Gaozu was not s Buddhist, he did not support the religion. He issued an official edict defining Daoism and Confucianism as the 2 pillars of Chinese culture. Taizong(Gaozu's son) had little interest in Buddhism when he was ruling. But Taizong did hold an important audience with a Buddhist monk just the year before he died. And also before Taizong died he converted to Buddhism.