Switch Optimization

compiler/testData/codegen/box/when/switchOptimization.kt

@@ -0,0 +1,75 @@
+fun foo1(x : Int) : Int {
+    return when (x % 10) {
+        1,2,3 -> 1
+        4,5,6 -> 2
+        7,8,9 -> 3
+        else -> 4
+    }
+}
+
+fun foo2(x : Int) : Int {
+    when (x % 10) {
+        1,2,3 -> return 1
+        4,5,6 -> return 2
+        7,8,9 -> return 3
+    }
+
+    return 4
+}
+
+fun foo3(x : Int) : Int {
+    when (x % 10) {
+        1 -> return 1
+        2 -> return 1
+        3 -> return 1
+        4 -> return 2
+        5 -> return 2
+        6 -> return 2
+        7 -> return 3
+        8 -> return 3
+        9 -> return 3
+    }
+
+    return 4
+}
+
+fun foo4(x : Int) : Int {
+    return when (x % 10) {
+        1 -> 1
+        2 -> 1
+        3 -> 1
+        4 -> 2
+        5 -> 2
+        6 -> 2
+        7 -> 3
+        8 -> 3
+        9 -> 3
+        else -> 4
+    }
+}
+
+fun test(foo : (Int) -> Int, name : String) : String {
+    val foo0 = foo(10)
+
+    var result = if (foo0 == 4) "" else "$name[10/$foo0/4]"
+
+    for (i in 11..19) {
+        val shouldBe = (i-11) / 3 + 1
+        val fooI = foo(i)
+        if (fooI != shouldBe) {
+            result += "$name[$i/$fooI/$shouldBe]"
+        }
+    }
+
+    return result
+}
+
+fun box(): String {
+    val testResult = test({x -> foo1(x)}, "foo1") +
+                     test({x -> foo2(x)}, "foo2") +
+                     test({x -> foo3(x)}, "foo3") +
+                     test({x -> foo4(x)}, "foo4")
+    if (testResult != "") return testResult
+    return "OK"
+}
+