diff --git a/cmake/OpenCVDetectCUDA.cmake b/cmake/OpenCVDetectCUDA.cmake
index 2d5c8bbbad..d7d085b607 100644
--- a/cmake/OpenCVDetectCUDA.cmake
+++ b/cmake/OpenCVDetectCUDA.cmake
@@ -200,6 +200,9 @@ if(CUDA_FOUND)
       string(REPLACE "-frtti" "" ${var} "${${var}}")
 
       string(REPLACE "-fvisibility-inlines-hidden" "" ${var} "${${var}}")
+
+      # cc1: warning: command line option '-Wsuggest-override' is valid for C++/ObjC++ but not for C
+      string(REPLACE "-Wsuggest-override" "" ${var} "${${var}}")
     endforeach()
   endmacro()
 
diff --git a/modules/core/src/cuda_gpu_mat.cpp b/modules/core/src/cuda_gpu_mat.cpp
index 8215dd0694..9514ec2037 100644
--- a/modules/core/src/cuda_gpu_mat.cpp
+++ b/modules/core/src/cuda_gpu_mat.cpp
@@ -344,13 +344,12 @@ void cv::cuda::ensureSizeIsEnough(int rows, int cols, int type, OutputArray arr)
 
 GpuMat cv::cuda::getInputMat(InputArray _src, Stream& stream)
 {
-    GpuMat src;
-
 #ifndef HAVE_CUDA
     (void) _src;
     (void) stream;
     throw_no_cuda();
 #else
+    GpuMat src;
     if (_src.kind() == _InputArray::CUDA_GPU_MAT)
     {
         src = _src.getGpuMat();
@@ -361,15 +360,12 @@ GpuMat cv::cuda::getInputMat(InputArray _src, Stream& stream)
         src = pool.getBuffer(_src.size(), _src.type());
         src.upload(_src, stream);
     }
-#endif
-
     return src;
+#endif
 }
 
 GpuMat cv::cuda::getOutputMat(OutputArray _dst, int rows, int cols, int type, Stream& stream)
 {
-    GpuMat dst;
-
 #ifndef HAVE_CUDA
     (void) _dst;
     (void) rows;
@@ -378,6 +374,7 @@ GpuMat cv::cuda::getOutputMat(OutputArray _dst, int rows, int cols, int type, St
     (void) stream;
     throw_no_cuda();
 #else
+    GpuMat dst;
     if (_dst.kind() == _InputArray::CUDA_GPU_MAT)
     {
         _dst.create(rows, cols, type);
@@ -388,9 +385,8 @@ GpuMat cv::cuda::getOutputMat(OutputArray _dst, int rows, int cols, int type, St
         BufferPool pool(stream);
         dst = pool.getBuffer(rows, cols, type);
     }
-#endif
-
     return dst;
+#endif
 }
 
 void cv::cuda::syncOutput(const GpuMat& dst, OutputArray _dst, Stream& stream)
diff --git a/modules/videoio/src/cap_openni2.cpp b/modules/videoio/src/cap_openni2.cpp
index ce380559d0..b4a7808363 100644
--- a/modules/videoio/src/cap_openni2.cpp
+++ b/modules/videoio/src/cap_openni2.cpp
@@ -490,6 +490,7 @@ double CvCapture_OpenNI2::getCommonProperty( int propIdx ) const
         break;
     case CV_CAP_PROP_OPENNI2_SYNC :
         propValue = const_cast<CvCapture_OpenNI2 *>(this)->device.getDepthColorSyncEnabled();
+        break;
     case CV_CAP_PROP_OPENNI2_MIRROR:
     {
         bool isMirroring = false;