On Thu, Jan 8, 2009 at 9:41 PM, Ian Lance Taylor <i...@google.com> wrote: > "H.J. Lu" <hjl.to...@gmail.com> writes: > >>> There are many ways to align data without exposing it in the >>> ABI--e.g., the alignment of a global array is not part of the ABI, in >>> that nothing breaks if the alignment is increased. Also, there are >>> many programs which simply don't care about an external ABI. >>> >> >> You can just use a value like __attribute ((aligned (8))) >> or some value suitable for the variable type. It is >> as good as any value we can use with >> __attribute__ ((aligned(max))) today since whatever >> we choose now may not be appropriate later. > > I feel like a broken record here, but if I want maximal performance > for copying data in and out of a buffer, then I want it maximally > aligned for the processor. If I am writing portable code, then I > don't know what that maximal alignment is. >
You can't use _attribute__ ((aligned(max))) directly with memory allocator. How about a new macro, __BIGGEST_ALIGNMENT__? -- H.J.
