https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109029
--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #5)
> We need to support signbit<mode>2 for vector double/_Float16. Also similar
> like popcnt, there's a mismatch of input and output between builtin and
> signbit_optab, it could be handled in vectorizer pattern match.
After support signbit{v2df,v4df,v8df}2, vectorizer still failed, currently, we
only support simple integer narrowing, but not for v4df->v8si.
3480 /* First try using an internal function. */
3481 tree_code convert_code = ERROR_MARK;
3482 if (cfn != CFN_LAST
3483 && (modifier == NONE
3484 || (modifier == NARROW
3485 && simple_integer_narrowing (vectype_out, vectype_in,
3486 &convert_code))))
3487 ifn = vectorizable_internal_function (cfn, callee, vectype_out,
3488 vectype_in);
3489
