[Bug math/15442] New: MIPS NewABI sqrtl (soft-fp) test-ldouble sqrt (qNaN) failure

[Bug math/15442] New: MIPS NewABI sqrtl (soft-fp) test-ldouble sqrt (qNaN) failure

[macro@linux-mips.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15442

             Bug #: 15442
           Summary: MIPS NewABI sqrtl (soft-fp) test-ldouble sqrt (qNaN)
                    failure
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
        AssignedTo: macro@linux-mips.org
        ReportedBy: macro@linux-mips.org
                CC: tschwinge@sourceware.org
    Classification: Unclassified
            Target: mips-linux-gnu


This problem:

Failure: sqrt (qNaN) == qNaN: Exception "Invalid operation" set
Failure: Test: sqrt (qNaN) == qNaN
Result:
 is:         sNaN
 should be:  qNaN

is reported for sqrtl by test-ldouble for the MIPS/Linux target and the
n64 and n64 ABIs.  This is because soft-fp does not respect the MIPS NaN
encoding convention, where the quiet bit being zero denotes a qNaN.
This is the only soft-fp function used by the MIPS port.

There are other failures too, for negative numeric inputs, e.g. -1, but
in those cases the result is passed through __kernel_standard that
returns a double value rather than a long double value.  Therefore the
result is converted with __extenddftf2, that is a part of GCC's fp-bit
soft-float support.  That support suffers from a related bug being
discussed here:

http://gcc.gnu.org/ml/gcc-patches/2013-04/msg00278.html

and therefore the remaining failures cannot be removed by simply
correcting our soft-fp support.

A proposed fix has been posted here:

http://sourceware.org/ml/libc-alpha/2013-04/msg00646.html

-- that removes the test-ldouble failure referred to above.

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[Bug math/15442] MIPS NewABI sqrtl (soft-fp) test-ldouble sqrt (qNaN) failure

[macro@linux-mips.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15442

Maciej W. Rozycki <macro@linux-mips.org> changed:

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

--- Comment #1 from Maciej W. Rozycki <macro@linux-mips.org> 2013-05-16 22:54:55 UTC ---
commit 2848b105856e49d98f3c5026b6d8d790f9723c0c
Author: Maciej W. Rozycki <macro@codesourcery.com>
Date:   Thu May 16 23:33:55 2013 +0100

    MIPS: soft-fp NaN representation corrections

    [BZ #15442] This adds support for the inverse interpretation of the
    quiet bit of IEEE 754 floating-point NaN data that some processors
    use.  This includes in particular MIPS architecture processors; the
    payload used for the canonical qNaN encoding is updated accordingly
    so as not to interfere with the quiet bit.

ChangeLog:

2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>

    [BZ #15442]
    * soft-fp/op-common.h (_FP_FRAC_SNANP): New macro.
    (_FP_FRAC_SNANP_SEMIRAW): Likewise.
    (_FP_UNPACK_CANONICAL): Use _FP_FRAC_SNANP.
    (_FP_CHECK_SIGNAN_SEMIRAW): Use _FP_FRAC_SNANP_SEMIRAW.
    (_FP_SETQNAN): New macro.
    (_FP_SETQNAN_SEMIRAW): Likewise.
    (_FP_PACK_SEMIRAW): Use _FP_SETQNAN.
    (_FP_PACK_CANONICAL): Use _FP_SETQNAN.
    (_FP_ISSIGNAN): Use _FP_FRAC_SNANP.
    (FP_EXTEND): Use _FP_FRAC_SNANP.
    (FP_TRUNC): Use _FP_SETQNAN_SEMIRAW.
    * soft-fp/testit.c (gen_special_double): Take _FP_QNANNEGATEDP
    into account.
    * sysdeps/sparc/sparc32/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP):
    New macro.
    * sysdeps/sparc/sparc64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP):
    Likewise.

ChangeLog.aarch64:

2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>

    [BZ #15442]
    * sysdeps/aarch64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
    macro.

ChangeLog.alpha:

2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>

    [BZ #15442]
    * sysdeps/alpha/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
    macro.

ChangeLog.mips:

2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>

    [BZ #15442]
    * sysdeps/mips/mips64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP):
    New macro.
    (_FP_NANFRAC_S): Don't set the quiet bit.
    (_FP_NANFRAC_D): Likewise.
    (_FP_NANFRAC_Q): Likewise.
    * sysdeps/mips/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
    macro.
    (_FP_NANFRAC_S): Don't set the quiet bit.
    (_FP_NANFRAC_D): Likewise.
    (_FP_NANFRAC_Q): Likewise.

ChangeLog.powerpc:

2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>

    [BZ #15442]
    * sysdeps/powerpc/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
    macro.

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[Bug math/15442] MIPS NewABI sqrtl (soft-fp) test-ldouble sqrt (qNaN) failure

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15442

Florian Weimer <fweimer at redhat dot com> changed:

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

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