gcc/testsuite/gcc.c-torture/execute/ieee/mul-subnormal-single-1.c

   1 /* Check that certain subnormal numbers (formerly known as denormalized
   2    numbers) are rounded to within 0.5 ulp.  PR other/14354.  */
   3
   4 /* This test requires that float and unsigned int are the same size and
   5    that the sign-bit of the float is at MSB of the unsigned int.  */
   6
   7 void abort (void);
   8 void exit (int);
   9
  10 #if __INT_MAX__ != 2147483647L
  11 int main () { exit (0); }
  12 #else
  13
  14 union uf
  15 {
  16   unsigned int u;
  17   float f;
  18 };
  19
  20 static float
  21 u2f (unsigned int v)
  22 {
  23   union uf u;
  24   u.u = v;
  25   return u.f;
  26 }
  27
  28 static unsigned int
  29 f2u (float v)
  30 {
  31   union uf u;
  32   u.f = v;
  33   return u.u;
  34 }
  35
  36 int ok = 1;
  37
  38 static void
  39 tstmul (unsigned int ux, unsigned int uy, unsigned int ur)
  40 {
  41   float x = u2f (ux);
  42   float y = u2f (uy);
  43
  44   if (f2u (x * y) != ur)
  45     /* Set a variable rather than aborting here, to simplify tracing when
  46        several computations are wrong.  */
  47     ok = 0;
  48 }
  49
  50 /* We don't want to make this const and static, or else we risk inlining
  51    causing the test to fold as constants at compile-time.  */
  52 struct
  53 {
  54   unsigned int p1, p2, res;
  55 } expected[] =
  56   {
  57     {0xfff, 0x3f800400, 0xfff},
  58     {0xf, 0x3fc88888, 0x17},
  59     {0xf, 0x3f844444, 0xf}
  60   };
  61
  62 int
  63 main ()
  64 {
  65   unsigned int i;
  66
  67   for (i = 0; i < sizeof (expected) / sizeof (expected[0]); i++)
  68     {
  69       tstmul (expected[i].p1, expected[i].p2, expected[i].res);
  70       tstmul (expected[i].p2, expected[i].p1, expected[i].res);
  71     }
  72
  73   if (!ok)
  74     abort ();
  75
  76   exit (0);
  77 }
  78 #endif