On Sat, May 12, 2012 at 11:15:59AM +0100, Måns Rullgård wrote: > Diego Biurrun <[email protected]> writes: > > > On Sat, May 12, 2012 at 08:59:00AM +0200, Vitor Sessak wrote: > >> --- > >> libavcodec/x86/fft.c | 45 +++++++++++++++++++++++---------------------- > >> 1 files changed, 23 insertions(+), 22 deletions(-) > > > > funcTIons > > > > This may be a naive question because I'm far from deeply familiar with > > the x86 code, but I don't understand why you make change you propose > > in this patch. > > Probably because I asked for it. Using if/else if chains, some > assignments have to be duplicated. In this particular case, the avx > part assigns sse versions of the imdct_calc and fft_permute functions > since those do not have sse2 or avx versions. > > Now suppose someone adds sse2 optimisations for all the functions. With > the current style, this would require updating the assignments in the > avx section in order for such machines to get the best implementation. > With the patch, higher-ranked extensions simply inherit whatever they do > not set explicitly from the next lower version, and things added at the > sse2 level would be automatically used by avx without the need to update > anything. This is how we do function selection in most other places.
Makes sense, patch queued, will push out with the next bunch. Diego _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
