rawhide report: 20050510 changes

Nils Philippsen nphilipp at redhat.com
Fri May 13 10:20:21 UTC 2005

On Tue, 2005-05-10 at 11:30 -0400, Owen Taylor wrote:
> On Tue, 2005-05-10 at 08:26 -0400, Jakub Jelinek wrote:
> > a) on x86-64 this is unnecessary, all x86-64's have -msse2 by default
> > b) -msse2 implies -msse
> > c) if you use -msse2 in CFLAGS for all files, you can't run the latest
> >    GIMP on e.g. Pentium2, or pre-x86_64 AMD chips.
> >    -msse2 should be ONLY used on sources that have SSE/SSE2 stuff in it,
> >    and GIMP should make sure that no routine from those sources will be
> >    ever called on pre-SSE2 chips
> This sounds like a big pain ... shouldn't there be a way to say 
> "use sse2/sse only for builtins" ? 
> Without that, there is no way to use builtins in single functions; you
> need to have one file for sse2, one for sse, one for mmx, and do the
> detection of the current processor somewhere else entirely.

I concur, with gcc <= 4.0.0-2 it was possible to use MMX/SSE calls in
inline assembly without having to use -mmmx/-msse/-msse2. In order to
build the gimp so that it uses MMX/SSE where available, I had to resort
to serious autofoo munging because it doesn't allow for setting
per-object compiler flags.

     Nils Philippsen    /    Red Hat    /    nphilipp at redhat.com
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 safety deserve neither liberty nor safety."     -- B. Franklin, 1759
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