[Bug middle-end/108657] [13 Regression] csmith: possible wrong checksum with -O3 and -ftrivial-auto-var-init=zero

[dcb314 at hotmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108657

--- Comment #14 from David Binderman <dcb314 at hotmail dot com> ---
After five hours of reduction, cvise has:

crc32_tab[256];
unsigned crc32_context = 4294967295;
void crc32_byte(b) {
  crc32_context = crc32_context >> 8 ^ crc32_tab[(crc32_context ^ b) & 255];
}
void transparent_crc(long val, char *vname) {
  crc32_context = crc32_context >> 8 ^ crc32_tab[(crc32_context ^ val) & 255];
  crc32_byte(val >> 8);
  crc32_byte(val >> 16);
  crc32_byte(val >> 24);
  crc32_byte(val >> 32);
  crc32_byte(val >> 40);
  crc32_byte(val >> 48);
  crc32_byte(val >> 56);
  printf("...checksum after hashing %s : %lX\n", vname,
         crc32_context ^ 4294967295);
}
g_21 = -8;
short g_41;
g_78;
static *g_451 = &g_78;
g_452;
func_11___trans_tmp_13;
main_i;
unsigned main_crc;
main_j;
void main() {
  for (; main_i < 256; main_i++) {
    main_crc = main_i;
    main_j = 8;
    for (; main_j; main_j--)
      if (main_crc & 1)
        main_crc = main_crc >> 1 ^ 3988292384;
      else
        main_crc >>= 1;
    crc32_tab[main_i] = main_crc;
  }
  int l_794;
  g_41 = 53935 & g_21;
  g_21 = -18;
  g_78 = 1;
  for (; g_78 >= 0; g_78 -= 1) {
    g_452 = l_794 = 0;
    for (; l_794 <= 3; l_794 += 1) {
      short l_895[1];
      if (g_452)
        break;
      g_452 ^= func_11___trans_tmp_13;
    }
  }
  *g_451 = 8 || 0;
  transparent_crc(g_21, "");
  transparent_crc(g_41, "");
  transparent_crc(2185655400, "");
  transparent_crc(g_78, "g_78");
}