From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 48148 invoked by alias); 9 Apr 2015 09:12:13 -0000 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 Received: (qmail 47984 invoked by uid 48); 9 Apr 2015 09:12:09 -0000 From: "redi at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/60976] Compilation with G++ 4.9.0 is 2-3 times slower than with 4.8.2 Date: Thu, 09 Apr 2015 09:12:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 4.9.0 X-Bugzilla-Keywords: compile-time-hog X-Bugzilla-Severity: normal X-Bugzilla-Who: redi at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2015-04/txt/msg00646.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60976 --- Comment #17 from Jonathan Wakely --- (In reply to Rene Koecher from comment #14) > I agree on your point here, however shouldn't an unchanged codebase (and > we're not using C++11 features or -std=c++11 yet) at least keep the same > performance? No, because the standard library headers you include are not unchanged if you upgrade the compiler. > It's understandable that standards compliance can counter performance but I > honestly wouldn't expect the compiler performance of older code / code not > using the new features to drop that drastically.. Please provide a testcase demonstrating the problem with pre-C++11 code.