Fix ldbl-128ibm coshl spurious overflows (bug 16407).

This patch fixes bug 16407, spurious overflows from ldbl-128ibm coshl.
The implementation assumed that a high part (reinterpreted as an
integer) of the absolute value of the argument of 0x408633ce8fb9f87dLL
or more meant overflow, but the actual threshold has high part
0x408633ce8fb9f87eLL (and a negative low part).  The patch adjusts the
threshold accordingly.

sinhl probably has the same issue, but I didn't get that far in adding
tests of special cases (such as just below and above overflow) before
the freeze and during the freeze is not a suitable time to add them
(as they'd require ulps to be regenerated again), so I'm not changing
that function for now; when I add more tests of special cases, we'll
discover whether sinhl indeed has this problem.

Tested powerpc32.

	* sysdeps/ieee754/ldbl-128ibm/e_coshl.c (__ieee754_coshl):
	Increase overflow threshold.

1 files changed, 6 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index be41012fd1..ce828b4222 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2014-01-07  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #16407]
+	* sysdeps/ieee754/ldbl-128ibm/e_coshl.c (__ieee754_coshl):
+	Increase overflow threshold.
+
 2014-01-07  Ondřej Bílka  <neleai@seznam.cz>
 
 	[BZ #14286]