replaced custom PI by OpenCL M_PI constant

modules/ocl/src/opencl/arithm_phase.cl

@@ -45,16 +45,16 @@
 //
 
 #if defined (DOUBLE_SUPPORT)
-    #ifdef cl_khr_fp64
-        #pragma OPENCL EXTENSION cl_khr_fp64:enable
-    #elif defined (cl_amd_fp64)
+    #ifdef cl_amd_fp64
         #pragma OPENCL EXTENSION cl_amd_fp64:enable
+    #elif defined (cl_khr_fp64)
+        #pragma OPENCL EXTENSION cl_khr_fp64:enable
     #endif
-    #define CV_PI 3.1415926535897932384626433832795
-    #define CV_2PI 2*CV_PI
+    #define CV_PI M_PI
+    #define CV_2PI (2 * CV_PI)
 #else
-    #define CV_PI 3.1415926535897932384626433832795f
-    #define CV_2PI 2*CV_PI
+    #define CV_PI M_PI_F
+    #define CV_2PI (2 * CV_PI)
 #endif
 
 /**************************************phase inradians**************************************/

modules/ocl/src/opencl/arithm_polarToCart.cl

@@ -44,10 +44,14 @@
 //M*/
 
 #ifdef DOUBLE_SUPPORT
+    #ifdef cl_amd_fp64
+        #pragma OPENCL EXTENSION cl_amd_fp64:enable
+    #elif defined (cl_khr_fp64)
         #pragma OPENCL EXTENSION cl_khr_fp64:enable
-    #define CV_PI   3.1415926535897932384626433832795
+    #endif
+    #define CV_PI M_PI
 #else
-    #define CV_PI   3.1415926535897932384626433832795f
+    #define CV_PI M_PI_F
 #endif
 
 /////////////////////////////////////////////////////////////////////////////////////////////////////