[Bug web/60933] New: Please do not advertise outdated version of gmp, mpfr, mpc

[Bug web/60933] New: Please do not advertise outdated version of gmp, mpfr, mpc

[andreas.enge at inria dot fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

            Bug ID: 60933
           Summary: Please do not advertise outdated version of gmp, mpfr,
                    mpc
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: web
          Assignee: unassigned at gcc dot gnu.org
          Reporter: andreas.enge at inria dot fr

This problem does not only concern the web, but "documentation" of
prerequisites in a broader sense.

On the mailing lists of gmp, mpfr and mpc we regularly receive reports with
installation errors concerning very old and no longer maintained versions of
our software, which creates quite some noise. For instance,
   https://gmplib.org/~tege/stats/usage_201404.html#TOPURLS
shows that gmp-4.3.2 is the most downloaded version, while gmp-5.0.0 came out
in early 2010, and gmp-6.0.0 this year. Mpc-1.0.0 came out in fall 2012, and
the 0.8 and 0.9 branches are no longer maintained.

I believe the culprit is gcc too actively promoting the minimally required
versions of the libraries. It is fine if gcc still compiles with older
versions, but all communication should point to the most recent releases.

For instance, trying to install gcc-4.9.0 without gmp results in the following:
configure: error: Building GCC requires GMP 4.2+, MPFR 2.4.0+ 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
ftp://gcc.gnu.org/pub/gcc/infrastructure/.  See also
http://gcc.gnu.org/install/prerequisites.html for additional info.  If
you obtained GMP, MPFR and/or MPC from a vendor distribution package,
make sure that you have installed both the libraries and the header
files.  They may be located in separate packages.

(As an aside, the minimal version numbers seem to be wrong here.) Your ftp
server mentioned in the message provides the outdated libraries corresponding
to the minimal versions with which gmp compiles (and not even the latest bug
fix release in a given release series). If you provide our libraries on your
server, please make sure to always copy the most up-to-date release. Or if this
is too much work, you may prefer to link to ftp.gnu.org/gnu/{gmp,mpfr,mpc}.

On the web at:
   http://gcc.gnu.org/install/prerequisites.html
the text
   GNU Multiple Precision Library (GMP) version 4.3.2 (or later)
could be changed to something like:
   GNU Multiple Precision Library (GMP), preferably the latest version,
   but at least 4.3.2.

I did not make an exhaustive search of the gcc documentation, but there may be
other places where you could point to the most recent gmp, mpfr and mpc
releases to ease our work and to make sure people use up-to-date software in
conjunction with gcc.

Your collaboration is very much appreciated.

Andreas

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |SUSPENDED
   Last reconfirmed|                            |2014-04-23
                 CC|                            |ebotcazou at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> I believe the culprit is gcc too actively promoting the minimally required
> versions of the libraries. It is fine if gcc still compiles with older
> versions, but all communication should point to the most recent releases.

It's common practice to list the minimally required versions of dependencies
for software packages, so I'm not sure why we shouldn't do it for GCC. 
Besides, we don't want to force the users to upgrade the libraries if this is
not necessary.

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
We've had situations in the past where the minimum suggested versions work and
the latest versions prevented GCC from building. The suggested versions are
known to work and have been thoroughly tested, which might not be true of the
latest versions.

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[vincent-gcc at vinc17 dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

--- Comment #6 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Eric Botcazou from comment #5)
> But, again, other software packages don't do that so I'm not sure why GCC
> should do it

I'm not aware of other software packages that provide such old versions of GMP
and MPFR.

> (and we certainly don't want to get bug reports for anything
> else than GCC, we already have enough of them).

and GMP and MPFR developers don't want to get bug reports for obsolete, no
longer maintained versions of GMP and MPFR.
>From gcc-bugs-return-449731-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Wed Apr 23 16:24:12 2014
Return-Path: <gcc-bugs-return-449731-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Delivered-To: listarch-gcc-bugs@gcc.gnu.org
Received: (qmail 17292 invoked by alias); 23 Apr 2014 16:24:11 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Delivered-To: mailing list gcc-bugs@gcc.gnu.org
Received: (qmail 17266 invoked by uid 55); 23 Apr 2014 16:24:09 -0000
From: "uros at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/60909] ICE: in extract_insn, at recog.c:2202 (unrecognizable insn) with -mrdrnd and __builtin_ia32_rdrand32_step()
Date: Wed, 23 Apr 2014 16:24:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: 4.10.0
X-Bugzilla-Keywords: ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: uros at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: ubizjak at gmail dot com
X-Bugzilla-Target-Milestone: 4.7.4
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields:
Message-ID: <bug-60909-4-SrrGPTABfP@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-60909-4@http.gcc.gnu.org/bugzilla/>
References: <bug-60909-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-04/txt/msg01751.txt.bz2
Content-length: 1031

http://gcc.gnu.org/bugzilla/show_bug.cgi?id`909

--- Comment #4 from uros at gcc dot gnu.org ---
Author: uros
Date: Wed Apr 23 16:23:36 2014
New Revision: 209709

URL: http://gcc.gnu.org/viewcvs?rev 9709&root=gcc&view=rev
Log:
    Backport from mainline
    2014-04-21  Uros Bizjak  <ubizjak@gmail.com>

    PR target/60909
    * config/i386/i386.c (ix86_expand_builtin)
    <case IX86_BUILTIN_RDRAND{16,32,64}_STEP>: Use temporary
    register for target RTX.
    <case IX86_BUILTIN_RDSEED{16,32,64}_STEP>: Ditto.

testsuite/ChangeLog:

    Backport from mainline
    2014-04-21  Uros Bizjak  <ubizjak@gmail.com>

    PR target/60909
    * gcc.target/i386/pr60909-1.c: New test.
    * gcc.target/i386/pr60909-2.c: Ditto.


