On Thu, Oct 07, 2021 at 11:24:35AM -0400, Michael Meissner wrote:
> On Thu, Oct 07, 2021 at 08:08:21AM +0200, Thomas Koenig wrote:
> > On 07.10.21 05:35, Michael Meissner via Fortran wrote:
> > > I tried this at one point. There are a lot of hidden assumptions that
> > > the kind
> > > number is the number of bytes. I'm sure it can be tracked down, but the
> > > problem is with these assumptions is you can't prove a negative (i.e. you
> > > never
> > > know that you've missed some).
> >
> > So, summing up from the Fortran side, I'd say the best course of action
> > is to
> >
> > - make KIND=16 into IEEE QP
>
> This is probably the right thing to do. Note, it will effectively mean that
> any fortran users on BE systems will no longer be able to use KIND=16.
Changing it on powerpc64le-linux doesn't imply we also have to change it
for powerpc64-linux, or perhaps can change it later than in GCC 12.
> It will also be a compatibility issue if users have code compiled on a LE
> system with GCC 11 and earlier with KIND=16, it will not link with GCC 12.
libgfortran ABI changed multiple times in the past already, e.g. the
so.1 -> so.2 transition in 4.2
so.2 -> so.3 transition in 4.3
so.3 -> so.4 transition in 7
so.4 -> so.5 transition in 8
and users have coped.
Jakub
