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From: "vultkayn at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug analyzer/109365] Double delete yields -Wanalyzer-use-after-free
 instead of -Wanalyzer-double-free
Date: Wed, 05 Jul 2023 11:31:41 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109365

Benjamin Priour <vultkayn at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vultkayn at gcc dot gnu.org

--- Comment #3 from Benjamin Priour <vultkayn at gcc dot gnu.org> ---
Changing the second delete expression into a direct call to "operator delet=
e"
results in the correct warning Wanalyzer-double-free being emitted.

This is due to delete expression first calling the destructor and performing
extra operations, whose one of them is a dereference.

"delete expression" compiled with -O0 results on my x86_64-linux-gnu
to analyzer ipa:

  if (a.0_11 !=3D 0B)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
  *a.0_11 =3D{v} {CLOBBER};
  operator delete (a.0_11, 8);

  <bb 4> :
  _14 =3D 0;

Entry statement of bb3 is the one actually detected as -Wanalyzer-double-fr=
ee.=