tree.c (contains_placeholder_p): Ensure function always returns a value.

        * tree.c (contains_placeholder_p): Ensure function always returns
        a value.
        * sparc.md (movdi_sp64_insn): Add default case in enumeration switch.
        (movsf_const_insn, movdf_const_insn, movtf_const_insn): Likewise.

From-SVN: r18196