https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109031
--- Comment #18 from David Binderman <dcb314 at hotmail dot com> --- Part way through reduction, the C code seems to be int crc32_tab_0; int crc32_context = 0xFFFFFFFFUL; void main(int , char []) { { int crc; int i; i = 0; for (; i < 256; i++) crc32_tab_0 = crc; { { crc32_context = 0 ^ crc32_tab_0; } } printf("...checksum after hashing %s : %lX\n", "g_50", crc32_context ^ 0xFFFFFFFFUL); } } This looks to me like reading rubbish off the local variable stack in main and then hashing it. AFAIK not a bug in gcc, but may be a bug in csmith.