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From: Michael Schreckenbauer <grimlog@gmx.de>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] ffmpeg - fails to compile on amd64
Date: Mon, 12 Dec 2011 21:52:04 +0100	[thread overview]
Message-ID: <4926919.gxlYKMO5pC@pc> (raw)
In-Reply-To: <20111212202839.GV3810@syscon4.inet>

Am Montag, 12. Dezember 2011, 13:28:39 schrieb Joseph:
> On 12/12/11 20:32, Michael Hampicke wrote:
> >> Configuring source in
> >> /var/tmp/portage/media-video/ffmpeg-0.7.8/work/ffmpeg-0.7.8 ...
> >> x86_64-pc-linux-gnu-gcc is unable to create an executable file.
> >> If x86_64-pc-linux-gnu-gcc is a cross-compiler, use the
> >> --enable-cross-compile option.
> >> Only do this if you know what cross compiling means.
> >> C compiler test failed.
> >
> >Do you have enabled the "cpudetection" and/or "custom-cflags" use flags?
> >Or do you use some crazy CFLAGS?
> >ffmpeg 0.7.8 compiles just fine on my amd64 box.
> 
> No nothing crazy:
> CFLAGS="-Os -pipe -mtune=i686"

i686? That's not amd64. You need something 64bit. Just use march=native 
instead of mtune=i686. 


> I'm not even sure if these flags are correct for my CPU:
> AMD FX(tm)-8150 Eight-Core Processor

:) They are not.

> The flags suggestion I found on gentoo wiki are crazy:
> http://en.gentoo-wiki.com/wiki/Safe_Cflags/AMD#AMD_FX-8xxx.2F6xxx.2F4xxx_.28
> Bulldozer.29
> 
> CFLAGS="-O2 -pipe -fomit-frame-pointer -march=bdver1 -mtune=bdver1 -mcx16
> -msahf -maes -mpclmul -mpopcnt -mabm -mlwp -mavx"
> Whoever suggested these flags must have been on some drugs :-/

Could well be, that this is what march=native gives for bdver1.

Best,
Michael




  parent reply	other threads:[~2011-12-12 20:53 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-12 19:28 [gentoo-user] ffmpeg - fails to compile on amd64 Joseph
2011-12-12 19:32 ` Michael Hampicke
2011-12-12 20:28   ` Joseph
2011-12-12 20:49     ` Michael Hampicke
2011-12-12 20:52     ` Michael Schreckenbauer [this message]
2011-12-12 21:09       ` Michael Hampicke
2011-12-12 21:15         ` Michael Hampicke
2011-12-13  0:28       ` [gentoo-user] [SOLVED] " Joseph
2011-12-12 19:52 ` [gentoo-user] " Michael Mol
2011-12-12 20:23   ` Joseph
2011-12-12 20:29     ` Dale
2011-12-12 20:43       ` Joseph

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