[K/N][IR][optmz] Global analysis for top-level initializers

The analysis' goal is to remove redundant calls to initializers

kotlin-native/backend.native/tests/codegen/initializers/return1.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+fun foo(x: Int) {
+    if (x <= 0) return
+    bar(x)
+}
+
+fun main() {
+    foo(0)
+    println(y)
+}

kotlin-native/backend.native/tests/codegen/initializers/return2.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+inline fun foo(x: Int) {
+    if (x <= 0) return
+    bar(x)
+}
+
+fun main() {
+    foo(0)
+    println(y)
+}

kotlin-native/backend.native/tests/codegen/initializers/throw1.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val x = computeX()
+
+private fun computeX() = 42
+
+fun baz1() { }
+
+fun baz2() { }
+
+// FILE: main.kt
+fun bar(x: Int) = if (x == 0) error("") else x
+
+fun foo(x: Int) {
+    try {
+        bar(x)
+        baz1()
+    } catch (t: Throwable) { }
+}
+
+fun main() {
+    foo(0)
+    println(x)
+}

kotlin-native/backend.native/tests/codegen/initializers/throw2.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = computeY()
+
+private fun computeY() = 42
+
+fun baz1() { }
+
+fun baz2() { }
+
+// FILE: main.kt
+fun bar(x: Int) = if (x == 0) error("") else x
+
+fun foo(x: Int) {
+    try {
+        bar(x)
+        baz1()
+    } catch (t: Throwable) {
+        println(y)
+    }
+}
+
+fun main() {
+    foo(0)
+}

kotlin-native/backend.native/tests/codegen/initializers/when1.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+fun foo(x: Int) = when {
+    x > 0 -> 42
+    bar(x) -> 117
+    else -> -1
+}
+
+fun main() {
+    foo(123)
+    println(y)
+}

kotlin-native/backend.native/tests/codegen/initializers/when2.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+fun foo(x: Int) {
+    if (x > 0) bar(x)
+}
+
+fun main() {
+    foo(-1)
+    println(y)
+}

kotlin-native/backend.native/tests/codegen/initializers/while1.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+fun foo(x: Int) {
+    var i = 0
+    while (i < x) {
+        bar(i)
+        ++i
+    }
+}
+
+fun main() {
+    foo(0)
+    println(y)
+}

kotlin-native/backend.native/tests/codegen/initializers/while2.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+fun foo(x: Int) {
+    var i = 0
+    do {
+        if (i == x) break
+        ++i
+    } while (bar(i))
+}
+
+fun main() {
+    foo(0)
+    println(y)
+}

kotlin-native/backend.native/tests/codegen/initializers/while3.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// FILE: lib.kt
+val y = getY()
+
+private fun getY() = 42
+
+fun bar(x: Int) = x == 0
+
+// FILE: main.kt
+fun foo(x: Int) {
+    var i = 0
+    do {
+        ++i
+        if (i > 0) continue
+        bar(i)
+    } while (i < x)
+}
+
+fun main() {
+    foo(0)
+    println(y)
+}