Aug 6, 2026 · 7 min
OxiFFT 0.4.2 Released — Wrong FFT Answers on Every Non-AVX2 x86_64 CPU, Found and Fixed
OxiFFT 0.4.2 fixes a wrong-answer bug (not a precision bug) in the x86_64 SSE3 SIMD butterfly kernel that every non-AVX2 x86_64 CPU takes — a wrong complex-multiply lane order and twiddle-recurrence drift together failed 93 of 1447 tests by 10-100x the tolerance. Found by running the suite on x86_64 for the first time. Plus a Miri-driven pointer-provenance fix, four new soundness hardenings against attacker-influenceable wisdom strings, and a fuzz-harness tolerance bug of its own. Pure Rust FFT, no FFTW.
releaseoxifftfft