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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id E8AE13857C4F for ; Thu, 26 Nov 2020 14:20:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E8AE13857C4F Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-319-HYquA0STNaqJ-cIvbZm1Xw-1; Thu, 26 Nov 2020 09:20:49 -0500 X-MC-Unique: HYquA0STNaqJ-cIvbZm1Xw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6DC68185E48E; Thu, 26 Nov 2020 14:20:48 +0000 (UTC) Received: from tucnak.zalov.cz (ovpn-113-127.ams2.redhat.com [10.36.113.127]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0343A60636; Thu, 26 Nov 2020 14:20:47 +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 0AQEKiLK2374231 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 26 Nov 2020 15:20:45 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.16.1/8.16.1/Submit) id 0AQEKhhO2374230; Thu, 26 Nov 2020 15:20:43 +0100 Date: Thu, 26 Nov 2020 15:20:43 +0100 From: Jakub Jelinek To: Roger Sayle , gcc-patches@gcc.gnu.org, "'Richard Biener'" , "'Joseph S. Myers'" Subject: Re: [PATCH] fold-const: Don't consider NaN non-negative [PR97965] Message-ID: <20201126142043.GZ3788@tucnak> Reply-To: Jakub Jelinek References: <20201126083155.GN3788@tucnak> <20201126094903.GV3788@tucnak> <02b501d6c3fb$e248fc90$a6daf5b0$@nextmovesoftware.com> <20201126141322.GY3788@tucnak> MIME-Version: 1.0 In-Reply-To: <20201126141322.GY3788@tucnak> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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=-5.9 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Nov 2020 14:20:53 -0000 On Thu, Nov 26, 2020 at 03:13:22PM +0100, Jakub Jelinek via Gcc-patches wrote: > On Thu, Nov 26, 2020 at 01:56:03PM -0000, Roger Sayle wrote: > > My completely untested solution is the attached patch. My apologies, I'm > > not > > even set up to compile things on the laptop that I'm composing this e-mail > > on, > > but my notes/proposals on tackling PR97965 are easier expressed as the > > actual > > suggested changes/edits. [Forgive me if I've made a typo]. > > Ah, thanks, I wasn't aware of that function. > Looking at the tree_expr_maybe_nan_p implementation, I wonder if: > case PLUS_EXPR: > case MINUS_EXPR: > case MULT_EXPR: > return !tree_expr_finite_p (TREE_OPERAND (x, 0)) > || !tree_expr_finite_p (TREE_OPERAND (x, 1)); > shouldn't try harder, for + and minus, isn't > return (tree_expr_maybe_nan_p (TREE_OPERAND (x, 0)) > || tree_expr_maybe_nan_p (TREE_OPERAND (x, 1)) > || (!tree_expr_finite_p (TREE_OPERAND (x, 0)) > && !tree_expr_finite_p (TREE_OPERAND (x, 1)))); > what we want to test? I mean, if neither operand is a NaN and > one of the operands is finite, then the result will be either finite > or inf or -inf, but not NaN. MULT_EXPR would presumably also need to > rule out zeros (i.e. use the *nonzero* APIs too, on the other side > +-inf * +-inf is not NaN). > > Another thing, tree_expr_nonzero_warnv_p handles not just trees, but also > GIMPLE, shouldn't these tree_expr_finite_p and tree_expr_maybe_nan_p APIs > be also rewritten so that they can also handle SSA_NAMEs by walking the def > chains? Though, of course, both of this can be done incrementally later on. I'll test your patch tonight. Jakub