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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.
This commit is contained in:
Joseph Myers 2016-02-19 17:19:53 +00:00
parent 59eda029a8
commit 7b428e744b
2 changed files with 10 additions and 0 deletions
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@ -1,3 +1,10 @@
2016-02-19 Joseph Myers <joseph@codesourcery.com>
[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.
2016-02-19 Florian Weimer <fweimer@redhat.com> 2016-02-19 Florian Weimer <fweimer@redhat.com>
* sysdeps/generic/malloc-machine.h: Assume mutex_init is always * sysdeps/generic/malloc-machine.h: Assume mutex_init is always

3
sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
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@ -87,6 +87,9 @@ long double __nextafterl(long double x, long double y)
math_force_eval (u); /* raise underflow flag */ math_force_eval (u); /* raise underflow flag */
__set_errno (ERANGE); __set_errno (ERANGE);
} }
/* Avoid returning -0 in FE_DOWNWARD mode. */
if (x == 0.0L)
return 0.0L;
return x; return x;
} }
/* If the high double is an exact power of two and the low /* If the high double is an exact power of two and the low