Why is DImode aligned at 8 byte for i386?

[Jan Hubicka]

> On Feb 4, 2008 4:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > DImode is aligned at 8 byte in i386. Since 32bit doesn't have
> > 64bit register, can we align DImode at 4byte instead of 8
> > for i386? It shouldn't have any negative impact on performance.
> 
> I don't think DImode is aligned at 8 bytes on i386, at least not as
> far as struct layout is concerned.

It is with -malign-double AFAIK.  The reasons for doing so predate me.
I guess it was a speculation that since alignment on double appeared
that in future same alignment on long long might too.

Honza
> 
> Richard.