log2l
__weak_reference(log2, log2l);
long double log2l(long double);
ATF_CHECK_EQ(i, log2l(ldexpl(1.0, i)));
test_tol(log2l, tests[i].x, tests[i].log2x, LDBL_ULP());
test(log2l, x, result, exceptmask, excepts); \