https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110534
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- There are different levels of -Wstrict-aliasing and iirc level 3 will warn. Note I don't think the uninitialized warning is a bad thing here. Because it does point out gcc is thinking it is uninitialized due to the alias violation.
