rawhide report: 20050510 changes
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
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." -- B. Franklin, 1759
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