regrename.c (find_oldest_value_reg): Ignore the value chain if the original register was copied in a mode with a...

        * regrename.c (find_oldest_value_reg): Ignore the value chain if
        the original register was copied in a mode with a fewer number of
        hard registers than the desired mode.
        (copyprop_hardreg_forward_1): Likewise.
        (debug_value_data): Fix loop test.
        * toplev.c (parse_options_and_default_flags): Reenable
        -fcprop-registers at -O1.

From-SVN: r48624