added v_reduce_sum4() universal intrinsic; corrected number of threads in cv::getNumThreads() in the case of GCD

* everything is put into softfloat.cpp and softfloat.hpp

* WIP: try to integrate softfloat into OpenCV

* extra functions removed

* softfloat made stateless

* CV_EXPORTS added

* operators fixed

* exp added, log: WIP

* log32 fixed

* shorter names; a lot of TODOs

* log64 rewritten

* cbrt32 added

* minors, refactoring

* "inline" -> "CV_INLINE"

* cast to bool warnings fixed

* several warnings fixed

* fixed warning about unsigned unary minus

* fixed warnings on type cast

* inline -> CV_INLINE

* special cases processing added (NaNs, Infs, etc.)

* constants for NaN and Inf added

* more macros and helper functions added

* added (or fixed) tests for pow32, pow64, cbrt32

* exp-like functions fixed

* minor changes

* fixed random number generation for tests

* tests for exp32 and exp64: values are compared to SoftFloat-based naive implementation

* minor warning fix

* pow(f, i) 32/64: special cases handling added

* unused functions removed

* refactoring is in progress (not compiling)

* CV_inline added

* unions {uint_t, float_t} removed

* tests compilation fixed

* static const members -> static methods returning const

* reinterpret_cast

* warning fixed

* const-ness fixed

* all FP calculations (even compile-time) are done in SoftFloat + minor fixes

* pow(f, i) removed from interface (can cause incorrect cast) to internals of pow(f, f), tests fixed

* CV_INLINE -> inline

* internal constants moved to .cpp file

* toInt_minMag() methods merged into toInt() methods

* macros moved to .cpp file

* refactoring: types renamed to softfloat and softdouble; explicit constructors, etc.

* toFloat(), toDouble() -> operator float(), operator double()

* removed f32/f64 prefixes from functions names

* toType() methods removed, round() and trunc() functions added

* minor change

* minors

* MSVC: warnings fixed

* added int cvRound(), cvFloor, cvCeil, cvTrunc, saturate_cast<T>()

* typo fixed

* type cast fixed

Improve solvePnP doc, add assert >= 4 in solvePnP, escape underscore character for Scalar_ documentation.

Add reference to SOLVEPNP_ITERATIVE in the doc.

Parallelize Canny with custom gradient (#8694)

* New Canny implementation. Restructuring code in parallelCanny class. Align mag buffer and map.

* Fix warnings.

* Missing SIMD check added.

* Replaced local trailingZeros in contours.cpp. Use alignSize in canny.cpp

* Fix warnings in alignSize and allocate just minimum extra columns.

* Fix another warning in map.create.

* Exchange for loop by do loop to avoid double check at the beginning.
Define extra SIMD CANNY_CHECK to avoid unnecessary continue.

* Correct the existing documented T-API functions to match the doxygen format.

* docs: fix comments style

* T-API documentation: minor formatting changes

This updates the public headers to use _Nm instead of _N in templates
since _N is defined by the widely used ctype.h.

Updated integrations for:
cv::split
cv::merge
cv::insertChannel
cv::extractChannel
cv::Mat::convertTo - now with scaled conversions support
cv::LUT - disabled due to performance issues
Mat::copyTo
Mat::setTo
cv::flip
cv::copyMakeBorder - currently disabled
cv::polarToCart
cv::pow - ipp pow function was removed due to performance issues
cv::hal::magnitude32f/64f - disabled for <= SSE42, poor performance
cv::countNonZero
cv::minMaxIdx
cv::norm
cv::canny - new integration. Disabled for threaded;
cv::cornerHarris
cv::boxFilter
cv::bilateralFilter
cv::integral

Add support for std::array<T, N> (#8535)

* Add support for std::array<T, N>

* Add std::array<Mat, N> support

* Remove UMat constructor with std::array parameter

Gemm kernels for Intel GPU (#8104)

* Fix an issue with Kernel object reset release when consecutive Kernel::run calls

Kernel::run launch OCL gpu kernels and set a event callback function
to decreate the ref count of UMat or remove UMat when the lauched workloads
are completed. However, for some OCL kernels requires multiple call of
Kernel::run function with some kernel parameter changes (e.g., input
and output buffer offset) to get the final computation result.
In the case, the current implementation requires unnecessary
synchronization and cleanupMat.

This fix requires the user to specify whether there will be more work or not.
If there is no remaining computation, the Kernel::run will reset the
kernel object
Signed-off-by: Woo, Insoo <insoo.woo@intel.com>

* GEMM kernel optimization for Intel GEN

The optimized kernels uses cl_intel_subgroups extension for better
performance.

Note: This optimized kernels will be part of ISAAC in a code generation
way under MIT license.
Signed-off-by: Woo, Insoo <insoo.woo@intel.com>

* Fix API compatibility error

This patch fixes a OCV API compatibility error. The error was reported
due to the interface changes of Kernel::run. To resolve the issue,
An overloaded function of Kernel::run is added. It take a flag indicating
whether there are more work to be done with the kernel object without
releasing resources related to it.
Signed-off-by: Woo, Insoo <insoo.woo@intel.com>

* Renaming intel_gpu_gemm.cpp to intel_gpu_gemm.inl.hpp
Signed-off-by: Woo, Insoo <insoo.woo@intel.com>

* Revert "Fix API compatibility error"

This reverts commit 2ef427db91b6c4aec170f691c5d2e6c47d6520d7.

Conflicts:
	modules/core/src/intel_gpu_gemm.inl.hpp

* Revert "Fix an issue with Kernel object reset release when consecutive Kernel::run calls"

This reverts commit cc7f9f54695dc293598addce9b9d7e345225bede.

* Fix the case of uninitialization D

When C is null and beta is non-zero, D is used without initialization.
This resloves the issue
Signed-off-by: Woo, Insoo <insoo.woo@intel.com>

* fix potential output error due to 0 * nan
Signed-off-by: Woo, Insoo <insoo.woo@intel.com>

* whitespace fix, eliminate non-ASCII symbols

* fix build warning

Tuned restrictions for Canny, Warp, FAST, Accumulate and Convolution OpenVX HAL calls on small images

Adding missing header for ostream decl. in line 384

Inform users that getCudaEnabledDeviceCount can return -1 in some cases.

Same as https://github.com/opencv/opencv/pull/8525/commits/9210cefb36868e201f7e0c8b84e4ee4f91b5432b but for this file too.

This issue concerns only matrices with more dimensions than columns.
See https://github.com/opencv/opencv/issues/8447

- use suffixes like '.avx.cpp'
- added CMake-generated files for '.simd.hpp' optimization approach
- wrap HAL intrinsic headers into separate namespaces for different build flags
- automatic vzeroupper insertion (via CV_INSTRUMENT_REGION macro)