From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20676 invoked by alias); 23 Aug 2011 09:59:46 -0000 Received: (qmail 20666 invoked by uid 22791); 23 Aug 2011 09:59:45 -0000 X-SWARE-Spam-Status: No, hits=-2.0 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 23 Aug 2011 09:59:29 +0000 Received: (qmail 26437 invoked from network); 23 Aug 2011 09:59:28 -0000 Received: from unknown (HELO ?84.152.222.249?) (bernds@127.0.0.2) by mail.codesourcery.com with ESMTPA; 23 Aug 2011 09:59:28 -0000 Message-ID: <4E5379A6.1020905@codesourcery.com> Date: Tue, 23 Aug 2011 10:34:00 -0000 From: Bernd Schmidt User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.18) Gecko/20110801 Lightning/1.0b3pre Thunderbird/3.1.11 MIME-Version: 1.0 To: Jakub Jelinek CC: Eric Botcazou , Richard Sandiford , Richard Henderson , GCC Patches Subject: Re: Add __builtin_clrsb, similar to clz/ctz References: <4DF9FA9A.8040505@codesourcery.com> <4DFA2E85.2030601@redhat.com> <4DFFA1AE.7070405@codesourcery.com> <20110823090549.GC2687@tyan-ft48-01.lab.bos.redhat.com> <4E53744B.6040502@codesourcery.com> <20110823095243.GD2687@tyan-ft48-01.lab.bos.redhat.com> In-Reply-To: <20110823095243.GD2687@tyan-ft48-01.lab.bos.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2011-08/txt/msg01860.txt.bz2 On 08/23/11 11:52, Jakub Jelinek wrote: > On Tue, Aug 23, 2011 at 11:35:07AM +0200, Bernd Schmidt wrote: >>> cse_process_notes_1 >>> perhaps could be changed for VOIDmode new_rtx to try to >>> simplify_replace_rtx it... >> >> Is this where the problem came from? Sounds like it's worth a try. > > In this case, yes. But there are many other places all around the > compiler that need to disallow unary op with VOIDmode operand. > In cse.c alone e.g. fold_rtx (twice), in combine.c e.g. in do_SUBST, > subst, etc. Do we want to special case all those 7 unary ops there too? > Is it really worth it to save one subreg or truncate in the md patterns > for rarely used rtxes? Maybe not. I'll approve a patch to change it back, even if I think it's not a good representation. Bernd