re PR debug/40012 (Revision 146817 generated bad debug info for local variables)

        PR debug/40012

        * cfgexpand.c (set_rtl): Store place also in DECL_RTL, if all
        partitions use the same.
        (expand_one_var): Deal with DECL_RTL sometimes begin set also
        for basevars of SSA_NAMEs.
        (expand_used_vars): Reset TREE_USED for basevars of SSA_NAMEs,
        to not expand them twice.
        (gimple_expand_cfg): Clear DECL_RTL for those decls that have
        multiple places.

From-SVN: r148273