gimplify_parameters

[Richard Kenner]

    Which is actually a symptom of a tree sharing problem between the 
    array size and the array dimension.  We leaked an SSA_NAME object
    into the type system.

There's sharing *all over the place* within the type system.  We
routinely use the size of one type to compute that of another, or to
compute DECL_OFFSET.  And the expressions for one DECL_OFFSET are used
to compute others.  I don't think we can outlaw all that sharing: it would
be a *huge* amount of work.