From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id A23CD3858D32 for ; Mon, 22 Aug 2022 11:48:38 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A23CD3858D32 Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-556-vV3qyFqsNUeNp-O_VeJnLg-1; Mon, 22 Aug 2022 07:48:37 -0400 X-MC-Unique: vV3qyFqsNUeNp-O_VeJnLg-1 Received: by mail-ej1-f70.google.com with SMTP id jg41-20020a170907972900b00738b83ea216so2624959ejc.11 for ; Mon, 22 Aug 2022 04:48:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc; bh=CZ+qttHUPvDKIyltrllfqQXVjoLmHymBbnT9mBWAU24=; b=inmlZ10ktNfuh+jO+ILvCTcVmPJX7+0oHIRTxUOFbBIKWgYDvdmqWg3Y3e8kW8gupJ fJZCSPgEbAoqPEZVIOTWrt1NgG7IJjoW5sCMWxYR4Lx8bOP2kVfIy8XssBWRO2dmjX+f oX2HbEmjGlQVJvrQRLoMFjm2gcKxXpi9f2FJh9X8dA+oSLDgXzFzd4/HeuLBC1jHWsIt IszOYwhgfWOwgAU0YGBQRfIyBa4qrut2aq8lJ7WOU1KkUdNvdnwX0MriCgYNFbtmIylT apPAadsq+odskeayvtXZSPqQ5G78WwJRSVkMNeDOqWRGFRiVxZllkwFR7DECwzlOpZst vG5g== X-Gm-Message-State: ACgBeo1mF5aMB4IqjGYO9qXCmytp6hIoDY+i+7CEz7L+r7G5ZivUtEA5 XZ7IiOXwEo3g1l3KsJ+x71C3S5KVIRN1Vw9Dn8gpZcXbQHN6jK5g8Y2To/OZoxm4OBHpa3RZu79 3iqeaI4S/5BqCvB1uDg== X-Received: by 2002:a17:906:98d5:b0:738:3402:197 with SMTP id zd21-20020a17090698d500b0073834020197mr12217311ejb.581.1661168916171; Mon, 22 Aug 2022 04:48:36 -0700 (PDT) X-Google-Smtp-Source: AA6agR7sdBb7JmRMczY7BxZbygmo6sq0aPJ+qDNLWD0358MuQ2U8tZ7zJfq78s36luPxwdx3jWIvOA== X-Received: by 2002:a17:906:98d5:b0:738:3402:197 with SMTP id zd21-20020a17090698d500b0073834020197mr12217297ejb.581.1661168915968; Mon, 22 Aug 2022 04:48:35 -0700 (PDT) Received: from [192.168.188.47] (dynamic-078-050-159-066.78.50.pool.telefonica.de. [78.50.159.66]) by smtp.gmail.com with ESMTPSA id p25-20020a056402045900b00445e506ddcasm8043883edw.57.2022.08.22.04.48.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Aug 2022 04:48:35 -0700 (PDT) Message-ID: Date: Mon, 22 Aug 2022 13:48:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [PATCH] c++: Extend -Wpessimizing-move to other contexts To: Marek Polacek , GCC Patches , Jason Merrill References: <20220802230447.721163-1-polacek@redhat.com> From: Stephan Bergmann In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, KAM_SHORT, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Aug 2022 11:48:42 -0000 On 16/08/2022 14:27, Marek Polacek via Gcc-patches wrote: > Ping. (The other std::move patches depend on this one.) "c++: Extend -Wpessimizing-move to other contexts" started to cause false positive > $ cat test.cc > #include > struct S1 { > S1(); > S1(S1 const &) = delete; > S1(S1 &&); > S1 operator =(S1 const &) = delete; > S1 operator =(S1 &&); > }; > struct S2 { S2(S1); }; > S2 f() { > S1 s; > return { std::move(s) }; > } > > $ g++ -fsyntax-only -Wredundant-move test.cc > test.cc: In function ‘S2 f()’: > test.cc:12:27: warning: redundant move in return statement [-Wredundant-move] > 12 | return { std::move(s) }; > | ^ > test.cc:12:27: note: remove ‘std::move’ call