gcc/testsuite/gcc.dg/pr56997-3.c

   1 /* Test volatile access to unaligned field.  */
   2 /* { dg-do run } */
   3 /* { dg-options "-fstrict-volatile-bitfields" } */
   4
   5 extern void abort (void);
   6
   7 #define test_type unsigned long long
   8 #define MAGIC 0x102030405060708ull
   9
  10 typedef struct s{
  11  unsigned char Prefix;
  12  test_type Type;
  13 }__attribute((__packed__)) ss;
  14
  15 volatile ss v;
  16 ss g;
  17
  18 void __attribute__((noinline))
  19 foo (test_type u)
  20 {
  21   v.Type = u;
  22 }
  23
  24 test_type __attribute__((noinline))
  25 bar (void)
  26 {
  27   return v.Type;
  28 }
  29
  30 int main()
  31 {
  32   test_type temp;
  33   foo(MAGIC);
  34   __builtin_memcpy(&g, (void *)&v, sizeof(g));
  35   if (g.Type != MAGIC)
  36     abort ();
  37
  38   g.Type = MAGIC;
  39   __builtin_memcpy((void *)&v, &g, sizeof(v));
  40   temp = bar();
  41   if (temp != MAGIC)
  42     abort ();
  43   return 0;
  44 }