Fix signs of zeros from casinh, cacosh etc. (bug 10716).

7 files changed, 148 insertions, 17 deletions

diff --git a/math/libm-test.inc b/math/libm-test.inc
index 9bdbc4cb98..39cda6663c 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -1065,6 +1065,32 @@ cacos_test (void)
 
   TEST_c_c (cacos, nan_value, nan_value, nan_value, nan_value);
 
+  TEST_c_c (cacos, plus_zero, -1.5L, M_PI_2l, 1.194763217287109304111930828519090523536L);
+  TEST_c_c (cacos, minus_zero, -1.5L, M_PI_2l, 1.194763217287109304111930828519090523536L);
+  TEST_c_c (cacos, plus_zero, -1.0L, M_PI_2l, 0.8813735870195430252326093249797923090282L);
+  TEST_c_c (cacos, minus_zero, -1.0L, M_PI_2l, 0.8813735870195430252326093249797923090282L);
+  TEST_c_c (cacos, plus_zero, -0.5L, M_PI_2l, 0.4812118250596034474977589134243684231352L);
+  TEST_c_c (cacos, minus_zero, -0.5L, M_PI_2l, 0.4812118250596034474977589134243684231352L);
+  TEST_c_c (cacos, plus_zero, 0.5L, M_PI_2l, -0.4812118250596034474977589134243684231352L);
+  TEST_c_c (cacos, minus_zero, 0.5L, M_PI_2l, -0.4812118250596034474977589134243684231352L);
+  TEST_c_c (cacos, plus_zero, 1.0L, M_PI_2l, -0.8813735870195430252326093249797923090282L);
+  TEST_c_c (cacos, minus_zero, 1.0L, M_PI_2l, -0.8813735870195430252326093249797923090282L);
+  TEST_c_c (cacos, plus_zero, 1.5L, M_PI_2l, -1.194763217287109304111930828519090523536L);
+  TEST_c_c (cacos, minus_zero, 1.5L, M_PI_2l, -1.194763217287109304111930828519090523536L);
+
+  TEST_c_c (cacos, -1.5L, plus_zero, M_PIl, -0.9624236501192068949955178268487368462704L);
+  TEST_c_c (cacos, -1.5L, minus_zero, M_PIl, 0.9624236501192068949955178268487368462704L);
+  TEST_c_c (cacos, -1.0L, plus_zero, M_PIl, minus_zero);
+  TEST_c_c (cacos, -1.0L, minus_zero, M_PIl, plus_zero);
+  TEST_c_c (cacos, -0.5L, plus_zero, 2.094395102393195492308428922186335256131L, minus_zero);
+  TEST_c_c (cacos, -0.5L, minus_zero, 2.094395102393195492308428922186335256131L, plus_zero);
+  TEST_c_c (cacos, 0.5L, plus_zero, 1.047197551196597746154214461093167628066L, minus_zero);
+  TEST_c_c (cacos, 0.5L, minus_zero, 1.047197551196597746154214461093167628066L, plus_zero);
+  TEST_c_c (cacos, 1.0L, plus_zero, plus_zero, minus_zero);
+  TEST_c_c (cacos, 1.0L, minus_zero, plus_zero, plus_zero);
+  TEST_c_c (cacos, 1.5L, plus_zero, plus_zero, -0.9624236501192068949955178268487368462704L);
+  TEST_c_c (cacos, 1.5L, minus_zero, plus_zero, 0.9624236501192068949955178268487368462704L);
+
   TEST_c_c (cacos, 0.75L, 1.25L, 1.11752014915610270578240049553777969L, -1.13239363160530819522266333696834467L);
   TEST_c_c (cacos, -2, -3, 2.1414491111159960199416055713254211L, 1.9833870299165354323470769028940395L);
 
@@ -1127,6 +1153,32 @@ cacosh_test (void)
 
   TEST_c_c (cacosh, nan_value, nan_value, nan_value, nan_value);
 
