[Bug c/50675] New: master and single OpenMP constructs broken

2011-10-09 Thread markflorisson88 at gmail dot com 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50675

 Bug #: 50675
   Summary: master and single OpenMP constructs broken
Classification: Unclassified
   Product: gcc
   Version: 4.6.2
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: markflorisso...@gmail.com


single and master do not work properly in loops. They are either not executed
as often as they should, or the program deadlocks entirely:

#include 

int main(int argc, char **argv) {
int i;
#pragma omp parallel
{
for (i = 0; i < 10; i++) {
#pragma omp single
puts("hello");
}
}
return 0;
}

This program deadlocks in gcc 4.4 and 4.6, whereas in 4.2 is is only executed 4
times (which is the number of cores on my machine). The same goes for the
master construct.

[Bug c/50675] master and single OpenMP constructs broken

2011-10-09 Thread markflorisson88 at gmail dot com 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50675

--- Comment #2 from markflorisson88  
2011-10-09 13:46:27 UTC ---
Indeed, you are right. My apologies, I should teach myself to use
default(none).

[Bug c/49897] New: nesting lastprivate gives incorrect result

2011-07-29 Thread markflorisson88 at gmail dot com 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49897

   Summary: nesting lastprivate gives incorrect result
   Product: gcc
   Version: 4.5.0
Status: UNCONFIRMED
  Severity: major
  Priority: P3
 Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: markflorisso...@gmail.com


Nesting lastprivate doesn't work in gcc 4.5: the inner loop has a lastprivate
variable that is then also declared lastprivate on the outer loop (otherwise
there would be a race), but the result after the loop is always 0. It works
fine in gcc 4.2 to 4.4.



SSH [1] [10:13] ~  ➤ gcc-4.5 -v
Using built-in specs.
COLLECT_GCC=gcc-4.5
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.5.1/lto-wrapper
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.5.1-7ubuntu2' --with-bugurl=file:///usr/share/doc/gcc-4.5/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.5 --enable-shared --enable-multiarch
--enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.5 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-plugin --enable-gold
--with-plugin-ld=ld.gold --enable-objc-gc --enable-targets=all --disable-werror
--with-arch-32=i686 --with-tune=generic --enable-checking=release
--build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
Thread model: posix
gcc version 4.5.1 (Ubuntu/Linaro 4.5.1-7ubuntu2) 
SSH [0] [10:13] ~  ➤ gcc-4.5 -g -Wall -fopenmp -lgomp testomp.c
SSH [0] [10:14] ~  ➤ ./a.out
x=9, y=0, sum = 450
SSH [0] [10:14] ~  ➤ cat testomp.c
#include 

int main(void) {
int i = 0, j = 0, x, y, sum = 0;
x = 0;


#pragma omp parallel reduction(+:sum)
{
#pragma omp for firstprivate(x) lastprivate(x, y)
for (i = 0; i < 10; i++) {
x = i;

y = 0;
#pragma omp parallel reduction(+:sum)
{

#pragma omp for firstprivate(y) lastprivate(y)
for (j = 0; j < 10; j++) {
y = j;
sum += y;
}
}
}
}
printf("x=%d, y=%d, sum = %d\n", x, y, sum);
return 0;
}


SSH [0] [10:15] ~  ➤ gcc-4.4 -g -Wall -fopenmp -lgomp testomp.c
SSH [0] [10:15] ~  ➤ ./a.out
x=9, y=9, sum = 450

[Bug c/49898] New: nested reduction on #pragma omp for gives incorrect result

2011-07-29 Thread markflorisson88 at gmail dot com 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49898

   Summary: nested reduction on #pragma omp for gives incorrect
result
   Product: gcc
   Version: 4.5.0
Status: UNCONFIRMED
  Severity: major
  Priority: P3
 Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: markflorisso...@gmail.com


The following example fails in gcc 4.5 but works in gcc 4.4. The inner loops
has a reduction that is again a reduction in the outer loop. The result should
be 450, but is always 0. If you put the reduction() clauses on the #pragma omp
parallel it does work.

# The code

SSH [0] [10:23] ~  ➤ gcc-4.5 -g -Wall -fopenmp -lgomp testomp.c
SSH [0] [10:24] ~  ➤ ./a.out
sum = 0
SSH [0] [10:24] ~  ➤ gcc-4.4 -g -Wall -fopenmp -lgomp testomp.c 
SSH [0] [10:24] ~  ➤ ./a.out   
sum = 450
SSH [0] [10:24] ~  ➤ cat testomp.c 
#include 

int main(void) {
int i, j, sum = 0;

#pragma omp parallel
{
#pragma omp for reduction(+:sum)
for (i = 0; i < 10; i++) {
#pragma omp parallel
{
#pragma omp for reduction(+:sum)
for (j = 0; j < 10; j++) {
sum += j;
}
}
}
}
printf("sum = %d\n", sum);
return 0;
}

[Bug middle-end/49897] [4.5/4.6/4.7 Regression] nesting lastprivate gives incorrect result

2011-07-29 Thread markflorisson88 at gmail dot com 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49897

--- Comment #4 from markflorisson88  
2011-07-29 16:05:50 UTC ---
(In reply to comment #3)
> Created attachment 24865 [details]
> gcc47-pr49897.patch
> 
> Fix.

Wow, thanks a lot for the quick fix!