[avx512] General AVX-512 tracking issue

[Lokathor]

There's a few problems with adding AVX-512 support:

• I don't have a device to develop on that even supports AVX-512 (for testing).
• Within Rust, it's all Nightly-only.

So (for now) we're blocked on adding avx512, but it'd be nice to have "some day".

This wouldn't be a 1.0 blocker, if we got to a state where we were otherwise 1.0 ready.

[Wunkolo]

The Intel software development emulator will allow you to at least verify a proper AVX-512 implementation, though debugging may be difficult.

[Lokathor]

I'm gonna close this since it's been a year and avx-512 is not even fully on Nightly. we can always revisit later

[polarathene]

With the recent AMD Zen 4 release introducing AVX-512 support too, has much changed since the issue was closed?

• Is this the issue to track for support on AVX-512?
• packed_simd_2 is where the nightly support is being worked on? Which mentions that stdsimd / portable-simd will eventually replace it (once stable I guess?).

So I gather not much has changed, other than hardware availability improving, the support may continue to depend on nightly for a while?

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For a device to test on, it might be possible to rent a VPS instance hourly as needed? I think some providers like Amazon also offer a free tier for a year to new sign-ups, which might make that viable? (You can find info on instance types here, eg M6i has AVX-512)

[Lokathor]

packed_simd_2 exists only so that required bugfixes can be added. Specifically, the person that had publishing rights to packed_simd had left rust development for a while, so we had to fork it and release it under packed_simd_2. Other than that it's not developing as far as I know.

portable-simd is what's in active development, but that intentionally is not attempting to offer specific individual instrinsics.

If any place is going to allow specific individual intrinsics, that would be stdarch I think.