+  TEST_c_c (cacosh, plus_zero, -1.5L, 1.194763217287109304111930828519090523536L, -M_PI_2l);
+  TEST_c_c (cacosh, minus_zero, -1.5L, 1.194763217287109304111930828519090523536L, -M_PI_2l);
+  TEST_c_c (cacosh, plus_zero, -1.0L, 0.8813735870195430252326093249797923090282L, -M_PI_2l);
+  TEST_c_c (cacosh, minus_zero, -1.0L, 0.8813735870195430252326093249797923090282L, -M_PI_2l);
+  TEST_c_c (cacosh, plus_zero, -0.5L, 0.4812118250596034474977589134243684231352L, -M_PI_2l);
+  TEST_c_c (cacosh, minus_zero, -0.5L, 0.4812118250596034474977589134243684231352L, -M_PI_2l);
+  TEST_c_c (cacosh, plus_zero, 0.5L, 0.4812118250596034474977589134243684231352L, M_PI_2l);
+  TEST_c_c (cacosh, minus_zero, 0.5L, 0.4812118250596034474977589134243684231352L, M_PI_2l);
+  TEST_c_c (cacosh, plus_zero, 1.0L, 0.8813735870195430252326093249797923090282L, M_PI_2l);
+  TEST_c_c (cacosh, minus_zero, 1.0L, 0.8813735870195430252326093249797923090282L, M_PI_2l);
+  TEST_c_c (cacosh, plus_zero, 1.5L, 1.194763217287109304111930828519090523536L, M_PI_2l);
+  TEST_c_c (cacosh, minus_zero, 1.5L, 1.194763217287109304111930828519090523536L, M_PI_2l);
+
+  TEST_c_c (cacosh, -1.5L, plus_zero, 0.9624236501192068949955178268487368462704L, M_PIl);
+  TEST_c_c (cacosh, -1.5L, minus_zero, 0.9624236501192068949955178268487368462704L, -M_PIl);
+  TEST_c_c (cacosh, -1.0L, plus_zero, plus_zero, M_PIl);
+  TEST_c_c (cacosh, -1.0L, minus_zero, plus_zero, -M_PIl);
+  TEST_c_c (cacosh, -0.5L, plus_zero, plus_zero, 2.094395102393195492308428922186335256131L);
+  TEST_c_c (cacosh, -0.5L, minus_zero, plus_zero, -2.094395102393195492308428922186335256131L);
+  TEST_c_c (cacosh, 0.5L, plus_zero, plus_zero, 1.047197551196597746154214461093167628066L);
+  TEST_c_c (cacosh, 0.5L, minus_zero, plus_zero, -1.047197551196597746154214461093167628066L);
+  TEST_c_c (cacosh, 1.0L, plus_zero, plus_zero, plus_zero);
+  TEST_c_c (cacosh, 1.0L, minus_zero, plus_zero, minus_zero);
+  TEST_c_c (cacosh, 1.5L, plus_zero, 0.9624236501192068949955178268487368462704L, plus_zero);
+  TEST_c_c (cacosh, 1.5L, minus_zero, 0.9624236501192068949955178268487368462704L, minus_zero);
+
   TEST_c_c (cacosh, 0.75L, 1.25L, 1.13239363160530819522266333696834467L, 1.11752014915610270578240049553777969L);
   TEST_c_c (cacosh, -2, -3, 1.9833870299165354323470769028940395L, -2.1414491111159960199416055713254211L);
 
@@ -1258,6 +1310,32 @@ casin_test (void)
 
   TEST_c_c (casin, nan_value, nan_value, nan_value, nan_value);
 
+  TEST_c_c (casin, plus_zero, -1.5L, plus_zero, -1.194763217287109304111930828519090523536L);
+  TEST_c_c (casin, minus_zero, -1.5L, minus_zero, -1.194763217287109304111930828519090523536L);
+  TEST_c_c (casin, plus_zero, -1.0L, plus_zero, -0.8813735870195430252326093249797923090282L);
+  TEST_c_c (casin, minus_zero, -1.0L, minus_zero, -0.8813735870195430252326093249797923090282L);
+  TEST_c_c (casin, plus_zero, -0.5L, plus_zero, -0.4812118250596034474977589134243684231352L);
+  TEST_c_c (casin, minus_zero, -0.5L, minus_zero, -0.4812118250596034474977589134243684231352L);
+  TEST_c_c (casin, plus_zero, 0.5L, plus_zero, 0.4812118250596034474977589134243684231352L);
+  TEST_c_c (casin, minus_zero, 0.5L, minus_zero, 0.4812118250596034474977589134243684231352L);
+  TEST_c_c (casin, plus_zero, 1.0L, plus_zero, 0.8813735870195430252326093249797923090282L);
+  TEST_c_c (casin, minus_zero, 1.0L, minus_zero, 0.8813735870195430252326093249797923090282L);
+  TEST_c_c (casin, plus_zero, 1.5L, plus_zero, 1.194763217287109304111930828519090523536L);
+  TEST_c_c (casin, minus_zero, 1.5L, minus_zero, 1.194763217287109304111930828519090523536L);
+
+  TEST_c_c (casin, -1.5L, plus_zero, -M_PI_2l, 0.9624236501192068949955178268487368462704L);
+  TEST_c_c (casin, -1.5L, minus_zero, -M_PI_2l, -0.9624236501192068949955178268487368462704L);
+  TEST_c_c (casin, -1.0L, plus_zero, -M_PI_2l, plus_zero);
+  TEST_c_c (casin, -1.0L, minus_zero, -M_PI_2l, minus_zero);
+  TEST_c_c (casin, -0.5L, plus_zero, -0.5235987755982988730771072305465838140329L, plus_zero);
+  TEST_c_c (casin, -0.5L, minus_zero, -0.5235987755982988730771072305465838140329L, minus_zero);
+  TEST_c_c (casin, 0.5L, plus_zero, 0.5235987755982988730771072305465838140329L, plus_zero);
+  TEST_c_c (casin, 0.5L, minus_zero, 0.5235987755982988730771072305465838140329L, minus_zero);
+  TEST_c_c (casin, 1.0L, plus_zero, M_PI_2l, plus_zero);
+  TEST_c_c (casin, 1.0L, minus_zero, M_PI_2l, minus_zero);
+  TEST_c_c (casin, 1.5L, plus_zero, M_PI_2l, 0.9624236501192068949955178268487368462704L);
+  TEST_c_c (casin, 1.5L, minus_zero, M_PI_2l, -0.9624236501192068949955178268487368462704L);
+
   TEST_c_c (casin, 0.75L, 1.25L, 0.453276177638793913448921196101971749L, 1.13239363160530819522266333696834467L);
   TEST_c_c (casin, -2, -3, -0.57065278432109940071028387968566963L, -1.9833870299165354323470769028940395L);
 
