gned loads are penalized (x86), or even fault (some ARM
chips). For simple cases like directly loading or storing a packed field, the
compiler might be able to paper over alignment issues with shifts and masks.
However if you take a reference to a packed field, it&#39;s unlikely that the
compiler will be able to emit code to avoid an unaligned load.</p>

<p><strong><a href="https://github.com/rust-lang/rust/issues/27060">As of Rust 1.0 this can cause undefined behavior.</a></strong></p>

<p><code>repr(packe