From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id EFA0F3858D39; Thu, 10 Mar 2022 23:51:37 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org EFA0F3858D39 From: "redi at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/104875] New: libstdc++-v3/src/c++11/codecvt.cc:312:24: warning: left shift count >= width of type Date: Thu, 10 Mar 2022 23:51:37 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Version: 12.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: redi at gcc dot gnu.org 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: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter target_milestone cf_gcctarget Message-ID: 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: Thu, 10 Mar 2022 23:51:38 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104875 Bug ID: 104875 Summary: libstdc++-v3/src/c++11/codecvt.cc:312:24: warning: left shift count >=3D width of type Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: redi at gcc dot gnu.org Target Milestone: --- Target: avr, msp430-elf /home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++11/codecvt.cc:312:24: warning: left shift count >=3D width of type [-Wshift-count-overflow] 312 | char32_t c =3D (c1 << 18) + (c2 << 12) + (c3 << 6) + c4 - 0x3C82080; | ~~~~^~~~~~ c1 is an unsigned char, so c1 << 18 promotes to int, but for 16-bit int that doesn't work as intended. It needs to be converted to a 32-bit type first, e.g. (char32_t)c1 << 18=