[Bug middle-end/92463] Cleanups due to minimum MPFR version bump to 3.1.0

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92463

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |burnus at gcc dot gnu.org

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to Janne Blomqvist from comment #4)
> Fortran parts done, reassigning to middle-end as there are similar MPFR
> modernization opportunities there.

See also https://gcc.gnu.org/ml/gcc-patches/2019-11/msg01969.html for grep for
the files where the type changes should be applied.

Background: r278058 changed the minimal version from 2.4.0 to 3.1.0.
The main changes are listed at https://www.mpfr.org/mpfr-3.0.0/#changes
and https://www.mpfr.org/mpfr-3.1.0/#changes

At a glance, I did not see function-call changes but I did just a simple grep
with glancing at the code. New but probably not needed is a function to set
zero (with + or - sign) and rounding away from zero (see MPFR changes linked
above).