From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3401 invoked by alias); 4 Feb 2010 11:12:00 -0000 Received: (qmail 3369 invoked by uid 48); 4 Feb 2010 11:11:48 -0000 Date: Thu, 04 Feb 2010 11:12:00 -0000 Message-ID: <20100204111148.3368.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug rtl-optimization/36712] Inefficient loop unrolling In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rearnsha at gcc dot gnu dot org" Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2010-02/txt/msg00270.txt.bz2 ------- Comment #9 from rearnsha at gcc dot gnu dot org 2010-02-04 11:11 ------- (In reply to comment #8) > ldr r2, [r1, #0] > mul r3, r2, r0 > str r3, [r1], #4 > ldr r2, [r1, #0] > mul r3, r2, r0 > str r3, [r1], #4 > ldr r2, [r1, #0] [...] Ug, on a dual-issue core with load delay slots that code will REALLY suck. there's almost nothing that can be dual issued and the loaded values are used in the instruction immediately after the load. -- rearnsha at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rearnsha at gcc dot gnu dot | |org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36712