Fix ldbl-128ibm log1pl (-1) sign of infinity (bug 19076) [committed]
Commit Message
The ldbl-128ibm implementation of log1pl produces an infinity with the
wrong sign for log1pl (-1) in FE_DOWNWARD mode. This patch fixes this
by changing a division (-1.0L / (x - x)) (incorrect in FE_DOWNWARD
mode) to (-1.0L / 0.0L) (correct in all rounding modes).
Tested for powerpc. Committed.
2015-10-06 Joseph Myers <joseph@codesourcery.com>
[BZ #19076]
* sysdeps/ieee754/ldbl-128ibm/s_log1pl.c (__log1pl): Divide by
constant 0.0L when computing infinite result.
@@ -149,7 +149,7 @@ __log1pl (long double xm1)
if (x <= 0.0L)
{
if (x == 0.0L)
- return (-1.0L / (x - x));
+ return (-1.0L / 0.0L);
else
return (zero / (x - x));
}