* math/libm-test.inc (lround_test): Add new test.
(llround_test): Likewise.
(lrint_test): Likewise.
(llrint_test): Likewise.
* sysdeps/ieee754/dbl-64/s_lround.c (__lround): Fix special case
with result taking up 20 bits.
* sysdeps/ieee754/dbl-64/s_lrint.c (__lrint): Likewise.
* sysdeps/ieee754/dbl-64/s_llrint.c (__llrint): Likewise..
* sysdeps/ieee754/ldbl-96/s_lroundl.c (__lroundl): Fix special
case with result taking up 31 bits.
* sysdeps/ieee754/ldbl-96/s_lrintl.c (__lrintl): Likewise.