On Fri, Oct 1, 2021 at 1:29 PM Patrick Palka <ppa...@redhat.com> wrote: > > On Fri, 1 Oct 2021, Jason Merrill wrote: > > > On 10/1/21 10:26, Patrick Palka wrote: > > > On Fri, 1 Oct 2021, Jason Merrill wrote: > > > > > > > On 10/1/21 09:46, Patrick Palka wrote: > > > > > Here during partial ordering of the two partial specializations we end > > > > > up in unify with parm=arg=NONTYPE_ARGUMENT_PACK<V0, V1>, and crash > > > > > shortly > > > > > thereafter because uses_template_parms calls > > > > > potential_constant_expression > > > > > which doesn't handle NONTYPE_ARGUMENT_PACK. > > > > > > > > > > This patch fixes this by checking dependent_template_arg_p instead of > > > > > uses_template_parms when parm==arg, which does handle > > > > > NONTYPE_ARGUMENT_PACK. > > > > > We could also perhaps fix uses_template_parms / inst_dep_expr_p to > > > > > better > > > > > handle NONTYPE_ARGUMENT_PACK, > > > > > > > > Please. > > > > > > Sounds good, like the following then? Passes light testing, bootstrap > > > and regtest on progress. > > > > > > -- >8 -- > > > > > > PR c++/102547 > > > > > > gcc/cp/ChangeLog: > > > > > > * pt.c (instantiation_dependent_expression_p): Sidestep checking > > > potential_constant_expression on NONTYPE_ARGUMENT_PACK. > > > > > > gcc/testsuite/ChangeLog: > > > > > > * g++.dg/cpp0x/variadic-partial2.C: New test. > > > * g++.dg/cpp0x/variadic-partial2a.C: New test. > > > --- > > > gcc/cp/pt.c | 4 +++- > > > .../g++.dg/cpp0x/variadic-partial2.C | 16 ++++++++++++++ > > > .../g++.dg/cpp0x/variadic-partial2a.C | 22 +++++++++++++++++++ > > > 3 files changed, 41 insertions(+), 1 deletion(-) > > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/variadic-partial2.C > > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/variadic-partial2a.C > > > > > > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c > > > index 1dcdffe322a..643204103c5 100644 > > > --- a/gcc/cp/pt.c > > > +++ b/gcc/cp/pt.c > > > @@ -27705,7 +27705,9 @@ instantiation_dependent_expression_p (tree > > > expression) > > > { > > > return (instantiation_dependent_uneval_expression_p (expression) > > > || (processing_template_decl > > > - && potential_constant_expression (expression) > > > + && expression != NULL_TREE > > > + && (TREE_CODE (expression) == NONTYPE_ARGUMENT_PACK > > > + || potential_constant_expression (expression)) > > > > I'd prefer to loop over the elements of the pack, either here or (probably > > better) in potential_constant_expression. > > Ah, makes sense. Like so? Bootstrapped and regtested on > x86_64-pc-linux-gnu.
On second thought given that a NONTYPE_ARGUMENT_PACK is by construction a sequence of non-type template arguments, is looping over its elements in potential_const_expr necessary? Maybe we should just return true unconditionally. > > -- >8 -- > > Subject: [PATCH] c++: unifying equal NONTYPE_ARGUMENT_PACKs [PR102547] > > Here during partial ordering of the two partial specializations we end > up in unify with parm=arg=NONTYPE_ARGUMENT_PACK<V0, V1>, and crash shortly > thereafter because uses_template_parms(parms) calls potential_const_expr > which doesn't handle NONTYPE_ARGUMENT_PACK. > > This patch fixes this by extending potential_constant_expression to handle > NONTYPE_ARGUMENT_PACK appropriately. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk/11? > > PR c++/102547 > > gcc/cp/ChangeLog: > > * constexpr.c (potential_constant_expression_1): Handle > NONTYPE_ARGUMENT_PACK. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/variadic-partial2.C: New test. > * g++.dg/cpp0x/variadic-partial2a.C: New test. > --- > gcc/cp/constexpr.c | 10 +++++++++ > .../g++.dg/cpp0x/variadic-partial2.C | 16 ++++++++++++++ > .../g++.dg/cpp0x/variadic-partial2a.C | 22 +++++++++++++++++++ > 3 files changed, 48 insertions(+) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/variadic-partial2.C > create mode 100644 gcc/testsuite/g++.dg/cpp0x/variadic-partial2a.C > > diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c > index 18d9d117a48..e95ff00774f 100644 > --- a/gcc/cp/constexpr.c > +++ b/gcc/cp/constexpr.c > @@ -9043,6 +9043,16 @@ potential_constant_expression_1 (tree t, bool > want_rval, bool strict, bool now, > case CO_RETURN_EXPR: > return false; > > + case NONTYPE_ARGUMENT_PACK: > + { > + tree args = ARGUMENT_PACK_ARGS (t); > + int len = TREE_VEC_LENGTH (args); > + for (int i = 0; i < len; ++i) > + if (!RECUR (TREE_VEC_ELT (args, i), any)) > + return false; > + return true; > + } > + > default: > if (objc_non_constant_expr_p (t)) > return false; > diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic-partial2.C > b/gcc/testsuite/g++.dg/cpp0x/variadic-partial2.C > new file mode 100644 > index 00000000000..df61f26a3c1 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/variadic-partial2.C > @@ -0,0 +1,16 @@ > +// PR c++/102547 > +// { dg-do compile { target c++11 } } > + > +template<int... Vs> > +struct vals { }; > + > +template<class V, class T> > +struct vals_client { }; > + > +template<int V0, int V1, class T> > +struct vals_client<vals<V0, V1>, T> { }; > + > +template<int V0, int V1> > +struct vals_client<vals<V0, V1>, void> { }; > + > +template struct vals_client<vals<1, 2>, void>; //- "sorry, unimplemented..., > ICE" > diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic-partial2a.C > b/gcc/testsuite/g++.dg/cpp0x/variadic-partial2a.C > new file mode 100644 > index 00000000000..e98bdbbc07b > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/variadic-partial2a.C > @@ -0,0 +1,22 @@ > +// PR c++/102547 > +// { dg-do compile { target c++11 } } > +// A version of variadic-partial2.C where partial ordering is performed > +// on function templates instead of class templates. > + > +template<int... Vs> > +struct vals { }; > + > +template<class V, class T> > +void f(V, T) { }; > + > +template<int V0, int V1, class T> > +void f(vals<V0, V1>, T) { }; > + > +template<int V0, int V1> > +void f(vals<V0, V1>, char) { }; > + > +template void f(vals<1, 2>, char); //- "sorry, unimplemented..., ICE" > + > +int main() { > + f(vals<1, 3>{}, 'a'); //- "sorry, unimplemented..., ICE" > +} > -- > 2.33.0.610.gcefe983a32 >