Unpoison SIMD dispatch results for MemorySanitizer#304
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ashvardanian merged 1 commit intoashvardanian:main-devfrom Mar 7, 2026
Merged
Unpoison SIMD dispatch results for MemorySanitizer#304ashvardanian merged 1 commit intoashvardanian:main-devfrom
ashvardanian merged 1 commit intoashvardanian:main-devfrom
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MSan cannot track initialization through SIMD intrinsics (SVE, NEON, SSE, AVX), causing false-positive "use-of-uninitialized-value" reports. Add `__msan_unpoison` calls after every dispatch macro to mark results as initialized. Co-Authored-By: Claude Opus 4.6 <[email protected]>
ashvardanian
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MSan cannot track initialization through SIMD intrinsics (SVE, NEON, SSE, AVX), causing false-positive "use-of-uninitialized-value" reports. Add `__msan_unpoison` calls after every dispatch macro to mark results as initialized. Co-authored-by: Alexey Milovidov <[email protected]>
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Summary
__msan_unpoisoncalls after every dispatch macro to mark results as initialized__has_feature(memory_sanitizer)to detect MSan builds; compiles to no-op otherwiseThe error was triggered in ClickHouse ARM MSan stress test:
simsimd_cos_f32_sve→svdupq_n_f32is opaque to MSan.CI report: https://s3.amazonaws.com/clickhouse-test-reports/json.html?PR=98677&sha=7d4c987f3c650a78b950b264d2676b8b7bc0979e&name_0=PR&name_1=Stress%20test%20%28arm_msan%29
ClickHouse PR: ClickHouse/ClickHouse#98807