https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51628
Alexey Salmin <alexey.salmin at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |alexey.salmin at gmail dot com --- Comment #36 from Alexey Salmin <alexey.salmin at gmail dot com> --- FYI a test case that actually triggers SIGSEGV on x86 with gcc 7.2: https://godbolt.org/g/kPw6NJ Compiler emits a movaps instruction which is alignment-sensitive. A warning would be helpful. struct pair_t { char c; __int128_t i; } __attribute__((packed)); struct pair_t p = {0, 1}; __int128_t *addr = &p.i; int main() { *addr = ~(__int128_t)0; return (p.i != 1) ? 0 : 1; }