From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5E25AC25B0D for ; Thu, 11 Aug 2022 15:32:22 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id E6C523C95D1 for ; Thu, 11 Aug 2022 17:32:19 +0200 (CEST) Received: from in-6.smtp.seeweb.it (in-6.smtp.seeweb.it [217.194.8.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 68C273C0211 for ; Thu, 11 Aug 2022 17:32:10 +0200 (CEST) Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-6.smtp.seeweb.it (Postfix) with ESMTPS id D459D1400DB8 for ; Thu, 11 Aug 2022 17:32:09 +0200 (CEST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id BFEB038D02; Thu, 11 Aug 2022 15:32:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1660231928; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AhN7BbJAf05b/Jf1ChHMg4JhKvUrHq/zZ7OO5PMdAAM=; b=tDNUy6B3WbB3zajl8imWC5RVyXc/MVy8WQIU7DqhgZIvNv5gnURI7R3tP8yfD/RQtdlBDn 9JePpC0toLYterLRZ9KG1lnJvR3o+XRwgO8Vv8SZ5IVyPubtBBh7639c+eDBpb0SeG2gG9 lJG5nzhPuVlTyv96DhzIuoBW67b+G4o= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1660231928; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AhN7BbJAf05b/Jf1ChHMg4JhKvUrHq/zZ7OO5PMdAAM=; b=zFXEn7gLelBei7JMLo1ApI674JHKk3Vb8MjPoY/OEgb33Bxosm6WVhVhg6f+AQGvSIjBUI b8+qds6/C0FS0nCA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id AAEE913A9B; Thu, 11 Aug 2022 15:32:08 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id RAHcKPgg9WLpIQAAMHmgww (envelope-from ); Thu, 11 Aug 2022 15:32:08 +0000 Date: Thu, 11 Aug 2022 17:33:59 +0200 From: Cyril Hrubis To: Edward Liaw Message-ID: References: <20220712173921.2623135-1-edliaw@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Virus-Scanned: clamav-milter 0.102.4 at in-6.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH v1] syscalls/signal06: add volatile to loop variable X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel-team@android.com, ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hi! > I think I finally understand what you mean by this now; it is rather > strange that the volatility of D does not protect loop from being > optimized away by the compiler. I don't have a good explanation as to > why it's happening but I'm not sure how to evaluate what's going on > either. Should I do anything to move this patch forward? It all boils down if we want to work around something that looks like a compiler bug in tests or not. I would be inclined not to do so since LTP was littered with quite a lot of workarounds for glibc/compiler bugs and we spend quite some time cleaning that mess up. But in this case I can agree that this is a borderland issue so I'm not strongly against that either. -- Cyril Hrubis chrubis@suse.cz -- Mailing list info: https://lists.linux.it/listinfo/ltp