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Re: Change x86 default arch for 4.5?
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Jason Merrill <jason at redhat dot com>
- Cc: GCC <gcc at gcc dot gnu dot org>
- Date: Fri, 19 Feb 2010 00:46:26 +0000 (UTC)
- Subject: Re: Change x86 default arch for 4.5?
- References: <4B7DBA8A.9000601@redhat.com>
On Thu, 18 Feb 2010, Jason Merrill wrote:
> I periodically get bitten by bug 34115: a compiler configured without
> --with-arch on i686-pc-linux-gnu doesn't support atomics. I think we would
> only need to bump the default to i486 to get atomic support. Can we
> reconsider the default for 4.5?
My position remains that configuring for i686-* should default to
-march=i686 rather than -mtune=i686.
http://gcc.gnu.org/ml/gcc/2008-06/msg00223.html
http://gcc.gnu.org/ml/gcc/2008-08/msg00445.html
Perhaps someone would like to review HJ's patch to that effect?
http://gcc.gnu.org/ml/gcc-patches/2008-08/msg02078.html
This will probably break building glibc, as problems building when __i686
is a predefined macro have been known since at least 2002 but none of the
many patches proposed since then have been accepted.
http://sourceware.org/ml/libc-alpha/2002-10/msg00156.html
...
http://sourceware.org/ml/libc-alpha/2009-07/msg00072.html
--
Joseph S. Myers
joseph@codesourcery.com