Support building on CPUs with AVX but not AVX2#3040
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This change corrects an issue causing AVX2 intrinsics to be called on CPUs that do not support them. These intrinsics were conditionally compiled in behind an `avx` feature gate. This change correctly uses them only if `avx2` is available. This change should have no impact on modern CPUs, but it allows older CPUs to work properly using the unoptimized code path.
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Thanks for the contribution! According to the Steam Hardware Survey, ~97% of users have AVX and ~95% have AVX2 support. Given this data, I agree that reworking the code to avoid AVX2 instructions isn't worth the effort just to provide optimizations for the ~2% of users on older hardware. For anyone looking at this in the future, at least one of the AVX2 instructions is found here: |
This was referenced Jul 31, 2025
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This change corrects an issue causing AVX2 intrinsics to be called on CPUs that do not support them. These intrinsics were conditionally compiled in behind an `avx` feature gate. This change correctly uses them only if `avx2` is available. This change should have no impact on modern CPUs, but it allows older CPUs to work properly using the unoptimized code path.
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This change corrects an issue causing AVX2 intrinsics to be called on CPUs that do not support them. These intrinsics were conditionally compiled in behind an
avxfeature gate. This change correctly uses them only ifavx2is available. This change should have no impact on modern CPUs, but it allows older CPUs to work properly using the unoptimized code path.An alternative to this change would be to rework the AVX code paths to avoid AVX2 intrinsics, but that would be a larger change and likely less desirable as AVX2 seems like a very reasonable baseline these days. Dropping AVX2 intrinsics would likely be a performance regression on modern CPUs.
This change corrects an issue that I was facing related to an
Illegal Instructionafter building the crate, and should also address similar issues that have been encountered by others such as #1327 and #2140.