tgt-vvp: Cast reads from 2-state dynamic arrays/queues

vvp does not track whether the values stored in a dynamic array or queue
are 2-state or 4-state. Internally the data is always stored as 4-state.

To make sure that the read value is actually 2-state do a cast for 2-state
reads.

E.g. performing an out-of-bounds access on a 2-state dynamic array or queue
will yield a undefined value.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

tgt-vvp/eval_vec4.c

@@ -957,6 +957,8 @@ static void draw_select_vec4(ivl_expr_t expr)
 	    assert(base);
 	    draw_eval_expr_into_integer(base, 3);
 	    fprintf(vvp_out, "    %%load/dar/vec4 v%p_0;\n", sig);
+	    if (ivl_expr_value(expr) == IVL_VT_BOOL)
+		  fprintf(vvp_out, "    %%cast2;\n");
 
 	    return;
       }