From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Daniel Colascione Newsgroups: gmane.emacs.devel Subject: Re: Preview: portable dumper Date: Tue, 20 Feb 2018 09:43:29 -0800 Message-ID: <1a9b40c9-3e24-14c2-f152-4a1a3b00e43a@dancol.org> References: <21ee28b4-c3cd-4664-a501-8df6b78d3e48@email.android.com> <5b0c48b5-1dc2-f220-37a2-09877c6a9dcc@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1519148653 27340 195.159.176.226 (20 Feb 2018 17:44:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 20 Feb 2018 17:44:13 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 Cc: emacs-devel@gnu.org To: Paul Eggert , Robert Pluim Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Feb 20 18:44:08 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eoBxX-0006jI-0d for ged-emacs-devel@m.gmane.org; Tue, 20 Feb 2018 18:44:07 +0100 Original-Received: from localhost ([::1]:56869 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eoBzZ-0007LW-37 for ged-emacs-devel@m.gmane.org; Tue, 20 Feb 2018 12:46:13 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47625) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eoBx5-00056q-B0 for emacs-devel@gnu.org; Tue, 20 Feb 2018 12:43:40 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eoBx4-0002cN-H5 for emacs-devel@gnu.org; Tue, 20 Feb 2018 12:43:39 -0500 Original-Received: from dancol.org ([2600:3c01::f03c:91ff:fedf:adf3]:34198) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eoBx4-0002bb-6l for emacs-devel@gnu.org; Tue, 20 Feb 2018 12:43:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dancol.org; s=x; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=fac2E6b9Qx26qchT8+cu/qlmI9losRGgsyjnGeaVik8=; b=JZvUcRTBUnJUj7MY8ZbPgbATCJf+DuOFQCmGG5Gtmq9ZbPBwEuTq7YKFlUnvB/8d7yFk6rkuR0J9eIIUAWW1jeSXpDf2n1vk3fZ1hKn9T5CbwR/KIwyCyJrETjW4fJsEXUVZVR95RqVUri/tNLXgCgCr6X2EQ9Ub9Jha6ObUZnBHbBiaNCEvqflCb4z+XQ6cx1vWJtqDM9i7nU4bWNz90sxe+P+qZsFKf/L2XkSdK0t0+3r6dUY1QpQ79IFxXUHBdFnAR4I7XD803kpMINQIKGP4oKRkMLmJIYFVy0bH4XOgRGXq15u9PESYIyF35xebXhew9JrNAPuSrFIO+t0DjA==; Original-Received: from [2604:4080:1321:8ab0:e568:87d3:fce4:c549] by dancol.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1eoBx2-00079Z-15; Tue, 20 Feb 2018 09:43:36 -0800 In-Reply-To: <5b0c48b5-1dc2-f220-37a2-09877c6a9dcc@cs.ucla.edu> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2600:3c01::f03c:91ff:fedf:adf3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:222932 Archived-At: On 02/20/2018 09:28 AM, Paul Eggert wrote: > On 02/20/2018 09:19 AM, Daniel Colascione wrote: >> Do you get an assertion failure if you enable assertion checking? If >> we're seeing this kind of problem from the compiler expectation alone, >> I'll definitely revert that change. > > In my experience, eassume (and 'assume') shouldn't be used for > complicated expressions, as GCC is too-easily confused by them. eassume > should be used only for expressions where the assumption really does > help the compiler, either by generating significantly-better code or by > pacifying a false alarm. I'd hoped things had gotten better, and some local testing seemed to suggest it was safe to use these days. Apparently it's not, which is a shame. It'd be nice, but not urgent, to track down which specific assumptions caused what I think must be miscompilations so we could report them upstream.