https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67419
--- Comment #8 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot
Uni-Bielefeld.DE> ---
> --- Comment #6 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
> (In reply to r...@cebitec.uni-bielefeld.de from comment #4)
>>> int main (void)
>>> {
>>> long double x;
>>> x = 789.1356;
>>> __builtin_printf ("%.30Lg\n", x);
>>> __builtin_printf ("%.30Lg\n", __builtin_sqrtl(x));
>>> }
>>
>> I get
>>
>> 789.13559999999995397956809029
>> -NaN
>
> OK, then it's definitely not Fortran-specific. The question is: is it just
> because of GCC's built-in handling (e.g., because the math.h header does
> something weird), or is it simply that the libm's sqrtl() is unusable?
I believe the results for invoking sqrtl instead of __builtin_sqrtl show
that gcc's builtin handling is wrong in some way. <math.h> and friends
show no weird constructs that might cause this.
Rainer
