From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27787 invoked by alias); 7 Aug 2017 20:58:09 -0000 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 Received: (qmail 27775 invoked by uid 89); 7 Aug 2017 20:58:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.8 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY autolearn=no version=3.3.2 spammy=H*Ad:U*kenner X-HELO: vlsi1.gnat.com Received: from vlsi1.gnat.com (HELO vlsi1.gnat.com) (205.232.38.7) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 07 Aug 2017 20:58:03 +0000 Received: by vlsi1.gnat.com (Postfix, from userid 3004) id 86DEC33CA8; Mon, 7 Aug 2017 16:58:01 -0400 (EDT) Date: Mon, 07 Aug 2017 20:58:00 -0000 To: Michael.Collison@arm.com Subject: Re: [PATCH] [Aarch64] Optimize subtract in shift counts Cc: gcc-patches@gcc.gnu.org, nd@arm.com In-Reply-To: References: Message-Id: <20170807205801.86DEC33CA8@vlsi1.gnat.com> From: kenner@vlsi1.ultra.nyu.edu (Richard Kenner) X-SW-Source: 2017-08/txt/msg00548.txt.bz2 > This patch improves code generation for shifts with subtract > instructions where the first operand to the subtract is equal to the > bit-size of the operation. I would suspect that this will work on lots of targets. Is doing it in combine an option?