From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20550 invoked by alias); 14 Jan 2014 18:19:06 -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 20512 invoked by uid 48); 14 Jan 2014 18:18:59 -0000 From: "jakub at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/59812] Missing aggressive loop optimization warning Date: Tue, 14 Jan 2014 18:19:00 -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: unknown X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: jakub 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: cc 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: 2014-01/txt/msg01488.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59812 Jakub Jelinek changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #1 from Jakub Jelinek --- The warning is documented to warn only about loops with constant number of iterations. Generally the number of iterations analysis which computes that the loop has at most 4 (valid) iterations on the other side doesn't have access to VRP to see what the values would be here, while for post-VRP it could use remembered SSA_NAME_RANGE_INFO, during VRP when this is optimized it can't, it isn't stored there yet.