tree-complex.c (init_dont_simulate_again): Clear DONT_SIMULATE_AGAIN for control-altering statements; set it again for returns.

        * tree-complex.c (init_dont_simulate_again): Clear DONT_SIMULATE_AGAIN
        for control-altering statements; set it again for returns.
        (complex_visit_stmt): Return SSA_PROP_VARYING for stmts that are
        not MODIFY_EXPR.

From-SVN: r101178