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From: "kip at thevertigo dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/107140] New: Potential false positive uninitialized
 variable warning with -Wmaybe-uninitialized
Date: Tue, 04 Oct 2022 00:38:18 +0000
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X-Bugzilla-Version: 12.2.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107140

            Bug ID: 107140
           Summary: Potential false positive uninitialized variable
                    warning with -Wmaybe-uninitialized
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kip at thevertigo dot com
  Target Milestone: ---

I am aware there have been other related issues that have already been open=
ed.
I am not sure if this adds anything new to the discussion, but I have, with
some effort, managed to isolate a minimal that reproduces the issue.

This code is not meant to be run, but it's merely a heavily butchered minim=
al
to re-create a "'MaximumPriorityQueue' may be used uninitialized" warning. =
This
originates in Test.cpp on L71. Here is the code:=20

    https://godbolt.org/z/a17Eoc3f3

This only appears to happen with >=3D -O2. My guess is this may be a result=
 of a
complex interaction with the optimizer and how part of the instantiated
template was inlined.

I note that if I reorder m_LessThanComparison with m_MinMaxHeap in Test.cpp,
the warning is suppressed.=