diff --git a/modules/core/src/opencl/reduce.cl b/modules/core/src/opencl/reduce.cl
index 12e73b5b72..851d36eb4d 100644
--- a/modules/core/src/opencl/reduce.cl
+++ b/modules/core/src/opencl/reduce.cl
@@ -158,10 +158,59 @@
 #define SRC2_INDEX int src2_index = mad24(id / cols, src2_step, mad24(id % cols, srcTSIZE, src2_offset))
 #endif
 
+#if kercn == 1
 #define REDUCE_GLOBAL \
     SRC2_INDEX; \
-    dstT temp = convertToDT(loadpix(srcptr + src_index)), temp2 = convertToDT(loadpix(src2ptr + src2_index)); \
+    dstTK temp = convertToDT(loadpix(srcptr + src_index)), temp2 = convertToDT(loadpix(src2ptr + src2_index)); \
     FUNC(accumulator, temp, temp2)
+#elif kercn == 2
+#define REDUCE_GLOBAL \
+    SRC2_INDEX; \
+    dstTK temp = convertToDT(loadpix(srcptr + src_index)), temp2 = convertToDT(loadpix(src2ptr + src2_index)); \
+    FUNC(accumulator, temp.s0, temp2.s0); \
+    FUNC(accumulator, temp.s1, temp2.s1)
+#elif kercn == 4
+#define REDUCE_GLOBAL \
+    SRC2_INDEX; \
+    dstTK temp = convertToDT(loadpix(srcptr + src_index)), temp2 = convertToDT(loadpix(src2ptr + src2_index)); \
+    FUNC(accumulator, temp.s0, temp2.s0); \
+    FUNC(accumulator, temp.s1, temp2.s1); \
+    FUNC(accumulator, temp.s2, temp2.s2); \
+    FUNC(accumulator, temp.s3, temp2.s3)
+#elif kercn == 8
+#define REDUCE_GLOBAL \
+    SRC2_INDEX; \
+    dstTK temp = convertToDT(loadpix(srcptr + src_index)), temp2 = convertToDT(loadpix(src2ptr + src2_index)); \
+    FUNC(accumulator, temp.s0, temp2.s0); \
+    FUNC(accumulator, temp.s1, temp2.s1); \
+    FUNC(accumulator, temp.s2, temp2.s2); \
+    FUNC(accumulator, temp.s3, temp2.s3); \
+    FUNC(accumulator, temp.s4, temp2.s4); \
+    FUNC(accumulator, temp.s5, temp2.s5); \
+    FUNC(accumulator, temp.s6, temp2.s6); \
+    FUNC(accumulator, temp.s7, temp2.s7)
+#elif kercn == 16
+#define REDUCE_GLOBAL \
+    SRC2_INDEX; \
+    dstTK temp = convertToDT(loadpix(srcptr + src_index)), temp2 = convertToDT(loadpix(src2ptr + src2_index)); \
+    FUNC(accumulator, temp.s0, temp2.s0); \
+    FUNC(accumulator, temp.s1, temp2.s1); \
+    FUNC(accumulator, temp.s2, temp2.s2); \
+    FUNC(accumulator, temp.s3, temp2.s3); \
+    FUNC(accumulator, temp.s4, temp2.s4); \
+    FUNC(accumulator, temp.s5, temp2.s5); \
+    FUNC(accumulator, temp.s6, temp2.s6); \
+    FUNC(accumulator, temp.s7, temp2.s7); \
+    FUNC(accumulator, temp.s8, temp2.s8); \
+    FUNC(accumulator, temp.s9, temp2.s9); \
+    FUNC(accumulator, temp.sA, temp2.sA); \
+    FUNC(accumulator, temp.sB, temp2.sB); \
+    FUNC(accumulator, temp.sC, temp2.sC); \
+    FUNC(accumulator, temp.sD, temp2.sD); \
+    FUNC(accumulator, temp.sE, temp2.sE); \
+    FUNC(accumulator, temp.sF, temp2.sF)
+#endif
+
 #else
 #if kercn == 1
 #define REDUCE_GLOBAL \
diff --git a/modules/core/src/umatrix.cpp b/modules/core/src/umatrix.cpp
index 11148bcded..e494f72dc5 100644
--- a/modules/core/src/umatrix.cpp
+++ b/modules/core/src/umatrix.cpp
@@ -836,7 +836,10 @@ UMat UMat::mul(InputArray m, double scale) const
 
 static bool ocl_dot( InputArray _src1, InputArray _src2, double & res )
 {
-    int type = _src1.type(), depth = CV_MAT_DEPTH(type), kercn = 1;
+    UMat src1 = _src1.getUMat().reshape(1), src2 = _src2.getUMat().reshape(1);
+
+    int type = src1.type(), depth = CV_MAT_DEPTH(type),
+            kercn = ocl::predictOptimalVectorWidth(src1, src2);
     bool doubleSupport = ocl::Device::getDefault().doubleFPConfig() > 0;
 
     if ( !doubleSupport && depth == CV_64F )
@@ -853,17 +856,18 @@ static bool ocl_dot( InputArray _src1, InputArray _src2, double & res )
 
     char cvt[40];
     ocl::Kernel k("reduce", ocl::core::reduce_oclsrc,
-                  format("-D srcT=%s -D dstT=%s -D ddepth=%d -D convertToDT=%s -D OP_DOT "
+                  format("-D srcT=%s -D srcT1=%s -D dstT=%s -D dstTK=%s -D ddepth=%d -D convertToDT=%s -D OP_DOT "
                          "-D WGS=%d -D WGS2_ALIGNED=%d%s%s%s -D kercn=%d",
-                         ocl::typeToStr(depth), ocl::typeToStr(ddepth), ddepth,
-                         ocl::convertTypeStr(depth, ddepth, 1, cvt),
+                         ocl::typeToStr(CV_MAKE_TYPE(depth, kercn)), ocl::typeToStr(depth),
+                         ocl::typeToStr(ddepth), ocl::typeToStr(CV_MAKE_TYPE(ddepth, kercn)),
+                         ddepth, ocl::convertTypeStr(depth, ddepth, kercn, cvt),
                          (int)wgs, wgs2_aligned, doubleSupport ? " -D DOUBLE_SUPPORT" : "",
                          _src1.isContinuous() ? " -D HAVE_SRC_CONT" : "",
                          _src2.isContinuous() ? " -D HAVE_SRC2_CONT" : "", kercn));
     if (k.empty())
         return false;
 
-    UMat src1 = _src1.getUMat().reshape(1), src2 = _src2.getUMat().reshape(1), db(1, dbsize, ddepth);
+    UMat db(1, dbsize, ddepth);
 
     ocl::KernelArg src1arg = ocl::KernelArg::ReadOnlyNoSize(src1),
             src2arg = ocl::KernelArg::ReadOnlyNoSize(src2),