[patch, libfortran] Implement KIND specific floating point formatted output

[Jerry DeLisle]

Dominique Dhumieres wrote:
> This patch breaks gfortran.dg/fmt_p_1.f90, gfortran.dg/output_exponents_1.f90,
> and gfortran.dg/large_real_kind_form_io_1.f90 on PPC Darwin. For the first two tests
> the failure comes from a truncated exponent:
> 
>      0.100E-99   0.200E-99                         
>      1.000-10   2.000-10                         
> 
> instead of 
> 
>      0.100E-99   0.200E-99                         
>      1.000-100   2.000-100                        
> 
> For the last test, the bug is less obvious: the last output is:
> 
>  .1000E+0000  .2000E+0000
>  
> giving the runtime error:
> 
> At line 28 of file large_real_kind_form_io_1_db.f90
> Fortran runtime error: Bad value during floating point read
> 
> See http://gcc.gnu.org/ml/gcc-testresults/2007-08/msg01010.html for
> results on Darwin.
> 
> Dominique
> 
> PS Note that gfortran.dg/edit_real_1.f90 now pass, but if I print the
> 
>  9 1.798+30z
>  
> instead of
> 
>  9 1.798+308z
>  
> Also the code
> 
> print *,  huge(1.0), -huge(1.0), huge(1.0d0), -huge(1.0d0)
> print *,  nearest(huge(1.0),-1.0), nearest(-huge(1.0),1.0), nearest(huge(1.0d0),-1.0d0), nearest(-huge(1.0d0),1.0d0)
> print *,  nearest(huge(1.0),1.0), nearest(-huge(1.0),-1.0), nearest(huge(1.0d0),1.0d0), nearest(-huge(1.0d0),-1.0d0)
> end
> 
> gives
> 
> edit_real_1_red_3.f90:3.18:
> 
> print *,  nearest(huge(1.0),1.0), nearest(-huge(1.0),-1.0), nearest(huge(1.0d0)
>                  1
> Error: Result of NEAREST overflows its kind at (1)
> edit_real_1_red_3.f90:3.42:
> 
> print *,  nearest(huge(1.0),1.0), nearest(-huge(1.0),-1.0), nearest(huge(1.0d0)
>                                          1
> Error: Result of NEAREST overflows its kind at (1)
> edit_real_1_red_3.f90:3.68:
> 
> print *,  nearest(huge(1.0),1.0), nearest(-huge(1.0),-1.0), nearest(huge(1.0d0)
>                                                                    1
> Error: Result of NEAREST overflows its kind at (1)
> edit_real_1_red_3.f90:3.96:
> 
> e(1.0),1.0), nearest(-huge(1.0),-1.0), nearest(huge(1.0d0),1.0d0), nearest(-hug
>                                                                           1                     
> Error: Result of NEAREST overflows its kind at (1)
> 
> I was expecting no errors and 
> 
>  3.4028235E+38 -3.4028235E+38 1.7976931348623157E+308 -1.7976931348623157E+308
>  3.4028233E+38 -3.4028233E+38 1.7976931348623155E+308 -1.7976931348623155E+308
>  +Inf -Inf +Inf -Inf
> 
> If I remove the offending line, the output is:
> 
>   3.4028235E+38 -3.4028235E+38  1.797693134862316E+30 -1.797693134862316E+30
>   3.4028233E+38 -3.4028233E+38  1.797693134862316E+30 -1.797693134862316E+30
> 

Would you please file a PR for this.  I have seen something similar to this 
before, but will have to think about it a bit.  I think this is target specific.

Please try touching all files in libgfortran/io and rebuild and see what happens.

Jerry