---
title: "Emulating avx-512 intrinsics in Miri"
url: https://daily.dev/posts/emulating-avx-512-intrinsics-in-miri-lmjf9tvwr
source_url: https://tweedegolf.nl/en/blog/199/emulating-avx-512-intrinsics-in-miri
type: article
source: "Tweede golf"
published: 2026-05-31T07:54:03.433Z
updated: 2026-05-31T09:06:09.078Z
tags: ["rust"]
reading_time: 7
upvotes: 0
comments: 0
language: en
---

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# Emulating avx-512 intrinsics in Miri

**[Tweede golf](https://daily.dev/sources/tweedegolf)** · 7 min read · 0 upvotes · 0 comments

## Summary

The zlib-rs team added AVX-512 SIMD intrinsic support to Miri, Rust's interpreter for detecting undefined behavior, enabling CI testing of AVX-512 code without requiring AVX-512 hardware. Since QEMU doesn't support AVX-512 and Intel's own emulator is slow, the team contributed four new intrinsic implementations to Miri: `_mm512_sad_epu8`, `_mm512_ternarylogic_epi32`, `_mm512_maddubs_epi16`, and `_mm512_permutexvar_epi32`. These are wider variants of already-supported instructions, so implementations share code with narrower AVX2 versions. The post walks through the implementation process using `psadbw` as a detailed example, showing how Miri shims map LLVM intrinsic names to Rust interpreter logic. The AVX-512 optimizations (for compare256, crc32, and adler32) are available in zlib-rs 0.5.3, requiring Rust 1.89+ and appropriate target feature flags.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://tweedegolf.nl/en/blog/199/emulating-avx-512-intrinsics-in-miri>

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