Yeah, that work in C# required a lot of other things to minimize allocations. What I was thinking is something similar to how they implemented things like Inde

Yeah, that work in C# required a lot of other things to minimize allocations. What I was thinking is something similar to how they implemented things like IndexOf [0] which is a pure C# implementation that gets translated by the JIT in C++ equivalent code. The advantage is of doing this kind of things this way is that when ARM adds a 256-bit wide SIMD extensions they will only need to support that as a Vector256 implementation to get that code working with no other changes. [0]: https://github.com/dotnet/runtime/blob/2a1b52a1b691c42a7f4079fa86625569584a1c66/src/libraries/System.Private.CoreLib/src/System/SpanHelpers.T.cs#L1706 https://github.com/dotnet/runtime/blob/2a1b52a1b691c42a7f407...