Update copyright dates with scripts/update-copyrights.

[thirdparty/glibc.git] / math / s_cacosh.c

diff --git a/math/s_cacosh.c b/math/s_cacosh.c
index 95bf005cd3f8d8f96cb10c6127b3dde9ee060c49..d5507cd47edc939e14a8ca0304e652c80ab2bc00 100644 (file)
--- 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) 1997-2015 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -64,27 +64,25 @@ __cacosh (__complex__ double x)
       __real__ res = 0.0;
       __imag__ res = __copysign (M_PI_2, __imag__ 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));
   else
     {
       __complex__ double y;
 
-      __real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
-      __imag__ y = 2.0 * __real__ x * __imag__ x;
+      __real__ y = -__imag__ x;
+      __imag__ y = __real__ x;
 
-      y = __csqrt (y);
+      y = __kernel_casinh (y, 1);
 
-      if (signbit (__real__ x))
-       y = -y;
-
-      __real__ y += __real__ x;
-      __imag__ y += __imag__ x;
-
-      res = __clog (y);
+      if (signbit (__imag__ x))
+       {
+         __real__ res = __real__ y;
+         __imag__ res = -__imag__ y;
+       }
+      else
+       {
+         __real__ res = -__real__ y;
+         __imag__ res = __imag__ y;
+       }
     }
 
   return res;