Fix sign errr in some cacosh results

5 files changed, 13 insertions, 32 deletions

diff --git a/ChangeLog b/ChangeLog
index 51f148d41e..1ccc3ddab0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-11-18  Richard B. Kreckel  <kreckel@ginac.de>
+
+	[BZ #13305]
+	* math/s_cacosh.c: Fix rare miscomputation in cacosh().
+	* math/s_cacoshf.c: Likewise.
+	* math/s_cacoshl.c: Likewise.
+
 2011-12-21  Ulrich Drepper  <drepper@gmail.com>
 
 	[BZ #13439]
diff --git a/NEWS b/NEWS
index aba4a8db75..7e4e1692e9 100644
--- a/NEWS
+++ b/NEWS
@@ -12,8 +12,8 @@ Version 2.15
   6779, 6783, 9696, 10103, 10709, 11589, 12403, 12847, 12868, 12852, 12874,
   12885, 12892, 12907, 12922, 12935, 13007, 13021, 13067, 13068, 13090,
   13092, 13114, 13118, 13123, 13134, 13138, 13147, 13150, 13179, 13192,
-  13268, 13276, 13291, 13335, 13337, 13344, 13358, 13367, 13439, 13446,
-  13472, 13484, 13506, 13515, 13524
+  13268, 13276, 13291, 13305, 13335, 13337, 13344, 13358, 13367, 13439,
+  13446, 13472, 13484, 13506, 13515, 13524
 
 * New program pldd to list loaded object of a process
   Implemented by Ulrich Drepper.
diff --git a/math/s_cacosh.c b/math/s_cacosh.c
index bec6d3827e..df5ce6945d 100644
--- a/math/s_cacosh.c
+++ b/math/s_cacosh.c
@@ -74,17 +74,13 @@ __cacosh (__complex__ double x)
 
       y = __csqrt (y);
 
-      if (__real__ x < 0.0)
+      if (signbit (__real__ x))
 	y = -y;
 
       __real__ y += __real__ x;
       __imag__ y += __imag__ x;
 
       res = __clog (y);
-
-      /* We have to use the positive branch.  */
-      if (__real__ res < 0.0)
-	res = -res;
     }
 
   return res;
diff --git a/math/s_cacoshf.c b/math/s_cacoshf.c
index 0d6bd75dd7..aa4696f10b 100644
--- a/math/s_cacoshf.c
+++ b/math/s_cacoshf.c
@@ -1,5 +1,5 @@
 /* Return arc hyperbole cosine for float value.
-   Copyright (C) 1997, 2006 Free Software Foundation, Inc.
+   Copyright (C) 1997, 2006, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -67,7 +67,6 @@ __cacoshf (__complex__ float x)
     }
   else
     {
-#if 1
       __complex__ float y;
 
       __real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
@@ -75,30 +74,13 @@ __cacoshf (__complex__ float x)
 
       y = __csqrtf (y);
 
-      if (__real__ x < 0.0)
+      if (signbit (__real__ x))
 	y = -y;
 
       __real__ y += __real__ x;
       __imag__ y += __imag__ x;
 
       res = __clogf (y);
-#else
-      float re2 = __real__ x * __real__ x;
-      float im2 = __imag__ x * __imag__ x;
-      float sq = re2 - im2 - 1.0;
-      float ro = __ieee754_sqrtf (sq * sq + 4 * re2 * im2);
-      float a = __ieee754_sqrtf ((sq + ro) / 2.0);
-      float b = __ieee754_sqrtf ((-sq + ro) / 2.0);
-
-      __real__ res = 0.5 * __ieee754_logf (re2 + __real__ x * 2 * a
-					   + im2 + __imag__ x * 2 * b
-					   + ro);
-      __imag__ res = __ieee754_atan2f (__imag__ x + b, __real__ x + a);
-#endif
-
-      /* We have to use the positive branch.  */
-      if (__real__ res < 0.0)
-	res = -res;
     }
 
   return res;
diff --git a/math/s_cacoshl.c b/math/s_cacoshl.c
index 36f7a5f70e..b90b196959 100644
--- a/math/s_cacoshl.c
+++ b/math/s_cacoshl.c
@@ -74,17 +74,13 @@ __cacoshl (__complex__ long double x)
 
       y = __csqrtl (y);
 
-      if (__real__ x < 0.0)
+      if (signbit (__real__ x))
 	y = -y;
 
       __real__ y += __real__ x;
       __imag__ y += __imag__ x;
 
       res = __clogl (y);
-
-      /* We have to use the positive branch.  */
-      if (__real__ res < 0.0)
-	res = -res;
     }
 
   return res;