> + if (type1 != type2 || TREE_CODE (type1) != RECORD_TYPE)
> + goto may_overlap;
>
> ick, can TREE_CODE (type1) != RECORD_TYPE happen as well here?
> Please add a comment similar to the Fortran ??? above.
It can happen because we stop at unions (and qualified unions) and for them we
cannot disambiguate based on the fields. I'll add a regular comment.
> Can you please also add at least one testcase as
> gcc.dg/tree-ssa/ssa-fre-??.c that tests the functionality of this and that
> wasn't handled before? I suppose it would be sth like
>
> struct S { int i; int j; };
> struct U
> {
> struct S a[10];
> } u;
>
> u.a[n].i= i;
> u.a[n].j = j;
> return u.a[n].i;
>
> where we miss to CSE the load from u.a[n].i.
Yes, the patch does eliminate the redundant load in .fre1:
u.a[n_2(D)].i = i_3(D);
u.a[n_2(D)].j = j_5(D);
_7 = u.a[n_2(D)].i;
return _7;
becomes:
u.a[n_2(D)].i = i_3(D);
u.a[n_2(D)].j = j_5(D);
_7 = i_3(D);
return _7;
> Otherwise the patch is ok.
Thanks.
--
Eric Botcazou
