https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70143 --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Note even GCC 5.x and earlier warn here with -Wstrict-aliasing=2 or -Wstrict-aliasing=1, it is just whether we warn about this with the most common one -Wstrict-aliasing=3.