https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92929
--- Comment #3 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
(In reply to myself from comment #1)
> /* For target {,enter ,exit }data only the array slice is
> mapped, but not the pointer to it. */
Some handling for OpenACC 'data' got added in r236678 "use firstprivate
pointers for subarrays in c and c++",
<http://mid.mail-archive.com/573244BE.5010708@codesourcery.com>, but is
somewhat spread out, and not easy to follow:
case OACC_DATA:
if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE)
break;
/* FALLTHRU */
case OMP_TARGET_DATA:
case [...]:
if (OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_POINTER
|| (OMP_CLAUSE_MAP_KIND (c)
== GOMP_MAP_FIRSTPRIVATE_REFERENCE))
/* For target {,enter ,exit }data only the array slice is
mapped, but not the pointer to it. */
remove = true;
[...]
if (code == OACC_DATA
&& OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
&& (OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_POINTER
|| OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_REFERENCE))
remove = true;
if (remove)
*list_p = OMP_CLAUSE_CHAIN (c);
..., and not sure if this also relates to the following:
'omp_notice_variable':
if (octx->region_type == ORT_ACC_DATA
&& (n2->value & GOVD_MAP_0LEN_ARRAY))
nflags |= GOVD_MAP_0LEN_ARRAY;
goto found_outer;
'gimplify_scan_omp_clauses':
if (code == OACC_DATA
&& OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
&& OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_POINTER)
flags |= GOVD_MAP_0LEN_ARRAY;
(Maybe the idea there is to preserve 'GOMP_MAP_FIRSTPRIVATE_POINTER',
'GOMP_MAP_FIRSTPRIVATE_REFERENCE' until some other processing
('GOVD_MAP_0LEN_ARRAY') has been done, and only then remove them, right at the
end. But that wouldn't be quite obvious.)
