clean up the code

* disable the warning in CMake, not int the code using pragma

cmake/OpenCVCompilerOptions.cmake

@@ -309,9 +309,6 @@ if(MSVC)
     if(MSVC_VERSION EQUAL 1400)
       ocv_warnings_disable(CMAKE_CXX_FLAGS /wd4510 /wd4610 /wd4312 /wd4201 /wd4244 /wd4328 /wd4267)
     endif()
-    if(MSVC_VERSION LESS 1900) # MSVS2015
-      ocv_warnings_disable(CMAKE_CXX_FLAGS /wd4127) # warning C4127: conditional expression is constant
-    endif()
   endif()
 
   # allow extern "C" functions throw exceptions
@@ -323,6 +320,7 @@ if(MSVC)
   endforeach()
 
   if(NOT ENABLE_NOISY_WARNINGS)
+    ocv_warnings_disable(CMAKE_CXX_FLAGS /wd4127) # conditional expression is constant
     ocv_warnings_disable(CMAKE_CXX_FLAGS /wd4251) # class 'std::XXX' needs to have dll-interface to be used by clients of YYY
     ocv_warnings_disable(CMAKE_CXX_FLAGS /wd4324) # 'struct_name' : structure was padded due to __declspec(align())
     ocv_warnings_disable(CMAKE_CXX_FLAGS /wd4275) # non dll-interface class 'std::exception' used as base for dll-interface class 'cv::Exception'

modules/cudalegacy/test/NCVTest.hpp

@@ -44,7 +44,7 @@
 #define _ncvtest_hpp_
 
 #if defined _MSC_VER
-# pragma warning( disable : 4201 4408 4127 4100)
+# pragma warning( disable : 4201 4408 4100)
 #endif
 
 #include <string>

modules/features2d/src/agast.cpp

@@ -45,10 +45,6 @@ The references are:
 #include "precomp.hpp"
 #include "agast_score.hpp"
 
-#ifdef _MSC_VER
-#pragma warning( disable : 4127 )
-#endif
-
 namespace cv
 {
 

modules/features2d/src/agast_score.cpp

@@ -44,10 +44,6 @@ The references are:
 
 #include "agast_score.hpp"
 
-#ifdef _MSC_VER
-#pragma warning( disable : 4127 )
-#endif
-
 namespace cv
 {
 

modules/features2d/src/fast.cpp

@@ -48,9 +48,6 @@ The references are:
 #include "opencv2/core/hal/intrin.hpp"
 
 #include "opencv2/core/openvx/ovx_defs.hpp"
-#if defined _MSC_VER
-# pragma warning( disable : 4127)
-#endif
 
 namespace cv
 {

modules/imgcodecs/src/grfmt_jpeg.cpp

@@ -78,18 +78,11 @@ extern "C" {
 namespace cv
 {
 
-#ifdef _MSC_VER
-# pragma warning(push)
-# pragma warning(disable:4324) //structure was padded due to __declspec(align())
-#endif
 struct JpegErrorMgr
 {
     struct jpeg_error_mgr pub;
     jmp_buf setjmp_buffer;
 };
-#ifdef _MSC_VER
-# pragma warning(pop)
-#endif
 
 struct JpegSource
 {

modules/imgproc/src/canny.cpp

@@ -47,10 +47,6 @@
 
 #include "opencv2/core/openvx/ovx_defs.hpp"
 
-#ifdef _MSC_VER
-#pragma warning( disable: 4127 ) // conditional expression is constant
-#endif
-
 #if CV_SIMD128
 #define CV_MALLOC_SIMD128 16
 #endif

modules/ts/include/opencv2/ts.hpp

@@ -34,7 +34,6 @@
 #endif
 
 #ifdef _MSC_VER
-#pragma warning( disable: 4127 ) // conditional expression is constant
 #pragma warning( disable: 4503 ) // decorated name length exceeded, name was truncated
 #endif
 

modules/ts/include/opencv2/ts/ts_gtest.h

@@ -7976,20 +7976,11 @@ GTEST_API_ std::string AppendUserMessage(
 // std::runtime_error inherits from std::exception, many testing
 // frameworks know how to extract and print the message inside it.
 
-#ifdef _MSC_VER
-# pragma warning(push)          // Saves the current warning state.
-# pragma warning(disable:4275)  // Temporarily disables warning 4275.
-#endif  // _MSC_VER
-
 class GTEST_API_ GoogleTestFailureException : public ::std::runtime_error {
  public:
   explicit GoogleTestFailureException(const TestPartResult& failure);
 };
 
-#ifdef _MSC_VER
-# pragma warning(pop)           // Restores the warning state.
-#endif  // _MSC_VER
-
 #endif  // GTEST_HAS_EXCEPTIONS
 
 // A helper class for creating scoped traces in user programs.

modules/videoio/src/cap_ffmpeg_impl.hpp

@@ -51,7 +51,7 @@
 #define CALC_FFMPEG_VERSION(a,b,c) ( a<<16 | b<<8 | c )
 
 #if defined _MSC_VER && _MSC_VER >= 1200
-#pragma warning( disable: 4244 4510 4512 4610 )
+#pragma warning( disable: 4244 4510 4610 )
 #endif
 
 #ifdef __GNUC__
@@ -83,7 +83,7 @@ extern "C" {
 #endif
 
 #if defined _MSC_VER && _MSC_VER >= 1200
-#pragma warning( default: 4244 4510 4512 4610 )
+#pragma warning( default: 4244 4510 4610 )
 #endif
 
 #ifdef NDEBUG

modules/videoio/src/cap_msmf.hpp

@@ -2084,11 +2084,6 @@ public:
 // succeed but return a nullptr pointer. By default, the list does not allow nullptr
 // pointers.
 
-#ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable: 4127) // constant expression
-#endif
-
 template <class T, bool NULLABLE = FALSE>
 class ComPtrList : public List<T*>
 {
@@ -2179,10 +2174,6 @@ protected:
     }
 };
 
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif
-
 /* Be sure to declare webcam device capability in manifest
   For better media capture support, add the following snippet with correct module name to the project manifest
     (videoio needs DLL activation class factoryentry points):