From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by sourceware.org (Postfix) with ESMTP id E2C28385701E for ; Fri, 23 Oct 2020 10:04:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E2C28385701E Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=segher@kernel.crashing.org Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 09NA2oGH028791; Fri, 23 Oct 2020 05:02:50 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 09NA2oQo028790; Fri, 23 Oct 2020 05:02:50 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 23 Oct 2020 05:02:50 -0500 From: Segher Boessenkool To: Henri Cloetens Cc: Jeff Law , gcc-help Subject: Re: How to recognize registers after reload ?. Message-ID: <20201023100250.GZ2672@gate.crashing.org> References: <20201022222438.GX2672@gate.crashing.org> <82fed76c-e343-a155-4b3d-ef8ab07d2baf@redhat.com> <734be852-33ed-ee19-88a9-99a5905db5cf@blueice.be> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <734be852-33ed-ee19-88a9-99a5905db5cf@blueice.be> User-Agent: Mutt/1.4.2.3i X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, TXREP, T_SPF_HELO_PERMERROR, T_SPF_PERMERROR autolearn=no 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-help@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-help mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Oct 2020 10:04:36 -0000 Hi, On Fri, Oct 23, 2020 at 09:28:49AM +0200, Henri Cloetens wrote: > R30 = 1  // move immediate to register > [R20] = R30 // move to *a > return > > Now, to get this, there is not one movsi - pattern, because if there is > only one, > combine will combine both moves into something like > [R20] = 1 > and this does not exist, and combine crashes. You keep saying this. The combine pass should *not* crash, and you haven't shown any evidence it did. It will attempt to do this combination, and your backend will either or not say that is an existing insn; in neither case will combine crash. Some later pass might well not like what you said is a valid insn. Just say *that* if that is what you mean! Segher