From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 82357 invoked by alias); 11 Aug 2015 08:57:27 -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 82280 invoked by uid 48); 11 Aug 2015 08:57:21 -0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/67167] cilkplus vectorization problems Date: Tue, 11 Aug 2015 08:57:00 -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: 5.1.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: 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: keywords bug_status cf_reconfirmed_on cc dependson everconfirmed 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: 2015-08/txt/msg00692.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67167 Richard Biener changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Status|UNCONFIRMED |NEW Last reconfirmed| |2015-08-11 CC| |kyukhin at gcc dot gnu.org Depends on| |66502 Ever confirmed|0 |1 --- Comment #1 from Richard Biener --- t.c:28:13: note: === get_loop_niters === t.c:28:13: note: not vectorized: number of iterations cannot be computed. t.c:28:13: note: bad loop form. t.c:22:6: note: vectorized 0 loops in function. Which is probably because the loop has two IVs and a combined exit test: : # _32 = PHI <0(4), _21(6)> # _33 = PHI <0(4), _22(6)> ... _21 = _32 + 1; _22 = _33 + 1; _25 = size_9(D) > _22; _23 = size_9(D) > _21; _24 = _23 & _25; if (_24 != 0) goto ; else goto ; related to PR66502 (proposed patch helps and makes the testcase vectorized, but as noted in the PR regresses another case). Not sure if this can be reasonably addressed in Cilk+ lowering as well? (generate a single IV) Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66502 [Bug 66502] SCCVN can't handle PHIs optimistically optimally