[Bug math/3919] New: Quiet NaNs not propagated quietly by some math functions

[Bug math/3919] New: Quiet NaNs not propagated quietly by some math functions

[kreckel at ginac dot de]

I've conducted a survey of the qNaN propagation of all C99 <math.h> functions on
i386 and found the following nonconformances:

- The acosh and acoshf functions raise the invalid exception flag if their
  argument is a quiet NaN. (The acoshl function does not do that.)

- The log, logf, and logl functions raise the invalid exception flag if
  their argument is a quiet NaN.

- The ilogb, ilogbf, and ilogbl raise the invalid exception flag if their
  argument is a quiet NaN. According to C99, they should compute
  P_ILOGBNAN. They do not appear to be required to raise a domain error
  and I have doublts this is in accordance with the spirit of IEEE754.

-- 
           Summary: Quiet NaNs not propagated quietly by some math functions
           Product: glibc
           Version: 2.4
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
        AssignedTo: aj at suse dot de
        ReportedBy: kreckel at ginac dot de
                CC: glibc-bugs at sources dot redhat dot com
  GCC host triplet: i686-pc-linux-gnu


http://sourceware.org/bugzilla/show_bug.cgi?id=3919

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[Bug math/3919] Quiet NaNs not propagated quietly by some math functions

[jakub at redhat dot com]

------- Additional Comments From jakub at redhat dot com  2007-03-15 13:49 -------
acosh{,f,l} certainly don't raise that:
#define _GNU_SOURCE
#include <math.h>
#include <fenv.h>
#include <stdio.h>

volatile double n = NAN;
volatile double d;
volatile float f;
volatile long double ld;
volatile int i;

int
main (void)
{
  feclearexcept (FE_ALL_EXCEPT);
  d = acosh (n);
  f = acoshf (n);
  ld = acoshl (n);
  printf ("%x\n", fetestexcept (FE_INVALID));
  i = ilogb (n);
  i = ilogbf (n);
  i = ilogbl (n);
  printf ("%x\n", fetestexcept (FE_INVALID));
  d = log (n);
  f = logf (n);
  ld = logl (n);
  printf ("%x\n", fetestexcept (FE_INVALID));
  return 0;
}

prints 0, 1, 1 with both -m32 -fno-builtin and -m64 -fno-builtin on x86_64
with current CVS glibc.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |WAITING


http://sourceware.org/bugzilla/show_bug.cgi?id=3919

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[Bug math/3919] Quiet NaNs not propagated quietly by some math functions

[jakub at redhat dot com]

------- Additional Comments From jakub at redhat dot com  2007-03-15 17:22 -------
For ilogb{,f,l} my reading of
http://www.opengroup.org/onlinepubs/009695399/functions/ilogb.html
is that FE_INVALID should be raised for 0/+-Inf/NaN.
log{,f,l}(NAN) raising FE_INVALID on the other side is a bug and I have posted
a patch for that already:
http://sources.redhat.com/ml/libc-hacker/2007-03/msg00024.html

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[Bug math/3919] Quiet NaNs not propagated quietly by some math functions

[drepper at redhat dot com]

------- Additional Comments From drepper at redhat dot com  2007-03-15 20:12 -------
Fixed in cvs.

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


http://sourceware.org/bugzilla/show_bug.cgi?id=3919

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[Bug math/3919] Quiet NaNs not propagated quietly by some math functions

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2007-07-12 14:58 -------
Subject: Bug 3919

CVSROOT:	/cvs/glibc
Module name:	libc
Branch: 	glibc-2_5-branch
Changes by:	jakub@sourceware.org	2007-07-12 14:58:36

Modified files:
	.              : ChangeLog 
	math           : libm-test.inc 
	sysdeps/i386/fpu: e_log.S e_logf.S e_logl.S 
	sysdeps/x86_64/fpu: e_log10l.S e_log2l.S e_logl.S s_log1pl.S 

Log message:
	2007-03-15  Jakub Jelinek  <jakub@redhat.com>
	
	[BZ #3919]
	* math/libm-test.inc (log_test): Test -Inf and NaN.
	(log10_test, log1p_test, log2_test): Test -Inf.
	* sysdeps/i386/fpu/e_log.S (__ieee754_log): Don't raise
	FE_INVALID when argument is qNaN.
	* sysdeps/i386/fpu/e_logl.S (__ieee754_logl): Likewise.
	* sysdeps/i386/fpu/e_logf.S (__ieee754_logf): Likewise.
	* sysdeps/x86_64/fpu/e_logl.S (__ieee754_logl): Likewise.
	* sysdeps/x86_64/fpu/e_log10l.S (__ieee754_log10l): Replace
	andb $1, %ah with testb $1, %ah, don't test for parity, instead
	testb $4, %ah and jump if non-zero.
	* sysdeps/x86_64/fpu/e_log2l.S (__ieee754_log2l): Likewise.
	* sysdeps/x86_64/fpu/s_log1pl.S (__log1pl): Likewise.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/ChangeLog.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.10362.2.52&r2=1.10362.2.53
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/math/libm-test.inc.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.73.2.1&r2=1.73.2.2
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/fpu/e_log.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.2&r2=1.2.2.1
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/fpu/e_logf.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.2&r2=1.2.2.1
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/fpu/e_logl.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.2&r2=1.2.2.1
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/x86_64/fpu/e_log10l.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.1&r2=1.1.10.1
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/x86_64/fpu/e_log2l.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.1&r2=1.1.10.1
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/x86_64/fpu/e_logl.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.1&r2=1.1.10.1
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/sysdeps/x86_64/fpu/s_log1pl.S.diff?cvsroot=glibc&only_with_tag=glibc-2_5-branch&r1=1.1&r2=1.1.10.1



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