how long to keep support for gcc on x86?

[John-Mark Gurney]

Konstantin Belousov wrote this message on Sun, Jan 13, 2013 at 15:24 +0200:
> On Sun, Jan 13, 2013 at 12:09:09AM -0800, Peter Wemm wrote:
> > On Sat, Jan 12, 2013 at 11:44 PM, Adrian Chadd <adrian at freebsd.org> wrote:
> > 
> > > Thus I think adding clang-only code to the system right now is very,
> > > very premature. There still seem to be reasons to run systems on GCC
> > > instead of clang.
> > 
> > I don't have a problem with it so long as the system isn't *broken* if
> > you're not using clang.  ie: if the status-quo is maintained for gcc
> > systems and g-faster bits are enabled with clang.  It's fine to
> > provide incentives to try clang, but it is not ok to regress the gcc
> > case.
> Absolutely agree.
> 
> Please note that in the AES-NI case, gcc 'support' is only partially
> gcc issue, if gcc at all. Our 2.17 gas does not know about AES-NI
> mnemonics and cannot assemble them.

gcc support would be better than gas support belive it or not..

> AFAIR the patch uses C built-in for AES-NI and SSE3 or 4, which I think
> could be implemented manually in the amount needed for the patch, for
> old gcc.

It was actually using assembly functions since gcc doesn't have the
necessary intrinsics...  If it did, I could make things go even faster
for both i386 and amd64...  As it stands, the i386 implementation will
be a bit slower since I'll have to pass in more of the blocks via stack
instead of registers...  amd64 allows 8 128bit args passed in via reg,
while i386 only allows three...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."