Re: [PATCH] Optimize generic get_unaligned / put_unaligned implementations.

[Jeremy Fitzhardinge <jeremy@goop.org>]

Andrew Morton wrote:
> hm.  So if I have
>
>       struct bar {
>               unsigned long b;
>       } __attribute__((packed));
>
>       struct foo {
>               unsigned long u;
>               struct bar b;
>       };
>
> then the compiler can see that foo.b.b is well-aligned, regardless of the
> packedness.

In Ralf's code, the structure is anonymous, and is used to declare a
pointer type, which is initialized from a void *.  So I think the
compiler isn't allowed to assume anything about its alignment.

    J