From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 6B4A73858C53 for ; Tue, 26 Apr 2022 13:32:58 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 6B4A73858C53 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-633-akwWBs8SOwGxyL1lQXdRZw-1; Tue, 26 Apr 2022 09:32:56 -0400 X-MC-Unique: akwWBs8SOwGxyL1lQXdRZw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3807A811E78; Tue, 26 Apr 2022 13:32:56 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C874D54ACB2; Tue, 26 Apr 2022 13:32:55 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.16.1/8.16.1) with ESMTPS id 23QDWq3T3663988 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 26 Apr 2022 15:32:53 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.16.1/8.16.1/Submit) id 23QDWp8B3663985; Tue, 26 Apr 2022 15:32:51 +0200 Date: Tue, 26 Apr 2022 15:32:50 +0200 From: Jakub Jelinek To: Tobias Burnus Cc: Mikael Morin , gfortran , gcc-patches , Harald Anlauf Subject: Re: [PATCH] fortran: Avoid infinite self-recursion [PR105381] Message-ID: Reply-To: Jakub Jelinek References: <8f082ce4-a6a9-72c1-a882-4663426adaff@orange.fr> <4567d0f0-3077-d582-e2d2-b0169c322009@codesourcery.com> MIME-Version: 1.0 In-Reply-To: <4567d0f0-3077-d582-e2d2-b0169c322009@codesourcery.com> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: fortran@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Fortran mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 26 Apr 2022 13:33:08 -0000 On Tue, Apr 26, 2022 at 03:22:08PM +0200, Tobias Burnus wrote: > LGTM - however: > > On 26.04.22 14:38, Mikael Morin wrote: > > --- a/gcc/fortran/trans-array.cc > > +++ b/gcc/fortran/trans-array.cc > > @@ -3698,7 +3698,8 @@ non_negative_strides_array_p (tree expr) > > if (DECL_P (expr) > > && DECL_LANG_SPECIFIC (expr)) > > if (tree orig_decl = GFC_DECL_SAVED_DESCRIPTOR (expr)) > > - return non_negative_strides_array_p (orig_decl); > > + if (orig_decl != expr) > > + return non_negative_strides_array_p (orig_decl); > > Is the if()if()if() cascade really needed? I can see a reason that an > extra 'if' is preferred for the variable declaration of orig_decl, but > can't we at least put the new 'orig_decl != expr' with an '&&' into the > same if as the decl/in the second if? Besides clearer, it also avoids > further identing the return line. I think we can't in C++11/C++14. The options can be if orig_decl would be declared earlier, then it can be tree orig_decl; if (DECL_P (expr) && DECL_LANG_SPECIFIC (expr) && (orig_decl = GFC_DECL_SAVED_DESCRIPTOR (expr)) && orig_decl != expr) return non_negative_strides_array_p (orig_decl); but I think this is generally frowned upon, or one can repeat it like: if (DECL_P (expr) && DECL_LANG_SPECIFIC (expr) && GFC_DECL_SAVED_DESCRIPTOR (expr) && GFC_DECL_SAVED_DESCRIPTOR (expr) != expr) return non_negative_strides_array_p (GFC_DECL_SAVED_DESCRIPTOR (expr)); or what Mikael wrote, perhaps with the && on one line: if (DECL_P (expr) && DECL_LANG_SPECIFIC (expr)) if (tree orig_decl = GFC_DECL_SAVED_DESCRIPTOR (expr)) if (orig_decl != expr) return non_negative_strides_array_p (orig_decl); In C++17 and later one can write: if (DECL_P (expr) && DECL_LANG_SPECIFIC (expr)) if (tree orig_decl = GFC_DECL_SAVED_DESCRIPTOR (expr); orig_decl && orig_decl != expr) return non_negative_strides_array_p (orig_decl); Jakub