--- /dev/null
+; RUN: opt < %s -lowerswitch -disable-output
+
+; This test verify -lowerswitch does not crash after deleting the default block.
+
+declare i32 @f(i32)
+
+define i32 @unreachable(i32 %x) {
+
+entry:
+ switch i32 %x, label %unreachable [
+ i32 5, label %a
+ i32 6, label %a
+ i32 7, label %a
+ i32 10, label %b
+ i32 20, label %b
+ i32 30, label %b
+ i32 40, label %b
+ ]
+unreachable:
+ unreachable
+a:
+ %0 = call i32 @f(i32 0)
+ ret i32 %0
+b:
+ %1 = call i32 @f(i32 1)
+ ret i32 %1
+}