From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 7DCAF3858293; Mon, 4 Mar 2024 22:56:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7DCAF3858293 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1709593009; bh=cm9S9h0KGr+UzpECNkqmGZLfhaOYiS24s4IeYdO/bI4=; h=From:To:Subject:Date:In-Reply-To:References:From; b=JKsadH2GFzL6uTvVBQ2IHYxHMp5YEJ4/LOS8NCam9qUC/Sk/HUc8WjcifxPgjFwpL LeoVD+ab2rVShT8IShH1J0+as5tO8G9jAGlWDuoA448eu4qb8WTcCeMUQIi5lXfiI/ oGVxvVldta4jFUmym4avF39WHxbcc77iAYzCXDgo= From: "pinskia at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/97759] Could std::has_single_bit be faster? Date: Mon, 04 Mar 2024 22:56:45 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Version: 10.2.1 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement X-Bugzilla-Who: pinskia at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: pinskia at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: everconfirmed assigned_to cf_reconfirmed_on bug_status 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 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97759 Andrew Pinski changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot = gnu.org Last reconfirmed| |2024-03-04 Status|UNCONFIRMED |ASSIGNED --- Comment #15 from Andrew Pinski --- >popcount (x) =3D=3D 1 || x =3D=3D 0 That could be optimized to just `popcount (x) <=3D 1`. I am going to look to see what is left in GCC 15.=