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authorJoseph Myers <joseph@codesourcery.com>2016-02-19 17:19:53 +0000
committerJoseph Myers <joseph@codesourcery.com>2016-02-19 17:19:53 +0000
commit7b428e744b1ae62c8f26b4e1db487230b796c984 (patch)
tree7af9532337ac60aa7ffe4005e5271a294aae4758 /sysdeps
parent59eda029a8a35e5f4e5cd7be0f84c6629e48ec6e (diff)
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Fix ldbl-128ibm nextafterl, nexttowardl sign of zero result (bug 19678).
The ldbl-128ibm implementation of nextafterl / nexttowardl returns -0
in FE_DOWNWARD mode when taking the next value below the least
positive subnormal, when it should return +0.  This patch fixes it to
check explicitly for this case.

Tested for powerpc.

	[BZ #19678]
	* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c (__nextafterl):
	Ensure +0.0 is returned when taking the next value below the least
	positive value.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c b/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
index 515aa1ef5b..0d6469d548 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
@@ -87,6 +87,9 @@ long double __nextafterl(long double x, long double y)
 		math_force_eval (u);		/* raise underflow flag */
 		__set_errno (ERANGE);
 	      }
+	      /* Avoid returning -0 in FE_DOWNWARD mode.  */
+	      if (x == 0.0L)
+		return 0.0L;
 	      return x;
 	    }
 	    /* If the high double is an exact power of two and the low