Desire to allocate bit in DT_PARM bitmask for DEC FORMAT compatibility purposes

[Jakub Jelinek]

On Fri, Mar 23, 2018 at 09:12:21AM +0100, Jakub Jelinek wrote:
> > I have some philosophical questions.
> > 
> > 1) Why do you want 15, 7, 2? Why is this so critical?
> 
> Because that is what all those compilers document and agree on.
> See e.g.
> https://software.intel.com/en-us/node/678750#32937290-265D-4805-B2B7-4E78F6AAD0D8
> for Intel documentation, I'm sure Jeff has links to other documentations.

BTW, it seems libgfortran already has a similar extension, at least my
reading of the standards (checked 97 and 2003) is that for Lw the standard
doesn't allow omitting the width, but we allow that as extension:
          else
            {
              fmt->saved_token = t;
              notify_std (&dtp->common, GFC_STD_GNU,
                          "Positive width required with L descriptor");
            }
          fmt->value = 1;       /* Default width */
(and sadly different from what Intel Fortran does, because it uses 2).
Wonder about other compilers, if they all agree on 2, perhaps we should
behave above differently based on the new bit?

	Jakub