KT-5075 Optimize array/collection indices usage in 'for' loop

Use specialized 'for' loop code generation strategy for loops over array indices and collection indices.

compiler/testData/codegen/box/ranges/forInIndices/forInCollectionImplicitReceiverIndices.kt

@@ -0,0 +1,19 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun Collection<Int>.sumIndices(): Int {
+    var sum = 0
+    for (i in indices) {
+        sum += i
+    }
+    return sum
+}
+
+fun box(): String {
+    val list = listOf(0, 0, 0, 0)
+    val sum = list.sumIndices()
+    assertEquals(6, sum)
+
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forInIndices/forInCollectionIndices.kt

@@ -0,0 +1,13 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun box(): String {
+    var sum = 0
+    for (i in listOf(0, 0, 0, 0).indices) {
+        sum += i
+    }
+    assertEquals(6, sum)
+
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forInIndices/forInNonOptimizedIndices.kt

@@ -0,0 +1,18 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun sumIndices(coll: Collection<*>?): Int {
+    var sum = 0
+    for (i in coll?.indices ?: return 0) {
+        sum += i
+    }
+    return sum
+}
+
+fun box(): String {
+    assertEquals(6, sumIndices(listOf(0, 0, 0, 0)))
+    assertEquals(0, sumIndices(null))
+
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forInIndices/forInObjectArrayIndices.kt

@@ -0,0 +1,13 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun box(): String {
+    var sum = 0
+    for (i in arrayOf("", "", "", "").indices) {
+        sum += i
+    }
+    assertEquals(6, sum)
+
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forInIndices/forInPrimitiveArrayIndices.kt

@@ -0,0 +1,13 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun box(): String {
+    var sum = 0
+    for (i in intArrayOf(0, 0, 0, 0).indices) {
+        sum += i
+    }
+    assertEquals(6, sum)
+
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forInIndices/forNullableIntInArrayIndices.kt

@@ -0,0 +1,16 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun suppressBoxingOptimization(ni: Int?) {}
+
+fun box(): String {
+    var sum = 0
+    for (i: Int? in arrayOf("", "", "", "").indices) {
+        suppressBoxingOptimization(i)
+        sum += i ?: 0
+    }
+    assertEquals(6, sum)
+
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forInIndices/forNullableIntInCollectionIndices.kt

@@ -0,0 +1,16 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun suppressBoxingOptimization(ni: Int?) {}
+
+fun box(): String {
+    var sum = 0
+    for (i: Int? in listOf("", "", "", "").indices) {
+        suppressBoxingOptimization(i)
+        sum += i ?: 0
+    }
+    assertEquals(6, sum)
+
+    return "OK"
+}