2014-11-24 Jakub Jelinek <jakub@redhat.com>
PR fortran/63938
* trans-openmp.c (gfc_trans_omp_atomic): Make sure lhsaddr is
simple enough for goa_lhs_expr_p.
* libgomp.fortran/pr63938-1.f90: New test.
* libgomp.fortran/pr63938-2.f90: New test.
Added:
branches/gcc-4_9-branch/libgomp/testsuite/libgomp.fortran/pr63938-1.f90
branches/gcc-4_9-branch/libgomp/testsuite/libgomp.fortran/pr63938-2.f90
Modified:
branches/gcc-4_9-branch/gcc/fortran/ChangeLog
branches/gcc-4_9-branch/gcc/fortran/trans-openmp.c
branches/gcc-4_9-branch/libgomp/ChangeLog
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
` (4 preceding siblings ...)
2014-11-28 13:37 ` jakub at gcc dot gnu.org
@ 2014-11-28 17:05 ` jakub at gcc dot gnu.org
2014-11-28 17:11 ` jakub at gcc dot gnu.org
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-11-28 17:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Nov 28 17:04:51 2014
New Revision: 218167
URL: https://gcc.gnu.org/viewcvs?rev=218167&root=gcc&view=rev
Log:
Backported from mainline
2014-11-24 Jakub Jelinek <jakub@redhat.com>
PR fortran/63938
* trans-openmp.c (gfc_trans_omp_atomic): Make sure lhsaddr is
simple enough for goa_lhs_expr_p.
* libgomp.fortran/pr63938-1.f90: New test.
* libgomp.fortran/pr63938-2.f90: New test.
Added:
branches/gcc-4_8-branch/libgomp/testsuite/libgomp.fortran/pr63938-1.f90
branches/gcc-4_8-branch/libgomp/testsuite/libgomp.fortran/pr63938-2.f90
Modified:
branches/gcc-4_8-branch/gcc/fortran/ChangeLog
branches/gcc-4_8-branch/gcc/fortran/trans-openmp.c
branches/gcc-4_8-branch/libgomp/ChangeLog
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/63938] OpenMP atomic update does not protect access to automatic array
2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
` (5 preceding siblings ...)
2014-11-28 17:05 ` jakub at gcc dot gnu.org
@ 2014-11-28 17:11 ` jakub at gcc dot gnu.org
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-11-28 17:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63938
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 8+ messages in thread
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2014-11-18 16:37 [Bug fortran/63938] New: OpenMP atomic update does not protect access to automatic array paul.k.romano at gmail dot com
2014-11-24 7:10 ` [Bug fortran/63938] " Joost.VandeVondele at mat dot ethz.ch
2014-11-24 10:39 ` jakub at gcc dot gnu.org
2014-11-24 10:39 ` jakub at gcc dot gnu.org
2014-11-24 23:09 ` jakub at gcc dot gnu.org
2014-11-28 13:37 ` jakub at gcc dot gnu.org
2014-11-28 17:05 ` jakub at gcc dot gnu.org
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