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From: "arthur.j.odwyer at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109945] Escape analysis hates copy elision:
 different result with -O1 vs -O2
Date: Tue, 23 May 2023 19:38:53 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109945

--- Comment #11 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
(In reply to Andrew Pinski from comment #8)
> (In reply to Arthur O'Dwyer from comment #7)
> > // https://godbolt.org/z/Ea43Y65z4
> > struct Widget {
> >     int i =3D 1;
> ...
> > In this case, Widget has no constructors,
>=20
> No, it has a constructor because of the NSDMI. NSDMI causes a non-trivial
> constexpr constructor to be created.

Fair. I meant Widget has no _program-defined_ constructors (such as would h=
ave
unknown effects and might invisibly-to-the-compiler escape a copy of `&w`).=
 I
might still be using the wrong term. But you found a better example without
that wrinkle, anyway. :)=