Document: P2964R2
Authors: Daniel Towner, Ruslan Arutyunyan
Date: 2026-02-19
Audience: SG6 Numerics, LEWG Library Evolution

This revision keeps pushing on a practical pain point: you have std::simd, but the element type story has been narrow. The paper spells out when a user-defined type can participate as a std::simd element type, adds exposition-only constraints for binary operations, and ties ABI selection to size and alignment so implementations have a coherent rule set instead of everyone guessing.

If you want the PDF/HTML in front of you, start from P2964R2 on wg21.link (fallback: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2026/p2964r2.html).