#define AV_CPU_FLAG_SSE4 0x0100 ///< Penryn SSE4.1 functions
#define AV_CPU_FLAG_SSE42 0x0200 ///< Nehalem SSE4.2 functions
#define AV_CPU_FLAG_AVX 0x4000 ///< AVX functions: requires OS support even if YMM registers aren't used
+#define AV_CPU_FLAG_AVXSLOW 0x8000000 ///< AVX supported, but slow when using YMM registers (e.g. Bulldozer)
#define AV_CPU_FLAG_XOP 0x0400 ///< Bulldozer XOP functions
#define AV_CPU_FLAG_FMA4 0x0800 ///< Bulldozer FMA4 functions
// #if LIBAVUTIL_VERSION_MAJOR <52