https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119677
Bug ID: 119677
Summary: [OpenMP][6.1] Support omp_default_device / Cleanup
modify_call_for_omp_dispatch via
GOMP_DEVICE_DEFAULT_OMP_61
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: openmp
Severity: normal
Priority: P3
Component: libgomp
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
CC: jakub at gcc dot gnu.org
Target Milestone: ---
Created attachment 61034
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=61034&action=edit
Patch that updates modify_call_for_omp_dispatch (+ testcase changes) but no
full libgomp/target.c update
OpenMP 5.2 added omp_initial_device and omp_invalid_device;
OpenMP 6.1/TR14 will add 'omp_default_device'.
Since r15-8654-g99e2906ae255fc, GCC already uses GOMP_DEVICE_DEFAULT_OMP_61
internally.
EXPECTED:
(1) Use GOMP_DEVICE_DEFAULT_OMP_61 internally to avoid 'omp_get_default_device'
call in modify_call_for_omp_dispatch -> See attached patch.
(2) Consider whether it makes sense also with other compiler-generated lib
calls
(3) API routines in libgomp/target.c have special code to handle:
if (device_num == omp_initial_device
|| device_num == gomp_get_num_devices ())
which needs to also handle device_num := omp_default_device to avoids
invalid code.
For instance, it could be replaced by:
if (is_intial_device (&device_num))
with
static inline bool
is_initial_device (int &device_num)
{
if (*device_num == GOMP_DEVICE_DEFAULT_OMP_61)
{
struct gomp_task_icv *icv = gomp_icv (false);
*device_num = icv->default_device_var;
}
return (*device_num == omp_initial_device
|| *device_num == omp_get_initial_device ());
}
BTW: Note that omp_set_default_device() ignores omp_default_device
(according to the spec and as implemented). Otherwise, call it would
make it impossible to recover a 'real' device number.
(4) Add omp_default_device to omp.h / omp_lib.
+ add some testcases
+ consider updating the documentation for it, cf. PR119676.
