Will Adam Sandler ever grow up? His comic persona remains a boyish boob even as he enters middle age. Jim Carrey, Bill Murray, Will Ferrell and Steve Carell show their versatility in roles that stretch and test their talents. Sandler sits apart, an overgrown goof stubbornly unwilling to evolve.

His latest, “Blended,” shows him still stuck in neutral. It’s a crude, silly romantic comedy whose best idea is reuniting him with Drew Barrymore, his co-star in “The Wedding Singer” and “50 First Dates.” This film is essentially a footnote to those originals. Miss it and you miss very little.

After their hate-at-first-sight date, the widowed Sandler and the divorced Barrymore find themselves sharing quarters at a luxury resort with his three daughters and her two sons. He’s a schlubby sporting-goods salesman; she’s a compulsively structured closet organizer. Sandler, whose testiness is never far from the surface whatever role he’s playing, inquires about her career path. “Did you start with organizing glove compartments and move up?” he asks with curdled nastiness.

It’s the sort of thing only a militant jerk would say. It’s also the wittiest line in this two-hour death march.

“Blended” follows the pattern of recent Sandler movies in which he picks a vacation spot he’d like to visit, pulls together a crew of his cronies and makes a movie of it. The setting here is a palatial hotel in South Africa, which sets up borderline racist gags about the black staff, who are uniformly asleep at the switch. Even the estimable Terry Crews is an embarrassment as an eye-popping, hambone, minstrel-style lounge singer.

Fans of the bestiality theme in Sandler’s films will be pleased to learn that there is man-on-giraffe tongue kissing and a gratuitous shot of rhinoceros copulation.

Sandler doesn’t break a sweat in his performance. His character is given one simple task — bond with his daughters, despite his entirely sports-centric worldview (he insists his blossoming eldest should bulk up for basketball season, and named his middle girl Espn after his favorite TV channel). The story trajectory that brings him and Barrymore into romantic alignment would have been a cliché in the Late Pleistocene epoch.

Barrymore is a winning, loosey-goosey comedian who can pick up the slack when Sandler can’t be bothered. She rises to every occasion, whether it’s a passage of broad physical humor or a moment of starry-eyed sentimentality. Early in the film she and Sandler have a disastrous dinner date. For reasons that don’t matter, she spit-coughs a quart of French onion soup all over the table. You don’t laugh at the action itself, unless you are very new to movies. You may well smile at her commitment to the idiocy required of her: What a good sport. She brings a game, go-along sense of fun the film desperately needs. What a shame she doesn’t have a better movie to frame her talent.