Yes, the optimizer (LLVM) can often optimize memcpy(), and this is not exclusive to Rust: the same optimizations happen with C and C++ (a well-known trick to avoid some undefined behaviors in C is to do a memcpy(), which the optimizer will then elide). It doesn't change that, before the optimization passes, it's doing the equivalent of a memcpy().

> memcpy sounds like what would happen in the case of a copy or clone, not a move.

In Rust, copy and move are nearly identical; the only difference is that, after a move, the compiler doesn't let you access the old value. Clone is different, since it can be overridden to do anything the programmer desires, but by default, it's identical to copy.