gcc/testsuite/gcc.dg/union-5.c

   1 /* { dg-do run { target i?86-*-* x86_64-*-* } } */
   2 /* { dg-options "-O -fgcse -fno-split-wide-types" } */
   3
   4 extern void abort(void);
   5
   6 typedef unsigned short int uint16_t;
   7 typedef unsigned int uint32_t;
   8 typedef unsigned long long uint64_t;
   9
  10 typedef struct
  11 {
  12   uint16_t thread;
  13   uint16_t phase;
  14 } s32;
  15
  16 typedef union
  17 {
  18   uint32_t i;
  19   s32 s;
  20 } u32;
  21
  22 typedef union
  23 {
  24   uint64_t i;
  25   u32 u;
  26 } u64;
  27
  28 static __attribute__((noinline))
  29 void foo(int val)
  30 {
  31   u64 data;
  32   uint32_t thread;
  33
  34   data.u.i = 0x10000L;
  35   thread = data.u.s.thread;
  36   if (val)
  37     abort ();
  38   if (thread)
  39     abort ();
  40 }
  41
  42 int main(void)
  43 {
  44   foo (0);
  45   return 0;
  46 }