[PATCH] Bump minimum MPFR version to 3.1.0

[Richard Biener]

On November 9, 2019 8:47:52 PM GMT+01:00, Janne Blomqvist <blomqvist.janne@gmail.com> wrote:
>Bump the minimum MPFR version to 3.1.0, released 2011-10-03. With this
>requirement one can still build GCC with the operating system provided
>MPFR on old but still supported operating systems like SLES 12 (MPFR
>3.1.2) or RHEL/CentOS 7.x (MPFR 3.1.1).
>
>This allows removing some code in the Fortran frontend, as well as
>fixing PR 91828.

OK. 

Thanks, 
Richard. 

>ChangeLog:
>
>2019-11-09  Janne Blomqvist  <jb@gcc.gnu.org>
>
>	PR fortran/91828
>	* configure.ac: Bump minimum MPFR to 3.1.0, recommended to 3.1.6+.
>	* configure: Regenerated.
>
>gcc/ChangeLog:
>
>2019-11-09  Janne Blomqvist  <jb@gcc.gnu.org>
>
>	PR fortran/91828
>	* doc/install.texi: Document that the minimum MPFR version is
>	3.1.0.
>
>gcc/fortran/ChangeLog:
>
>2019-11-09  Janne Blomqvist  <jb@gcc.gnu.org>
>
>	PR fortran/91828
>	* simplify.c (gfc_simplify_fraction): Remove fallback path for
>	MPFR < 3.1.0.
>---
> configure.ac           |  6 +++---
> gcc/doc/install.texi   |  2 +-
> gcc/fortran/simplify.c | 37 -------------------------------------
> 3 files changed, 4 insertions(+), 41 deletions(-)
>
>diff --git a/configure.ac b/configure.ac
>index b8ce2ad20b9..d63a8bae940 100644
>--- a/configure.ac
>+++ b/configure.ac
>@@ -1601,12 +1601,12 @@ if test -d ${srcdir}/gcc && test "x$have_gmp" =
>xno; then
>     AC_MSG_CHECKING([for the correct version of mpfr.h])
>     AC_TRY_COMPILE([#include <gmp.h>
>     #include <mpfr.h>],[
>-    #if MPFR_VERSION < MPFR_VERSION_NUM(2,4,0)
>+    #if MPFR_VERSION < MPFR_VERSION_NUM(3,1,0)
>     choke me
>     #endif
>     ], [AC_TRY_COMPILE([#include <gmp.h>
>     #include <mpfr.h>],[
>-    #if MPFR_VERSION < MPFR_VERSION_NUM(2,4,2)
>+    #if MPFR_VERSION < MPFR_VERSION_NUM(3,1,6)
>     choke me
>     #endif
>  ], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([buggy but acceptable])])],
>@@ -1661,7 +1661,7 @@ if test -d ${srcdir}/gcc && test "x$have_gmp" =
>xno; then
> # The library versions listed in the error message below should match
> # the HARD-minimums enforced above.
>   if test x$have_gmp != xyes; then
>-    AC_MSG_ERROR([Building GCC requires GMP 4.2+, MPFR 2.4.0+ and MPC
>0.8.0+.
>+    AC_MSG_ERROR([Building GCC requires GMP 4.2+, MPFR 3.1.0+ and MPC
>0.8.0+.
> Try the --with-gmp, --with-mpfr and/or --with-mpc options to specify
> their locations.  Source code for these libraries can be found at
> their respective hosting sites as well as at
>diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
>index 2cb8a342a2c..93b01ff7971 100644
>--- a/gcc/doc/install.texi
>+++ b/gcc/doc/install.texi
>@@ -384,7 +384,7 @@ and @option{--with-gmp-include}.
> The in-tree build is only supported with the GMP version that
> download_prerequisites installs.
> 
>-@item MPFR Library version 2.4.2 (or later)
>+@item MPFR Library version 3.1.0 (or later)
> 
> Necessary to build GCC@.  It can be downloaded from
> @uref{https://www.mpfr.org}.  If an MPFR source distribution is found
>diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
>index 2eb1943c3ee..0461d31cd88 100644
>--- a/gcc/fortran/simplify.c
>+++ b/gcc/fortran/simplify.c
>@@ -3076,12 +3076,7 @@ gfc_expr *
> gfc_simplify_fraction (gfc_expr *x)
> {
>   gfc_expr *result;
>-
>-#if MPFR_VERSION < MPFR_VERSION_NUM(3,1,0)
>-  mpfr_t absv, exp, pow2;
>-#else
>   mpfr_exp_t e;
>-#endif
> 
>   if (x->expr_type != EXPR_CONSTANT)
>     return NULL;
>@@ -3095,41 +3090,9 @@ gfc_simplify_fraction (gfc_expr *x)
>       return result;
>     }
> 
>-#if MPFR_VERSION < MPFR_VERSION_NUM(3,1,0)
>-
>-  /* MPFR versions before 3.1.0 do not include mpfr_frexp.
>-     TODO: remove the kludge when MPFR 3.1.0 or newer will be required
>*/
>-
>-  if (mpfr_sgn (x->value.real) == 0)
>-    {
>-      mpfr_set (result->value.real, x->value.real, GFC_RND_MODE);
>-      return result;
>-    }
>-
>-  gfc_set_model_kind (x->ts.kind);
>-  mpfr_init (exp);
>-  mpfr_init (absv);
>-  mpfr_init (pow2);
>-
>-  mpfr_abs (absv, x->value.real, GFC_RND_MODE);
>-  mpfr_log2 (exp, absv, GFC_RND_MODE);
>-
>-  mpfr_trunc (exp, exp);
>-  mpfr_add_ui (exp, exp, 1, GFC_RND_MODE);
>-
>-  mpfr_ui_pow (pow2, 2, exp, GFC_RND_MODE);
>-
>-  mpfr_div (result->value.real, x->value.real, pow2, GFC_RND_MODE);
>-
>-  mpfr_clears (exp, absv, pow2, NULL);
>-
>-#else
>-
>   /* mpfr_frexp() correctly handles zeros and NaNs.  */
>   mpfr_frexp (&e, result->value.real, x->value.real, GFC_RND_MODE);
> 
>-#endif
>-
>   return range_check (result, "FRACTION");
> }
>