sort-research-rs VS fancy-memcmp

If you want a particularity cursed example, I've recently called Go code from Rust via C in the middle, including passing a Rust closure with state into the Go code as callback into a Go stdlib function, including panic unwinding from inside the Rust closure https://github.com/Voultapher/sort-research-rs/commit/df6c91....

See also https://github.com/Voultapher/sort-research-rs/blob/main/wri.... Discussion at https://news.ycombinator.com/item?id=37781612

There was a recent post by Voultapher from the sort-research-rs project on Branchless Lomuto Partitioning

https://github.com/Voultapher/sort-research-rs/blob/main/wri...

Discussion here:

https://news.ycombinator.com/item?id=38528452

This post by orlp (creator of Pattern-defeating Quicksort and Glidesort) was linked to in the above post, and I found both to be interesting.

Hrm—that's another case of missing isel from gcc/clang (c.f. <https://pp.ipd.kit.edu/firm/selgen>)—my implementation (<https://github.com/moon-chilled/fancy-memcmp/blob/master/mem...>) does it in one less instruction. (An alternative is to skip the xors and do cmp/setcc/setcc/sub/movsx, which matches my approach on instruction count, but relies on good handling of partial renames, which is uarch-dependent. And I can never remember if anybody can eliminate movsx. Otoh it is non-destructive.)

I only have experience with their amd64 code.

> What problems do they have?

Nothing in particular, just not particularly amazing performance. They work fine. One thing they have going for them is that they typically have separate versions for every interesting architecture feature level/set, whereas e.g. bionic only has sse code. I guess I can point at my own implementations of memset and memcmp (https://github.com/moon-chilled/fancy-memset https://github.com/moon-chilled/fancy-memcmp), both of which employ novel techniques not used by glibc; but I've not yet gotten around to doing proper benchmarks on either.