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From: "jg at jguk dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/108646] nonnull attribute does not detect variables that
 are NULL being passed
Date: Tue, 07 Feb 2023 12:19:59 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108646

--- Comment #5 from Jonny Grant <jg at jguk dot org> ---
(In reply to Jonathan Wakely from comment #4)
> (In reply to Jonny Grant from comment #3)
> > Is it worth -Wnonnull emitting a warning message that it needs optimiza=
tion
> > to get the needed data flow analysis?
>=20
> No, there are dozens of warnings that work poorly, or not at all, unless
> optimization is enabled. It's in the manual.
>=20
> "The effectiveness of some warnings depends on optimizations also being
> enabled. For example -Wsuggest-final-types is more effective with link-ti=
me
> optimization and some instances of other warnings may not be issued at all
> unless optimization is enabled. While optimization in general improves the
> efficacy of control and data flow sensitive warnings, in some cases it may
> also cause false positives."

Ok I see. Thank you for clarifying.=