Bug#617894: [ARMel] tgammal isn't accurate enough

[Aurelien Jarno <aurelien@aurel32.net>]

tag 617894 + moreinfo
thanks

On Sat, Mar 12, 2011 at 09:48:53AM +0100, Julien PUYDT wrote:
> Package: libc6
> Version: 2.11.2-13
> 
> The following piece of code :
> 
> #include <stdio.h>
> #include <math.h>
> 
> int
> main (int argc,
>       char* argv[])
> {
>   long double x = 6.0;
>   printf ("tgammal (%20Lf)=%20Lf\n", x, tgammal (x));
>   return 0;
> }
> 
> Prints, on an x86 debian unstable (eglibc 2.11.2-11) :
> tgammal (            6.000000)=          120.000000
> And on an ARMel debian unstable (eglibc 2.11.2-13) :
> tgammal (6.00000000000000000000)=119.99999999999997157829
> 

On armel, long double is same the type as a double, and thus tgamma()
and tgammal() are the same functions. On x86 long double and double are
different types, and thus tgamma() and tgammal() are different
functions.

Your test code with long double and tgammal() on armel gives as expected
exactly the same result as double and tgamma() on x86. I don't see any 
problem here, this function works as expected.

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net