gcc/testsuite/gcc.dg/torture/pr78546-2.c

/* PR rtl-optimization/78546 */
/* { dg-do run { target int128 } } */

typedef unsigned __int128 u128;
u128 b;

int
main ()
{
  asm volatile ("" : : : "memory");
  u128 x = ((u128) ~0x7fffffffffffffffLL) - b;
  u128 y = 1 - x;
  if (y != 0x8000000000000001ULL)
    __builtin_abort ();
  return 0;
}