Singapore stocks finished higher on Tuesday, with the benchmark Straits Times Index (STI) up 21.05 points, or 0.64 percent, to close at 3,288.53.A total of 3.69 billion shares changed hands with turnover of 1. 33 billion Singapore dollars (1.07 billion U.S. dollars).Gainers outnumbered losers 220 to 212, while 518 others finished unchanged.The STI index gained 8.91 points, or 0.27 percent, to close at 3,267.48 on Monday