Let me write the std::ranges code and ask you to write them with highway.
https://godbolt.org/z/3s1b8P3sj
PS: this is how it looks in eve: https://godbolt.org/z/Kzxqqdrez
I cannot recall anyone saying this kind of thing is a bottleneck for them. We don't use std::range, but searching for a negative value can look like: https://gcc.godbolt.org/z/8bbb16Eea
It looks like smaller codegen than EVE's https://godbolt.org/z/fEn9r175v?
Can you write the second one two? With two ranges? That's where I believe the variadics will be.
FYI: The codegen is smaller because the loop is not unrolled. That's a 2x slower on my measurements. + at least I don't see any aligning of memory accesses, that'd give you another third improment when the data is in L1. You really should fix that.
We have not added a FindIf for two ranges because no one has yet requested that or mentioned it is time-critical for their use cases.
In eve the ability to zip ranges is fundamental and is very important