Fwd: about mpfr in gcc/gfortran

[Paul Brook <paul at codesourcery dot com>]

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Paul

----------  Forwarded Message  ----------

I've had a look at the files using MPFR in the current cvs of gcc/fortran:

./gcc/doc/install.texi:
   Necessary to build the Fortran frontend.  It can be downloaded from
   @uref{http://www.mpfr.org/}.  It is also included in the current GMP
   release (4.1.3) when configured with @option{--enable-mpfr}.

Better advise to use the latest mpfr version on mpfr.org (2.1.1 now),
since that bundled with GMP is old, and not maintained any more by the
GMP developers.

Also make sure that when both versions are present (that in GMP and that
with --with-mpfr-dir), the later is used.

   "@samp{--with-mpfr-dir=gmpbuilddir}"

Should be "--with-mpfr-dir=mpfrbuilddir".

./gcc/fortran/arith.c
- mpfr now has a mpfr_get_z() function (to replace gfc_mpfr_to_mpz)

Also, I wonder why you set the default precision to 128 bits
(file arith.c, function gfc_arith_init_1). Isn't it possible
to set the precision to what is exactly wanted, to avoid
double rounding problems?

Regards,
Paul Zimmermann
MPFR developer