[Bug math/16517] New: Missing underflow exception from tanf

[Bug math/16517] New: Missing underflow exception from tanf

[zimmerma+gcc at loria dot fr]

https://sourceware.org/bugzilla/show_bug.cgi?id=16517

            Bug ID: 16517
           Summary: Missing underflow exception from tanf
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
          Assignee: unassigned at sourceware dot org
          Reporter: zimmerma+gcc at loria dot fr

Created attachment 7382
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7382&action=edit
test program

on x86_64 the attached test program gives:

GNU libc version: 2.18.90
GNU libc release: development
x=0x1p-149 (1.401298464e-45)
libc: tanf(x)=0x1p-149 (1.401298464e-45) underflow=0
mpfr: tanf(x)=0x1p-149 (1.401298464e-45)
ulp difference: 0.000000

Since the result is the smallest positive subnormal, an underflow exception
should be raised

See http://webloria.loria.fr/~zimmerma/glibc/

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[Bug math/16517] Missing underflow exception from tanf

[zimmerma+gcc at loria dot fr]

https://sourceware.org/bugzilla/show_bug.cgi?id=16517

--- Comment #1 from Paul Zimmermann <zimmerma+gcc at loria dot fr> ---
same in extended precision:

Testing function tan for exponent 0 [seed=8344].
 rounding mode MPFR_RNDU:
      wrong underflow flag for x=-8.0000000000000000@-4112
      library gives -8.0000000000000000@-4112
      mpfr    gives -8.0000000000000000@-4112
      underflow: mpfr 1, library 0

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[Bug math/16517] Missing underflow exception from tanf/tan/tanl

[zimmerma+gcc at loria dot fr]

https://sourceware.org/bugzilla/show_bug.cgi?id=16517

Paul Zimmermann <zimmerma+gcc at loria dot fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Missing underflow exception |Missing underflow exception
                   |from tanf                   |from tanf/tan/tanl

--- Comment #2 from Paul Zimmermann <zimmerma+gcc at loria dot fr> ---
idem in double precision:

Testing function tan for exponent 0 [seed=17940].
 rounding mode MPFR_RNDU:
      wrong underflow flag for x=-4.0000000000000@-269
      library gives -4.0000000000000@-269
      mpfr    gives -4.0000000000000@-269
      underflow: mpfr 1, library 0

This is the smallest subnormal 0x1p-1074.

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[Bug math/16517] Missing underflow exception from tanf/tan/tanl

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16517

Florian Weimer <fweimer at redhat dot com> changed:

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

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[Bug math/16517] Missing underflow exception from tanf/tan/tanl

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16517

--- Comment #3 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
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The branch, master has been updated
       via  37550cb3d6591a8f443467707ec80b4ab5c2e157 (commit)
      from  db2bcbcb631f1c1aa023ef9f23a968e1ac288423 (commit)

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=37550cb3d6591a8f443467707ec80b4ab5c2e157

commit 37550cb3d6591a8f443467707ec80b4ab5c2e157
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Fri Aug 7 23:10:35 2015 +0000

    Fix tan missing underflows (bug 16517).

    Similar to various other bugs in this area, some tan implementations
    do not raise the underflow exception for subnormal arguments, when the
    result is tiny and inexact.  This patch forces the exception in a
    similar way to previous fixes.

    Tested for x86_64, x86, mips64 and powerpc.

        [BZ #16517]
        * sysdeps/ieee754/dbl-64/s_tan.c: Include <float.h>.
        (tan): Force underflow exception for arguments with small absolute
        value.
        * sysdeps/ieee754/flt-32/k_tanf.c: Include <float.h>.
        (__kernel_tanf): Force underflow exception for arguments with
        small absolute value.
        * sysdeps/ieee754/ldbl-128/k_tanl.c: Include <float.h>.
        (__kernel_tanl): Force underflow exception for arguments with
        small absolute value.
        * sysdeps/ieee754/ldbl-128ibm/k_tanl.c: Include <float.h>.
        (__kernel_tanl): Force underflow exception for arguments with
        small absolute value.
        * sysdeps/ieee754/ldbl-96/k_tanl.c: Include <float.h>.
        (__kernel_tanl): Force underflow exception for arguments with
        small absolute value.
        * math/auto-libm-test-in: Add more tests of tan.
        * math/auto-libm-test-out: Regenerated.

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

Summary of changes:
 ChangeLog                            |   21 +++
 NEWS                                 |    2 +-
 math/auto-libm-test-in               |    4 +
 math/auto-libm-test-out              |  316 ++++++++++++++++++++++++++++++++++
 sysdeps/ieee754/dbl-64/s_tan.c       |    6 +
 sysdeps/ieee754/flt-32/k_tanf.c      |   13 ++-
 sysdeps/ieee754/ldbl-128/k_tanl.c    |   12 ++-
 sysdeps/ieee754/ldbl-128ibm/k_tanl.c |   12 ++-
 sysdeps/ieee754/ldbl-96/k_tanl.c     |   12 ++-
 9 files changed, 393 insertions(+), 5 deletions(-)

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[Bug math/16517] Missing underflow exception from tanf/tan/tanl

[jsm28 at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16517

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |2.23

--- Comment #4 from Joseph Myers <jsm28 at gcc dot gnu.org> ---
Fixed for 2.23.

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