frontend: add asserts to assess the correct behaviour of the replay mechanism

Signed-off-by: Alban Gruin <alban.gruin@irit.fr>

src/frontend/frontend.sv

@@ -438,6 +438,15 @@ module frontend import ariane_pkg::*; #(
       initial begin
         assert (FETCH_WIDTH == 32 || FETCH_WIDTH == 64) else $fatal("[frontend] fetch width != not supported");
       end
+
+      assert property (
+        @(posedge clk_i) disable iff (!rst_ni) replay |-> (replay_addr == icache_vaddr_q))
+          else $warning(1, "[frontend] replay_addr != icache_vaddr_q");
+
+      assert property (
+        @(posedge clk_i) disable iff (!rst_ni) replay |-> ~instr_queue_ready)
+          else $warning(1, "[frontend] replay & instr_queue_ready...");
+
     `endif
     // pragma translate_on
 endmodule