https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90859
Thomas Schwinge <tschwinge at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |openmp
Last reconfirmed|2019-06-20 00:00:00 |2020-4-29
--- Comment #3 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
I've come across this again. And again, I'm just documenting this here, don't
have bandwidth right now to figure out what's going on.
(In reply to Thomas Schwinge from comment #0)
> I noticed the following (with OpenACC, not yet tried to reproduce with
> OpenMP 'target').
Now also reproduced for OpenMP.
> Is there something wrong, or can that behavior be
> explained?
>
> Only 'sizeof array' appears in the offloaded region, yet for 'target { c &&
> { ! lp64 } }' (only!), the gimplifier also creates a mapping for the array
> itself.
Now also reproduced on x86_64-pc-linux-gnu with default '-m64' instead of
'-m32'.
(In reply to Thomas Schwinge from comment #2)
> Experimenting on x86_64-pc-linux-gnu with '-m32', this depends on the data
> type used for 'array_so'. If I change 'uint32_t' to 'unsigned int', I see
> the same strange behavior. If however I change it to 'unsigned long', the
> issue goes away, as it does for 'unsigned short', for example. The code
> inside the region is the same (aside from some type casting); in particular
> there aren't any 'array' references.
Similarly, with test case:
#include <stdint.h>
static void
vla (int array_li)
{
_Complex double array[array_li];
TYPE array_so;
#pragma omp target \
map(from:array_so)
{
array_so = sizeof array;
}
if (array_so != sizeof array)
__builtin_abort ();
}
... compiled with '-fopenmp -O0 -fdump-tree-gimple -DTYPE=int64_t', we get:
#pragma omp target num_teams(1) thread_limit(0) map(from:array_so [len: 8])
firstprivate(array_li.0)
{
sizetype D.2157;
sizetype D.2158;
long int array_so.2;
D.2157 = (sizetype) array_li.0;
D.2158 = D.2157 * 16;
array_so.2 = (long int) D.2158;
array_so = array_so.2;
}
..., but compiled with '-fopenmp -O0 -fdump-tree-gimple -DTYPE=uint64_t', we
get:
#pragma omp target num_teams(1) thread_limit(0) map(from:array_so [len: 8])
firstprivate(array_li.0) map(tofrom:(*array.1) [len: D.2153])
map(firstprivate:array [pointer assign, bias: 0])
{
sizetype D.2157;
sizetype array_so.2;
D.2157 = (sizetype) array_li.0;
array_so.2 = D.2157 * 16;
array_so = array_so.2;
}
..., that is, in the latter case, the 'array' itself gets mapped additionally,
even though unused inside the region.
