modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/pr61306-2.c (about)

     1  #ifdef __INT16_TYPE__
     2  typedef __INT16_TYPE__ int16_t;
     3  #else
     4  typedef short int16_t;
     5  #endif
     6  
     7  #ifdef __UINT32_TYPE__
     8  typedef __UINT32_TYPE__ uint32_t;
     9  #else
    10  typedef unsigned uint32_t;
    11  #endif
    12  
    13  #define __fake_const_swab32(x) ((uint32_t)(			      \
    14  	(((uint32_t)         (x) & (uint32_t)0x000000ffUL) << 24) |   \
    15  	(((uint32_t)(int16_t)(x) & (uint32_t)0x00ffff00UL) <<  8) |   \
    16  	(((uint32_t)         (x) & (uint32_t)0x00ff0000UL) >>  8) |   \
    17  	(((uint32_t)         (x) & (uint32_t)0xff000000UL) >> 24)))
    18  
    19  
    20  /* Previous version of bswap optimization failed to consider sign extension
    21     and as a result would replace an expression *not* doing a bswap by a
    22     bswap.  */
    23  
    24  __attribute__ ((noinline, noclone)) uint32_t
    25  fake_bswap32 (uint32_t in)
    26  {
    27    return __fake_const_swab32 (in);
    28  }
    29  
    30  int
    31  main(void)
    32  {
    33    if (sizeof (uint32_t) * __CHAR_BIT__ != 32)
    34      return 0;
    35    if (sizeof (int16_t) * __CHAR_BIT__ != 16)
    36      return 0;
    37    if (fake_bswap32 (0x81828384) != 0xff838281)
    38      __builtin_abort ();
    39    return 0;
    40  }