WASHINGTON—General Motors Co. Chief Executive Mary Barra said Friday the largest U.S. automaker plans to make changes in its supply chain as it works to address the continuing semiconductor chip crisis that has forced significant production cuts. “We’re going to make some pretty substantial shifts in our supply chain,” Barra said in an online interview. “We’re already working much deeper into the tiered supply base because generally General Motors doesn’t buy chips (directly) but (our suppliers do). But now we’re building direct relationships with the manufacturers.” A GM spokesman declined to comment further on how the company might shift its supply chain. Next week, the White House and the U.S. Commerce Department plan a meeting on the chip crisis, which has caused production cuts by automakers around the world. On Thursday, GM said it was cutting production at six North American assembly plants due to the shortage. Earlier this month, …