diff --git a/modules/cudaarithm/src/core.cpp b/modules/cudaarithm/src/core.cpp
index aefcfc5af27..368c2fcc419 100644
--- a/modules/cudaarithm/src/core.cpp
+++ b/modules/cudaarithm/src/core.cpp
@@ -163,10 +163,12 @@ void cv::cuda::flip(InputArray _src, OutputArray _dst, int flipCode, Stream& str
 
     _dst.create(src.size(), src.type());
     GpuMat dst = getOutputMat(_dst, src.size(), src.type(), stream);
-    if (src.data == dst.data && ((src.cols & 1) == 1 || (src.rows & 1) == 1))
+    bool isInplace = (src.data == dst.data) || (src.refcount == dst.refcount);
+    bool isSizeOdd = (src.cols & 1) == 1 || (src.rows & 1) == 1;
+    if (isInplace && isSizeOdd)
         CV_Error(Error::BadROISize, "In-place version of flip only accepts even width/height");
 
-    if (src.data != dst.data)
+    if (isInplace == false)
         funcs[src.depth()][src.channels() - 1](src, dst, flipCode, StreamAccessor::getStream(stream));
     else // in-place
         ifuncs[src.depth()][src.channels() - 1](src, flipCode, StreamAccessor::getStream(stream));
diff --git a/modules/cudaarithm/test/test_core.cpp b/modules/cudaarithm/test/test_core.cpp
index 04b144ff37b..728ee12b164 100644
--- a/modules/cudaarithm/test/test_core.cpp
+++ b/modules/cudaarithm/test/test_core.cpp
@@ -281,11 +281,14 @@ CUDA_TEST_P(Flip, Accuracy)
 
 CUDA_TEST_P(Flip, AccuracyInplace)
 {
-    size.width  = (size.width  >> 1) << 1; // in-place version only accepts even number
-    size.height = (size.height >> 1) << 1; // in-place version only accepts even number
     cv::Mat src = randomMat(size, type);
-
+    bool isSizeOdd = ((size.width & 1) == 1) || ((size.height & 1) == 1);
     cv::cuda::GpuMat srcDst = loadMat(src, useRoi);
+    if(isSizeOdd)
+    {
+        EXPECT_THROW(cv::cuda::flip(srcDst, srcDst, flip_code), cv::Exception);
+        return;
+    }
     cv::cuda::flip(srcDst, srcDst, flip_code);
 
     cv::Mat dst_gold;
diff --git a/modules/xfeatures2d/src/stardetector.cpp b/modules/xfeatures2d/src/stardetector.cpp
index b15ccc3ce5f..bcd4cccb618 100644
--- a/modules/xfeatures2d/src/stardetector.cpp
+++ b/modules/xfeatures2d/src/stardetector.cpp
@@ -227,7 +227,12 @@ StarDetectorComputeResponses( const Mat& img, Mat& responses, Mat& sizes,
     for(int i = 0; i < npatterns; i++ )
     {
         int innerArea = f[pairs[i][1]].area;
+#if 0  // workaround MSVS2019 bug: error C2109: subscript requires array or pointer type
         int outerArea = f[pairs[i][0]].area - innerArea;
+#else
+        int outerArea = f[pairs[i][0]].area;
+        outerArea -= innerArea;
+#endif
         invSizes[i][0] = 1.f/outerArea;
         invSizes[i][1] = 1.f/innerArea;
     }
@@ -283,7 +288,7 @@ StarDetectorComputeResponses( const Mat& img, Mat& responses, Mat& sizes,
 
                 for(int i = 0; i <= maxIdx; i++ )
                 {
-                    const iiMatType** p = (const iiMatType**)&f[i].p[0];
+                    const iiMatType** p = (const iiMatType**)f[i].p;
                     __m128i r0 = _mm_sub_epi32(_mm_loadu_si128((const __m128i*)(p[0]+ofs)),
                                                _mm_loadu_si128((const __m128i*)(p[1]+ofs)));
                     __m128i r1 = _mm_sub_epi32(_mm_loadu_si128((const __m128i*)(p[3]+ofs)),
@@ -325,7 +330,7 @@ StarDetectorComputeResponses( const Mat& img, Mat& responses, Mat& sizes,
 
             for(int i = 0; i <= maxIdx; i++ )
             {
-                const iiMatType** p = (const iiMatType**)&f[i].p[0];
+                const iiMatType** p = (const iiMatType**)f[i].p;
                 vals[i] = (int)(p[0][ofs] - p[1][ofs] - p[2][ofs] + p[3][ofs] +
                     p[4][ofs] - p[5][ofs] - p[6][ofs] + p[7][ofs]);
             }