Ralf Baechle wrote: > Gcc info page says: > > [...] > `packed' > The `packed' attribute specifies that a variable or structure field > should have the smallest possible alignment--one byte for a > variable, and one bit for a field, unless you specify a larger > value with the `aligned' attribute. > [...] > > Qed? So that the compiler has to assume that if its accessing this __packed structure, it may be embedded unaligned within something else? And because the pointer is cast through (void *) it isn't allowed to use alias analysis to notice that the pointer wasn't originally (apparently) unaligned. Seems sound to me. J