diff --git a/Programs/Source/test_flow_optimization.mpc b/Programs/Source/test_flow_optimization.mpc
new file mode 100644
index 00000000..ba7af650
--- /dev/null
+++ b/Programs/Source/test_flow_optimization.mpc
@@ -0,0 +1,23 @@
+n = 10 ** 7
+a = regint.Array(n)
+b = regint.Array(n)
+
+for i in range(n):
+    if i > 1000:
+        a[i] = i
+
+    if i < 1000:
+        b[i] = -1
+    else:
+        b[i] = 2 * i
+
+def test(a, index, value):
+    print_ln('expected %s got %s at %s', value, a[index], index)
+    crash(a[index] != value)
+
+test(a, 999, 0)
+test(b, 999, -1)
+test(a, 10000, 10000)
+test(b, 10000, 20000)
+test(a, 1000000, 1000000)
+test(b, 1000000, 2000000)
diff --git a/Scripts/test_flow_optimization.sh b/Scripts/test_flow_optimization.sh
new file mode 100755
index 00000000..b9ec62f6
--- /dev/null
+++ b/Scripts/test_flow_optimization.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+
+./compile.py -l test_flow_optimization || exit 1
+Scripts/rep-field.sh test_flow_optimization || exit 1