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

   1 /* Test for bitfield alignment in structs and unions.  */
   2 /* { dg-do run }  */
   3 /* { dg-options "-O2" }  */
   4
   5 extern void abort (void);
   6 extern void exit (int);
   7
   8 typedef long la __attribute__((aligned (8)));
   9
  10 struct A
  11 {
  12   char a;
  13   union UA
  14   {
  15     char x;
  16     la y : 6;
  17   } b;
  18   char c;
  19 } a;
  20
  21 struct B
  22 {
  23   char a;
  24   union UB
  25   {
  26     char x;
  27     long y : 6 __attribute__((aligned (8)));
  28   } b;
  29   char c;
  30 } b;
  31
  32 struct C
  33 {
  34   char a;
  35   struct UC
  36   {
  37     la y : 6;
  38   } b;
  39   char c;
  40 } c;
  41
  42 struct D
  43 {
  44   char a;
  45   struct UD
  46   {
  47     long y : 6 __attribute__((aligned (8)));
  48   } b;
  49   char c;
  50 } d;
  51
  52 int main (void)
  53 {
  54   if (sizeof (a) != sizeof (b))
  55     abort ();
  56   if (sizeof (a) != sizeof (c))
  57     abort ();
  58   if (sizeof (a) != sizeof (d))
  59     abort ();
  60   if ((&a.c - &a.a) != (&b.c - &b.a))
  61     abort ();
  62   if ((&a.c - &a.a) != (&c.c - &c.a))
  63     abort ();
  64   if ((&a.c - &a.a) != (&d.c - &d.a))
  65     abort ();
  66   exit (0);
  67 }