Added IfNullExpressionsFusionLowering in pipeline

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanLoweringPhases.kt

@@ -341,4 +341,10 @@ internal val returnsInsertionPhase = makeKonanFileLoweringPhase(
         name = "ReturnsInsertion",
         description = "Returns insertion for Unit functions",
         prerequisite = setOf(autoboxPhase, coroutinesPhase, enumClassPhase)
+)
+
+internal val ifNullExpressionsFusionPhase = makeKonanFileLoweringPhase(
+        ::IfNullExpressionsFusionLowering,
+        name = "IfNullExpressionsFusionLowering",
+        description = "Simplify '?.' and '?:' operator chains"
 )

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/ToplevelPhases.kt

@@ -347,6 +347,7 @@ internal val allLoweringsPhase = namedIrModulePhase(
                                 innerClassPhase then
                                 dataClassesPhase then
                                 singleAbstractMethodPhase then
+                                ifNullExpressionsFusionPhase then
                                 builtinOperatorPhase then
                                 finallyBlocksPhase then
                                 testProcessorPhase then