[Bug math/15287] New: casinh inaccurate for imaginary part of argument = 1 and small real part

[Bug math/15287] New: casinh inaccurate for imaginary part of argument = 1 and small real part

[jsm28 at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15287

             Bug #: 15287
           Summary: casinh inaccurate for imaginary part of argument = 1
                    and small real part
           Product: glibc
           Version: 2.17
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
        AssignedTo: unassigned@sourceware.org
        ReportedBy: jsm28@gcc.gnu.org
    Classification: Unclassified


The implementation of casinh is substantially inaccurate for arguments with
imaginary part 1 (or -1) and small real part.  For example, on x86_64, casinh
(0x1p-30 + 1.0i) should return 0x1.64564057723e9p-15 + 0x1.921cec97c2264p+0i
but returns 0x1.0000000155515p-15 + 0x1.921db54442d43p+0i, with both parts
substantially inaccurate.  For subnormal arguments (e.g. 0x1.fp-1025), the
inaccurate results underflow where the correct results would not, with
associated underflow exceptions.  Much the same issues affect casin and cacos
for appropriate inputs to those functions.

Patch: http://sourceware.org/ml/libc-alpha/2013-03/msg00465.html

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[Bug math/15287] casinh inaccurate for imaginary part of argument = 1 and small real part

[jsm28 at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15287

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

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

--- Comment #1 from Joseph Myers <jsm28 at gcc dot gnu.org> 2013-03-21 10:28:10 UTC ---
Fixed for 2.18 by:

commit 0a1b2ae6f6d511519ab3c0ccbf54982ae65bc444
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Thu Mar 21 10:27:10 2013 +0000

    Fix casinh inaccuracy for argument with imaginary part 1 (bug 15287).

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[Bug math/15287] casinh inaccurate for imaginary part of argument = 1 and small real part

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15287

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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