JVM IR: Optimize field initializers in secondary constructors

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -26809,6 +26809,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/secondaryConstructors/enums.kt");
         }
 
+        @TestMetadata("fieldInitializerOptimization.kt")
+        public void testFieldInitializerOptimization() throws Exception {
+            runTest("compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt");
+        }
+
         @TestMetadata("generics.kt")
         public void testGenerics() throws Exception {
             runTest("compiler/testData/codegen/box/secondaryConstructors/generics.kt");

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt

@@ -558,10 +558,9 @@ class ExpressionCodegen(
     override fun visitSetField(expression: IrSetField, data: BlockInfo): PromisedValue {
         val expressionValue = expression.value
         // Do not add redundant field initializers that initialize to default values.
-        val inPrimaryConstructor = irFunction is IrConstructor && irFunction.isPrimary
         val inClassInit = irFunction.origin == JvmLoweredDeclarationOrigin.CLASS_STATIC_INITIALIZER
         val isFieldInitializer = expression.origin == IrStatementOrigin.INITIALIZE_FIELD
-        val skip = (inPrimaryConstructor || inClassInit) && isFieldInitializer && expressionValue is IrConst<*> &&
+        val skip = (irFunction is IrConstructor || inClassInit) && isFieldInitializer && expressionValue is IrConst<*> &&
                 isDefaultValueForType(expression.symbol.owner.type.asmType, expressionValue.value)
         return if (skip) unitValue else super.visitSetField(expression, data)
     }

compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt

@@ -0,0 +1,20 @@
+// IGNORE_BACKEND: JS
+// IGNORE_BACKEND: JS_IR
+
+open class Base {
+    open fun setup() {}
+    init { setup() }
+}
+
+class Derived : Base {
+    constructor() : super()
+    override fun setup() { x = 1 }
+
+    // Technically, this field initializer comes after the superclass
+    // constructor is called. However, we optimize away field initializers
+    // which set fields to their default value, which is why x ends up with
+    // value 1 after the constructor call.
+    var x = 0
+}
+
+fun box(): String = if (Derived().x == 1) "OK" else "Fail"

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -28395,6 +28395,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/secondaryConstructors/enums.kt");
         }
 
+        @TestMetadata("fieldInitializerOptimization.kt")
+        public void testFieldInitializerOptimization() throws Exception {
+            runTest("compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt");
+        }
+
         @TestMetadata("generics.kt")
         public void testGenerics() throws Exception {
             runTest("compiler/testData/codegen/box/secondaryConstructors/generics.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -27212,6 +27212,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/secondaryConstructors/enums.kt");
         }
 
+        @TestMetadata("fieldInitializerOptimization.kt")
+        public void testFieldInitializerOptimization() throws Exception {
+            runTest("compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt");
+        }
+
         @TestMetadata("generics.kt")
         public void testGenerics() throws Exception {
             runTest("compiler/testData/codegen/box/secondaryConstructors/generics.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -26809,6 +26809,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/secondaryConstructors/enums.kt");
         }
 
+        @TestMetadata("fieldInitializerOptimization.kt")
+        public void testFieldInitializerOptimization() throws Exception {
+            runTest("compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt");
+        }
+
         @TestMetadata("generics.kt")
         public void testGenerics() throws Exception {
             runTest("compiler/testData/codegen/box/secondaryConstructors/generics.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -21690,6 +21690,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/secondaryConstructors/enums.kt");
         }
 
+        @TestMetadata("fieldInitializerOptimization.kt")
+        public void testFieldInitializerOptimization() throws Exception {
+            runTest("compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt");
+        }
+
         @TestMetadata("generics.kt")
         public void testGenerics() throws Exception {
             runTest("compiler/testData/codegen/box/secondaryConstructors/generics.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -21750,6 +21750,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/secondaryConstructors/enums.kt");
         }
 
+        @TestMetadata("fieldInitializerOptimization.kt")
+        public void testFieldInitializerOptimization() throws Exception {
+            runTest("compiler/testData/codegen/box/secondaryConstructors/fieldInitializerOptimization.kt");
+        }
+
         @TestMetadata("generics.kt")
         public void testGenerics() throws Exception {
             runTest("compiler/testData/codegen/box/secondaryConstructors/generics.kt");