From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 9EEC13851416; Fri, 18 Jun 2021 07:00:26 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9EEC13851416 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/87555] There is no need for UNSPEC_FMADDSUB Date: Fri, 18 Jun 2021 07:00:26 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 9.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Jun 2021 07:00:26 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D87555 --- Comment #9 from Richard Biener --- I don't think there's a documented canonical form but if I were to write one I'd say the smaller (as in integer) merge mask should win? There might als= o be the argument that fma vs fms (or add vs sub in the addsub case) can be the tie-breaker. Note I'm not sure that doing fmaddsub as merge of fma and fms will be optimal since that most definitely will preclude combine from recognizing fmaddsub from (addsub (mul ..) x) which would be another goal to support (PR81904) I'm looking at merging the addsub patterns with the (const_int ) trick, but I'm struggling with alternatives - time to learn ;)=