Ganesh Ajjanagadde <gajjanag <at> mit.edu> writes: > It is well known that fabs and fabsf are at least as fast and usually > faster than the FFABS macro, at least on the gcc+glibc combination.
I wasn't aware of this. And I believe we support other compilers and other libc implementations. > For instance, see the reference: > http://patchwork.sourceware.org/patch/6735/. > This was a patch to glibc in order to remove their usages. Given their > general performance obsession (more than FFmpeg in many cases), they > have ensured that fabs and fabsf never peform worse than FFABS. Ok but is this really related? > I have tested on x86-64 Haswell with GCC 5.2 - even with no strict IEEE > mode enabled, and just the standard -O3 optimizations, there is a > performance benefit. This is the only relevant information imo. Please provide (very, very short) information on what you tested. Since you mention libc so often: Does the patch work on win*, aix and other strange platforms? Carl Eugen _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
