On Wed, 21 Dec 2022, Patrick Palka wrote: > Here during ahead of time checking of C{}, we indirectly call get_nsdmi > for C::m from finish_compound_literal, which in turn calls > break_out_target_exprs for C::m's (non-templated) initializer, during > which we end up building a call to A::~A and checking expr_noexcept_p > for it (from build_vec_delete_1). But this is all done with > processing_template_decl set, so the built A::~A call is templated > (whose form r12-6897-gdec8d0e5fa00ceb2 recently changed) which > expr_noexcept_p doesn't expect and we crash. > > In r10-6183-g20afdcd3698275 we fixed a similar issue by guarding a > expr_noexcept_p call with !processing_template_decl, which works here > too. But it seems to me since the initializer we obtain in get_nsdmi is > always non-templated, it should be calling break_out_target_exprs with > processing_template_decl cleared since otherwise the function might end > up mixing templated and non-templated trees. > > I'm not sure about this though, perhaps this is not the best fix here. > Alternatively, when processing_template_decl we could make get_nsdmi > avoid calling break_out_target_exprs at all or something. Additionally, > perhaps break_out_target_exprs should be a no-op more generally when > processing_template_decl since we shouldn't see any TARGET_EXPRs inside > a template? > > Bootstrapped and regtested on x86_64-pc-linux-gnu.
Note this is a 12 regression so I suppose there's also the question of what's safest to backport vs what's the best fix.. > > PR c++/108116 > > gcc/cp/ChangeLog: > > * init.cc (get_nsdmi): Clear processing_template_decl before > processing the non-templated initializer. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/nsdmi-template24.C: New test. > --- > gcc/cp/init.cc | 8 ++++++- > gcc/testsuite/g++.dg/cpp0x/nsdmi-template24.C | 22 +++++++++++++++++++ > 2 files changed, 29 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template24.C > > diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc > index 73e6547c076..c4345ebdaea 100644 > --- a/gcc/cp/init.cc > +++ b/gcc/cp/init.cc > @@ -561,7 +561,8 @@ perform_target_ctor (tree init) > return init; > } > > -/* Return the non-static data initializer for FIELD_DECL MEMBER. */ > +/* Return the non-static data initializer for FIELD_DECL MEMBER. > + The initializer returned is always non-templated. */ > > static GTY((cache)) decl_tree_cache_map *nsdmi_inst; > > @@ -670,6 +671,11 @@ get_nsdmi (tree member, bool in_ctor, tsubst_flags_t > complain) > current_class_ptr = build_address (current_class_ref); > } > > + /* Since INIT is always non-templated clear processing_template_decl > + before processing it so that we don't interleave templated and > + non-templated trees. */ > + processing_template_decl_sentinel ptds; > + > /* Strip redundant TARGET_EXPR so we don't need to remap it, and > so the aggregate init code below will see a CONSTRUCTOR. */ > bool simple_target = (init && SIMPLE_TARGET_EXPR_P (init)); > diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template24.C > b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template24.C > new file mode 100644 > index 00000000000..202c67d7321 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template24.C > @@ -0,0 +1,22 @@ > +// PR c++/108116 > +// { dg-do compile { target c++11 } } > + > +#include <initializer_list> > + > +struct A { > + A(int); > + ~A(); > +}; > + > +struct B { > + B(std::initializer_list<A>); > +}; > + > +struct C { > + B m{0}; > +}; > + > +template<class> > +void f() { > + C c = C{}; > +}; > -- > 2.39.0.95.g7c2ef319c5 > >