From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20649 invoked by alias); 2 Oct 2015 07:39:32 -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 20634 invoked by uid 89); 2 Oct 2015 07:39:31 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.0 required=5.0 tests=AWL,BAYES_00,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx2.suse.de Received: from mx2.suse.de (HELO mx2.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (CAMELLIA256-SHA encrypted) ESMTPS; Fri, 02 Oct 2015 07:39:31 +0000 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 32F03ABD9; Fri, 2 Oct 2015 07:39:27 +0000 (UTC) Date: Fri, 02 Oct 2015 07:39:00 -0000 From: Richard Biener To: Eric Botcazou cc: gcc-patches@gcc.gnu.org, Jan Hubicka Subject: Re: Do not use TYPE_CANONICAL in useless_type_conversion In-Reply-To: <57801859.QRu7TrYMFC@polaris> Message-ID: References: <20150930211235.GB30640@kam.mff.cuni.cz> <3212548.nTy76256t9@polaris> <57801859.QRu7TrYMFC@polaris> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SW-Source: 2015-10/txt/msg00157.txt.bz2 On Thu, 1 Oct 2015, Eric Botcazou wrote: > > Do we require that to match? I don't remember that we do. > > For scalar types (and arrays of scalars), the alignment is essentially encoded > in the size/mode pair but that's not the case for non-array aggregate types, > so declaring a conversion that changes the alignment as useless seems weird. Yeah, though we don't have conversions of aggregates. We use the predicate to tell whether an aggregate assignment is valid GIMPLE. LHS and RHS alignment do not have to match AFAIK. Richard.