Fedora development switch to GCC 4.1.0-RH prerelease

Jesse Barnes jbarnes at virtuousgeek.org
Thu Dec 8 18:05:13 UTC 2005


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




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