[Ffmpeg-devel] [PATCH] SSE counterpart of ff_imdct_calc_3dn2

[Loren Merritt]

On Tue, 19 Sep 2006, Guillaume POIRIER wrote:
> Michael Niedermayer a ?crit :
>> On Tue, Sep 19, 2006 at 01:25:14PM +0200, Guillaume POIRIER wrote:
>>
>>> Michael, what's your opinion about it?
>>> 
>>> Should lavc's makefile append '-fomit-frame-pointer' to compile
>>> libavcodec/i386/fft_3dn2.c as well as ff_imdct_calc_sse.diff?
>>> 
>>> It's a bit of a hack, but it would work.
>> 
>> hmm, dunno, what about PIC?
>> 
>> if noPIC works and PIC needs -fomit-frame-pointer then ive no objections
>> but if noPIC needs -fomit-frame-pointer then PIC as it has 1 register less
>> shouldnt work even with -fomit-frame-pointer and thats IMHO not so ideal
>
> Ok, I'm not sure I fully understand, but here's the situation put in a 
> nutshell:
> I can't get the code to compile _at all_ with -fPIC, with or without 
> -fomit-frame-pointer.
> The code compiles _without_ -fPIC _only_ if I append -fomit-frame-pointer.

Here (gcc4.1.1) -fPIC makes no difference, but it requires 
-fomit-frame-pointer either way.
Looking at the disassembly, that block does use 6 regs with "-fPIC 
-fomit-frame-pointer" and 7 regs with "-fno-PIC -fomit-frame-pointer", but 
somehow can't compile in 6 regs with "-fno-PIC -fno-omit-frame-pointer".

--Loren Merritt