diff --git a/modules/gpu/include/opencv2/gpu/gpu.hpp b/modules/gpu/include/opencv2/gpu/gpu.hpp
index 39836ec012..c5d1df3a36 100644
--- a/modules/gpu/include/opencv2/gpu/gpu.hpp
+++ b/modules/gpu/include/opencv2/gpu/gpu.hpp
@@ -640,7 +640,8 @@ namespace cv
         //! performs a forward or inverse discrete Fourier transform (1D or 2D) of floating point matrix
         //!
         //! If the source matrix is not continous, then additional copy will be done,
-        //! so to avoid copying ensure the source matrix is continous one.
+        //! so to avoid copying ensure the source matrix is continous one. If you want to use
+        //! preallocated output ensure it is continuous too, otherwise it will be reallocated.
         //!
         //! Being implemented via CUFFT real-to-complex transform result contains only non-redundant values
         //! in CUFFT's format. Result as full complex matrix for such kind of transform cannot be retrieved.
diff --git a/tests/gpu/src/dft_routines.cpp b/tests/gpu/src/dft_routines.cpp
index 0bda401c95..bdfea44c19 100644
--- a/tests/gpu/src/dft_routines.cpp
+++ b/tests/gpu/src/dft_routines.cpp
@@ -226,8 +226,9 @@ struct CV_GpuDftTest: CvTest
             srand(0);
             int cols = 2 + rand() % 100, rows = 2 + rand() % 100;
 
-            for (int inplace = 0; inplace < 2; ++inplace)
+            for (int i = 0; i < 2; ++i)
             {
+                bool inplace = i != 0;
                 testC2C("no flags", cols, rows, 0, inplace);
                 testC2C("no flags 0 1", cols, rows + 1, 0, inplace);
                 testC2C("no flags 1 0", cols, rows + 1, 0, inplace);
diff --git a/tests/gpu/src/meanshift.cpp b/tests/gpu/src/meanshift.cpp
index 1c32550b68..b655da6109 100644
--- a/tests/gpu/src/meanshift.cpp
+++ b/tests/gpu/src/meanshift.cpp
@@ -124,8 +124,8 @@ struct CV_GpuMeanShiftTest : public CvTest
 
 };
 
-/////////////////////////////////////////////////////////////////////////////
-/////////////////// tests registration  /////////////////////////////////////
+/////////////////////////////////////////////////////////////////////////////
+/////////////////// tests registration  /////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////
 
 CV_GpuMeanShiftTest CV_GpuMeanShift_test;