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 6ED033857BB2 for ; Thu, 26 May 2022 07:11:50 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 6ED033857BB2 Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-34-VIP55A2mPmmDWjKGhWYpGg-1; Thu, 26 May 2022 03:11:46 -0400 X-MC-Unique: VIP55A2mPmmDWjKGhWYpGg-1 Received: by mail-wm1-f72.google.com with SMTP id j14-20020a05600c1c0e00b003973bf0d146so652426wms.4 for ; Thu, 26 May 2022 00:11:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:references:from:in-reply-to :content-transfer-encoding; bh=r/Kn842Y7xqq/TSGZRmPEi9uWeOpoasYEV6AkgbBXo4=; b=GDvIrpe6i8WqH9ryaadc6vQ8lzkP1jtEz+JHHWjZ8CJiasd5jxG/Jc/VXB4+EFzqlC vTxWoO0v0QBgmjijrNby/+0w9EBLELU0+ZBNZ348HXtao6AJwyHglxGiUOomNScHja93 wCIEMsON0vshmgjUlgy+7OMzQfIJEJ8b6A0MbinpXxxlX4yva5aX+wzDJ6NiU1zsGy7/ FDH1w0EtPVBiUfjVgEyhINQBYHd/q9e7lsIDkjztqtSFHH/wrlFXJKmIh5uhCxmrGUs9 qIrqReCvJoEYWDCPApg/2QW3bL2IqXBtqvpN8OcRjN3zE9sBzQ3VYqlviQ1dk8DfsKEe Bq1A== X-Gm-Message-State: AOAM533Ub+cHtXNyRQJyLqTPyg80OqX6Mwu20/vcj01/fWmKSynDMkCJ sn4HYrOtrcceyeSXVypOyzKNPbQR/+/B1xHA7Xa7Yp/mM+DQAjy8K3kuy0nG8dWSq654YiXgql8 lSLs36NrL6kbQ/aL4JtkGLEwTpWQb9HSncNm/lp6qNzPgYGveCbGwkupdI6Y= X-Received: by 2002:a05:6000:1a88:b0:20e:6ee9:c78e with SMTP id f8-20020a0560001a8800b0020e6ee9c78emr28412591wry.622.1653549105448; Thu, 26 May 2022 00:11:45 -0700 (PDT) X-Google-Smtp-Source: ABdhPJz8g4zAA3klUqpYM4cLG68RkJGEVd6NXNkkaB8N4Ahqmlj84dRj76WDf8oUZbgzmGQGhMP0zw== X-Received: by 2002:a05:6000:1a88:b0:20e:6ee9:c78e with SMTP id f8-20020a0560001a8800b0020e6ee9c78emr28412566wry.622.1653549105180; Thu, 26 May 2022 00:11:45 -0700 (PDT) Received: from [10.0.0.8] (cpc108959-cmbg20-2-0-cust731.5-4.cable.virginm.net. [80.0.22.220]) by smtp.gmail.com with ESMTPSA id l1-20020a5d6d81000000b0020d02cbbb87sm909371wrs.16.2022.05.26.00.11.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 26 May 2022 00:11:44 -0700 (PDT) Message-ID: Date: Thu, 26 May 2022 08:11:43 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: -march=x86_64 -mtune=generic question To: gcc-help@gcc.gnu.org References: From: Andrew Haley 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: 7bit X-Spam-Status: No, score=-5.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, 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-help@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-help mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 May 2022 07:11:51 -0000 On 5/25/22 19:58, Tom Kacvinsky via Gcc-help wrote: > Does anyone have a quick rundown on what would have changed between GCC > 8.3.0 and 12.1.0 in terms of what -mtune=generic does for optimizations? There was a vast amount of work done on many things, so we can't easily say what affected you. Generally speaking GCC gets better release to release, but bear in mind that compiler optimizations are often based on heuristics. That is to say, they make code better on average, but sometimes they might make things worse. If your degradation is slight overall, there might be an actual regression in the compiler, but chances are you just got unlucky. -- Andrew Haley (he/him) Java Platform Lead Engineer Red Hat UK Ltd. https://keybase.io/andrewhaley EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671