Silicon Valley once chafed at dictatorships. Then came a Middle East gold rush.

On trips to the glittering capital of the United Arab Emirates, he’s toured a government-built synagogue and a local outpost of the Louvre. The city is so teeming with the tech sector that he ran into fellow California start-up founders in the lobby of the Four Seasons Hotel. Meanwhile, millions from the oil-rich UAE are allowing Feldman’s Cerebras to build advanced supercomputer data centers in Stockton, Calif., Dallas and on the outskirts of the Emirati desert city.