[CFT] gcc: support for barcelona

[Warner Losh]

On May 27, 2013, at 1:48 PM, Pedro Giffuni wrote:

> On 27.05.2013 14:12, Rui Paulo wrote:
>> On 27 May 2013, at 09:41, Pedro Giffuni <pfg at freebsd.org> wrote:
>> 
>>> Hello;
>>> 
>>> Almost a year ago I tried to bring in the support for AMD's barcelona
>>> chipset into our gcc. This actually filled a lot of holes in that were left
>>> when similar intel support was brought in.
>>> 
>>> Unfortunately I had to revert rapidly such support as it broke building
>>> some C++ ports even when it was not being used.
>>> 
>>> jkim@ did some cleanup of the support and the patch has been
>>> gathering rust here:
>>> 
>>> http://people.freebsd.org/~jkim/reworked-r236962-3.diff
>>> 
>>> The patch still applies cleanly and there is a good chance it will work
>>> since there have been other fixes merged since the last time.
>>> 
>>> I did some basic testing and so far it works for me but I don't have
>>> the specific chipset. Additional testing would be welcome.
>> 
>> I have to question the general direction of this work. We switched to Clang as the default compiler for i386/amd64 some months ago and now you're working on improving our base GCC especially for amd64? I don't really understand how useful this is. It doesn't strike me as a good idea to see people working on things that will eventually be replaced / removed.
> 
> I have absolutely no intention to give gcc a second air: it's dead
> and I am anxious to see it axed from -current (soon?).

That's not going to happen soon. While it works OK for amd64, there's still many bugs in its ARM support and even more in its MIPS support. There's 0 chance it will be gone in 10...

> This said,
> there are still many FreeBSD users trapped with the base gcc for
> at least as long as 9.x is alive.
> 
> If you look at the ChangeLog.gcc43 in the above patch, you will
> notice I am just completing some code that was incompletely
> merged in previous revisions.
> 
> The basic work was done almost a year ago, and I have no hurry
> to merge it but given that the effort was done already it would
> seem a pity to just throw it away.
> 
> Of course I may be completely wrong here.

I see some value in adding this stuff.  While we have made clang the default, it still isn't fully vetted by surviving a release with it enabled. the fallback plan will continue to be gcc.

While it would ALSO be good to cleanup the tree so it can compile cleanly with 4.7 or 4.8, this effort won't stand in the way of that. Excluding it seems more like a political or emotional one than a practical one.

Warner