------- Comment #16 from rguenth at gcc dot gnu dot org 2008-03-25 12:28
-------
The C/C++ standards say that if you access memory through int, the data has
to be aligned suitably according to what the ABI specifies for alignment of
int.
If you mis-align the access on purpose you have to tell the compiler, one
means of doing so is by using the aligned attribute or by using a packed
structure. The vectorizer will then see the misalignment if it (hopefully)
uses get_pointer_alignment (or TYPE_ALIGN or whatever is suitable).
It is not expected that the vectorizer can deal with the situation in the
original report.
For this reason I think this bugreport is invalid.
char c[4];
*(int *)&c[0]
the access invokes undefined behavior at runtime if you do not make sure
c is properly aligned. On strict alignment targets this will fault
regardless of vectorization or not.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35653
