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From: "marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107467] [12/13 Regression] Miscompilation
 involing -Os , -flto and -fno-strict-aliasing
Date: Wed, 28 Dec 2022 10:07:49 +0000
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X-Bugzilla-Keywords: lto, wrong-code
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107467

Martin Li=C5=A1ka <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|marxin at gcc dot gnu.org          |unassigned at gcc d=
ot gnu.org
           Keywords|needs-bisection             |
             Status|ASSIGNED                    |NEW

--- Comment #6 from Martin Li=C5=A1ka <marxin at gcc dot gnu.org> ---
Running that under valgrind I see it started with r12-656-ga564da506f52be66:

=3D=3D13643=3D=3D Conditional jump or move depends on uninitialised value(s)
=3D=3D13643=3D=3D    at 0x401148: bool compare_pairs<SomeClass*>(pair<SomeC=
lass*>
const&, pair<SomeClass*> const&) (pr107467-2.C:12)
=3D=3D13643=3D=3D    by 0x401176: Combined<OtherClass>::clashy() [clone .is=
ra.0]
(pr107467-2.C:23)
=3D=3D13643=3D=3D    by 0x4011B2: other_func() (pr107467-2.C:40)
=3D=3D13643=3D=3D    by 0x4011ED: main (pr107467-2.C:48)

So I guess it might be something in between DSE and aliasing info investiga=
ted
by IPA modref.

@Honza: Can you take a look?=