--TEST-- Bug #75170: mt_rand() bias on 64-bit machines --CREDITS-- Solar Designer in https://externals.io/message/100229 --FILE-- > 1) & 1]++; } printf("%.1f%% vs. %.1f%%\n", 100. * $halves[0] / $total, 100. * $halves[1] / $total); // PHP 7.1.0 to 7.2.0beta2 modulo bias bug found during work // on http://www.openwall.com/php_mt_seed/ mt_srand(1234567890); $total = 10000; $max = 0x66666666; $halves[0] = $halves[1] = 0; for ($i = 0; $i < $total; $i++) { $halves[mt_rand(0, $max - 1) / ($max / 2)]++; } printf("%.1f%% vs. %.1f%%\n", 100. * $halves[0] / $total, 100. * $halves[1] / $total); ?> --EXPECT-- 49.5% vs. 50.5% 50.5% vs. 49.5%