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From: "albrecht.guendel at web dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/114904] New: Bogus Warning [-Wreturn-type] in function with
 do-while loop
Date: Wed, 01 May 2024 12:25:57 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 13.2.1
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X-Bugzilla-Who: albrecht.guendel at web dot de
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114904

            Bug ID: 114904
           Summary: Bogus Warning [-Wreturn-type] in function with
                    do-while loop
           Product: gcc
           Version: 13.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: albrecht.guendel at web dot de
  Target Milestone: ---

Hi,=20
from GCC 8.1 onwards using >=3DC++14, i get hit with
> warning: control reaches end of non-void function [-Wreturn-type]
in the following code:

auto test()
{
    do
    {
        volatile int a =3D 0;
        if (a)
            continue;
        return 1;
    } while(0);
}

or use https://godbolt.org/z/PxE95vqe6

This code uses a do-while construct to conditionally repeat code above the
continue-statement, but always returns within the loop.
The bogus warning occurs as soon as loop-control-flow is added. However the
'continue' would never leave the loop.

The warning can be fixed with __builtin_unreachable(); below the while(0). =
or
by using goto instead of loop control-flow. However this should not be
necessary.
Clang shows the same behavior.=