[Patch, libgFortran] Increase the default precision for real(16) by one

[Jerry DeLisle]

Tobias Burnus wrote:
> Using the current settings  write(*,*) x  sometimes does not print all
> possible digits of real(16) variables on S/380.
> 
> The result is that gfortran.dg/default_format_2.f90 FAILs. That test
> case contains effectively:
> 
>       x = 1.0_16
>       do i = 0, 200
>         write (s,*) x
>         read (s,*) y
>         if (y /= x) res = res + 1
>         x = nearest(x,-huge(x))
>       end do
> 
> On S/380 this fails 7 times with the current setting; for these abs(x-y)
> = 9.6296497219361792652798897129246366E-0035.
> 
> The solution is to simply print one more digit by default; one
> additionally has to enlarge then the size of one character string in the
> test suite as it is otherwise to short. I don't know whether it solves
> some of the other failures on REAL(16) systems such as Debian's SPARC;
> presumably it won't help on PowerPCs where the glibc seems to have a bug
> (if I read PR24685 correctly).
> 
> The following patch has been build on x86-64 by me and bootstrapped and
> regtested on S/390 by Andreas Krebbel.
> OK for the trunk?
> 
> Tobias
> 
> 
> 2008-01-17  Tobias Burnus  <burnus@net-b.de>
> 
> 	* io/write.c (write_real): Increase default precision for REAL(16) by one.
> 
> 2008-01-17  Tobias Burnus  <burnus@net-b.de>
> 
> 	* gfortran.dg/large_real_kind_form_io_1.f90: Enlarge string for internal I/O.
> 

This is OK, thanks.

Jerry