1  /* { dg-do compile { target { ! int128 } } } */
       2  /* { dg-options "" } */
       3  /* { dg-final { scan-assembler "__builtin_" } } */
       4  
       5  int foo (int x)
       6  {
       7    return __builtin_bswap128 (x); /* { dg-warning "implicit declaration" } */
       8  }