ghdl: fix llvm backend, add passthru.tests

pkgs/development/compilers/ghdl/simple.vhd

@@ -0,0 +1,45 @@
+library IEEE;
+use IEEE.STD_LOGIC_1164.all;
+use IEEE.NUMERIC_STD.ALL;
+use IEEE.STD_LOGIC_MISC.or_reduce;
+
+entity simple is
+
+port (
+    CLK, RESET : in std_ulogic;
+    DATA_OUT : out std_ulogic_vector(7 downto 0);
+    DONE_OUT : out std_ulogic
+);
+end simple;
+
+architecture beh of simple is
+
+signal data : std_ulogic_vector(7 downto 0);
+signal done: std_ulogic;
+
+begin
+
+proc_ctr : process(CLK)
+begin
+if (CLK = '1' and CLK'event) then
+    if (RESET = '1') then
+        data <= "01011111";
+        done <= '0';
+    else
+    case data is
+        when "00100000" =>  data <= "01001110";
+        when "01001110" =>  data <= "01101001";
+        when "01101001" =>  data <= "01111000";
+        when "01111000" =>  data <= "01001111";
+        when "01001111" =>  data <= "01010011";
+        when others =>  data <= "00100000";
+    end case;
+    done <= not or_reduce(data xor "01010011");
+    end if;
+end if;
+end process;
+
+DATA_OUT <= data;
+DONE_OUT <= done;
+
+end beh;