Question: Is the method is_available correct?

[zzau13]

I'm using part of your code to implement one of my libraries. And I have a question about the method is_available.

If I compile with avx2 support and run it on a processor without the avx2 flag, wouldn't that result in a SIGILL, illegal instruction? I don't understand, shouldn't I check it at runtime?

Forgive my ignorance, could you explain a little?

[BurntSushi]

It is checked at runtime:

memchr/src/arch/x86_64/avx2/memchr.rs

Line 101 in ceef3c9

std::is_x86_feature_detected!("avx2")

The runtime check is only done when it isn't known whether avx2 is enabled at compile time. If it is enabled at compile time, then there's no reason to do the check at runtime.