On Tue, 25 Jun 2024 at 03:12, Jason Merrill <ja...@redhat.com> wrote: > > On 6/18/24 10:31, Marek Polacek wrote: > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/14/13? > > Makes sense to me, though probably the [meta.unary.prop] table should be > adjusted in the same way. Jonathan, what do you think?
Just to make sure I understand correctly, the suggestion is to change the precondition for the trait to something like: "remove_all_extents_t<T> shall be a complete type or cv void." i.e. if T is incomplete then T[] cannot be used with the trait, right? > > > -- >8 -- > > Here we started to ICE with r13-25: in check_trait_type, for "X[]" we > > return true here: > > > > if (kind == 1 && TREE_CODE (type) == ARRAY_TYPE && !TYPE_DOMAIN (type)) > > return true; // Array of unknown bound. Don't care about completeness. > > > > and then end up crashing in record_has_unique_obj_representations: > > > > 4836 if (cur != wi::to_offset (sz)) > > > > because sz is null. > > > > https://eel.is/c++draft/type.traits#tab:meta.unary.prop-row-47-column-3-sentence-1 > > says that the preconditions for __has_unique_object_representations are: > > "T shall be a complete type, cv void, or an array of unknown bound" and > > that "For an array type T, the same result as > > has_unique_object_representations_v<remove_all_extents_t<T>>" so T[] > > should be treated as T. So we should use kind==2 for the trait. > > > > PR c++/115476 > > > > gcc/cp/ChangeLog: > > > > * semantics.cc (finish_trait_expr) > > <case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS>: Move below to call > > check_trait_type with kind==2. > > > > gcc/testsuite/ChangeLog: > > > > * g++.dg/cpp1z/has-unique-obj-representations4.C: New test. > > --- > > gcc/cp/semantics.cc | 2 +- > > .../cpp1z/has-unique-obj-representations4.C | 16 ++++++++++++++++ > > 2 files changed, 17 insertions(+), 1 deletion(-) > > create mode 100644 > > gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C > > > > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc > > index 08f5f245e7d..42251b6764b 100644 > > --- a/gcc/cp/semantics.cc > > +++ b/gcc/cp/semantics.cc > > @@ -12966,7 +12966,6 @@ finish_trait_expr (location_t loc, cp_trait_kind > > kind, tree type1, tree type2) > > case CPTK_HAS_NOTHROW_COPY: > > case CPTK_HAS_TRIVIAL_COPY: > > case CPTK_HAS_TRIVIAL_DESTRUCTOR: > > - case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS: > > if (!check_trait_type (type1)) > > return error_mark_node; > > break; > > @@ -12976,6 +12975,7 @@ finish_trait_expr (location_t loc, cp_trait_kind > > kind, tree type1, tree type2) > > case CPTK_IS_STD_LAYOUT: > > case CPTK_IS_TRIVIAL: > > case CPTK_IS_TRIVIALLY_COPYABLE: > > + case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS: > > if (!check_trait_type (type1, /* kind = */ 2)) > > return error_mark_node; > > break; > > diff --git a/gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C > > b/gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C > > new file mode 100644 > > index 00000000000..d6949dc7005 > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C > > @@ -0,0 +1,16 @@ > > +// PR c++/115476 > > +// { dg-do compile { target c++11 } } > > + > > +struct X; > > +static_assert(__has_unique_object_representations(X), ""); // { > > dg-error "invalid use of incomplete type" } > > +static_assert(__has_unique_object_representations(X[]), ""); // { > > dg-error "invalid use of incomplete type" } > > +static_assert(__has_unique_object_representations(X[1]), ""); // { > > dg-error "invalid use of incomplete type" } > > +static_assert(__has_unique_object_representations(X[][1]), ""); // { > > dg-error "invalid use of incomplete type" } > > + > > +struct X { > > + int x; > > +}; > > +static_assert(__has_unique_object_representations(X), ""); > > +static_assert(__has_unique_object_representations(X[]), ""); > > +static_assert(__has_unique_object_representations(X[1]), ""); > > +static_assert(__has_unique_object_representations(X[][1]), ""); > > > > base-commit: 7f9be55a4630134a237219af9cc8143e02080380 >
