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authorJoseph Myers <joseph@codesourcery.com>2012-03-07 15:15:19 +0000
committerJoseph Myers <joseph@codesourcery.com>2012-03-07 15:15:19 +0000
commitd1d3431a3a9dd14501eedb701436bd5005b1db7d (patch)
tree39d3514fc227717e59ebd11e94c822491a8b382d /math/s_cacosh.c
parenta4300c7a4d65e24a4a0215460c063ea9c7b4605a (diff)
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Fix signs of zeros from casinh, cacosh etc. (bug 10716).
Diffstat (limited to 'math/s_cacosh.c')
-rw-r--r--math/s_cacosh.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/math/s_cacosh.c b/math/s_cacosh.c
index 95bf005..ef49088 100644
--- a/math/s_cacosh.c
+++ b/math/s_cacosh.c
@@ -1,5 +1,5 @@
/* Return arc hyperbole cosine for double value.
- Copyright (C) 1997, 2006, 2011 Free Software Foundation, Inc.
+ Copyright (C) 1997-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
@@ -66,9 +66,13 @@ __cacosh (__complex__ double x)
}
/* The factor 16 is just a guess. */
else if (16.0 * fabs (__imag__ x) < fabs (__real__ x))
- /* Kahan's formula which avoid cancellation through subtraction in
- some cases. */
- res = 2.0 * __clog (__csqrt ((x + 1.0) / 2.0) + __csqrt ((x - 1.0) / 2.0));
+ {
+ /* Kahan's formula which avoid cancellation through subtraction in
+ some cases. */
+ res = 2.0 * __clog (__csqrt ((x + 1.0) / 2.0) + __csqrt ((x - 1.0) / 2.0));
+ if (signbit (__real__ res))
+ __real__ res = 0.0;
+ }
else
{
__complex__ double y;