On Wed, May 20, 2015 at 10:23:21AM +0200, Thomas Schwinge wrote:
> > + if (gwv && auto_clause)
> > + c_parser_error (parser, "incompatible use of clause %<auto%>");
> > + else if (gwv && seq_clause)
> > + c_parser_error (parser, "incompatible use of clause %<seq%>");
> > + else if (auto_clause && seq_clause)
> > + c_parser_error (parser, "incompatible use of clause %<seq%> and
> > %<auto%>");
> > +
> > block = c_begin_compound_stmt (true);
> > stmt = c_parser_omp_for_loop (loc, parser, OACC_LOOP, clauses, NULL);
> > block = c_end_compound_stmt (loc, block, true);
>
> I would have expected such checking to be done in c_omp_finish_clauses --
> But maybe it's also OK to do it here, given that the loop construct is
> the only one where these clauses can appear. Jakub, any strong
> preference?
In the C FE, it is kind of arbitrary, some checks are done during parsing
immediately, others are done in c_omp_finish_clauses.
In the C++ FE, obviously more care on where things are diagnosed is needed,
so many more checks are done in finish_omp_clauses, because we might want to
wait until templates are instantiated.
>
> ..., and this: why not do such nesting checking in
> gcc/omp-low.c:check_omp_nesting_restrictions? Currently (changed by
> Bernd in internal r442824, 2014-11-29) we're allowing all
> OpenACC-inside-OpenACC nesting -- shouldn't that be changed instead of
> repeating the checks in every front end (Jakub?)?
Yeah, testing nesting restrictions should be done in omp-low.c if possible.
Adding ugly hacks to the FEs tracking the current state and duplicating
across all 3 FEs is undesirable. Note, in C++ FE we already have sk_omp
so some kind of OpenMP binding scope, but I think we don't have anything
similar in the C FE.
> I see that some checking is also being done gcc/omp-low.c:scan_omp_for:
> »gang, worker and vector may occur only once in a loop nest«, and »gang,
> worker and vector must occur in this order in a loop nest«. Don't know
> if that conceptually also belongs into
> gcc/omp-low.c:check_omp_nesting_restrictions?
Doesn't look like anything related to construct/region nesting...
Jakub
