From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28581 invoked by alias); 20 Jun 2012 09:28:15 -0000 Received: (qmail 28571 invoked by uid 22791); 20 Jun 2012 09:28:14 -0000 X-SWARE-Spam-Status: No, hits=-4.1 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED,TW_CP,TW_OV,TW_TM,TW_VZ,TW_ZB,T_FRT_LOLITA1 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 20 Jun 2012 09:27:53 +0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/53726] [4.8 Regression] aes test performance drop for eembc_2_0_peak_32 Date: Wed, 20 Jun 2012 09:28:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: WAITING X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.8.0 X-Bugzilla-Changed-Fields: Status Last reconfirmed Component CC Ever Confirmed Target Milestone Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 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: 2012-06/txt/msg01307.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53726 Richard Guenther changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |WAITING Last reconfirmed| |2012-06-20 Component|c |tree-optimization CC| |rguenth at gcc dot gnu.org Ever Confirmed|0 |1 Target Milestone|--- |4.8.0 --- Comment #2 from Richard Guenther 2012-06-20 09:27:52 UTC --- You mean the fix lead to recognition of memcpy? At least I see memcpy calls in the bad assembly. There is always a cost consideration for memcpy - does performance recover with -minline-all-stringops? I suppose BC is actually very small? The testcase does not include a runtime part so I can't check myself. Definitely a byte-wise copy loop as in the .good assembly variant, .L5: - .loc 1 14 0 is_stmt 1 discriminator 2 - movzbl 16(%esp,%eax), %edx - movb %dl, (%esi,%eax) - leal 1(%eax), %eax -.LVL5: - cmpl %ebx, %eax - jl .L5 does not look good - even a rep movb should be faster, no?