From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29398 invoked by alias); 12 Aug 2014 21:03:15 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 29320 invoked by uid 89); 12 Aug 2014 21:03:14 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Tue, 12 Aug 2014 21:03:07 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s7CL35xJ015363 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Tue, 12 Aug 2014 17:03:06 -0400 Received: from stumpy.slc.redhat.com (ovpn-113-24.phx2.redhat.com [10.3.113.24]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s7CL35V5011183; Tue, 12 Aug 2014 17:03:05 -0400 Message-ID: <53EA8109.2060402@redhat.com> Date: Tue, 12 Aug 2014 21:03:00 -0000 From: Jeff Law User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 MIME-Version: 1.0 To: David Malcolm , gcc-patches@gcc.gnu.org Subject: Re: [PATCH 005/236] Introduce as_a_nullable References: <1407345815-14551-1-git-send-email-dmalcolm@redhat.com> <1407345815-14551-6-git-send-email-dmalcolm@redhat.com> In-Reply-To: <1407345815-14551-6-git-send-email-dmalcolm@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2014-08/txt/msg01206.txt.bz2 On 08/06/14 11:19, David Malcolm wrote: > In many circumstances, is_a_helper ::test assumes that the pointer is > non-NULL, but sometimes you have a pointer of type T that can be NULL. > > Earlier versions of this patch kit made numerous uses of the ternary > operator to handle nullable pointers e.g.: > > return insn ? as_a (insn) : NULL; > > but this was ugly. Instead, introduce an as_a_nullable variant that > adds a check for NULL, so the above can be written simply as: > > return as_a_nullable (insn); > > gcc/ > * is-a.h (template as_a_nullable ) New function. Presumably the cases where we wanted to use as_a on a NULL pointer were places were we can legitimately have a NULL pointer? I guess since they'll be using as_a_nullable, they're effectively documented as potentially being NULL and we can go back and look at them at a future date. OK. jeff