On Thu, Nov 26, 2015 at 8:07 AM, Ganesh Ajjanagadde <gajja...@mit.edu> wrote: > On Thu, Nov 26, 2015 at 5:23 AM, John Warburton <j...@johnwarburton.net> > wrote: >> On Fri, Nov 13, 2015 at 4:42 PM, Ganesh Ajjanagadde >> <gajjanaga...@gmail.com> wrote: >>> >>> 4/4 is a "best effort" patch that maximizes accuracy on all platforms for >>> avcodec/faandct. It results in concrete accuracy benefits on the "default" >>> x86-64 >>> GNU/Linux platform. >>> >>> Patches tested with FATE. ppc untested. >> >> Sorry to say the libavcodec/faandct.c patch prevents compilation on a >> ppc using GCC 5.2.0. In all cases (the first of which are given >> below), the GCC "note" states: >> >> "in expansion of macro 'Bn'" >> >> ...where n is the digit following B > > Does removing the L fix it?
Read up a bit and suspect it should, and more generally long double is a can of worms on ppc with bugs on some compilers: https://gcc.gnu.org/wiki/Ieee128PowerPC, ABI in transition, https://llvm.org/bugs/show_bug.cgi?id=11933 etc etc. Well known projects have gone through pain: https://github.com/numpy/numpy/issues/2001. So basically, a good lesson for FFmpeg is not to touch long double for at least some time to come, even though ironically it is C89. I am pretty sure with appropriate configure flags something can be done, but I have negative interest in hacking around upstream for such nonsense. I will push the removal soon unless there are further comments. > >> >> libavcodec/faandct.c:39:12: error: initializer element is not constant >> #define B1 0.720959822006947913789091890943021267L // >> (cos(pi*1/16)sqrt(2))^-1 >> ... >> libavcodec/faandct.c:40:12: error: initializer element is not constant >> #define B2 0.765366864730179543456919968060797734L // >> (cos(pi*2/16)sqrt(2))^-1 >> ... >> libavcodec/faandct.c:41:12: error: initializer element is not constant >> #define B3 0.850430094767256448766702844371412325L // >> (cos(pi*3/16)sqrt(2))^-1 >> ... >> libavcodec/faandct.c:43:12: error: initializer element is not constant >> #define B5 1.272758580572833938461007018281767032L // >> (cos(pi*5/16)sqrt(2))^-1 >> ... >> libavcodec/faandct.c:44:12: error: initializer element is not constant >> #define B6 1.847759065022573512256366378793576574L // >> (cos(pi*6/16)sqrt(2))^-1 >> ... >> libavcodec/faandct.c:45:12: error: initializer element is not constant >> #define B7 3.624509785411551372409941227504289587L // >> (cos(pi*7/16)sqrt(2))^-1 >> ... >> kind regards, >> John >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
