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* [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma
@ 2011-11-30 17:20 kmccarty at gmail dot com
2011-12-14 23:51 ` [Bug c/51360] [4.6/4.7 Regression] " pinskia at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: kmccarty at gmail dot com @ 2011-11-30 17:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
Bug #: 51360
Summary: spurious unused-but-set-variable warning for var used
in OpenMP pragma
Classification: Unclassified
Product: gcc
Version: 4.6.2
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: kmccarty@gmail.com
Hi,
gcc 4.6.2 produces a spurious unused variable warning for the following code.
The variable 'num' is used in setting the number of threads within an OpenMP
parallel region but the compiler does not realize this.
The warning is:
% /usr/local/gcc46/bin/gcc -Wall -fopenmp omp.c
omp.c: In function ‘main’:
omp.c:12:12: warning: variable ‘num’ set but not used
[-Wunused-but-set-variable]
% cat omp.c
#include <omp.h>
#include <stdlib.h>
#include <stdio.h>
// Compile with: gcc -Wall -fopenmp omp.c
// Run with: ./a.out <num_threads> e.g. "./a.out 4"
int main(int argc, char ** argv) {
if (argc != 2) return EXIT_FAILURE;
int vec[20] = { 0, };
int i, num = atoi(argv[1]);
#pragma omp parallel for num_threads(num)
for (i = 0; i < 20; ++i) {
#pragma omp critical
{
printf("thread %d\n", (int)omp_get_thread_num());
fflush(stdout);
}
vec[i] *= 5;
}
return 0;
}
Running the generated binary (RHEL 4 update 6 on x86_64) with a specified value
for argv[1] indicates that the value of 'num' is being used as expected.
gcc 4.2.4 and 4.4.3 do not warn with the same compiler flags.
Thanks,
- Kevin B. McCarty
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c/51360] [4.6/4.7 Regression] spurious unused-but-set-variable warning for var used in OpenMP pragma
2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
@ 2011-12-14 23:51 ` pinskia at gcc dot gnu.org
2011-12-15 13:38 ` jakub at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2011-12-14 23:51 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Keywords| |diagnostic
Last reconfirmed| |2011-12-14
Ever Confirmed|0 |1
Summary|spurious |[4.6/4.7 Regression]
|unused-but-set-variable |spurious
|warning for var used in |unused-but-set-variable
|OpenMP pragma |warning for var used in
| |OpenMP pragma
Target Milestone|--- |4.6.3
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-12-14 23:46:31 UTC ---
Confirmed.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c/51360] [4.6/4.7 Regression] spurious unused-but-set-variable warning for var used in OpenMP pragma
2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
2011-12-14 23:51 ` [Bug c/51360] [4.6/4.7 Regression] " pinskia at gcc dot gnu.org
@ 2011-12-15 13:38 ` jakub at gcc dot gnu.org
2011-12-15 17:51 ` jakub at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2011-12-15 13:38 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |jakub at gcc dot gnu.org
|gnu.org |
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-12-15 13:27:29 UTC ---
Created attachment 26101
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26101
gcc47-pr51360.patch
Untested fix.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c/51360] [4.6/4.7 Regression] spurious unused-but-set-variable warning for var used in OpenMP pragma
2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
2011-12-14 23:51 ` [Bug c/51360] [4.6/4.7 Regression] " pinskia at gcc dot gnu.org
2011-12-15 13:38 ` jakub at gcc dot gnu.org
@ 2011-12-15 17:51 ` jakub at gcc dot gnu.org
2011-12-15 20:51 ` [Bug c/51360] [4.6 " jakub at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2011-12-15 17:51 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-12-15 17:29:29 UTC ---
Author: jakub
Date: Thu Dec 15 17:29:25 2011
New Revision: 182381
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=182381
Log:
PR c/51360
* c-parser.c (c_parser_omp_clause_num_threads,
c_parser_omp_clause_schedule): Call mark_exp_read.
* semantics.c (finish_omp_clauses): For OMP_CLAUSE_NUM_THREADS_EXPR
and OMP_CLAUSE_SCHEDULE_CHUNK_EXPR call mark_rvalue_use.
