Crate multiversed 

Attribute macros wrapping multiversion with predefined SIMD target presets.

This crate provides the #[multiversed] attribute that wraps #[multiversion::multiversion] with carefully curated target sets for each architecture.

Usage

use multiversed::multiversed;

// Use targets from enabled cargo features (default: x86-64-v3, x86-64-v4-modern, arm64)
#[multiversed]
pub fn dot_product(a: &[f32], b: &[f32]) -> f32 {
    a.iter().zip(b).map(|(x, y)| x * y).sum()
}

// Explicit presets
#[multiversed("x86-64-v4", "arm64")]
pub fn optimized_sum(data: &[f32]) -> f32 {
    data.iter().sum()
}

// Mix presets with custom raw target strings
#[multiversed("x86-64-v3", "aarch64+neon+dotprod")]
pub fn custom_targets(data: &[f32]) -> f32 {
    data.iter().sum()
}

Cargo Features (Presets)

Each feature is a complete, non-cumulative preset based on the x86-64 psABI microarchitecture levels and ARM architecture versions.

x86/x86_64

Feature	Key Features	Hardware
x86-64-v2	SSE4.2, POPCNT	Nehalem 2008+, Bulldozer 2011+
x86-64-v3	AVX2, FMA, BMI1/2	Haswell 2013+, Zen 1 2017+
x86-64-v4	AVX-512 (F/BW/DQ/VL/CD)	Skylake-X 2017+, Zen 4 2022+
x86-64-v4-modern	+ VNNI, VBMI2, BF16, GFNI, VAES	Ice Lake 2019+, Zen 4 2022+

Note: Intel consumer CPUs (Alder Lake 12th gen through Arrow Lake) do NOT have AVX-512 due to E-core limitations. Only Xeon server, i9-X workstation, and AMD Zen 4+ have AVX-512.

aarch64 (above baseline - NEON is always present)

Feature	Key Features	Hardware
arm64	NEON, FP16	Cortex-A75+, Apple M1+, Neoverse N1+, Snapdragon X

Note: Only the minimal NEON+FP16 baseline is provided. Use raw target strings for additional features like dotprod, sha3, or SVE.

Attribute Arguments

The #[multiversed] attribute accepts:

• No arguments: Uses targets from enabled cargo features
• Preset names: "x86-64-v3", "arm64", etc.
• Raw target strings: Any string containing + is passed through as-is

Multiple arguments are comma-separated and all are included in the target list.

Attribute Macros

multiversed

Apply multiversion with SIMD target presets.