From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1574 invoked by alias); 29 Jan 2015 20:13:40 -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 1540 invoked by uid 89); 29 Jan 2015 20:13:39 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.1 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: gate.crashing.org Received: from gate.crashing.org (HELO gate.crashing.org) (63.228.1.57) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Thu, 29 Jan 2015 20:13:38 +0000 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.13.8) with ESMTP id t0TKDYRd017474; Thu, 29 Jan 2015 14:13:34 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id t0TKDX1Z017469; Thu, 29 Jan 2015 14:13:33 -0600 Date: Thu, 29 Jan 2015 20:50:00 -0000 From: Segher Boessenkool To: Jeff Law Cc: "gcc-patches@gcc.gnu.org >> gcc-patches" Subject: Re: [PATCH][PR target/15184] Fix for direct byte access on x86 Message-ID: <20150129201331.GD28561@gate.crashing.org> References: <54CA4407.5050905@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54CA4407.5050905@redhat.com> User-Agent: Mutt/1.4.2.3i X-IsSubscribed: yes X-SW-Source: 2015-01/txt/msg02659.txt.bz2 On Thu, Jan 29, 2015 at 07:30:31AM -0700, Jeff Law wrote: > @@ -2643,6 +2644,34 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, > || GET_CODE (src) == LSHIFTRT) > nshift++; > } > + > + /* If I0 loads a memory and I3 sets the same memory, then I2 and I3 > + are likely manipulating its value. Ideally we'll be able to combine > + all four insns into a bitfield insertion of some kind. "I1 and I2"? Very simple patch, nice :-) Segher