https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65816
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:ac0bc21bd634a334ba8f323c39a11f01dfdc2aae commit r12-1153-gac0bc21bd634a334ba8f323c39a11f01dfdc2aae Author: Patrick Palka <ppa...@redhat.com> Date: Tue Jun 1 12:23:49 2021 -0400 c++: value-init vs zero-init in expand_aggr_init_1 [PR65816] In the case of value-initializing an object of class type T, [dcl.init.general]/8 says: - if T has either no default constructor ([class.default.ctor]) or a default constructor that is user-provided or deleted, then the object is default-initialized; - otherwise, the object is zero-initialized and ... if T has a non-trivial default constructor, the object is default-initialized; But when determining whether to first zero-initialize the object, expand_aggr_init_1 incorrectly considers the user-providedness of _all_ constructors rather than only that of the _default_ constructors. This causes us to skip the zero-initialization step when the class type has a defaulted default constructor alongside a user-defined constructor. It seems the predicate type_has_non_user_provided_default_constructor accurately captures the above rule for when to first perform a zero-initialization during value-initialization, so this patch adjusts expand_aggr_init_1 to use this predicate instead. PR c++/65816 gcc/cp/ChangeLog: * init.c (expand_aggr_init_1): Check type_has_non_user_provided_default_constructor instead of type_has_user_provided_constructor. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/constexpr-delegating3.C: New test. * g++.dg/cpp0x/dc10.C: New test. * g++.dg/cpp0x/initlist-base4.C: New test. * g++.dg/cpp2a/constexpr-init22.C: New test. libstdc++-v3/ChangeLog: * testsuite/23_containers/deque/allocator/default_init.cc, testsuite/23_containers/forward_list/allocator/default_init.cc, testsuite/23_containers/list/allocator/default_init.cc, testsuite/23_containers/map/allocator/default_init.cc, testsuite/23_containers/set/allocator/default_init.cc, testsuite/23_containers/vector/allocator/default_init.cc, testsuite/23_containers/vector/bool/allocator/default_init.cc: Remove xfail.