@@ -1322,6 +1400,32 @@ casinh_test (void)
 
   TEST_c_c (casinh, nan_value, nan_value, nan_value, nan_value);
 
+  TEST_c_c (casinh, plus_zero, -1.5L, 0.9624236501192068949955178268487368462704L, -M_PI_2l);
+  TEST_c_c (casinh, minus_zero, -1.5L, -0.9624236501192068949955178268487368462704L, -M_PI_2l);
+  TEST_c_c (casinh, plus_zero, -1.0L, plus_zero, -M_PI_2l);
+  TEST_c_c (casinh, minus_zero, -1.0L, minus_zero, -M_PI_2l);
+  TEST_c_c (casinh, plus_zero, -0.5L, plus_zero, -0.5235987755982988730771072305465838140329L);
+  TEST_c_c (casinh, minus_zero, -0.5L, minus_zero, -0.5235987755982988730771072305465838140329L);
+  TEST_c_c (casinh, plus_zero, 0.5L, plus_zero, 0.5235987755982988730771072305465838140329L);
+  TEST_c_c (casinh, minus_zero, 0.5L, minus_zero, 0.5235987755982988730771072305465838140329L);
+  TEST_c_c (casinh, plus_zero, 1.0L, plus_zero, M_PI_2l);
+  TEST_c_c (casinh, minus_zero, 1.0L, minus_zero, M_PI_2l);
+  TEST_c_c (casinh, plus_zero, 1.5L, 0.9624236501192068949955178268487368462704L, M_PI_2l);
+  TEST_c_c (casinh, minus_zero, 1.5L, -0.9624236501192068949955178268487368462704L, M_PI_2l);
+
+  TEST_c_c (casinh, -1.5L, plus_zero, -1.194763217287109304111930828519090523536L, plus_zero);
+  TEST_c_c (casinh, -1.5L, minus_zero, -1.194763217287109304111930828519090523536L, minus_zero);
+  TEST_c_c (casinh, -1.0L, plus_zero, -0.8813735870195430252326093249797923090282L, plus_zero);
+  TEST_c_c (casinh, -1.0L, minus_zero, -0.8813735870195430252326093249797923090282L, minus_zero);
+  TEST_c_c (casinh, -0.5L, plus_zero, -0.4812118250596034474977589134243684231352L, plus_zero);
+  TEST_c_c (casinh, -0.5L, minus_zero, -0.4812118250596034474977589134243684231352L, minus_zero);
+  TEST_c_c (casinh, 0.5L, plus_zero, 0.4812118250596034474977589134243684231352L, plus_zero);
+  TEST_c_c (casinh, 0.5L, minus_zero, 0.4812118250596034474977589134243684231352L, minus_zero);
+  TEST_c_c (casinh, 1.0L, plus_zero, 0.8813735870195430252326093249797923090282L, plus_zero);
+  TEST_c_c (casinh, 1.0L, minus_zero, 0.8813735870195430252326093249797923090282L, minus_zero);
+  TEST_c_c (casinh, 1.5L, plus_zero, 1.194763217287109304111930828519090523536L, plus_zero);
+  TEST_c_c (casinh, 1.5L, minus_zero, 1.194763217287109304111930828519090523536L, minus_zero);
+
   TEST_c_c (casinh, 0.75L, 1.25L, 1.03171853444778027336364058631006594L, 0.911738290968487636358489564316731207L);
   TEST_c_c (casinh, -2, -3, -1.9686379257930962917886650952454982L, -0.96465850440760279204541105949953237L);
 
diff --git a/math/s_cacosh.c b/math/s_cacosh.c
index 95bf005cd3..ef49088c3d 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;
diff --git a/math/s_cacoshf.c b/math/s_cacoshf.c
index d634a1b756..fc716ac519 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, 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.
 
