U.S. stocks rose Tuesday as President Trump said he is willing to delay next month’s deadline for resolving the U.S.’s trade conflict with China if negotiations with Beijing are progressing smoothly.

Mr. Trump, asked whether the deadline for boosting U.S. tariffs to 25% on Chinese products would stay in place, said, “If we’re close to a deal…I could see myself letting that slide for a little while.”

“We...