I haven't benchmarked that, but in Rust `ScalarPair`s (i.e., structs who have up to to scalars) are passed in two registers, while bigger structs are always pas

I haven't benchmarked that, but in Rust `ScalarPair`s (i.e., structs who have up to to scalars) are passed in two registers, while bigger structs are always passed by pointer. Therefore, passing bigger structs by move will require the compiler to copy them, while with references it is not required to, so references may be faster in that case.