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From: "carlosgalvezp at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/111714] New: Strange behavior when casting std::size_t to
 bool, UB or compiler bug?
Date: Fri, 06 Oct 2023 13:59:15 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111714

            Bug ID: 111714
           Summary: Strange behavior when casting std::size_t to bool, UB
                    or compiler bug?
           Product: gcc
           Version: 9.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: carlosgalvezp at gmail dot com
  Target Milestone: ---

Created attachment 56067
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D56067&action=3Dedit
Test case

Hi!

We are bumping from GCC 7.5 to 9.4 and one of our tests fail. The test work=
s on
GCC 10 and above, as well as Clang trunk. Sanitizers (GCC and Clang) and
Valgrind don't report anything.

I have managed to create a minimal example here:
https://godbolt.org/z/3q7c4qYzE (attached to the bug as a file as well).

There's also comments about changes to the code that can make the test pass.

This smells a lot like UB, but I can't figure out what is wrong with the co=
de.
Otherwise it could well be a compiler bug. Is there anything obvious you can
see that could explain the behavior?

Thanks!=