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 [63.128.21.124]) by sourceware.org (Postfix) with ESMTP id 22E643860C35 for ; Mon, 30 Nov 2020 20:54:19 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 22E643860C35 Received: from mail-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-212-gunLmQSwPm6yAJS6pfXNgA-1; Mon, 30 Nov 2020 15:54:16 -0500 X-MC-Unique: gunLmQSwPm6yAJS6pfXNgA-1 Received: by mail-qv1-f72.google.com with SMTP id e11so8417568qvu.18 for ; Mon, 30 Nov 2020 12:54:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=bbPL/IRty+8GA2useajvXWSWYw+pdu7D10KY8QjJyWg=; b=kr/eur1IuL3ToXnKx6tdK0idjtI+jXO+hp6lt3EO81NsnwdYa9NWMfSARpwwYnDaa4 dkMhRhTlj5P4GV+7NyjrxDoWRHLfKdrUmGD6bHdxdAkrmqHD6C+IuDm+dtPiVLNcma6s kUSYMJwuTGWutkH7tRKqYU7sKEZmg91z7zf47WnFV4huVDJyO+Cec/poH4XskafzW/H8 PAEe5qe9DHwjZ0wisYPPoJc2LebW+dE3TeR4ZTp+HHUnmL90CUkUWL+5v14KWlv8s7Gi rTn6KjZ5f14JOuWseCVfCig5oBbm4m8tyOzTYB4eqQiiCDCHbjrMa5BrqtHcgYtzWuqe vQ7g== X-Gm-Message-State: AOAM533k3FHk2gh1D6foNRu0ZdJZDIQbvsxI/hN2dWhwurFyMzCIuy5r W46Xn+Im5gMIWB2qgdDfDZsrv1rqvdfUJ8f/C4QAhRG6duiHYBCcraLCxM/Q3vaYHPSXakBwIXX 2dTfEpW8Fom8DUYjbEg== X-Received: by 2002:ad4:5041:: with SMTP id m1mr24585662qvq.33.1606769655438; Mon, 30 Nov 2020 12:54:15 -0800 (PST) X-Google-Smtp-Source: ABdhPJwuAledTR7aW56FpqfGX1iS9uEV2qmk/2hyuiQX8J/Dg4sxMMdEYJnbskbgiB/KEeF6gCUN6g== X-Received: by 2002:ad4:5041:: with SMTP id m1mr24585641qvq.33.1606769655067; Mon, 30 Nov 2020 12:54:15 -0800 (PST) Received: from [192.168.1.148] (209-6-216-142.s141.c3-0.smr-cbr1.sbo-smr.ma.cable.rcncustomer.com. [209.6.216.142]) by smtp.gmail.com with ESMTPSA id a6sm15928757qkg.136.2020.11.30.12.54.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Nov 2020 12:54:14 -0800 (PST) Subject: Re: [PING] [PATCH] Avoid atomic for guard acquire when that is expensive To: Bernd Edlinger , "Richard Earnshaw (lists)" , "gcc-patches@gcc.gnu.org" , Ramana Radhakrishnan , Nathan Sidwell , Christophe Lyon References: <8383d817-8622-4d1f-9564-8c10131db664@arm.com> From: Jason Merrill Message-ID: <35a6fb5c-db78-d2b8-7b00-4bfa54f8976f@redhat.com> Date: Mon, 30 Nov 2020 15:54:12 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-10.5 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, KAM_MANYTO, KAM_SHORT, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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, 30 Nov 2020 20:54:20 -0000 On 11/30/20 3:08 PM, Bernd Edlinger wrote: > Hi, > > I'd like to ping for this patch: I reviewed it on the 24th: https://gcc.gnu.org/pipermail/gcc-patches/2020-November/560118.html > > https://gcc.gnu.org/pipermail/gcc-patches/2020-November/559882.html > > Thanks > Bernd. > > On 11/22/20 9:05 AM, Bernd Edlinger wrote: >> Hi, >> >> this avoids the need to use -fno-threadsafe-statics on >> arm-none-eabi or working around that problem by supplying >> a dummy __sync_synchronize function which might >> just lead to silent code failure of the worst kind >> (non-reproducable, racy) at runtime, as was pointed out >> on previous discussions here. >> >> When the atomic access involves a call to __sync_synchronize >> it is better to call __cxa_guard_acquire unconditionally, >> since it handles the atomics too, or is a non-threaded >> implementation when there is no gthread support for this target. >> >> This fixes also a bug for the ARM EABI big-endian target, >> that is, previously the wrong bit was checked. >> >> >> Regression tested successfully on arm-none-eabi with newlib-3.3.0. >> >> Is it OK for trunk? >> >> >> Thanks >> Bernd. >> >