avfilter,swresample,swscale: use fabs, fabsf instead of FFABS
authorGanesh Ajjanagadde <gajjanagadde@gmail.com>
Mon, 12 Oct 2015 05:30:22 +0000 (01:30 -0400)
committerGanesh Ajjanagadde <gajjanagadde@gmail.com>
Thu, 22 Oct 2015 20:13:26 +0000 (16:13 -0400)
commit8507b98c10d948653375400e2b0a3d4389f74be4
tree2b17e0bd420990847602cc352c87328abace3483
parentdde8e5ad02ad60b149d9a532e67587f45f3aecc5
avfilter,swresample,swscale: use fabs, fabsf instead of FFABS

It is well known that fabs and fabsf are at least as fast and sometimes
faster than the FFABS macro, at least on the gcc+glibc combination.
For instance, see the reference:
http://patchwork.sourceware.org/patch/6735/.
This was a patch to glibc in order to remove their usages of a macro.

The reason essentially boils down to fabs using the __builtin_fabs of
the compiler, while FFABS needs to infer to not use a branch and to
simply change the sign bit. Usually the inference works, but sometimes
it does not. This may be easily checked by looking at the asm.

This also has the added benefit of reducing macro usage, which has
problems with side-effects.

Note that avcodec is not handled here, as it is huge and
most things there are integer arithmetic anyway.

Tested with FATE.

Reviewed-by: Clément Bœsch <u@pkh.me>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
libavfilter/af_stereotools.c
libavfilter/avf_avectorscope.c
libavfilter/avf_showcqt.c
libavfilter/avf_showfreqs.c
libavfilter/f_ebur128.c
libavfilter/vf_blend.c
libavfilter/vf_dctdnoiz.c
libavfilter/vf_framerate.c
libavfilter/vf_hqdn3d.c
libavformat/mux.c
libswresample/swresample-test.c