Portable SIMD Charter

Build and stabilize a portable SIMD API to the standard library under core::simd and std::simd. Draw elements from the existing portable SIMD implementations out in the ecosystem:

• generic-simd
• packed_simd
• wide

Goals

• Determine the shape of the portable SIMD API.
• Get an unstable std::simd and core::simd API in the standard library. This may mean renaming packed_simd to stdsimd and working directly on it, or creating a new repository and pulling in chunks of code as needed.
• Produce a stabilization plan to allow portions of the API to be stabilized when they're ready, and coordinate with other unstable features.
• Respond to user feedback and review contributions to the API.
• Update RFC 2948 based on the final API and stabilization plan.
• Stabilize!

Constraints And Considerations

The initial implementation will be built on LLVM intrinsics directly rather than core::arch. This is so we don't have to block the portable API on filling in a lot of missing intrinsics in core::arch on non-x86 platforms.

Membership

• Shepherds: @calebzulawski, @Lokathor, @workingjubilee
• Team Liason: @KodrAus
• Members: @BurntSushi, @calebzulawski, @hsivonen, @KodrAus, @Lokathor, @workingjubilee