http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58346
--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> --- On Mon, 9 Sep 2013, joseph at codesourcery dot com wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58346 > > --- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery > dot com> --- > I think some of the uses of the zero-size-objects extension are ones for > which making an array of such objects is reasonable, but it makes sense to > give an error for trying to subtract pointers to such objects. A similar (runtime) error can be provoked by subtracting pointers to array elements of variable size that happen to have zero size at runtime. This all seems to be a can of worms which I'd rather shield the middle-end from. For example we assume that a[0] and a[1] never alias. Can we at least make arrays of zero-sized elements trigger undefined behavior in our extension documentation? We probably can paper over the ICEs as they occur (testing coverage is very weak of course).
