Re: mpfr, gmp and mpc versions prior to 4.6.0 and download_prerequisites

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

On 13 April 2017 at 16:24, Toebs Douglass wrote:
> Hi, all.
>
> I have two questions.
>
> As you probably remember, I'm working to build all released versions of
> GCC, starting with 4.1.2, on four different platforms (arm, aarch64,
> mipsel, x86_64).
>
> I am now working to find out which version of libmpfr, libgmp and libmpc
> are needed for each version of GCC.
>
> Prior to replies from my earlier questions to this list, I had assumed
> the latest versions available at the time of a GCC release would be
> used, but this is not the case; GCC only changes version where there's a
> good reason to do so.
>
> This means however I can no longer use release dates to know which
> versions of the dependency libraries are used by any given version of GCC.
>
> Starting with GC 4.6.0, there is a contrib script,
> "download_prerequisites", which indictes the recommended version of
> these libraries.  So for GCC 4.6.0 and later, I have the information I need.
>
> For earlier versions though, things seem not so easy or clear.
>
> What I see in general with GCC is that there is fact a *minimum* version
> of these libraries, and a *recommended* version, which is normally only
> a slightly higher version, but still, is different.
>
> I want to use the recommended version.
>
> I can by looking in the configure script go back to and including 4.5.0
> and make a pretty solid guess at the recommended versions (you can see
> the script treating minimum and recommended versions differently) - but
> before that, the build system changes and again, it's not so clear.
>
> Perhaps prior to that point there is only a minimum version, and no
> recommended version?
>
> So the first question is : does anyone have anything useful they could
> tell me about finding out this information?  which is to say,
> recommended dependency versions for GCC 4.4.7 and earlier, back to and
> including 4.1.2.

The prerequisites for a release are documented in gcc/doc/install.texi
in the sources of that release.

> Currently I'm looking at the build files, and I can make a guess, but I
> can't really tell if I'm finding the *minimum* version rather than
> *recommended* version.  So I can get *a* version - but it may not be the
> version I'm looking for.
>
> My second question has to do with Graphite loop optimizations.
>
> These were folded into the main branch with version 4.8.0, I think it was.
>
> Prior to this, back to version 4.5.0 (I think) they depended on libmpc,
> and from 4.4.7 and further back (to when they were introduced - I don't
> yet know when this was), they depended on libppl and cloog-ppl (and
> libmpc was then not a dependency).
>
> My second question is whether or not people have any idea if graphite
> was typically compiled in (it's optional) prior to 4.8.0?  I get the
> impression it could have been a bit buggy/experimental prior to that
> point, and so was perhaps not normally used.

It is still not widely used today. Graphite optimisations are very
unlikely to make any difference for your code. I wouldn't bother with
Graphite if I were you.