From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 12421 invoked by alias); 2 Nov 2012 10:56:37 -0000 Received: (qmail 11995 invoked by uid 48); 2 Nov 2012 10:56:18 -0000 From: "ebotcazou at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/55177] missed optimizations with __builtin_bswap Date: Fri, 02 Nov 2012 10:56:00 -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: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: ebotcazou at gcc dot gnu.org 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: Status Last reconfirmed CC Component Summary Ever Confirmed Severity 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/msg00130.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55177 Eric Botcazou changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2012-11-02 CC| |ebotcazou at gcc dot | |gnu.org Component|tree-optimization |rtl-optimization Summary|Missed optimisation: bswap, |missed optimizations with |mask with constant, bswap |__builtin_bswap |back again. | Ever Confirmed|0 |1 Severity|normal |enhancement --- Comment #2 from Eric Botcazou 2012-11-02 10:56:17 UTC --- If you don't need to swap, then do not use __builtin_bswap! The first example is really dumb. That being said, the second example has some merit and we should do something to optimize it at the RTL level.