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| author | Joseph Myers <joseph@codesourcery.com> | 2014-04-02 17:41:02 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2014-04-02 17:41:02 +0000 |
| commit | a84e78c8b3c4de94b488fdc5321f71feeb99358f (patch) | |
| tree | b4e8a63fd2eb10f4598a5af855e6462a9b06767e /math/s_catanh.c | |
| parent | 6f05bafebac30a389807979f8efbb709f84b486f (diff) | |
| download | glibc-a84e78c8b3c4de94b488fdc5321f71feeb99358f.tar.gz | |
Fix catan, catanh, __ieee754_logf in round-downward mode (bug 16799, bug 16800).
This patch fixes incorrect results from catan and catanh of certain
special inputs in round-downward mode (bug 16799), and incorrect
results of __ieee754_logf (+/-0) in round-downward mode (bug 16800)
that show up through catan/catanh when tested in all rounding modes,
but not directly in the testing for logf because the bug gets hidden
by the wrappers.
Both bugs involve a zero that should be +0 being -0 instead: one
computed as (1-x)*(1+x) in the catan/catanh case, and one as (x-x) in
the logf case. The fixes ensure positive zero is used. Testing of
catan and catanh in all rounding modes is duly enabled.
I expect there are various other bugs in special cases in __ieee754_*
functions that are normally hidden by the wrappers but would show up
for testing with -lieee (or in future with -fno-math-errno if we
replace -lieee and _LIB_VERSION with compile-time redirection to new
*_noerrno symbol names).
Tested x86_64 and x86 and ulps updated accordingly.
[BZ #16799]
[BZ #16800]
* math/s_catan.c (__catan): Avoid passing -0 denominator to atan2
with 0 numerator.
* math/s_catanf.c (__catanf): Likewise.
* math/s_catanh.c (__catanh): Likewise.
* math/s_catanhf.c (__catanhf): Likewise.
* math/s_catanhl.c (__catanhl): Likewise.
* math/s_catanl.c (__catanl): Likewise.
* sysdeps/ieee754/flt-32/e_logf.c (__ieee754_logf): Always divide
by positive zero when computing -Inf result.
* math/libm-test.inc (catan_test): Use ALL_RM_TEST.
(catanh_test): Likewise.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
Diffstat (limited to 'math/s_catanh.c')
| -rw-r--r-- | math/s_catanh.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/math/s_catanh.c b/math/s_catanh.c index 2ba1298bb6..7ef9142b0d 100644 --- a/math/s_catanh.c +++ b/math/s_catanh.c @@ -110,7 +110,11 @@ __catanh (__complex__ double x) } if (absy < DBL_EPSILON / 2.0) - den = (1.0 - absx) * (1.0 + absx); + { + den = (1.0 - absx) * (1.0 + absx); + if (den == -0.0) + den = 0.0; + } else if (absx >= 1.0) den = (1.0 - absx) * (1.0 + absx) - absy * absy; else if (absx >= 0.75 || absy >= 0.5) |