[FFmpeg-cvslog] r29011 - in trunk/libswscale: swscale.c swscale_internal.h swscale_template.c

[Alexander Strange]

On Mar 20, 2009, at 1:04 PM, Reimar D?ffinger wrote:

> On Fri, Mar 20, 2009 at 05:58:30PM +0100, Gwenole Beauchesne wrote:
>> On Fri, 20 Mar 2009, Reimar D?ffinger wrote:
>>
>>> When you write a special x86_64 version where you have 16 registers
>>> available, what in the seven hells makes you use rbx, which is  
>>> almost
>>> guaranteed to have issues?
>>> Fixed it, though I did not test it particularly thoroughly.
>>
>> I don't think this would change anything, %rbx is not the PIC  
>> register on
>> x86_64. The GOT is %rip relative, that was the goal. ;-)
>
> Quoted from FATE:
>> /Users/melanson/fate/source/libswscale/swscale_template.c:1247:  
>> error: PIC register ?%rbx? clobbered in ?asm?
>
> Either you are wrong or gcc is wrong. I guess you are because you
> actually don't know the OSX x86_64 ABI.
> Not that it matters either way.

It's a compiler bug. OS X's x86-64 ABI is nearly the same as SysV, and  
gcc 4.2 allows ebx clobbers.
I filed http://openradar.me/6704763.