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From: "rguenth at tat dot physik dot uni-tuebingen dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/11706] New: std::pow(T, int) implementation pessimizes code Date: Tue, 29 Jul 2003 12:03:00 -0000 [thread overview] Message-ID: <20030729120327.11706.rguenth@tat.physik.uni-tuebingen.de> (raw) PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11706 Summary: std::pow(T, int) implementation pessimizes code Product: gcc Version: 3.4 Status: UNCONFIRMED Severity: normal Priority: P2 Component: libstdc++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rguenth at tat dot physik dot uni-tuebingen dot de CC: gcc-bugs at gcc dot gnu dot org GCC host triplet: i686-pc-linux-gnu The std::__pow_helper() implementation ends up emitting a call to std::__cmath_power() for all constant powers as f.i. in the call to std::pow(x, 2). This severly pessimizes code and can be cured by teaching optimal computation to std::__pow_helper() via the __builtin_constant_p mechanism of gcc. See http://gcc.gnu.org/ml/gcc/2003-07/msg01950.html for an example improved implementation. The same problem exists on the 3.3 branch.
next reply other threads:[~2003-07-29 12:03 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2003-07-29 12:03 rguenth at tat dot physik dot uni-tuebingen dot de [this message] 2003-07-29 12:39 ` [Bug libstdc++/11706] " steven at gcc dot gnu dot org 2003-07-29 12:53 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-07-29 13:01 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-07-29 13:19 ` gdr at integrable-solutions dot net 2003-08-23 1:56 ` dhazeghi at yahoo dot com 2003-09-29 15:05 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-09-29 15:11 ` gdr at integrable-solutions dot net 2003-09-29 15:29 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-09-29 15:41 ` gdr at integrable-solutions dot net 2003-09-29 15:43 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-09-29 17:30 ` Gabriel Dos Reis 2003-09-29 17:36 ` gdr at integrable-solutions dot net 2003-11-13 21:42 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-12-05 23:52 ` bkoz at gcc dot gnu dot org 2003-12-06 18:26 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-12-06 19:26 ` gdr at integrable-solutions dot net 2003-12-06 19:50 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-12-06 20:05 ` rguenth at tat dot physik dot uni-tuebingen dot de 2003-12-06 20:33 ` gdr at integrable-solutions dot net 2004-03-10 15:14 ` pcarlini at suse dot de 2004-03-10 15:34 ` gdr at integrable-solutions dot net 2004-03-10 15:43 ` pcarlini at suse dot de 2004-03-10 19:51 ` gdr at integrable-solutions dot net 2004-03-10 20:01 ` pcarlini at suse dot de 2004-03-10 20:19 ` gdr at integrable-solutions dot net 2004-03-10 20:26 ` pcarlini at suse dot de 2004-03-10 20:43 ` gdr at integrable-solutions dot net 2004-03-10 22:27 ` pcarlini at suse dot de 2004-03-10 22:39 ` gdr at integrable-solutions dot net 2004-03-10 22:45 ` bangerth at dealii dot org 2004-03-10 22:47 ` pcarlini at suse dot de 2004-03-10 23:39 ` gdr at integrable-solutions dot net 2004-03-11 10:42 ` cvs-commit at gcc dot gnu dot org 2004-03-11 11:37 ` cvs-commit at gcc dot gnu dot org 2004-03-11 12:06 ` pcarlini at suse dot de 2004-03-11 18:55 ` rguenth at tat dot physik dot uni-tuebingen dot de 2004-03-11 19:04 ` rguenth at tat dot physik dot uni-tuebingen dot de 2004-03-11 20:14 ` rguenth at tat dot physik dot uni-tuebingen dot de 2004-03-12 1:43 ` rakdver at gcc dot gnu dot org 2004-05-16 22:22 ` pinskia at gcc dot gnu dot org 2004-09-23 18:22 ` pinskia at gcc dot gnu dot org 2004-10-02 4:04 ` pinskia at gcc dot gnu dot org 2004-10-02 4:06 ` pinskia at gcc dot gnu dot org 2005-01-12 16:17 ` rguenth at tat dot physik dot uni-tuebingen dot de 2005-02-07 22:33 ` rguenth at gcc dot gnu dot org 2005-02-10 0:43 ` rguenth at gcc dot gnu dot org 2005-02-10 1:13 ` rguenth at gcc dot gnu dot org 2005-02-10 1:13 ` pcarlini at suse dot de 2005-02-13 19:18 ` pcarlini at suse dot de 2005-02-13 19:18 ` cvs-commit at gcc dot gnu dot org 2005-05-07 19:56 ` pinskia at gcc dot gnu dot org
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