From owner-freebsd-questions@freebsd.org Mon Jun 12 15:18:06 2017 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DF965BFE79E for ; Mon, 12 Jun 2017 15:18:06 +0000 (UTC) (envelope-from ml@netfence.it) Received: from smtp207.alice.it (smtp207.alice.it [82.57.200.103]) by mx1.freebsd.org (Postfix) with ESMTP id 75A9372E2C for ; Mon, 12 Jun 2017 15:18:05 +0000 (UTC) (envelope-from ml@netfence.it) Received: from soth.ventu (87.19.230.171) by smtp207.alice.it (8.6.060.28) (authenticated as acanedi@alice.it) id 588F428367A95A29 for freebsd-questions@freebsd.org; Mon, 12 Jun 2017 17:17:54 +0200 Received: from alamar.ventu (alamar.local.netfence.it [10.1.2.18]) by soth.ventu (8.15.2/8.15.2) with ESMTP id v5CFHrWP091075 for ; Mon, 12 Jun 2017 17:17:53 +0200 (CEST) (envelope-from ml@netfence.it) X-Authentication-Warning: soth.ventu: Host alamar.local.netfence.it [10.1.2.18] claimed to be alamar.ventu Subject: Re: -O2 flag To: freebsd-questions@freebsd.org References: <593C4679.5010104@gmail.com> <20170610230928.581e3cf9@DaemONX> <593C892D.4070200@gmail.com> <20170611142517.5898c64e@DaemONX> From: Andrea Venturoli Message-ID: Date: Mon, 12 Jun 2017 17:17:53 +0200 User-Agent: Mozilla/5.0 (X11; FreeBSD i386; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <20170611142517.5898c64e@DaemONX> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Jun 2017 15:18:07 -0000 On 06/11/17 14:25, Serpent7776 wrote: > You might want to try to: > - rebuild with enabled compiler warning flags (-W flags) > https://clang.llvm.org/docs/DiagnosticsReference.html > - rebuild with sanitizer enabled > https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html > - try running in debugger and find place where this error occurs Perhaps running your (unoptimized) code under Valgrind can help find such an error. bye av.