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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/104215] bogus -Wuse-after-free=3 due to
 forwprop moving a pointer test after realloc
Date: Tue, 25 Jan 2022 08:07:33 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104215

Richard Biener <rguenth at gcc dot gnu.org> changed:

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

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
A use of the pointer value (not dereferencing it) after releasing the stora=
ge
it points to is perfectly valid, so I don't see how that could be considere=
d an
error.  Esp. for equality compares which can compare pointers to distinct
objects.  Esp. also because 'q' may be equal to 'r', so

 void *r =3D __builtin_realloc (q, 7);
 if (r =3D=3D q)
   {
...
   }

would also be diagnosed?  IMHO -Wuse-after-free needs to be fixed here.=