[Bug c++/107140] New: Potential false positive uninitialized variable warning with -Wmaybe-uninitialized

[kip at thevertigo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107140

            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 opened.
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 minimal
to re-create a "'MaximumPriorityQueue' may be used uninitialized" warning. This
originates in Test.cpp on L71. Here is the code: 

    https://godbolt.org/z/a17Eoc3f3

This only appears to happen with >= -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.