Re: [Tinycc-devel] Fwd: Bug#698351: tcc: FE_INVALID flag not set on comparison with NAN (unordered)

[Thomas Preud'homme]

Le vendredi 3 janvier 2014, 04:54:57 Vincent Lefevre a écrit :
> Hi Thomas,
> 
> On 2014-01-03 10:30:15 +0800, Thomas Preud'homme wrote:
> > There is quite a few differences in the output about -0.0 where gcc
> > uses 0.0.
> > I'm not sure it's worth doing anything to change that since it's not
> > a bug but less divergence with gcc (and probably clang) could be
> > good. If it's just a few lines to add, why not. I might take a look
> > later this month, or never. ;)
> 
> Actually I think that this is more than an output bug, but I don't
> know whether this is related. The fact is that tcc doesn't seem to
> support signed zeros (required by IEEE 754).

Oh ok. I didn't look at the code that generated this output. Then I'll try to 
take a look. Maybe not now but I'll keep it on my bug list.

> 
> I've updated my program with the following test:
> 
> static void signed_zero_inf (void)
> {
>   double x = 0.0, y = -0.0;
> 
>   printf ("\n");
>   if (x == y)
>     printf ("Test 1.0 / 0.0 != 1.0 / -0.0 returns %d (should be 1).\n",
>             1.0 / x != 1.0 / y);
>   else
>     printf ("0.0 != -0.0; this is wrong!\n");
> }

Thanks for providing a nice test case.

Best regards,

Thomas