RFA (mmix): FIx PR46739

[Joern Rennecke]

Quoting "Joseph S. Myers" <joseph@codesourcery.com>:

> On Mon, 6 Dec 2010, Joern Rennecke wrote:
>
>> > should be substantially simplified given that 2.95 not 2.7.2 is the
>> > minimum version for building a cross compiler.
>>
>> It looks as if this was a specific decision to support 2.7.2 by the port
>> maintainer, albeit that was a while ago.  I'll leave it to the port
>> maintainers to decide if this is now obsolete.
>
> It's obviously obsolete, since ports can't unilaterally support older host
> compilers than the rest of GCC.

It's not quite that obvious.  When we say we require a minimum version of
GCC, we may say this because of same part that is not built for all targets,
or for which a miscompilation might be a non-issue for some target as the
code is never reached.
Or some issues might be host-specific.
Some issues might be sporadic, triggered by particular code patterns,
and very time consuming to specify what host/target combinations are
affected.  The hack in mmix_intval looks like it works around an issue
in this category.