Hi, On Tue, Feb 24, 2015 at 8:05 PM, James Almer <jamr...@gmail.com> wrote: > > +#if HAVE_FAST_POPCNT > +#if AV_GCC_VERSION_AT_LEAST(4,5) > +#ifndef av_popcount > + #define av_popcount __builtin_popcount > +#endif /* av_popcount */ > +#if HAVE_FAST_64BIT > +#ifndef av_popcount64 > + #define av_popcount64 __builtin_popcountll > +#endif /* av_popcount64 */ > +#endif /* HAVE_FAST_64BIT */ > +#endif /* AV_GCC_VERSION_AT_LEAST(4,5) */ > +#endif /* HAVE_FAST_POPCNT */ >
Is this just to get the sse4 popcnt instruction if we compile with -mcpu=sse4? The slightly odd thing is that we're using a built-in, yet configure still does an arch/cpu check. I'd expect the built-in/compiler to do that for us based on -mcpu, and we could always unconditionally use this (as long as gcc >= 4.5); alternatively, you could use inline asm and then have the configure check (HAVE_FAST_POPCNT). But doing both seems a little odd. I have no objection to it, patch is still fine, just odd. Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
