From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24135 invoked by alias); 21 Nov 2012 18:00:04 -0000 Received: (qmail 23743 invoked by uid 48); 21 Nov 2012 17:59:32 -0000 From: "amylaar at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/38785] [4.5/4.6/4.7/4.8 Regression] huge performance regression on EEMBC bitmnp01 Date: Wed, 21 Nov 2012 18:00:00 -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: missed-optimization, patch X-Bugzilla-Severity: normal X-Bugzilla-Who: amylaar at gcc dot gnu.org X-Bugzilla-Status: REOPENED X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: amylaar at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.8.0 X-Bugzilla-Changed-Fields: 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: 2012-11/txt/msg02075.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38785 --- Comment #36 from Jorn Wolfgang Rennecke 2012-11-21 17:59:10 UTC --- (In reply to comment #35) > Too bad, we really need to make some model on how many PHI copies we > introduce... I agree with Richard's comment that Joern's patch is rather bad in > respect to optimization oppurtunities. This is more or less register pressure > problem. I will try think about it a bit more ;) This is not just register pressure, these constant loads and register-register copies do not come free, either.