diff options
| author | Joseph Myers <joseph@codesourcery.com> | 2015-09-17 21:21:39 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-09-17 21:21:39 +0000 |
| commit | 61f893789862db1dfdf188f77cd215bab0814d2c (patch) | |
| tree | 9fd0f9b8395f451e24f8ce1c12253847740f8e31 /math/s_ctanh.c | |
| parent | b8682397ab2db1aed7f25d0a0c7c81134a97c8c7 (diff) | |
Fix sign of zero part from ctan / ctanh when argument infinite (bug 17118).
C99/C11 Annex G specifies the sign of the zero part of the result of
ctan (x +/- i * Inf) and ctanh (+/-Inf + i * y). This patch fixes glibc
to follow that specification, along the lines I described in my review
of Andreas's previous patch for this issue
<https://sourceware.org/ml/libc-alpha/2014-08/msg00142.html>.
Tested for x86_64.
2015-09-17 Joseph Myers <joseph@codesourcery.com>
Andreas Schwab <schwab@suse.de>
[BZ #17118]
* math/s_ctan.c (__ctan): Determine sign of zero real part of
result when imaginary part of argument is infinite using sine and
cosine.
* math/s_ctanf.c (__ctanf): Likewise.
* math/s_ctanl.c (__ctanl): Likewise.
* math/s_ctanh.c (__ctanh): Determine sign of zero imaginary part
of result when real part of argument is infinite using sine and
cosine.
* math/s_ctanhf.c (__ctanhf): Likewise.
* math/s_ctanhl.c (__ctanhl): Likewise.
* math/libm-test.inc (ctan_test_data): Add more tests of ctan.
(ctanh_test_data): Add more tests of ctanh.
Diffstat (limited to 'math/s_ctanh.c')
| -rw-r--r-- | math/s_ctanh.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/math/s_ctanh.c b/math/s_ctanh.c index 76a0501a73..a41cd1a0a6 100644 --- a/math/s_ctanh.c +++ b/math/s_ctanh.c @@ -33,7 +33,14 @@ __ctanh (__complex__ double x) if (__isinf_ns (__real__ x)) { __real__ res = __copysign (1.0, __real__ x); - __imag__ res = __copysign (0.0, __imag__ x); + if (isfinite (__imag__ x) && fabs (__imag__ x) > 1.0) + { + double sinix, cosix; + __sincos (__imag__ x, &sinix, &cosix); + __imag__ res = __copysign (0.0, sinix * cosix); + } + else + __imag__ res = __copysign (0.0, __imag__ x); } else if (__imag__ x == 0.0) { |