gcc/testsuite/gcc.dg/builtin-bswap-12.c

   1 /* { dg-do run } */
   2 /* { dg-require-effective-target int128 } */
   3 /* { dg-require-effective-target stdint_types } */
   4 /* { dg-options "-O" } */
   5
   6 #include <stdint.h>
   7
   8 typedef union
   9 {
  10   struct { uint64_t lo; uint64_t hi; } s;
  11   __uint128_t n;
  12 } u;
  13
  14 int
  15 main (void)
  16 {
  17   /* Test constant folding.  */
  18   extern void link_error (void);
  19
  20   const u U1 = { .s = { 0x1122334455667788ULL, 0xffffffffffffffffULL } };
  21   const u U2 = { .s = { 0xffffffffffffffffULL, 0x8877665544332211ULL } };
  22
  23   if (__builtin_bswap128 (U1.n) != U2.n)
  24     link_error ();
  25
  26   return 0;
  27 }