https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118322
Bug ID: 118322
Summary: [OpenMP] OpenMP in constexpr not properly diagnosed
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: accepts-invalid, diagnostic, openmp
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
Target Milestone: ---
OpenMP (up to 6.0) has a rather broad restriction:
[C++] Directives may not appear in constexpr functions or in
constant expressions
Side notes:
* While C has constexpr, so far [C23] it has no constexpr functions
* There are plans to relax the this restriction, cf. OpenMP spec issue #4454
While there is:
cp_parser_omp_construct (cp_parser *parser, cp_token *pragma_tok, bool *if_p)
{
...
error_at (cp_lexer_peek_token (parser->lexer)->location,
"OpenMP directives may not appear in %<constexpr%> functions");
...
}
This check is missing from:
cp_parser_pragma (cp_parser *parser, enum pragma_context context, bool *if_p)
for all directives that directly go to parsing without calling
cp_parser_omp_construct. That's the case for:
case PRAGMA_OMP_DEPOBJ:
case PRAGMA_OMP_FLUSH:
case PRAGMA_OMP_INTEROP:
case PRAGMA_OMP_TASKWAIT:
case PRAGMA_OMP_TASKYIELD:
case PRAGMA_OMP_CANCEL:
case PRAGMA_OMP_CANCELLATION_POINT:
case PRAGMA_OMP_THREADPRIVATE:
case PRAGMA_OMP_DECLARE:
case PRAGMA_OMP_ALLOCATE:
case PRAGMA_OMP_NOTHING:
case PRAGMA_OMP_ERROR:
case PRAGMA_OMP_ORDERED:
case PRAGMA_OMP_TARGET:
Disclaimer: I have not checked whether any of those has internally a check nor
whether they can be simply moved or whether some special handling needs to be
done. Additionally, at least one item will be fixed by a nearly ready patch.
