On Mon, Jun 4, 2018 at 11:03 PM, Marek Polacek <pola...@redhat.com> wrote: > On Mon, Jun 04, 2018 at 01:28:01PM -0400, Jason Merrill wrote: >> On Mon, Jun 4, 2018 at 11:44 AM, Marek Polacek <pola...@redhat.com> wrote: >> > I've had no luck in reducing the testcase in this PR, creduce won't get >> > even >> > past the initial passes, and reducing by hand didn't get me very far, >> > either. >> > >> > But the problem seems to be merely that we're not handling USING_DECLs in >> > cp_tree_equal, and we can get there via comp_template_arguments. In this >> > case >> > we have two USING_DECLs with different full names. >> > >> > So this patch just adds the USING_DECL case, similarly to e.g. >> > https://gcc.gnu.org/ml/gcc-patches/2012-10/msg00799.html >> > >> > Bootstrapped/regtested on x86_64-linux, ok for trunk/8? I verified >> > manually >> > that this fixes the testcase from the PR. >> >> Hmm, do these USING_DECLs have DECL_DEPENDENT_P set? What do they >> represent? In the case of dependent USING_DECL I'd think we want to >> compare the scope and name rather than just return false. > > They represent a using-declaration in this testcase. > > Yep, they're DECL_DEPENDENT_P. So let's check their scope and name. > >> I think we do want a reduced testcase. Maybe add the needs-reduction >> tag if you're having trouble reducing it yourself? > > I got lucky: I managed to remove some random unnecessary code which then > allowed creduce to do its job, the result is pretty nice! > > Bootstrapped/regtested on x86_64-linux, ok for trunk/8? > > 2018-06-04 Marek Polacek <pola...@redhat.com> > > PR c++/85976 > * tree.c (cp_tree_equal): Handle USING_DECL. > > * g++.dg/cpp0x/alias-decl-64.C: New test. > > diff --git gcc/cp/tree.c gcc/cp/tree.c > index c5b6e9689b6..bbbda7e98b6 100644 > --- gcc/cp/tree.c > +++ gcc/cp/tree.c > @@ -3878,6 +3878,14 @@ cp_tree_equal (tree t1, tree t2) > DEFERRED_NOEXCEPT_ARGS (t2))); > break; > > + case USING_DECL: > + if (DECL_DEPENDENT_P (t1) && DECL_DEPENDENT_P (t2)) > + return (cp_tree_equal (USING_DECL_SCOPE (t1), > + USING_DECL_SCOPE (t2)) > + && cp_tree_equal (DECL_NAME (t1), > + DECL_NAME (t2))); > + return false; > + > default: > break; > } > diff --git gcc/testsuite/g++.dg/cpp0x/alias-decl-64.C > gcc/testsuite/g++.dg/cpp0x/alias-decl-64.C > index e69de29bb2d..019eb269750 100644 > --- gcc/testsuite/g++.dg/cpp0x/alias-decl-64.C > +++ gcc/testsuite/g++.dg/cpp0x/alias-decl-64.C > @@ -0,0 +1,15 @@ > +// PR c++/85976 > +// { dg-do compile { target c++11 } } > + > +template <int> class A; > +template <typename> class B; > +template <typename> struct C; > +template <typename P_expr> class D { > + using B<typename P_expr::T_numtype>::rank_; > + void operator()(typename C<A<rank_>>::i); > +}; > + > +template <typename P_expr> class F { > + using B<typename P_expr::T_numtype>::rank_; > + void operator()(typename C<A<rank_>>::i); > +};
Hmm, this testcase looks a bit over-reduced; these templates can never be instantiated, so they are ill-formed (no diagnostic required). But I suppose that's not too much of an issue. The patch is OK. Jason
