diff --git a/tests/arch/ice40/ice40_dsp.ys b/tests/arch/ice40/ice40_dsp.ys
index 250273859..b13e525fd 100644
--- a/tests/arch/ice40/ice40_dsp.ys
+++ b/tests/arch/ice40/ice40_dsp.ys
@@ -8,4 +8,5 @@ assign o4 = a * b;
 SB_MAC16 m3 (.A(a), .B(b), .O(o5));
 endmodule
 EOT
+read_verilog -lib +/ice40/cells_sim.v
 ice40_dsp