From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15411 invoked by alias); 21 Dec 2011 03:44:23 -0000 Received: (qmail 15402 invoked by uid 22791); 21 Dec 2011 03:44:23 -0000 X-SWARE-Spam-Status: No, hits=-2.9 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 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, 21 Dec 2011 03:44:09 +0000 From: "amker.cheng at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/43491] Unnecessary temporary for global register variable Date: Wed, 21 Dec 2011 04:35:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: rtl-optimization X-Bugzilla-Keywords: missed-optimization, ra X-Bugzilla-Severity: enhancement X-Bugzilla-Who: amker.cheng at gmail dot com X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- 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: 2011-12/txt/msg02313.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43491 --- Comment #4 from amker.cheng 2011-12-21 03:44:03 UTC --- This bug is even worse on mips. The cause is ssa-pre eliminates global register variable when it is the RHS of single assign statment, while following passes do not handle the const/register attributes of the variable. It can be handled in tree-ssa-pre.c without hurting true redundancy elimination on global register variables. So could somebody change the tag from rtl-optimization to tree-optimization?