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From: "m.cencora at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/109770] [10/11/12/13/14 Regression] wrong(?)
 devirtualization
Date: Tue, 09 May 2023 08:24:56 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109770

m.cencora at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |m.cencora at gmail dot com

--- Comment #6 from m.cencora at gmail dot com ---
(In reply to Richard Biener from comment #0)
> #include <new>
>=20
> struct Base
> {
>   virtual ~Base() {}
> };
> struct A : Base
> {
>   virtual ~A() {}
> };
> struct B : Base
> {
>   [[gnu::noinline]] B() { new (this) A; }
>   virtual ~B() { __builtin_abort (); }
> };
> int main()
> {
>   Base *p =3D new B;
>   delete p;
> }
>=20
> aborts when compiled with -O2 (with devirtualization enabled).  Neither
> GCC nor clang diagnose the placement new in B::B() (but it looks fishy).

I believe you need to std::launder the p pointer before calling delete:
https://en.cppreference.com/w/cpp/utility/launder=