From owner-freebsd-bugs@freebsd.org Sun Apr 1 16:04:51 2018 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id CA846F63995 for ; Sun, 1 Apr 2018 16:04:51 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5A11B726AA for ; Sun, 1 Apr 2018 16:04:51 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 8BD882A397 for ; Sun, 1 Apr 2018 16:04:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w31G4obw007949 for ; Sun, 1 Apr 2018 16:04:50 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w31G4oqG007948 for freebsd-bugs@FreeBSD.org; Sun, 1 Apr 2018 16:04:50 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 227179] powl has lower than advertised precision Date: Sun, 01 Apr 2018 16:04:50 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: misc X-Bugzilla-Version: 11.0-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: yuri@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter attachments.mimetype attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 Apr 2018 16:04:52 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D227179 Bug ID: 227179 Summary: powl has lower than advertised precision Product: Base System Version: 11.0-STABLE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: misc Assignee: freebsd-bugs@FreeBSD.org Reporter: yuri@freebsd.org Attachment #192060 text/plain mime type: Created attachment 192060 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D192060&action= =3Dedit pow.cc powl produces inaccurate results. The attached program prints different results, depending on it using powl or not. In the unoptimized case, it used powl: > $ c++ -o pow pow.cc && pow > /tmp/pow-a03910.o: In function `main': > pow.cc:(.text+0x5b): warning: powl has lower than advertised precision > pow(integer{2}, 4.5l) -> 22.627416997969518774880270939320 > std::pow(2.l, 4.5l) -> 22.627416997969518774880270939320 In the optimized case, powl is pre-computed by the compiler: > $ c++ -O3 -o pow pow.cc && pow > pow(integer{2}, 4.5l) -> 22.627416997969520780220609168509 > std::pow(2.l, 4.5l) -> 22.627416997969520780220609168509 The results are different. --=20 You are receiving this mail because: You are the assignee for the bug.=