In the context of a force/assign you cannot reuse a saved signal value.

This patch removes the overly optimistic lookaside save for a signal
that has been set (%set/v). This is incorrect because if a force or
assign are active the value will not be set as expected.

tgt-vvp/vvp_process.c

@@ -174,9 +174,11 @@ static void set_to_lvariable(ivl_lval_t lval,
 
 
       } else {
-	    save_signal_lookaside(bit, sig, use_word, wid);
 	    fprintf(vvp_out, "    %%set/v v%p_%lu, %u, %u;\n",
 		    sig, use_word, bit, wid);
+	      /* save_signal width of 0 CLEARS the signal from the
+	         lookaside. */
+	    save_signal_lookaside(bit, sig, use_word, 0);
 
       }
 }