[Bug c/65467] [libgomp] sorry, unimplemented: '_Atomic' with OpenMP

["pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65467

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
From the original discussions on why this is disabled:
_Atomic support is currently disabled for Objective-C and OpenMP.  For
both (but mainly OpenMP), the relevant parser code needs checking to
determine where convert_lvalue_to_rvalue calls need inserting to
ensure that accesses to atomic variables involve atomic loads.  For
Objective-C, there are also various special cases of compound
assignment that need special handling for atomics just as standard C
compound assignment is handled differently for atomics, as well as
some TYPE_MAIN_VARIANT calls to check for correctness for atomics; see
the comment on the relevant sorry () call for details.  OpenMP should
also have TYPE_MAIN_VARIANT uses checked as well as a use of
TYPE_QUALS_NO_ADDR_SPACE for a diagnostic in
c_parser_omp_declare_reduction (where the diagnostic refers to a
particular list of qualifiers).

So it looks like there is more than even what Jakub listed.

Also patches are welcome to handle OpenMP and _Atomic better.