diff --git a/kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt b/kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt
index 34b48803b92..c8c4958c416 100644
--- a/kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt
+++ b/kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt
@@ -456,7 +456,7 @@ internal object Devirtualization {
             }
 
             context.logMultiple {
-                val edgesCount = constraintGraph.nodes.sumBy {
+                val edgesCount = constraintGraph.nodes.sumOf {
                     (directEdges[it.id + 1] - directEdges[it.id]) + (it.directCastEdges?.size ?: 0)
                 }
                 +"CONSTRAINT GRAPH: ${constraintGraph.nodes.size} nodes, $edgesCount edges"
@@ -773,12 +773,12 @@ internal object Devirtualization {
             private val preliminaryNumberOfNodes =
                     allTypes.size + // A possible source node for each type.
                             functions.size * 2 + // <returns> and <throws> nodes for each function.
-                            functions.values.sumBy {
-                                it.body.allScopes.sumBy { it.nodes.size } // A node for each DataFlowIR.Node.
+                            functions.values.sumOf {
+                                it.body.allScopes.sumOf { it.nodes.size } // A node for each DataFlowIR.Node.
                             } +
                             functions.values
-                                    .sumBy { function ->
-                                        function.body.allScopes.sumBy {
+                                    .sumOf { function ->
+                                        function.body.allScopes.sumOf {
                                             it.nodes.count { node ->
                                                 // A cast if types are different.
                                                 node is DataFlowIR.Node.Call