https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111884
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:281699fbff6262766674ab13087d37db751cd40a commit r14-4802-g281699fbff6262766674ab13087d37db751cd40a Author: Marek Polacek <pola...@redhat.com> Date: Thu Oct 19 16:32:10 2023 -0400 c-family: char8_t and aliasing in C vs C++ [PR111884] In the PR, Joseph says that in C char8_t is not a distinct type. So we should behave as if it can alias anything, like ordinary char. In C, unsigned_char_type_node == char8_type_node, so with this patch we return 0 instead of -1. And the following comment says: /* The C standard guarantees that any object may be accessed via an lvalue that has narrow character type (except char8_t). */ if (t == char_type_node || t == signed_char_type_node || t == unsigned_char_type_node) return 0; Which appears to be wrong, so I'm adjusting that as well. PR c/111884 gcc/c-family/ChangeLog: * c-common.cc (c_common_get_alias_set): Return -1 for char8_t only in C++. gcc/testsuite/ChangeLog: * c-c++-common/alias-1.c: New test.
