bgsegm: Enable __popcnt intrinsic for MSVC on ARM to fix LSBP test failure #3953
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
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. |
|
Hello, at Microsoft blog, Visual Studio 2022 v17.11 and later seems to support See https://devblogs.microsoft.com/cppblog/msvc-backend-updates-in-visual-studio-2022-version-17-11/
To relax this macro guards for ARM64, We have to validate MSVC version. |
|
ok, msvs version check should be added then |
asmorkalov
reviewed
Jun 24, 2025
pratham-mcw
force-pushed
the
fix/bgsegm-lsbp-arm-failure
branch
from
1cb9449 to
2347ac5
Compare
asmorkalov
approved these changes
Sep 9, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR enables use of the
__popcntintrinsic 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.
Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
Patch to opencv_extra has the same branch name.