The ldbl-128ibm implementation of roundl is only correct in
round-to-nearest mode (in other modes, there are incorrect results and
overflow exceptions in some cases). This patch reimplements it along
the lines used for floorl, ceill and truncl, using __round on the high
part, and on the low part if the high part is an integer, and then
adjusting in the cases where this is incorrect.
Tested for powerpc.
[BZ #19594]
* sysdeps/ieee754/ldbl-128ibm/s_roundl.c (__roundl): Use __round
on high and low parts then adjust result and use
ldbl_canonicalize_int if needed.
b9a76339be