diff --git a/tests/arch/ice40/bug1644.il.gz b/tests/arch/ice40/bug1644.il.gz
new file mode 100644
index 000000000..363c510ef
Binary files /dev/null and b/tests/arch/ice40/bug1644.il.gz differ
diff --git a/tests/arch/ice40/bug1644.ys b/tests/arch/ice40/bug1644.ys
new file mode 100644
index 000000000..5950f0e3c
--- /dev/null
+++ b/tests/arch/ice40/bug1644.ys
@@ -0,0 +1,2 @@
+read_ilang bug1644.il.gz
+synth_ice40 -top top -dsp -json adc_dac_pass_through.json -run :map_bram