From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 44A26385609D; Sun, 12 Jun 2022 22:25:29 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 44A26385609D
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/105937] [12/13 Regression]
 maybe-uninitialized with std::optional
Date: Sun, 12 Jun 2022 22:25:29 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 12.1.0
X-Bugzilla-Keywords: diagnostic, needs-reduction
X-Bugzilla-Severity: normal
X-Bugzilla-Who: pinskia at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 12.2
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: keywords target_milestone short_desc
Message-ID: <bug-105937-4-WNqZEBy74a@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-105937-4@http.gcc.gnu.org/bugzilla/>
References: <bug-105937-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Sun, 12 Jun 2022 22:25:29 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105937

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |needs-reduction
   Target Milestone|---                         |12.2
            Summary|[12] Regression with        |[12/13 Regression]
                   |maybe-uninitialized         |maybe-uninitialized with
                   |                            |std::optional

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---

  # ttfRunIndex_64 =3D PHI <ttfRunIndex_6(52), [/app/example.cpp:207:27] 0(=
30)>
  # ttfRunIndex$8_65 =3D PHI <ttfRunIndex$8_8(52), [/app/example.cpp:207:27]
0(30)>
...


<L17>:
  [/app/example.cpp:213:13] if (ttfRunIndex$8_65 !=3D 0)
    goto <bb 22>; [33.00%]
  else
    goto <bb 48>; [67.00%]

...

  <bb 22> [local count: 157594832]:
  [/app/example.cpp:216:62] len_15 =3D _20 - ttfRunIndex_64;

...
  # ttfRunIndex_6 =3D PHI <ttfRunIndex_14(D)(26), ttfRunIndex_64(48), _20(2=
1),
ttfRunIndex_64(49)>
  # ttfRunIndex$8_8 =3D PHI <0(26), 0(48), [/app/example.cpp:227:29] 1(21),
1(49)>

So if anything this is both a missed optimization and the maybe uninitializ=
ed
predicates is not doing its job correctly.=