From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15668 invoked by alias); 10 Dec 2007 19:55:15 -0000 Received: (qmail 15656 invoked by uid 22791); 10 Dec 2007 19:55:14 -0000 X-Spam-Check-By: sourceware.org Received: from a82-93-67-168.adsl.xs4all.nl (HELO laptop.moene.indiv.nluug.nl) (82.93.67.168) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 10 Dec 2007 19:55:08 +0000 Received: from [127.0.0.1] (ident=toon) by laptop.moene.indiv.nluug.nl with esmtp (Exim 4.68) (envelope-from ) id 1J1oiS-00039W-NX; Mon, 10 Dec 2007 20:55:00 +0100 Message-ID: <475D9994.200@moene.indiv.nluug.nl> Date: Mon, 10 Dec 2007 19:55:00 -0000 From: Toon Moene User-Agent: Icedove 1.5.0.10 (X11/20070328) MIME-Version: 1.0 To: Kenneth Zadeck CC: Jakub Jelinek , Richard Guenther , gcc-patches@gcc.gnu.org, Nathan Froyd , Mark Mitchell , Diego Novillo Subject: Re: [lto] set alias info, poorly References: <20071206222919.GS14706@codesourcery.com> <84fc9c000712070247g6ac73f01m94e71acfdac039c1@mail.gmail.com> <20071207105948.GE13207@devserv.devel.redhat.com> <475D4552.6090306@naturalbridge.com> In-Reply-To: <475D4552.6090306@naturalbridge.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes 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 X-SW-Source: 2007-12/txt/msg00467.txt.bz2 Kenneth Zadeck wrote: > If you want to ask a question about two types, the first part of > that check will to see if the types come from the same front end. If > they do, then this issue can be resolved by asking some language > dependent code that will be located in the middle end of the compiler. Well, that will mean that it'll be a fascinating piece of "language dependent code [...] located in the middle end of the compiler". The Fortran rules are basically: If you don't *tell* the compiler (hence the front end) that two items alias, they don't. I think this means that LTO *with* Fortran-sensible alias analysis will only work if the Fortran front end actually determines alias equivalence sets and passes that down to the middle end, which then (in this magically "language dependent code") has to do something intelligent with it ... Hmmmm, magic ... -- Toon Moene - e-mail: toon@moene.indiv.nluug.nl - phone: +31 346 214290 Saturnushof 14, 3738 XG Maartensdijk, The Netherlands At home: http://moene.indiv.nluug.nl/~toon/ GNU Fortran's path to Fortran 2003: http://gcc.gnu.org/wiki/Fortran2003