https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112830
--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> --- x86 testcase: void foo (int n, __seg_fs void *p, __seg_gs void *q) { typedef struct { char t[n]; } T; *(__seg_fs T *)p = *(__seg_gs T *)q; }