altera fifos: remove unused warnings

There were many constructs like this:
  gen_with_empty : if(g_with_empty) generate
    empty_o <= empty;
  end generate gen_with_empty;

If g_with_empty is true, then there are no warnings.
If g_with_empty is false, then empty_o is unset and empty is unused.

There is no improvement in performance/resource utilization to explicitly
cutting these signals. The optimizer will happily discard unused logic.

The alternative of adding
  gen_without_empty : if(not g_with_empty) generate
    empty_o <= 'X';
  end generate gen_without_empty;
will remove the empty_o unset warning, but not the empty unused warning.

This patch does make it possible for designs to  use empty_o without
setting g_with_empty; an error. On the other hand, those designs had
undefined behaviour before anyway, so they might have worked unreliably.

modules/genrams/altera/generic_async_fifo.vhd

@@ -170,44 +170,15 @@ begin  -- syn
       wrusedw => wrusedw,
       rdusedw => rdusedw);
 
-  gen_with_wr_count : if(g_with_wr_count) generate
-    wr_count_o <= wrusedw;
-  end generate gen_with_wr_count;
-
-  gen_with_rd_count : if(g_with_rd_count) generate
-    rd_count_o <= rdusedw;
-  end generate gen_with_rd_count;
-
-  gen_with_wr_empty : if(g_with_wr_empty) generate
-    wr_empty_o <= wrempty;
-  end generate gen_with_wr_empty;
-
-  gen_with_rd_empty : if(g_with_rd_empty) generate
-    rd_empty_o <= rdempty;
-  end generate gen_with_rd_empty;
-
-  gen_with_wr_full : if(g_with_wr_full) generate
-    wr_full_o <= wrfull;
-  end generate gen_with_wr_full;
-
-  gen_with_rd_full : if(g_with_rd_full) generate
-    rd_full_o <= rdfull;
-  end generate gen_with_rd_full;
-
-  gen_with_wr_almost_empty : if(g_with_wr_almost_empty) generate
-    wr_almost_empty_o <= '1' when unsigned(wrusedw) < to_unsigned(g_almost_empty_threshold, wrusedw'length) else '0';
-  end generate gen_with_wr_almost_empty;
-
-  gen_with_rd_almost_empty : if(g_with_rd_almost_empty) generate
-    rd_almost_empty_o <= '1' when unsigned(rdusedw) < to_unsigned(g_almost_empty_threshold, rdusedw'length) else '0';
-  end generate gen_with_rd_almost_empty;
-
-  gen_with_wr_almost_full : if(g_with_wr_almost_full) generate
-    wr_almost_full_o <= '1' when unsigned(wrusedw) > to_unsigned(g_almost_full_threshold, wrusedw'length) else '0';
-  end generate gen_with_wr_almost_full;
-
-  gen_with_rd_almost_full : if(g_with_rd_almost_full) generate
-    rd_almost_full_o <= '1' when unsigned(rdusedw) > to_unsigned(g_almost_full_threshold,rdusedw'length) else '0';
-  end generate gen_with_rd_almost_full;
+  wr_count_o <= wrusedw;
+  rd_count_o <= rdusedw;
+  wr_empty_o <= wrempty;
+  rd_empty_o <= rdempty;
+  wr_full_o <= wrfull;
+  rd_full_o <= rdfull;
+  wr_almost_empty_o <= '1' when unsigned(wrusedw) < to_unsigned(g_almost_empty_threshold, wrusedw'length) else '0';
+  rd_almost_empty_o <= '1' when unsigned(rdusedw) < to_unsigned(g_almost_empty_threshold, rdusedw'length) else '0';
+  wr_almost_full_o <= '1' when unsigned(wrusedw) > to_unsigned(g_almost_full_threshold, wrusedw'length) else '0';
+  rd_almost_full_o <= '1' when unsigned(rdusedw) > to_unsigned(g_almost_full_threshold,rdusedw'length) else '0';
 
 end syn;

modules/genrams/altera/generic_sync_fifo.vhd

@@ -144,27 +144,10 @@ begin  -- syn
       data         => d_i,
       rdreq        => rd_i);
 
-  
-
-  gen_with_count : if(g_with_count) generate
-    count_o <= usedw;
-  end generate gen_with_count;
-
-
-  gen_with_empty : if(g_with_empty) generate
-    empty_o <= empty;
-  end generate gen_with_empty;
-
-  gen_with_full : if(g_with_full) generate
-    full_o <= full;
-  end generate gen_with_full;
-
-  gen_with_almost_empty : if(g_with_almost_empty) generate
-    almost_empty_o <= almost_empty;
-  end generate gen_with_almost_empty;
-
-  gen_with_almost_full : if(g_with_almost_full) generate
-    almost_full_o <= almost_full;
-  end generate gen_with_almost_full;
+  count_o <= usedw;
+  empty_o <= empty;
+  full_o <= full;
+  almost_empty_o <= almost_empty;
+  almost_full_o <= almost_full;
 
 end syn;