gcc/testsuite/gcc.c-torture/execute/pr61306-2.c

#ifdef __INT16_TYPE__
typedef __INT16_TYPE__ int16_t;
#else
typedef short int16_t;
#endif

#ifdef __UINT32_TYPE__
typedef __UINT32_TYPE__ uint32_t;
#else
typedef unsigned uint32_t;
#endif

#define __fake_const_swab32(x) ((uint32_t)(			      \
	(((uint32_t)         (x) & (uint32_t)0x000000ffUL) << 24) |   \
	(((uint32_t)(int16_t)(x) & (uint32_t)0x00ffff00UL) <<  8) |   \
	(((uint32_t)         (x) & (uint32_t)0x00ff0000UL) >>  8) |   \
	(((uint32_t)         (x) & (uint32_t)0xff000000UL) >> 24)))


/* Previous version of bswap optimization failed to consider sign extension
   and as a result would replace an expression *not* doing a bswap by a
   bswap.  */

__attribute__ ((noinline, noclone)) uint32_t
fake_bswap32 (uint32_t in)
{
  return __fake_const_swab32 (in);
}

int
main(void)
{
  if (sizeof (uint32_t) * __CHAR_BIT__ != 32)
    return 0;
  if (sizeof (int16_t) * __CHAR_BIT__ != 16)
    return 0;
  if (fake_bswap32 (0x81828384) != 0xff838281)
    __builtin_abort ();
  return 0;
}