This is the mail archive of the
gcc-help@gcc.gnu.org
mailing list for the GCC project.
Re: gcc 4.3 generates less efficient code than gcc 4.1 or 4.2
- From: Eljay Love-Jensen <eljay at adobe dot com>
- To: Vincent Lefevre <vincent+gcc at vinc17 dot org>, GCC-help <gcc-help at gcc dot gnu dot org>
- Date: Thu, 03 Jul 2008 07:14:31 -0500
- Subject: Re: gcc 4.3 generates less efficient code than gcc 4.1 or 4.2
Hi Vincent,
> In fact, -march solved the problem, and after all, it's not abnormal
> that a later gcc version generates less efficient code if the
> architecture is incorrect. Now, I thought that gcc would have used
> sensible default values (I couldn't find anything in the manual about
> the default architecture).
I think the value used is the one specified when GCC is built.
If the builder does not specify an architecture explicitly, then the lowest
common denominator for that platform is used (typically). That's the safest
assumption for configure.
HTH,
--Eljay