cmake: reuse OpenCV NEON detection in carotene

- use carotene if NEON available only

3rdparty/carotene/hal/CMakeLists.txt

@@ -58,22 +58,6 @@ function(compile_carotene)
   endif()
 
   add_subdirectory("${CAROTENE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/carotene")
-
-  if(ARM OR AARCH64)
-    if(CMAKE_BUILD_TYPE)
-      set(CMAKE_TRY_COMPILE_CONFIGURATION ${CMAKE_BUILD_TYPE})
-    endif()
-    check_cxx_compiler_flag("-mfpu=neon" CXX_HAS_MFPU_NEON)
-    check_c_compiler_flag("-mfpu=neon" C_HAS_MFPU_NEON)
-    if(${CXX_HAS_MFPU_NEON} AND ${C_HAS_MFPU_NEON} AND NOT "${CMAKE_CXX_FLAGS} " MATCHES "-mfpu=neon[^ ]*")
-      get_target_property(old_flags "carotene_objs" COMPILE_FLAGS)
-      if(old_flags)
-        set_target_properties("carotene_objs" PROPERTIES COMPILE_FLAGS "${old_flags} -mfpu=neon")
-      else()
-        set_target_properties("carotene_objs" PROPERTIES COMPILE_FLAGS "-mfpu=neon")
-      endif()
-    endif()
-  endif()
 endfunction()
 
 compile_carotene()

CMakeLists.txt

@@ -797,9 +797,13 @@ endif()
 
 foreach(hal ${OpenCV_HAL})
   if(hal STREQUAL "carotene")
-    add_subdirectory(3rdparty/carotene/hal)
-    ocv_hal_register(CAROTENE_HAL_LIBRARIES CAROTENE_HAL_HEADERS CAROTENE_HAL_INCLUDE_DIRS)
-    list(APPEND OpenCV_USED_HAL "carotene (ver ${CAROTENE_HAL_VERSION})")
+    if(";${CPU_BASELINE_FINAL};" MATCHES ";NEON;")
+      add_subdirectory(3rdparty/carotene/hal)
+      ocv_hal_register(CAROTENE_HAL_LIBRARIES CAROTENE_HAL_HEADERS CAROTENE_HAL_INCLUDE_DIRS)
+      list(APPEND OpenCV_USED_HAL "carotene (ver ${CAROTENE_HAL_VERSION})")
+    else()
+      message(STATUS "Carotene: NEON is not available, disabling carotene...")
+    endif()
   elseif(hal STREQUAL "openvx")
     add_subdirectory(3rdparty/openvx)
     ocv_hal_register(OPENVX_HAL_LIBRARIES OPENVX_HAL_HEADERS OPENVX_HAL_INCLUDE_DIRS)