[Bug tree-optimization/33562] [4.3 Regression] aggregate DSE disabled

[Andrew Pinski]

On 27 Sep 2007 09:08:17 -0000, rguenther at suse dot de
<gcc-bugzilla@gcc.gnu.org> wrote:
> I did wonder what optimized that before...  (maybe a separate bug for
> this is more appropriate)

Must_def cause the optimization to work IIRC.  In fact this is the
reason why aggregate DSE was added was specifically to fix this
testcase.

See http://gcc.gnu.org/ml/gcc-patches/2006-05/msg01115.html which
specifically mentions this.  I am still trying to understand why we
removed must_def anyways.  Everything points to the removal of
must_def caused many different regressions.

Thanks,
Andrew Pinski