Merge pull request #2836 from s98felix:2.4

modules/core/include/opencv2/core/core.hpp

@@ -284,6 +284,7 @@ CV_EXPORTS_W int64 getCPUTickCount();
   - CV_CPU_SSE4_2 - SSE 4.2
   - CV_CPU_POPCNT - POPCOUNT
   - CV_CPU_AVX - AVX
+  - CV_CPU_AVX2 - AVX2
 
   \note {Note that the function output is not static. Once you called cv::useOptimized(false),
   most of the hardware acceleration is disabled and thus the function will returns false,

modules/core/include/opencv2/core/core_c.h

@@ -1706,6 +1706,7 @@ CVAPI(double) cvGetTickFrequency( void );
 #define CV_CPU_SSE4_2  7
 #define CV_CPU_POPCNT  8
 #define CV_CPU_AVX    10
+#define CV_CPU_AVX2   11
 #define CV_HARDWARE_MAX_FEATURE 255
 
 CVAPI(int) cvCheckHardwareSupport(int feature);

modules/core/include/opencv2/core/internal.hpp

@@ -141,6 +141,10 @@ CV_INLINE IppiSize ippiSize(const cv::Size & _size)
 #      define __xgetbv() 0
 #    endif
 #  endif
+#  if defined __AVX2__
+#    include <immintrin.h>
+#    define CV_AVX2 1
+#  endif
 #endif
 
 
@@ -176,6 +180,9 @@ CV_INLINE IppiSize ippiSize(const cv::Size & _size)
 #ifndef CV_AVX
 #  define CV_AVX 0
 #endif
+#ifndef CV_AVX2
+#  define CV_AVX2 0
+#endif
 #ifndef CV_NEON
 #  define CV_NEON 0
 #endif