Devirtualization fails to eliminate boxing in function reference context

^KT-49847 Fixed

Merge-request: KT-MR-6460
Merged-by: Vladimir Sukharev <Vladimir.Sukharev@jetbrains.com>

kotlin-native/backend.native/tests/filecheck/kt49847_class.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+class C {
+    fun foo(x: Int) = x
+}
+
+// CHECK: define void @"kfun:#main(){}"()
+// CHECK-NOT: Int-box
+//   TODO Remove next check after fix of https://youtrack.jetbrains.com/issue/KT-53100/Optimization-needed-T-unboxCONSTANTPRIMITIVEx-T-x
+// CHECK: Int-unbox
+// CHECK-NOT: Int-unbox
+// CHECK: ret void
+fun main() {
+    val c = C()
+    val fooref = c::foo
+    if( fooref(42) == 42)
+        println("ok")
+}

kotlin-native/backend.native/tests/filecheck/kt49847_generic.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+class C<T> {
+    fun foo(x: T) = x
+}
+
+// CHECK: define void @"kfun:#main(){}"()
+// CHECK-NOT: Int-box
+//   TODO Remove next check after fix of https://youtrack.jetbrains.com/issue/KT-53100/Optimization-needed-T-unboxCONSTANTPRIMITIVEx-T-x
+// CHECK: Int-unbox
+// CHECK-NOT: Int-unbox
+// CHECK: ret void
+fun main() {
+    val c = C<Int>()
+    val fooref = c::foo
+    if( fooref(42) == 42)
+        println("ok")
+}

kotlin-native/backend.native/tests/filecheck/kt49847_generic_receiver.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+// CHECK: define internal void @"kfun:$foo$FUNCTION_REFERENCE$0.<init>#internal"
+// CHECK-SAME: i32
+
+fun <T> T.foo() { println(this) }
+
+fun main() {
+    println(5::foo)
+}

kotlin-native/backend.native/tests/filecheck/kt49847_sam_Any.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+fun interface Foo {
+    fun bar(x: Int): Any
+}
+
+fun baz(x: Any): Int = x.hashCode()
+
+// CHECK: define void @"kfun:#main(){}"()
+// Boxing/unboxing need to be used now due to non-devirtualized call
+// CHECK: Int-box
+
+//  TODO  Remove two next checks, when advanced optimization of Int-unbox(Int-box(x)) would be done for snippet like:
+//  TODO  VAR IR_TEMPORARY_VARIABLE name:arg0 type:kotlin.Any [val]
+//  TODO    BLOCK type=kotlin.Any origin=null
+//  TODO      CALL <Int-box>
+//  TODO        GET_VAR 'val arg1: kotlin.Int [val]'
+//  TODO  CALL <Int-unbox>
+//  TODO    GET_VAR 'val arg0: kotlin.Any [val]'
+// CHECK: Int-box
+// CHECK: Int-unbox
+
+// CHECK-NOT: Int-box
+// CHECK-NOT: Int-unbox
+// CHECK: ret void
+
+fun main() {
+    val foo: Foo = Foo(::baz)
+    if( foo.bar(42) == 42 )
+        println("passed")
+}

kotlin-native/backend.native/tests/filecheck/kt49847_sam_Any_generic.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+fun interface Foo<T> {
+    fun bar(x: T): Any
+}
+
+fun baz(x: Any): Int = x.hashCode()
+
+// CHECK: define void @"kfun:#main(){}"()
+// Boxing/unboxing need to be used now due to non-devirtualized call
+// CHECK: Int-box
+// CHECK-NOT: Int-box
+// CHECK: Int-unbox
+// CHECK-NOT: Int-unbox
+// CHECK-NOT: Int-box
+// CHECK: ret void
+fun main() {
+    val foo: Foo<Int> = Foo(::baz)
+    if( foo.bar(42) == 42 )
+        println("passed")
+}

kotlin-native/backend.native/tests/filecheck/kt49847_sam_Int.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+fun interface Foo {
+    fun bar(x: Int): Int
+}
+
+fun baz(x: Int): Int = x.hashCode()
+
+// CHECK: define void @"kfun:#main(){}"()
+// CHECK-NOT: Int-box
+// CHECK-NOT: Int-unbox
+// CHECK: ret void
+fun main() {
+    val foo: Foo = Foo(::baz)
+    if( foo.bar(42) == 42 )
+        println("passed")
+}

kotlin-native/backend.native/tests/filecheck/kt49847_sam_Int_generic.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+fun interface Foo<T> {
+    fun bar(x: T): Int
+}
+
+fun baz(x: Any): Int = x.hashCode()
+
+// CHECK: define void @"kfun:#main(){}"()
+// CHECK-NOT: Int-box
+// CHECK-NOT: Int-unbox
+// CHECK: ret void
+fun main() {
+    val foo: Foo<Int> = Foo(::baz)
+    if( foo.bar(42) == 42 )
+        println("passed")
+}

kotlin-native/backend.native/tests/filecheck/kt49847_simple_function_reference.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+fun plus1(x: Int) = x + 1
+
+// CHECK: define void @"kfun:#main(){}"()
+// CHECK-NOT: Int-box
+// CHECK-NOT: Int-unbox
+// CHECK: ret void
+fun main() {
+    val ref = ::plus1
+    var y = 0
+    repeat(100000) {
+        y += ref(it)  // Should be devirtualized and invoked without boxing/unboxing (`Int-box`/`Int-unbox`)
+    }
+    if (y > 999999)
+        println("y > 999999")
+}