[FFmpeg-devel] [PATCH] add cflags filtering rules for suncc

Måns Rullgård mans
Sun Nov 1 13:10:49 CET 2009

Michael Kostylev <michael.kostylev at gmail.com> writes:

> On Sat Oct 31 20:11:16 2009
> M?ns Rullg?rd wrote:
>>>>>>> The -Os mapping may be ajusted/safely removed, -O2 is set just because 
>>>>>>> the -O[3-5] options are currently unusable on x86.
>>>>>> Are you sure you attached the patch you're talking about there?  I see
>>>>>> nothing about 3-5.
>>>>> Theoretically, `-O[3-5] -xspace' should work too, -xspace is an additional
>>>>> flag, it is used to disable optimizations which increase code size.
>>>>> Maybe `-O5 -xspace' works ok on sparc, I don't know.
>>>> The bugs should be tracked down and fixed or worked around.  Disabling
>>>> optimisations is a bad idea (except for the gcc vectoriser, which will
>>>> never be of any use).
>>> I thought that O2 is better than nothing and slightly better than O1.
>>> Currently, non-working O3 requires some hackery with the options like 
>>> --disable-optimizations --extra-cflags='-O2 -xregs=frameptr' or
>>> --enable-small --disable-optimizations --extra-cflags='-O2 -xspace -xregs=frameptr'
>> But _why_ does -O[1-5] not work?  We should make sure the bug isn't in
>> our code.
> To be more precisely, compiling postprocess.c is a showstopper (yes, even 
> motion_est is not an issue) on both x86 configurations. Iropt looks to be
> deadlocked and can be stopped only with kill -9.
> Building h264.c on amd64 with -O[3-5] raises
> "h264.c", [decode_mb_cavlc]:ube: error: SIGNAL: Segmentation Fault
> or a bunch of "syntax errors" reported by assembler (no optimization, -O[12]).

Both of those are obviously compiler bugs, whether or not the code is
kosher.  Have you reported them to Sun?

M?ns Rullg?rd
mans at mansr.com

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