JVM_IR: Fix field initialization in secondary enum constructors.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/EnumClassLowering.kt

@@ -68,6 +68,7 @@ private class EnumClassLowering(val context: JvmBackendContext) : ClassLoweringP
         private lateinit var valueOfFunction: IrFunction
 
         fun run() {
+            insertInstanceInitializer()
             assignOrdinalsToEnumEntries()
             lowerEnumConstructors(irClass)
             lowerEnumEntries()
@@ -75,6 +76,35 @@ private class EnumClassLowering(val context: JvmBackendContext) : ClassLoweringP
             lowerEnumClassBody()
         }
 
+        // Make sure that an instance initializer call exists, so that field initialization code will be generated.
+        // TODO: This function is identical to the one used in the JS lowerings. Share them.
+        private fun insertInstanceInitializer() {
+            irClass.transformChildrenVoid(object : IrElementTransformerVoid() {
+                override fun visitClass(declaration: IrClass) = declaration
+
+                override fun visitConstructor(declaration: IrConstructor): IrStatement {
+                    declaration.transformChildrenVoid(this)
+
+                    val blockBody = declaration.body as IrBlockBody
+
+                    if (!blockBody.statements.any { it is IrInstanceInitializerCall }) {
+                        blockBody.statements.transformFlat {
+                            if (it is IrEnumConstructorCall)
+                                listOf(
+                                    it, IrInstanceInitializerCallImpl(
+                                        declaration.startOffset, declaration.startOffset,
+                                        irClass.symbol, context.irBuiltIns.unitType
+                                    )
+                                )
+                            else null
+                        }
+                    }
+
+                    return declaration
+                }
+            })
+        }
+
         private fun assignOrdinalsToEnumEntries() {
             var ordinal = 0
             irClass.declarations.forEach {

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

@@ -1,5 +1,5 @@
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JVM_IR
+
 enum class A1(val prop1: String) {
     X("asd"),
     Y() {