http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48716
Summary: gcc OpenMP static variable declared in scope inside
construct is predetermined shared
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: g...@cray.com
A static variable is declared inside a task construct having a
default(none) clause. The OpenMP API says that this variable is
predetermined shared. Currently the GNU gcc compiler wants this
variable to appear in a SHARED clause.
The OpenMP API version 3.0 (May 2008) on p. 78 lines 10 & 20 states:
"The following variables have predetermined data-sharing attributes:
. . .
* Static variables which are declared in a scope inside the construct
are shared."
On p. 87 lines 22-25 the following appears:
"The default(none) clause requires that each variable that is referenced
in the construct, and that does not have a predetermined data-sharing
attribute, must have its data-sharing attribute explicitly determined by
being listed in a data-sharing attribute clause."
In Section 2.7 task Construct on p. 59, line 17, we see that the
default(none) clause may appear on the #pragma omp task construct.
Test case:
$ cat ISU3305.c
// derived from OpenMP test omp3c/c03_2_9_3_1_3k.c
// REFERENCES : OpenMP 3.0, p. 59, line 17
// OpenMP 3.0, p. 78, line 20
// OpenMP 3.0, p. 87, lines 22-25
int main(void) {
#pragma omp task default(none)
{
static int shared_var;
shared_var = 1;
}
return 0;
}
$ gcc --version
gcc (GCC) 4.6.0 20110325 (Cray Inc.)
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ gcc -c -fopenmp ISU3305.c
ISU3305.c: In function 'main':
ISU3305.c:9:20: error: 'shared_var' not specified in enclosing parallel
ISU3305.c:6:13: error: enclosing task
$
Expected results from Intel and PGI compilers:
$ pgcc -c -mp ISU3305.c
$ icc -c -openmp ISU3305.c
$
