2018-07-30  Sandra Loosemore  <sandra@codesourcery.com>

         C-SKY port: Documentation

         gcc/
         * doc/extend.texi (C-SKY Function Attributes): New section.
         * doc/invoke.texi (Option Summary): Add C-SKY options.
         (C-SKY Options): New section.
         * doc/md.texi (Machine Constraints): Document C-SKY constraints.