From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id C0BA33854800; Thu, 29 Oct 2020 07:17:37 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C0BA33854800 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/97623] [9/10/11 Regression] Extremely slow O2 compile (>>O(n^2)) Date: Thu, 29 Oct 2020 07:17:37 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 9.3.1 X-Bugzilla-Keywords: compile-time-hog X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED 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: bug_status everconfirmed short_desc cf_known_to_work component cf_reconfirmed_on Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Oct 2020 07:17:37 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97623 Richard Biener changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Ever confirmed|0 |1 Summary|Extremely slow O2 compile |[9/10/11 Regression] |(>>O(n^2)) |Extremely slow O2 compile | |(>>O(n^2)) Known to work| |7.5.0 Component|middle-end |tree-optimization Last reconfirmed| |2020-10-29 --- Comment #2 from Richard Biener --- tree PRE : 6.83 ( 96%) 0.02 ( 50%) 6.90 ( = 96%) 11764 kB ( 37%) Confirmed. insert iterations =3D=3D 187: 1 RPO blocks: 843 RPO iterations =3D=3D 10: 1 compute_antic iterations =3D=3D 2: 1 RPO blocks visited: 843 New PHIs: 15021 RPO num values =3D=3D 7009: 1 Insertions: 23846 RPO max_rpo iterations =3D=3D 0: 1 RPO blocks executable: 843 RPO block visited times =3D=3D 1: 843 HOIST inserted: 13098 RPO num lattice =3D=3D 7009: 1 RPO num avail =3D=3D 6755: 1 Symbol to SSA rewrite: 1 Eliminated: 27807 So the number of insert iterations is troubling. Now the testcase is a bit big to analyze what's going on there, we seem to need about 2 insert iterations for each of the statements. It looks like the statements are 1:1 copies besides sometimes changing the constant index into the tbt__rvtop__swerv__ifu__bp__bht_bank_wr_data array? I will have a closer look.=