[Bug math/15004] New: `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[Bug math/15004] New: `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[ilmalakhov at yandex dot ru]

http://sourceware.org/bugzilla/show_bug.cgi?id=15004

             Bug #: 15004
           Summary: `Y/X' is incorrectly estimated in
                    sysdeps/ieee754/ldbl-96/e_atan2l.c
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
        AssignedTo: unassigned@sourceware.org
        ReportedBy: ilmalakhov@yandex.ru
    Classification: Unclassified


Hi.

 `k = sy-sx' in the code below should obviously be replaced with `k = iy-ix'.
Otherwise K may appear unexpectedly big if `Y > 0' and `X < 0'.

 E.g., `atan2l (1.0L, -1.0L)' returns `PI / 2' rather than `3 * PI / 4'.

$ cat sysdeps/ieee754/ldbl-96/e_atan2l.c
. . .
long double
__ieee754_atan2l (long double y, long double x)
{
. . .
        GET_LDOUBLE_WORDS(sx,hx,lx,x);
        ix = sx&0x7fff;
. . .
        GET_LDOUBLE_WORDS(sy,hy,ly,y);
        iy = sy&0x7fff;
. . .
   /* compute y/x */
   k = sy-sx;
   if(k > 70) z=pi_o_2+0.5*pi_lo;       /* |y/x| >  2**70 */
. . .

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[joseph at codesourcery dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15004

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2013-01-08 16:04:26 UTC ---
This file doesn't appear to be used by any configuration of glibc (x86, 
x86_64, ia64, m68k all have their own versions) so I suggest we just 
remove it (and any other ldbl-96 files that are in fact unused).

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[aj at suse dot de]

http://sourceware.org/bugzilla/show_bug.cgi?id=15004

Andreas Jaeger <aj at suse dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aj at suse dot de

--- Comment #2 from Andreas Jaeger <aj at suse dot de> 2013-01-08 18:43:33 UTC ---
If it's not used, then I wonder why we get the bug report ;) 

Il'ya Malakhov, could you tell us how you found the bug, please?

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[ilmalakhov at yandex dot ru]

http://sourceware.org/bugzilla/show_bug.cgi?id=15004

--- Comment #3 from Il'ya Malakhov <ilmalakhov at yandex dot ru> 2013-01-09 08:54:37 UTC ---
(In reply to comment #2)
. . .
> Il'ya Malakhov, could you tell us how you found the bug, please?
. . .
 We use a number of functions implemented in `sysdeps/ieee754/ldbl-96' for our
experimental architecture, which hasn't found its way to the official glibc
repository yet . . .

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[cvs-commit at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15004

--- Comment #4 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, master has been updated
       via  8bca7cd830e3563e214a6e3cf93da839f937f1a2 (commit)
      from  91a1f3fea0d6c5bc304562c313171d8cf765b910 (commit)

Those revisions listed above that are new to this repository have
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revisions in full, below.

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=8bca7cd830e3563e214a6e3cf93da839f937f1a2

commit 8bca7cd830e3563e214a6e3cf93da839f937f1a2
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Thu Nov 28 20:50:03 2013 +0000

    Remove unused ldbl-96 functions (bug 15004).

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                               |   18 +++++
 NEWS                                    |   18 ++--
 sysdeps/ieee754/ldbl-96/e_atan2l.c      |  125 -------------------------------
 sysdeps/ieee754/ldbl-96/e_ilogbl.c      |   59 ---------------
 sysdeps/ieee754/ldbl-96/e_remainderl.c  |   72 ------------------
 sysdeps/ieee754/ldbl-96/s_ceill.c       |   85 ---------------------
 sysdeps/ieee754/ldbl-96/s_fabsl.c       |   35 ---------
 sysdeps/ieee754/ldbl-96/s_finitel.c     |   36 ---------
 sysdeps/ieee754/ldbl-96/s_floorl.c      |   86 ---------------------
 sysdeps/ieee754/ldbl-96/s_fpclassifyl.c |   44 -----------
 sysdeps/ieee754/ldbl-96/s_isinfl.c      |   30 --------
 sysdeps/ieee754/ldbl-96/s_isnanl.c      |   40 ----------
 sysdeps/ieee754/ldbl-96/s_logbl.c       |   51 -------------
 sysdeps/ieee754/ldbl-96/s_nearbyintl.c  |   88 ----------------------
 sysdeps/ieee754/ldbl-96/s_nextafterl.c  |   96 -----------------------
 sysdeps/ieee754/ldbl-96/s_rintl.c       |   82 --------------------
 sysdeps/ieee754/ldbl-96/s_scalbnl.c     |   61 ---------------
 sysdeps/ieee754/ldbl-96/s_truncl.c      |   56 --------------
 18 files changed, 27 insertions(+), 1055 deletions(-)
 delete mode 100644 sysdeps/ieee754/ldbl-96/e_atan2l.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/e_ilogbl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/e_remainderl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_ceill.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_fabsl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_finitel.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_floorl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_fpclassifyl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_isinfl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_isnanl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_logbl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_nearbyintl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_nextafterl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_rintl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_scalbnl.c
 delete mode 100644 sysdeps/ieee754/ldbl-96/s_truncl.c

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[jsm28 at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=15004

Joseph Myers <jsm28 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Joseph Myers <jsm28 at gcc dot gnu.org> ---
The buggy code has been removed for 2.19, along with other unused ldbl-96
function implementations (it's quite likely others were buggy, never being
covered by the testsuite; certainly rintl and nearbyintl did not include global
cleanups that had been made to various other versions to fix bugs).  Feel free
to add functions back if submitting a port that needs them.

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15004

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fweimer at redhat dot com
              Flags|                            |security-

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[Bug math/15004] `Y/X' is incorrectly estimated in sysdeps/ieee754/ldbl-96/e_atan2l.c

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15004

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|fweimer at redhat dot com          |

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