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From: "gnu.iodaj at simplelogin dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/108556] New: std::sort changes objects' member values
Date: Thu, 26 Jan 2023 10:05:13 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: libstdc++
X-Bugzilla-Version: 11.3.0
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X-Bugzilla-Who: gnu.iodaj at simplelogin dot com
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108556

            Bug ID: 108556
           Summary: std::sort changes objects' member values
           Product: gcc
           Version: 11.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gnu.iodaj at simplelogin dot com
  Target Milestone: ---

When working on a project, I tried using std::sort to sort a vector of obje=
cts,
and it resulted in a crash. After looking closer, valgrind reports lots of
invalid writes and the data is effectively modified during the sort.

This issue doesn't happen with stable_sort nor with small enough vectors.

The g++ versions tested are 11.3.0 and 12.1.0.

The system is a Dell Precision 5570 running Linux Mint 21.

g++ command is g++ -Wall -Wextra sort-bug.cpp (file in attachment)

The compiler output is none (no warnings, no errors, no line displayed)

Please find the attached file that serves as a minimal working example of t=
his
bug.

Thank you.=