* c-c++-common/gomp/pr51360.c: New test.
* g++.dg/gomp/pr51360.C: New test.
Added:
trunk/gcc/testsuite/c-c++-common/gomp/pr51360.c
trunk/gcc/testsuite/g++.dg/gomp/pr51360.C
Modified:
trunk/gcc/ChangeLog
trunk/gcc/c-parser.c
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/semantics.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c/51360] [4.6 Regression] spurious unused-but-set-variable warning for var used in OpenMP pragma
2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
` (2 preceding siblings ...)
2011-12-15 17:51 ` jakub at gcc dot gnu.org
@ 2011-12-15 20:51 ` jakub at gcc dot gnu.org
2012-02-09 17:16 ` jakub at gcc dot gnu.org
2012-02-09 17:41 ` jakub at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2011-12-15 20:51 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[4.6/4.7 Regression] |[4.6 Regression] spurious
|spurious |unused-but-set-variable
|unused-but-set-variable |warning for var used in
|warning for var used in |OpenMP pragma
|OpenMP pragma |
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-12-15 20:51:03 UTC ---
Fixed on the trunk so far.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c/51360] [4.6 Regression] spurious unused-but-set-variable warning for var used in OpenMP pragma
2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
` (3 preceding siblings ...)
2011-12-15 20:51 ` [Bug c/51360] [4.6 " jakub at gcc dot gnu.org
@ 2012-02-09 17:16 ` jakub at gcc dot gnu.org
2012-02-09 17:41 ` jakub at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-02-09 17:16 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-09 17:15:39 UTC ---
Author: jakub
Date: Thu Feb 9 17:15:29 2012
New Revision: 184049
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=184049
Log:
Backported from mainline
2011-12-15 Jakub Jelinek <jakub@redhat.com>
PR c/51360
* c-parser.c (c_parser_omp_clause_num_threads,
c_parser_omp_clause_schedule): Call mark_exp_read.
* semantics.c (finish_omp_clauses): For OMP_CLAUSE_NUM_THREADS_EXPR
and OMP_CLAUSE_SCHEDULE_CHUNK_EXPR call mark_rvalue_use.
* gcc.dg/gomp/pr51360.c: New test.
* g++.dg/gomp/pr51360.C: New test.
* g++.dg/gomp/pr51360-2.C: New test.
Added:
branches/gcc-4_6-branch/gcc/testsuite/g++.dg/gomp/pr51360-2.C
branches/gcc-4_6-branch/gcc/testsuite/g++.dg/gomp/pr51360.C
branches/gcc-4_6-branch/gcc/testsuite/gcc.dg/gomp/pr51360.c
Modified:
branches/gcc-4_6-branch/gcc/ChangeLog
branches/gcc-4_6-branch/gcc/c-parser.c
branches/gcc-4_6-branch/gcc/cp/ChangeLog
branches/gcc-4_6-branch/gcc/cp/semantics.c
branches/gcc-4_6-branch/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c/51360] [4.6 Regression] spurious unused-but-set-variable warning for var used in OpenMP pragma
2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
` (4 preceding siblings ...)
2012-02-09 17:16 ` jakub at gcc dot gnu.org
@ 2012-02-09 17:41 ` jakub at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-02-09 17:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51360
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> 2012-02-09 17:39:48 UTC ---
Fixed.
^ permalink raw reply [flat|nested] 7+ messages in thread
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2011-11-30 17:20 [Bug c/51360] New: spurious unused-but-set-variable warning for var used in OpenMP pragma kmccarty at gmail dot com
2011-12-14 23:51 ` [Bug c/51360] [4.6/4.7 Regression] " pinskia at gcc dot gnu.org
2011-12-15 13:38 ` jakub at gcc dot gnu.org
2011-12-15 17:51 ` jakub at gcc dot gnu.org
2011-12-15 20:51 ` [Bug c/51360] [4.6 " jakub at gcc dot gnu.org
2012-02-09 17:16 ` jakub at gcc dot gnu.org
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