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From: "burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/44612] -flto -fwhole-program: Never read variable
 not optimized away
Date: Mon, 31 Aug 2020 09:31:22 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D44612

--- Comment #8 from Tobias Burnus <burnus at gcc dot gnu.org> ---
For what it is worth, still occurs with on mainline (GCC 11).


(In reply to Richard Biener from comment #6)
> Confirmed.
>=20
> DSE doesn't remove memset or memcpy calls.
>=20
> We also do not have a flag to mark functions only clobbering local or
> incoming memory (thus effectively not have side-effects if the argument
> reachable memory is unused after a call).

(In reply to Jakub Jelinek from comment #7)
> Well, RTL DSE to some extent knows about memset.
> And, for tree DSE handling it would be much easier and desirable.=