[Bug math/6814] expm1() raises bogus invalid exception

[Bug math/6814] expm1() raises bogus invalid exception

[jsm28 at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=6814

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

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

--- Comment #4 from Joseph Myers <jsm28 at gcc dot gnu.org> 2012-02-29 22:33:42 UTC ---
This appears to have been fixed, probably by various changes in 2009 (there is
a test in the testsuite of expm1 overflow, which will verify there is no such
inappropriate exception, and that test was added in 2009).  However, the
OVERFLOW exception for expm1 seems to have disappeared on x86, so I've filed
bug 13787 for that problem.

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[Bug math/6814] expm1() raises bogus invalid exception

[mtk.manpages at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=6814

--- Comment #5 from Michael Kerrisk <mtk.manpages at gmail dot com> ---
Fix documented for man-pages-5.07.

commit fdd3fe51793b75b03ab7e48797e11dc46c935f3b
Author: Michael Kerrisk <mtk.manpages@gmail.com>
Date:   Sat May 23 11:56:12 2020 +0200

    expm1.3: The bogus invalid floating-point exception bug has been fixed

    Sometime around 2009 (approximately 2.11) according to
    https://www.sourceware.org/bugzilla/show_bug.cgi?id=6814.

    Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man3/expm1.3 b/man3/expm1.3
index 460068a6d..8b60c3453 100644
--- a/man3/expm1.3
+++ b/man3/expm1.3
@@ -153,16 +153,16 @@ for some large negative
 .I x
 values (where the function result approaches \-1),
 .PP
-For some large positive
-.I x
-values,
-.BR expm1 ()
-raises a bogus invalid floating-point exception in addition to the expected
-overflow exception, and returns a NaN instead of positive infinity.
-.\" FIXME .
-.\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6814
+Before approximately glibc version 2.11,
+.\" http://sources.redhat.com/bugzilla/show_bug.cgi?id=6814
 .\" e.g., expm1(1e5) through expm1(1.00199970127e5),
 .\" but not expm1(1.00199970128e5) and beyond.
+.BR expm1 ()
+raised a bogus invalid floating-point exception in addition to the expected
+overflow exception, and returned a NaN instead of positive infinity.
+for some large positive
+.I x
+values,
 .PP
 Before version 2.11,
 .\" It looks like the fix was in 2.11, or possibly 2.12.

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[Bug math/6814] expm1() raises bogus invalid exception

[mtk dot manpages at gmail dot com]

------- Additional Comments From mtk dot manpages at gmail dot com  2008-08-04 04:50 -------
Comment #2 should have started with thw words: "The first two runs below
demonstrate the problem:"

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[Bug math/6814] expm1() raises bogus invalid exception

[mtk dot manpages at gmail dot com]

------- Additional Comments From mtk dot manpages at gmail dot com  2008-08-04 04:49 -------
Created an attachment (id=2885)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=2885&action=view)
test program


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[Bug math/6814] expm1() raises bogus invalid exception

[mtk dot manpages at gmail dot com]

------- Additional Comments From mtk dot manpages at gmail dot com  2008-08-04 04:49 -------
$ /tmp/mt_expm1 1e5
errno == 0
fetestexcept() says:  FE_INVALID FE_OVERFLOW FE_INEXACT
expm1(1.00000000000000000e+05)=nan
0 FE_OVERFLOW nan

$ /tmp/mt_expm1 1.00199970127e5
errno == 0
fetestexcept() says:  FE_INVALID FE_OVERFLOW FE_INEXACT
expm1(1.00199970126999993e+05)=nan
0 FE_OVERFLOW nan

$ /tmp/mt_expm1 1.00199970128e5
errno == 0
fetestexcept() says:  FE_OVERFLOW FE_INEXACT
expm1(1.00199970128000001e+05)=inf
0 FE_OVERFLOW +inf



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