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From: "jamborm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/112616] [11/12/13/14 Regression] wrong code at -O{s,2,3} on
 x86_64-linux-gnu since r10-3311
Date: Tue, 16 Jan 2024 12:48:33 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112616

--- Comment #6 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
>   # q_11 =3D PHI <0B(2), removed_return.14_14(D)(4),
> removed_return.14_14(D)(3)>
>   _12 =3D *q_11;
>=20
>=20
> WTF????

Well, _12 is not used anywhere, so the code expects the entire load to be D=
CEd.
 But it gets optimized to=20

  _2 =3D MEM[(int *)0B];=20

before DCE sees it and then even if _2 is never used anywhere, apparently t=
he
statement is kept there as an intended trap (I guess).

I have adjusted my patch to make DCE for removed returnd part of IPA edge
redirection so that it does not have compare-debug problems and submitted it
for review in: https://inbox.sourceware.org/gcc-patches/ri6cyu1e9kw.fsf@/T/=
#u=