[PATCH] Fix PRs 8781 and 37892

[Daniel Berlin]

On Fri, Apr 3, 2009 at 10:36 AM, Richard Guenther <rguenther@suse.de> wrote:
>
> This fixes value-numbering and phi-translation to simplify the VNs
> reference operands if we substitute &foobar into the address SSA name
> of an indirect reference.  This allows the same optimization as
> phiprop does during PRE and also allows chaining of redundant
> load elminiation like for the PR8781 testcase for which I also
> added folding indirect calls to direct ones (otherwise we have to
> wait for DOM which is supposed to go away anyway).
>
> Bootstrapped on x86_64-unknown-linux-gnu, regtests still running.
>
> I want to sneak this in before Danny re-writes the VN again ;)

I only rewrite how it iterates and how it decides what has changed.
So now it has equivalence classes of value numbers (which PRE used to
track with value_id's anyway).

LGTM