https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107212
--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> --- Hmm, have a test-case that is miscompiled since r10-4200-gb7ff7cef5005721e: $ cat pr107212.c int sum_1 = 0; int main() { unsigned int tab[6][2] = {{150, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}}; int sum_0 = 0; for (int t = 0; t < 6; t++) { sum_0 += tab[t][0]; sum_1 += tab[t][0]; } if (sum_0 < 100 || sum_0 > 200) __builtin_abort(); return 0; } $ gcc pr107212.c -O3 -std=c99 && ./a.out Aborted (core dumped)