[pratham-mcw]

This PR enables use of the __popcnt intrinsic for ARM/ARM64 targets when building with MSVC. Previously, these targets(ARM/ARM64) were explicitly excluded using macro guards.

When building OpenCV on Windows on ARM64 with MSVC (cl.exe), the BackgroundSubtractor_LSBP.Accuracy test fails because the code falls into the else block using different bit counting method, which leads to incorrect results and causes the test to fail.

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• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

[asmorkalov]

I do not see __popcnt support for ARM in the Microsoft documentation: https://learn.microsoft.com/en-us/cpp/intrinsics/popcnt16-popcnt-popcnt64?view=msvc-170. It describes x86 specific.

[Kumataro]

Hello, at Microsoft blog, Visual Studio 2022 v17.11 and later seems to support __popcnt family instructions for ARM64 platform (not ARM32).

See https://devblogs.microsoft.com/cppblog/msvc-backend-updates-in-visual-studio-2022-version-17-11/

Support popcnt instructions, __popcnt, popcnt16, and popcnt64, thanks to our friends at ARM.

To relax this macro guards for ARM64, We have to validate MSVC version.

[asmorkalov]

ok, msvs version check should be added then