[Bug c/60819] dse1 removing not-dead insn (aliasing issue?)

["rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60819

--- Comment #13 from rguenther at suse dot de <rguenther at suse dot de> ---
On April 12, 2014 10:30:31 AM CEST, "glisse at gcc dot gnu.org"
<gcc-bugzilla@gcc.gnu.org> wrote:
>http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60819
>
>--- Comment #12 from Marc Glisse <glisse at gcc dot gnu.org> ---
>Created attachment 32586
>  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32586&action=edit
>Richard's small patch
>
>I regtested it (patch from comment #9 plus a testcase) on
>x86_64-linux-gnu and
>it passed. I think we should go with this in the short term. Would you
>care to
>handle it? Or should I post it for review by Joseph/Jason?

I'll handle it. Plus i'll look into the expansion issue.

>The array-based expansion (for later) would require the same may_alias
>treatment. may_alias morally belongs to TYPE_QUALS (like
>const/volatile, it is
>safe to add, not to remove) and it is logical to propagate it in the
>same
>place.