Xilinx Inc. shares led gainers on the S&P 500 index Thursday after the chip maker topped Wall Street forecasts for the quarter and raised its outlook for the year late Wednesday. Xilinx shares rallied nearly 16% to $79.82 at last check as Thursday's best performing stock on the S&P 500 index, which was up 1.8%. Xilinx is also on the PHLX Semiconductor Index , which was up 2.7% despite a big fall for Advanced Micro Devices Inc. shares. Xilinx reported fiscal second-quarter net income of $215.7 million, or 84 cents a share, compared with $173.6 million, or 67 cents a share, in the year-ago period. Revenue rose to $746.3 million from $627.4 million in the year-ago period. Analysts surveyed by FactSet had estimated 76 cents a share on revenue of $710.3 million. Xilinx estimated revenue of $760 million to $780 million for the third quarter, and $2.95 billion to $3 billion for the year, above Wall Street estimates at the time. Analysts now expect revenue, on average, of $765.6 million for the third quarter, and $2.97 billion for the year. Of the 26 analysts who cover Xilinx, 12 have buy or overweight ratings, 13 have hold ratings, and one has a sell rating. Following earnings, 12 analysts hiked their price targets on the stock, raising the average target price to $84.65 from $82.24, according to FactSet data.