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From: "siddhesh at redhat dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug math/14412] Removal of sysdeps/x86_64/fpu/s_sincos.S causes regressions Date: Tue, 30 Apr 2013 05:41:00 -0000 [thread overview] Message-ID: <bug-14412-131-XcPHji4tSN@http.sourceware.org/bugzilla/> (raw) In-Reply-To: <bug-14412-131@http.sourceware.org/bugzilla/> http://sourceware.org/bugzilla/show_bug.cgi?id=14412 --- Comment #45 from Siddhesh Poyarekar <siddhesh at redhat dot com> 2013-04-30 05:41:27 UTC --- (In reply to comment #32) > I suspect this is just a boundary issue (the [] should be () in the range) > since slightly smaller values give more reasonable, but still badly wrong, > results. For example if x is 0x1p62, Yes, it is () and not [], according to the manual. > > -0.702922443619209 -0.707132927452779 > > which is wrong in the third decimal place. > This is not restricted to numbers on the boundary. A quick google search on accuracy of fsincos will show that there are numbers even close to pi/2 that are way off in terms of accuracy. > Siddhesh, could you explain the motivation for "overloading" the meaning of > "_finite" with "fast but wrong"? I'm guessing the idea is that you're thinking > finite math implies not just lack of infinities but also "unreasonably large" > inputs? This is definitely the glibc team's call, since there's no reasonable > basis for assuming you'll get correct results from non-default > performance-oriented math settings, but I think some justification would be > nice. That was a mistake - I somehow muddled it up with -ffast-math in my head. I'm going to first try to see if the default sincos can be made faster. Jakub pointed out offline that the argument reduction code is duplicated in the calls to __sin and __cos and consolidating that in sincos should definitely be a good first step. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.
next prev parent reply other threads:[~2013-04-30 5:41 UTC|newest] Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-26 21:08 [Bug math/14412] New: Removal of sysdeps/x86_64/fpu/s_sincos.S causes pdf rendering time regression markus at trippelsdorf dot de 2012-07-26 21:09 ` [Bug math/14412] " markus at trippelsdorf dot de 2012-07-26 21:14 ` markus at trippelsdorf dot de 2012-07-27 6:44 ` aj at suse dot de 2012-07-27 7:18 ` markus at trippelsdorf dot de 2012-07-27 12:33 ` markus at trippelsdorf dot de 2012-07-28 22:15 ` bugdal at aerifal dot cx 2012-08-03 3:51 ` carlos_odonell at mentor dot com 2012-08-09 10:14 ` markus at trippelsdorf dot de 2012-08-19 9:31 ` markus at trippelsdorf dot de 2012-08-19 9:37 ` [Bug math/14412] Removal of sysdeps/x86_64/fpu/s_sincos.S causes regressions markus at trippelsdorf dot de 2012-12-03 22:13 ` davem at davemloft dot net 2012-12-04 0:00 ` carlos at systemhalted dot org 2013-04-25 21:48 ` wbrana at gmail dot com 2013-04-25 23:35 ` carlos at redhat dot com 2013-04-25 23:58 ` bugdal at aerifal dot cx 2013-04-26 0:14 ` bugdal at aerifal dot cx 2013-04-26 2:55 ` siddhesh at redhat dot com 2013-04-26 3:08 ` bugdal at aerifal dot cx 2013-04-26 3:50 ` siddhesh at redhat dot com 2013-04-26 6:29 ` markus at trippelsdorf dot de 2013-04-26 6:40 ` jakub at redhat dot com 2013-04-26 10:00 ` siddhesh at redhat dot com 2013-04-26 11:31 ` joseph at codesourcery dot com 2013-04-26 11:33 ` joseph at codesourcery dot com 2013-04-26 11:42 ` siddhesh at redhat dot com 2013-04-26 13:52 ` bugdal at aerifal dot cx 2013-04-26 13:55 ` bugdal at aerifal dot cx 2013-04-26 15:07 ` joseph at codesourcery dot com 2013-04-26 15:20 ` wbrana at gmail dot com 2013-04-29 10:29 ` siddhesh at redhat dot com 2013-04-29 10:50 ` wbrana at gmail dot com 2013-04-29 11:55 ` bugdal at aerifal dot cx 2013-04-29 12:32 ` wbrana at gmail dot com 2013-04-29 13:21 ` Ondřej Bílka 2013-04-29 13:21 ` neleai at seznam dot cz 2013-04-29 13:28 ` bugdal at aerifal dot cx 2013-04-29 14:04 ` Ondřej Bílka 2013-04-29 13:32 ` bugdal at aerifal dot cx 2013-04-29 13:36 ` wbrana at gmail dot com 2013-04-29 13:44 ` siddhesh at redhat dot com 2013-04-29 13:51 ` bugdal at aerifal dot cx 2013-04-29 14:04 ` neleai at seznam dot cz 2013-04-29 14:19 ` siddhesh at redhat dot com 2013-04-29 14:29 ` markus at trippelsdorf dot de 2013-04-29 14:48 ` bugdal at aerifal dot cx 2013-04-29 16:29 ` Ondřej Bílka 2013-04-29 16:29 ` neleai at seznam dot cz 2013-04-29 17:30 ` bugdal at aerifal dot cx 2013-04-29 20:58 ` joseph at codesourcery dot com 2013-04-30 5:41 ` siddhesh at redhat dot com [this message] 2013-04-30 21:37 ` bugdal at aerifal dot cx 2013-05-01 22:25 ` bugdal at aerifal dot cx 2013-07-16 20:08 ` nshmyrev at yandex dot ru 2013-09-07 6:55 ` carlos at redhat dot com 2014-02-06 18:31 ` jsm28 at gcc dot gnu.org 2014-06-17 18:55 ` fweimer at redhat dot com
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