https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64798
--- Comment #14 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 27 Jan 2015, jakub at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64798 > > --- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I > think aligned attribute is similarly useless for this, I'd really go for > testing alignments you need, rather than expecting some magic value. > I'm not aware of any target that would have bigger alignment for say > char/short/int/long than long long, ditto with float/double, so I'd just > check maximum of long long, long double, void * alignment. For the actual bug I can use __alignof__ (__cxa_refcounted_exception), but that again ends up using __attribute__((__aligned__)) via the _Unwind_Exception member: struct _Unwind_Exception { _Unwind_Exception_Class exception_class; _Unwind_Exception_Cleanup_Fn exception_cleanup; #if !defined (__USING_SJLJ_EXCEPTIONS__) && defined (__SEH__) _Unwind_Word private_[6]; #else _Unwind_Word private_1; _Unwind_Word private_2; #endif /* @@@ The IA-64 ABI says that this structure must be double-word aligned. Taking that literally does not make much sense generically. Instead we provide the maximum alignment required by any type for the machine. */ } __attribute__((__aligned__)); so I think that using __attribute__((__aligned__)) is very much the correct and easiest thing to use.
