Preheat oven to 375. Unroll crescent roll dough, and separate into 4 rectangles; pinch perforations within rectangles to seal. Stir together sugar and cinnamon; sprinkle mixture evenly over rectangles. Roll up, jelly roll fashion, starting with a long side. Pinch edges to seal. Gently cut each log into 5 slices, and put, cut sides down in slightly greased 8 or 9 inch round cake pan.
Bake at 375 for 15 minutes or til rolls begin to brown.
Mix powdered sugar, milk and vanilla. Stir til smooth. Drizzle over warm cinnamon rolls. Makes 20 rolls.