#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; }