target/7559: kdelibs miscompilation

[Jan Hubicka]

> 3) The last testcase is ultra-reduced to a two eightbytes object, with 
> only one member in each one. That one do fails.
> 
> extern void abort();
> 
> struct A {
>   long x;
> };
> 
> struct R {
>   struct A a, b;
> };
> 
> struct R R = {
>   100, 200
> };
> 
> void f(struct R r) {
>   if (r.a.x != R.a.x || r.b.x != R.b.x)
>     abort();
> }
> 
> int main() {
>   f(R);
>   return 0;
> }

This looks like a bug in code computing offests of nested aggregates.  I
am just checking it.
Thanks a lot for reducing the testcase! This is really usefull one :)

Honza
> 
> 4) The <struct.c> testcase won't fail if we add some garbage in struct R, 
> because the size of the object will be > 16 bytes, thus having MEMORY 
> class.
> 
> HTH,
> Gwenole.