[x264-devel] [PATCH 2/3] RFC: checkasm: Warn if a better SIMD function is slower than the simpler one

[Henrik Gramner]

On Thu, Aug 13, 2015 at 11:00 PM, Martin Storsjö <martin at martin.st> wrote:
> ---
> This naively assumes that a later tested SIMD function is supposed
> to be better than the earlier ones - this probably doesn't
> hold for all x86 SIMD flags.

This would most likely result in a huge amount of false positives.
There are plenty of AVX functions for example that are neither slower
nor faster than non-AVX functions on many CPUs which would often
trigger the warning since the cycle counter can drift a bit from run
to run for multiple reasons.