From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28078 invoked by alias); 1 Aug 2012 16:24:25 -0000 Received: (qmail 28057 invoked by uid 22791); 1 Aug 2012 16:24:24 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED,TW_CP X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 01 Aug 2012 16:24:11 +0000 From: "burnus at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug fortran/45586] [4.8 Regression] ICE non-trivial conversion at assignment Date: Wed, 01 Aug 2012 16:24:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: fortran X-Bugzilla-Keywords: ice-checking, ice-on-valid-code, lto, wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: burnus at gcc dot gnu.org X-Bugzilla-Status: REOPENED X-Bugzilla-Priority: P4 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.8.0 X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2012-08/txt/msg00062.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45586 --- Comment #80 from Tobias Burnus 2012-08-01 16:22:52 UTC --- (In reply to comment #79) > > this%y = this%find_y() ! FAILS > > > > the lhs is a target, and the rhs is NOT a target, so that the middle-end types > > are different. :-( > > But how can this be a valid fortran program? You assign something > that is not aliased to something that suddenly makes it aliased? > If that's valid then you can make the middle-end happy by wrapping > the RHS inside a VIEW_CONVERT_EXPR with the LHS type. I have not closely looked at the dump, however, this%y = this%find_y() means that one assigns component-wise the values from the RHS to the LHS; if there are pointer components, the pointer address is assigned; if there are allocatable components, those are - if needed - first (re)allocated and then (element-wise) assigned. Thus, one only assigns the values and no pointers - and, hence, the RHS can be a nontarget while the LHS can be a target. In this example, "this%y" is a derived type with an allocatable-array component. I think the current algorithm is something like: *dst = *src; if (src->data) { (re)allocate dst->data memcpy (dst->data, src->data); } Thus, one first transfers the pointer address [besides the array bounds], but if "data" is not NULL, the data is copied. Thus, it should be safe - but an ARRAY_RANGE_REF could be nicer than a memcpy, and the VIEW_CONVERT_EXPR could be inserted.