[tree-ssa] Eliminate unnecessary copies

[Jason Merrill]

On Thu, 22 May 2003 11:34:01 -0600, law@redhat.com wrote:

> I'm also seeing a number of trivial redundancies we're not catching 
> because of the way we handle component references.  Odds are we're going
> to want to lower component references at some point to pick up all 
> the silly redundancies we currently miss.

We don't lower them currently due to limitations of alias analysis; my
first gimplifier broke apart component refs and array_refs, but that broke
struct-alias-1.c.

Jason