gcc/testsuite/gcc.c-torture/execute/bf-sign-2.c

   1 /*
   2  This test checks promotion of bitfields.  Bitfields should be promoted
   3  very much like chars and shorts:
   4
   5  Bitfields (signed or unsigned) should be promoted to signed int if their
   6  value will fit in a signed int, otherwise to an unsigned int if their
   7  value will fit in an unsigned int, otherwise we don't promote them (ANSI/ISO
   8  does not specify the behavior of bitfields larger than an unsigned int).
   9
  10  We test the behavior by subtracting two from the promoted value: this will
  11  result in a negitive value for signed types, a positive value for unsigned
  12  types.  This test (of course) assumes that the compiler is correctly
  13  implementing signed and unsigned arithmetic.
  14  */
  15
  16 struct X {
  17   unsigned int       u3:3;
  18     signed long int  s31:31;
  19     signed long int  s32:32;
  20   unsigned long int  u31:31;
  21   unsigned long int  u32:32;
  22   unsigned long long ull3 :3;
  23   unsigned long long ull35:35;
  24   unsigned u15:15;
  25 };
  26
  27 struct X x;
  28
  29 main ()
  30 {
  31   if ((x.u3 - 2) >= 0)          /* promoted value should be signed */
  32     abort ();
  33
  34   if ((x.s31 - 2) >= 0)         /* promoted value should be signed */
  35     abort ();
  36
  37   if ((x.s32 - 2) >= 0)         /* promoted value should be signed */
  38     abort ();
  39
  40   if ((x.u15 - 2) >= 0)         /* promoted value should be signed */
  41     abort ();
  42
  43   /* Conditionalize check on whether integers are 4 bytes or larger, i.e.
  44      larger than a 31 bit bitfield.  */
  45   if (sizeof (int) >= 4)
  46     {
  47       if ((x.u31 - 2) >= 0)     /* promoted value should be signed */
  48         abort ();
  49     }
  50   else
  51     {
  52       if ((x.u31 - 2) < 0)      /* promoted value should be UNsigned */
  53         abort ();
  54     }
  55
  56   if ((x.u32 - 2) < 0)          /* promoted value should be UNsigned */
  57     abort ();
  58
  59   if ((x.ull3 - 2) >= 0)        /* promoted value should be signed */
  60     abort ();
  61
  62   if ((x.ull35 - 2) < 0)        /* promoted value should be UNsigned */
  63     abort ();
  64
  65   exit (0);
  66 }