PR tree-optimization/30771
        * tree-vect-analyze.c (vect_determine_vectorization_factor): Traverse
        also phi nodes.
        (vect_analyze_operations): Induction phis can now be marked as
        used_in_loop.
        (vect_mark_stmts_to_be_vectorized): No special treatment for phis.
        Update documentation accordingly.

From-SVN: r121950