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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/104475] [12/13 Regression] Wstringop-overflow
 + atomics incorrect warning on dynamic object
Date: Tue, 06 Dec 2022 10:26:29 +0000
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X-Bugzilla-Component: tree-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104475

--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> ---
The change improved the wording of the diagnostic by appending the note
indicating an object at zero address.  It didn't mitigate the diagnostic wh=
ich
as far as I analyzed is technically correct (but not very helpful).

An improvement for these diagnostics would be analyzer-style reporting of
the guarding conditions.  Another possible improvement would be to somehow
keep a pointer to the symbolic base we equality-propagated from the
conditional so that we, for

 if (!d)
   if (enabled)
     *d =3D 0;

can say the object pointed-to by 'd' when 'd' is nullptr is accessed here.
The IL currently just has a pointer constant and doesn't know that was
originally derived from 'd'.=