Hi, thanks for your feedback, we are being "incorrect" on purpose. All intrinsics up to and including SSE4.2 were including as part of SSE4.2. We have no intention of providing full granularity for any ISA extension esp one that is 20 years old. For the same reason, we are listing VSX as including in Power ISA 3.0, but not eg. Altivec or Power7/Power8 VSX. If you need such granularity, you are better off visiting the Intel Intrinsics Guide or the ISA manuals. So the separation for x86 is split into 3 groups, SSE4.2 (up to and including), AVX2 (including AVX) and AVX512 (also including some but not all variants). Something like x86_64-v1, x86_64-v2, etc that is used on compilers. We will probably do a finer granularity listing the exact extension in the description in the future, but not as part of the categorization.

Now the search is indeed less than ideal, we're working on replacing our search engine with a much more robust that doesn't favour one architecture over the other, especially in such words.

In any case, thank you for your feedback. It's still in beta but it is already very useful for us, as we're actually using it for development on our own projects.