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author | Joseph Myers <joseph@codesourcery.com> | 2015-09-17 21:21:39 +0000 |
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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) | |
download | glibc-61f893789862db1dfdf188f77cd215bab0814d2c.tar.gz glibc-61f893789862db1dfdf188f77cd215bab0814d2c.tar.xz glibc-61f893789862db1dfdf188f77cd215bab0814d2c.zip |
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) { |