modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/ffs-1.c (about)

     1  __volatile int a = 0;
     2  
     3  extern void abort (void);
     4  extern void exit (int);
     5  
     6  int
     7  main (void)
     8  {
     9    if (__builtin_ffs (a) != 0)
    10      abort ();
    11    exit (0);
    12  }