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From: "dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/92479] missing warnings for unreachable codes with break
 (i.e. revive the subset of -Wunreachable-code that fits under clang's
 -Wunreachable-code-break)
Date: Thu, 20 Jan 2022 18:48:51 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D92479

David Binderman <dcb314 at hotmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dcb314 at hotmail dot com

--- Comment #12 from David Binderman <dcb314 at hotmail dot com> ---
Interestingly, both gcc and clang have nothing to say about this code:

extern void g( int);

void f( int a)
{
        if (a >=3D 0)
        {
                if (a < 0)
                {
                        g(a);
                }
        }
}

$ /home/dcb/gcc/results/bin/gcc -c -g -O2 -Wall -Wextra -Wunreachable-code
jan20e.cc
$

cppcheck finds the problem:

$ cppcheck --enable=3Dall jan20e.cc
Checking jan20e.cc ...
jan20e.cc:10:9: warning: Opposite inner 'if' condition leads to a dead code
block. [oppositeInnerCondition]
  if (a < 0)
        ^
jan20e.cc:8:8: note: outer condition: a>=3D0
 if (a >=3D 0)
       ^=