I was commenting there with some suggested change and you can find more performance comparison [0].
For example with small adjustment to C and compiling it for AVX512:
after (gcc -ftree-vectorize --march=znver4)
detect_range_8_c: 285.6 ( 1.00x)
detect_range_8_avx2: 256.0 ( 1.12x)
detect_range_8_avx512: 107.6 ( 2.65x)
Also I argued that it may be a little bit misleading to post comparison without stating the compiler and flags used for said comparison [1].P.S. There is related work to enable -ftree-vectorize by default [2]
[0] https://ffmpeg.org/pipermail/ffmpeg-devel/2025-July/346813.h...
[1] https://ffmpeg.org/pipermail/ffmpeg-devel/2025-July/346794.h...
[2] https://ffmpeg.org/pipermail/ffmpeg-devel/2025-July/346439.h...