Flex10k - LE optimization?

Use an lpm_counter configured for down mode (this ensures that fast carry chains are used, and the compare with zero comes for free).

-- Altera LPM components
library lpm;
use lpm.lpm_components.all;
...
    -- Bit counter
    bit_d <= to_slv(BIT_VALUE, BIT_WIDTH);
    u3: lpm_counter
        generic map (
            LPM_WIDTH     => BIT_WIDTH,
            LPM_DIRECTION => "DOWN"
        )
        port map (
            -- Simulation-only output (suppress Quartus II warning)
            --
            -- altera translate_off
            q      => bit_q,
            -- altera translate_on
            aclr   => rst,
            clock  => clk,
            sload  => bit_load,
            cnt_en => bit_en,
            cout   => bit_done,
            data   => bit_d
        );