More on c-gimplify.c:gimplify_decl_stmt

[Richard Kenner]

    > Saying that the first reference uses field F1 of a type and the second
    > reference uses field F2 of that same type says they can't alias.

    True, but only for structures (as opposed to unions or variant records).
    And for structures, the offsets are unique.

I don't follow.  We're talking about a nest of references and there are
intermediate fields.

    Not at all.  We've *got* a biased index -- the offset into the record.
    We can strength reduce on offset 15+4*i just as easy as we can for [i].

For strength-reduction, sure.  But I was thinking more of the LNO-style
optimizations.