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 E38113858C52; Sat,  4 Feb 2023 00:07:10 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E38113858C52
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1675469230;
	bh=PSGnWSi/iT7XVz6wv8aQHwVAKWq1+SVak/O9FW5aHgA=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=P5MJlr68CWRB+Di1qgK+QMi0ZBBCuGenxO8JMhxrSEKxTeoCYEwhUpR+6cu2Ur1oe
	 yhkKbsV3VcOJIgVKkkOWc1yj+mELyOPAriFpvLEnVmdTh/5BEUzUJoE7VjZX4lSp6M
	 QWchVu103taiDSgrwdnj2+f+5UeqeGGJzrWsnRKE=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108667] Spurious "may be used uninitialized
 [-Wmaybe-uninitialized]" warning
Date: Sat, 04 Feb 2023 00:07:10 +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: 12.2.0
X-Bugzilla-Keywords: diagnostic
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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-108667-4-jWEYgPU9oS@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-108667-4@http.gcc.gnu.org/bugzilla/>
References: <bug-108667-4@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
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108667

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---

This is partly caused by not inlining everything as main is marked as called
once.
If instead I call main, main1, the warning goes away and the following call=
 is
inlined now:
  std::_Function_handler<void(), main()::<lambda()> >::_M_manager (&MEM[(st=
ruct
function *)&s + 32B].D.47025._M_functor, &D.47426.D.47025._M_functor, 2);

The warning in this case is about D.47426 which does not have any
initialization before the call here.
Note the call with last operand as 2 does not actually do anything and just
returns.

I don't know the best way to solve this specific case as it depends on inli=
ning
heurstics.

Question for the reporter, was this a reduction from some real code or did =
you
just notice the warning while testing some code?=