Re: [gfortran] patch for PR 15292 missing round and roundf

[Paolo Bonzini <bonzini at gnu dot org>]

> (2) We can include a implementation of fpclassify().  I don't have 
>     such code.

if (x != x) can be used to check for NaN.

if (x - x != 0.0) can be used to check for NaN or infinity.

if (x + x == x) can be used to check for infinity or zero.

See the attached test programlet.

Hope this helps,

Paolo
char * is_nan_test (float x, char *what)
{
  if (x != x)
    return what;
  else
    return "    ";
}

char * is_nan_inf_test (float x, char *what)
{
  if (x - x != 0.0)
    return what;
  else
    return "    ";
}

char * is_inf_zero_test (float x, char *what)
{
  if (x + x == x)
    return what;
  else
    return "    ";
}

void test (float x, char *what)
{
  printf ("%s | %s |  %s   |  %s\n", what,
	  is_nan_test (x, what),
	  is_nan_inf_test (x, what),
	  is_inf_zero_test (x, what));
}

int main()
{
  printf ("     |  NaN |  oo/NaN |  oo/0\n");
  printf ("-----------------------------\n");

  test (0.0, " 0.0");
  test (__builtin_inf(), " +oo");
  test (-__builtin_inf(), " -oo");
  test (__builtin_nan("0x0"), " NaN");
  test (5.0, " 5.0");
  test (-5.0, "-5.0");
}