On Fri, Jan 31, 2014 at 09:18:33PM +0400, Ilya Verbin wrote:
> Looks like there is a bug (in GOMP_target lowering? or in
> gomp_map_vars_existing?)
> The reproducer:
>
> #define N 1000
>
> void foo ()
> {
> int *a = malloc (N * sizeof (int));
> printf ("1: %p\n", a);
> #pragma omp target data map(tofrom: a[0:N])
> {
> printf ("2: %p\n", a);
> #pragma omp target
> {
> int i;
> for (i = 0; i < N; i++)
> a[i] = i;
> }
> printf ("3: %p\n", a);
> }
> printf ("4: %p\n", a);
> free (a);
> }
>
> Here GOMP_target believes that the pointer 'a' has a type TOFROM, so
> it sets copy_from to true for the existing mapping of the pointer 'a',
> that was mapped in GOMP_target_data. Therefore the output is
> incorrect:
Implicit map(tofrom: a) on #pragma omp target is what the standard
requires, so I don't see a bug on the compiler side.
I'd need to go back to omp-lang endless discussions regarding the copy_from
stuff and/or discuss this further.
I'd suggest just using map(tofrom: a[0:N]) also on the #pragma omp target,
then it is clear what should happen.
Jakub