Added:
    branches/gcc-4_9-branch/gcc/testsuite/gcc.target/i386/pr60909-1.c
    branches/gcc-4_9-branch/gcc/testsuite/gcc.target/i386/pr60909-2.c
Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/config/i386/i386.c
    branches/gcc-4_9-branch/gcc/testsuite/ChangeLog

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[andreas.enge at inria dot fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

--- Comment #7 from Andreas <andreas.enge at inria dot fr> ---
As stated in my report, there is no problem with mentioning the minimal
versions of helper libraries required to compile gcc. The problem is with
actively promoting outdated versions, which can be helped by choosing different
wordings, for instance as I suggested in the report. And a worse problem is
created by actively pushing outdated versions upon the users via
ftp://gcc.gnu.org/pub/gcc/infrastructure/.

I do not know the policy of gcc with regards to continuous integration; I think
gcc should always be thoroughly tested with the latest versions of its helper
libraries, and potential problems be reported upstream; after all, we should
help each other out in improving our free GNU software! (But this becomes
somewhat off-topic.)

Even if you are weary of the latest and greatest version, a position I can
understand, you should not actively distribute releases that have been
unmaintained for quite a while and contain known bugs.

I would like to point out that this position is shared by the current
maintainers of GNU MPC (me) and GNU MPFR (Vincent) and the main developer of
GNU MP (Torbjörn, see his posting on the gmp mailing list at
   https://gmplib.org/list-archives/gmp-devel/2014-April/003770.html
).

Andreas
>From gcc-bugs-return-449733-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Wed Apr 23 16:33:37 2014
Return-Path: <gcc-bugs-return-449733-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Delivered-To: listarch-gcc-bugs@gcc.gnu.org
Received: (qmail 30212 invoked by alias); 23 Apr 2014 16:33:37 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Delivered-To: mailing list gcc-bugs@gcc.gnu.org
Received: (qmail 30178 invoked by uid 48); 23 Apr 2014 16:33:34 -0000
From: "law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/60902] [4.9/4.10 Regression] ffmpeg built with gcc 4.9 RC produces incorrect flac playback code
Date: Wed, 23 Apr 2014 16:33:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 4.9.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: law at redhat dot com
X-Bugzilla-Status: NEW
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: law at redhat dot com
X-Bugzilla-Target-Milestone: 4.9.1
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields:
Message-ID: <bug-60902-4-X48BgaAHHi@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-60902-4@http.gcc.gnu.org/bugzilla/>
References: <bug-60902-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-04/txt/msg01753.txt.bz2
Content-length: 334

http://gcc.gnu.org/bugzilla/show_bug.cgi?id`902

--- Comment #30 from Jeffrey A. Law <law at redhat dot com> ---
Sorry.  I expect to check the fix & testcase onto the trunk today.  For various
reasons my work time is limited right now.  For the 4.9.x releases, final call
will be with jakub, jsm and richi as the releaes managers.

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Andreas from comment #7)
> Even if you are weary of the latest and greatest version, a position I can
> understand, you should not actively distribute releases that have been
> unmaintained for quite a while and contain known bugs.

I tend to agree with this and think it would be good if we updated the versions
at ftp://gcc.gnu.org/pub/gcc/infrastructure/ and made the corresponding update
to the contrib/download_prerequisites script.

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

--- Comment #9 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> As stated in my report, there is no problem with mentioning the minimal
> versions of helper libraries required to compile gcc. The problem is with
> actively promoting outdated versions, which can be helped by choosing
> different wordings, for instance as I suggested in the report. And a worse
> problem is created by actively pushing outdated versions upon the users via
> ftp://gcc.gnu.org/pub/gcc/infrastructure/.

You must admit that the difference between "mentioning the minimal versions of
helper libraries required" and "actively promoting outdated versions" is not
very clear.  The policy is not to force the users to upgrade if he happens to
have a supported version.  Can you suggest a better wording?

> I do not know the policy of gcc with regards to continuous integration; I
> think gcc should always be thoroughly tested with the latest versions of its
> helper libraries, and potential problems be reported upstream; after all, we
> should help each other out in improving our free GNU software!

Yes, this could make sense, but this isn't the current policy.

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|SUSPENDED                   |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.

[Bug web/60933] Please do not advertise outdated version of gmp, mpfr, mpc

[bugfeed at online dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60933

--- Comment #11 from Leif Leonhardy <bugfeed at online dot de> ---
(In reply to Jonathan Wakely from comment #2)
> We've had situations in the past where the minimum suggested versions work
> and the latest versions prevented GCC from building.
Well, in the past... ;-)


> The suggested versions
> are known to work and have been thoroughly tested, which might not be true
> of the latest versions.
Sure.

But note that this is not (or no longer) true for at least GMP 4.3.2, assuming
"works" includes "the library's test suite passes [when compiled] with GCC".  

I.e., GMP 4.3.2's test suite contains a subtle bug (fixed long ago, in all
later versions) that will cause a single test (t-scan) to fail when compiled
with GCC 4.8.0 and any later version; it only incidentally doesn't show up with
earlier ones.

While the bug doesn't affect the library code or GCC itself, it is annoying to
users building GCC as well, as most won't know until they report it to
gmp-bugs, which happens pretty often.  (In fact, the error message of course
asks them to do so.  And people are encouraged to run 'make check'.)