Fix ldbl-128ibm ceill, rintl etc. for sNaN arguments (bug 20156).

The ldbl-128ibm implementations of ceill, floorl, roundl, truncl,
rintl and nearbyintl wrongly return an sNaN when given an sNaN
argument.  This patch fixes them to add such an argument to itself to
turn it into a quiet NaN.  (The code structure means this "else" case
applies to any argument which is zero or not finite; it's OK to do
this in all such cases.)

Tested for powerpc.

	[BZ #20156]
	* sysdeps/ieee754/ldbl-128ibm/s_ceill.c (__ceill): Add high part
	to itself when zero or not finite.
	* sysdeps/ieee754/ldbl-128ibm/s_floorl.c (__floorl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_rintl.c (__rintl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_roundl.c (__roundl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_truncl.c (__truncl): Likewise.

6 files changed, 25 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 2516304..1cf86d7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2016-05-27  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #20156]
+	* sysdeps/ieee754/ldbl-128ibm/s_ceill.c (__ceill): Add high part
+	to itself when zero or not finite.
+	* sysdeps/ieee754/ldbl-128ibm/s_floorl.c (__floorl): Likewise.
+	* sysdeps/ieee754/ldbl-128ibm/s_rintl.c (__rintl): Likewise.
+	* sysdeps/ieee754/ldbl-128ibm/s_roundl.c (__roundl): Likewise.
+	* sysdeps/ieee754/ldbl-128ibm/s_truncl.c (__truncl): Likewise.
+
 2016-05-26  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #20153]
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_ceill.c b/sysdeps/ieee754/ldbl-128ibm/s_ceill.c
index 635fddc..71f5623 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_ceill.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_ceill.c
@@ -52,6 +52,9 @@ __ceill (long double x)
 	  ldbl_canonicalize_int (&xh, &xl);
 	}
     }
+  else
+    /* Quiet signaling NaN arguments.  */
+    xh += xh;
 
   return ldbl_pack (xh, xl);
 }
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_floorl.c b/sysdeps/ieee754/ldbl-128ibm/s_floorl.c
index a146964..61ac568 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_floorl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_floorl.c
@@ -52,6 +52,9 @@ __floorl (long double x)
 	  ldbl_canonicalize_int (&xh, &xl);
 	}
     }
+  else
+    /* Quiet signaling NaN arguments.  */
+    xh += xh;
 
   return ldbl_pack (xh, xl);
 }
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_rintl.c b/sysdeps/ieee754/ldbl-128ibm/s_rintl.c
index e4af01c..f7ff673 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_rintl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_rintl.c
@@ -119,6 +119,9 @@ __rintl (long double x)
       fesetround (save_round);
 #endif
     }
+  else
+    /* Quiet signaling NaN arguments.  */
+    xh += xh;
 
   return ldbl_pack (xh, xl);
 }
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_roundl.c b/sysdeps/ieee754/ldbl-128ibm/s_roundl.c
index b01510f..2d75eb0 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_roundl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_roundl.c
@@ -77,6 +77,9 @@ __roundl (long double x)
 	  ldbl_canonicalize_int (&xh, &xl);
 	}
     }
+  else
+    /* Quiet signaling NaN arguments.  */
+    xh += xh;
 
   return ldbl_pack (xh, xl);
 }
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_truncl.c b/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
index b7d4bb5..a2c60a8 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
@@ -52,6 +52,9 @@ __truncl (long double x)
 	  ldbl_canonicalize_int (&xh, &xl);
 	}
     }
+  else
+    /* Quiet signaling NaN arguments.  */
+    xh += xh;
 
   return ldbl_pack (xh, xl);
 }