build: eliminate uninitialized warnings from GCC12

modules/core/include/opencv2/core/hal/intrin.hpp

@@ -50,6 +50,12 @@
 #include <stdlib.h>
 #include "opencv2/core/cvdef.h"
 
+#if defined(__GNUC__) && __GNUC__ == 12
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wuninitialized"
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
+
 #define OPENCV_HAL_ADD(a, b) ((a) + (b))
 #define OPENCV_HAL_AND(a, b) ((a) & (b))
 #define OPENCV_HAL_NOP(a) (a)
@@ -695,4 +701,8 @@ CV_CPU_OPTIMIZATION_HAL_NAMESPACE_END
 
 //! @endcond
 
+#if defined(__GNUC__) && __GNUC__ == 12
+#pragma GCC diagnostic pop
+#endif
+
 #endif

modules/imgproc/src/sumpixels.avx512_skx.hpp

@@ -6,6 +6,12 @@
 
 #include "opencv2/core/hal/intrin.hpp"
 
+#if defined(__GNUC__) && __GNUC__ == 12
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wuninitialized"
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
+
 namespace cv { namespace hal {
 CV_CPU_OPTIMIZATION_NAMESPACE_BEGIN
 
@@ -465,3 +471,7 @@ void calculate_integral_avx512(const uchar *src,   size_t _srcstep,
 
 CV_CPU_OPTIMIZATION_NAMESPACE_END
 }} // end namespace cv::hal
+
+#if defined(__GNUC__) && __GNUC__ == 12
+#pragma GCC diagnostic pop
+#endif