On Thursday, December 8, 2005 1:51 am, Jakub Jelinek wrote:
Hi!
Some time between today and tomorrow we plan to switch Fedora
development primary compiler from GCC 4.0.2-RH to 4.1.0-RH prerelease.
We hope GCC 4.1.0 will be officially released in time for the
Fedora Core 5 release, but if we want to switch, we need to do it now
so that the compiler and packages built with it are sufficiently
tested.
Arjan mentioned the other day that the Fedora linker is capable of
loading CPU specific libraries, depending on which ISA extensions are
available. Since gcc 4.1 has a much improved autovectorizer, maybe now
is the time to start making use of it? It seems like codec libraries
are good candidates for autovectorization, maybe their spec files could
build SSE2, SSE3, and 3dnow variants along with the regular, non-SIMD
versions of the libraries? Of course, if the vectorizer doesn't
actually vectorize anything in a given library, trying to use it is a
waste of time, but fortunately gcc makes it fairly easy to see how
effective the vectorizing pass was using -ftree-vectorizer-verbose
(sp?).
Anyway, just a thought. I'm pretty sure my VIA CPU would benefit from
3dnow versions of libraries, and it seems a shame to let the SSE3
extensions sit idle when gcc can take advantage of them fairly easily
these days...
Jesse