http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51628
--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-02 08:30:54 UTC --- (In reply to comment #15) > I believe the discussion here is missing the point. Currently (at least with > version 4.5 and ARM, which I am currently using) the situation is that the > compiler generates broken code WITHOUT COMMENT when the address of something > like an integer in a packed structure is assigned to a int* . Since the > pointer > type does not provide any information about the actual alignment of the > integer, it is obviously impractical to fix when accessing the integer and we > certainly do not want to have extra code inserted for handling the possibility > that the int may not be aligned correctly. Therefore the compiler MUST see > this > as a type conflict and at least warn that the address of the member in a > packed > struct is incompatible with the pointer type. > > I have several projects which require the use of packed structures and I > simply > cannot rule out that that I have not at some point accidentally assigned the > address of a member variable to a pointer. It would therefore be very handy if > the compiler could point this out. -Wcast-align certainly doesn't do this. Because there is no cast involved. And that's because the types of the fields are "wrong" as well.