@@ -66,10 +66,14 @@ __cacoshf (__complex__ float x)
     }
   /* The factor 16 is just a guess.  */
   else if (16.0 * fabsf (__imag__ x) < fabsf (__real__ x))
-    /* Kahan's formula which avoid cancellation through subtraction in
-       some cases.  */
-    res = 2.0 * __clogf (__csqrtf ((x + 1.0) / 2.0)
-			 + __csqrtf ((x - 1.0) / 2.0));
+    {
+      /* Kahan's formula which avoid cancellation through subtraction in
+	 some cases.  */
+      res = 2.0 * __clogf (__csqrtf ((x + 1.0) / 2.0)
+			   + __csqrtf ((x - 1.0) / 2.0));
+      if (signbit (__real__ res))
+	__real__ res = 0.0f;
+    }
   else
     {
       __complex__ float y;
diff --git a/math/s_cacoshl.c b/math/s_cacoshl.c
index dcdb1d5a64..3bcab1d277 100644
--- a/math/s_cacoshl.c
+++ b/math/s_cacoshl.c
@@ -1,5 +1,5 @@
 /* Return arc hyperbole cosine for long double value.
-   Copyright (C) 1997, 1998, 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.
 
@@ -66,10 +66,14 @@ __cacoshl (__complex__ long double x)
     }
   /* The factor 16 is just a guess.  */
   else if (16.0L * fabsl (__imag__ x) < fabsl (__real__ x))
-    /* Kahan's formula which avoid cancellation through subtraction in
-       some cases.  */
-    res = 2.0L * __clogl (__csqrtl ((x + 1.0L) / 2.0L)
-			  + __csqrtl ((x - 1.0L) / 2.0L));
+    {
+      /* Kahan's formula which avoid cancellation through subtraction in
+	 some cases.  */
+      res = 2.0L * __clogl (__csqrtl ((x + 1.0L) / 2.0L)
+			    + __csqrtl ((x - 1.0L) / 2.0L));
+      if (signbit (__real__ res))
+	__real__ res = 0.0L;
+    }
   else
     {
       __complex__ long double y;
diff --git a/math/s_casinh.c b/math/s_casinh.c
index e06be1cdc6..24ae676a8f 100644
--- a/math/s_casinh.c
+++ b/math/s_casinh.c
@@ -1,5 +1,5 @@
 /* Return arc hyperbole sine for double value.
-   Copyright (C) 1997, 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.
 
@@ -73,6 +73,11 @@ __casinh (__complex__ double x)
       __imag__ y += __imag__ x;
 
       res = __clog (y);
+
+      /* Ensure zeros have correct sign and results are correct if
+	 very close to branch cuts.  */
+      __real__ res = __copysign (__real__ res, __real__ x);
+      __imag__ res = __copysign (__imag__ res, __imag__ x);
     }
 
   return res;
diff --git a/math/s_casinhf.c b/math/s_casinhf.c
index 37c67401a3..c7098ef309 100644
--- a/math/s_casinhf.c
+++ b/math/s_casinhf.c
@@ -1,5 +1,5 @@
 /* Return arc hyperbole sine for float value.
-   Copyright (C) 1997, 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.
 
@@ -73,6 +73,11 @@ __casinhf (__complex__ float x)
       __imag__ y += __imag__ x;
 
       res = __clogf (y);
+
+      /* Ensure zeros have correct sign and results are correct if
+	 very close to branch cuts.  */
+      __real__ res = __copysignf (__real__ res, __real__ x);
+      __imag__ res = __copysignf (__imag__ res, __imag__ x);
     }
 
   return res;
diff --git a/math/s_casinhl.c b/math/s_casinhl.c
index de41cb8999..80d7bf500d 100644
--- a/math/s_casinhl.c
+++ b/math/s_casinhl.c
@@ -1,5 +1,5 @@
 /* Return arc hyperbole sine for long double value.
-   Copyright (C) 1997, 1998, 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.
 
@@ -73,6 +73,11 @@ __casinhl (__complex__ long double x)
       __imag__ y += __imag__ x;
 
       res = __clogl (y);
+
+      /* Ensure zeros have correct sign and results are correct if
+	 very close to branch cuts.  */
+      __real__ res = __copysignl (__real__ res, __real__ x);
+      __imag__ res = __copysignl (__imag__ res, __imag__ x);
     }
 
   return res;