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Re: [PATCH] Rs6000 infrastructure cleanup (switches), revised patch #2c
- From: Michael Meissner <meissner at linux dot vnet dot ibm dot com>
- To: Gunther Nikl <gnikl at users dot sourceforge dot net>
- Cc: Michael Meissner <meissner at linux dot vnet dot ibm dot com>, David Edelsohn <dje dot gcc at gmail dot com>, bergner at vnet dot ibm dot com, segher at kernel dot crashing dot org, iain at codesourcery dot com, andreast-list at fgznet dot ch, gcc-patches at gcc dot gnu dot org
- Date: Tue, 2 Oct 2012 12:11:50 -0400
- Subject: Re: [PATCH] Rs6000 infrastructure cleanup (switches), revised patch #2c
- References: <20120912224303.GA19348@ibm-tiger.the-meissners.org> <20120917195131.GA22648@ibm-tiger.the-meissners.org> <CAGWvnykaJM0LFiwVJRcoay4uVJtrFR-V8G=_aK6=4VQygmAx0w@mail.gmail.com> <20120920195755.GA18581@ibm-tiger.the-meissners.org> <20120927224228.GA24889@ibm-tiger.the-meissners.org> <20120928181106.GA28376@ibm-tiger.the-meissners.org> <506AA225.6020409@users.sourceforge.net>
On Tue, Oct 02, 2012 at 10:13:25AM +0200, Gunther Nikl wrote:
> Michael Meissner wrote:
> > Segher Boessenkool asked me on IRC to break out the fix in the last change.
> > This patch is just the change to set the default options if the user did not
> > use -mcpu=<xxx> and the compiler was not configured with --with-cpu=<xxx>.
> > Here are the patches.
>
> Which GCC releases are affected by this bug?
All of them. Now, in general users don't see this bug, because distribution
maintainers usually build with an explicit --with-cpu= option, which sets the
default CPU in case the user did not use -mcpu=<xxx> on the command line. If
neither option was used, the default "powerpc" or "powerpc64" is usually good
enough.
David noticed it when building AIX compilers, because he wanted to add a
default option (-mmfcrf) to the aix*.h definitions to insure that the new get
timebase builtin would generate the correct instructions by default (the
original PowerPCs had a different SPR for the time base than the newer
server machines starting with power4). He asked me to fix this bug before we
tackle the infrastructure changes.
--
Michael Meissner, IBM
5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA
meissner@linux.vnet.ibm.com fax +1 (978) 399-6899