modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/20001228-1.c (about)

     1  int foo1(void)
     2  {
     3    union {
     4      char a[sizeof (unsigned)];
     5      unsigned b;
     6    } u;
     7    
     8    u.b = 0x01;
     9    return u.a[0];
    10  }
    11  
    12  int foo2(void)
    13  {
    14    volatile union {
    15      char a[sizeof (unsigned)];
    16      unsigned b;
    17    } u;
    18    
    19    u.b = 0x01;
    20    return u.a[0];
    21  }
    22  
    23  int main(void)
    24  {
    25    if (foo1() != foo2())
    26      abort ();
    27    exit (0);
    28  }