From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id C07053857831; Mon, 26 Oct 2020 19:40:52 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C07053857831 From: "eyalroz at technion dot ac.il" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/97553] [missed optimization] constexprness not noticed when UBsan enabled Date: Mon, 26 Oct 2020 19:40:52 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 10.2.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: eyalroz at technion dot ac.il X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Oct 2020 19:40:52 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97553 --- Comment #3 from Eyal Rozenberg --- > And, the runtime sanitization intentionally isn't heavily optimized away,= because the intent is to detect when the code is invalid, so it can't e.g.= optimize away those checks based on assumption that undefined behavior wil= l not happen. So, doesn't that essentially mean that -O3 cannot properly apply with UBsan= ?=