General Mills Inc GIS.N gained 2.9% after the Cheerios maker's sales surpassed estimates despite higher prices. By Amruta Khandekar June 29 (Reuters) - U.S. stock index futures struggled for direction on Wednesday after several Federal Reserve policymakers made a case for faster interest rate hikes to tamp down inflation as a string of recent data continued to paint a dour picture for the economy. The latest data highlighted the contraction of the U.S. economy in the first quarter amid a record trade deficit and followed a Tuesday report that showed U.S. consumer confidence hitting a 16-month low.