JS: do not create variable for result, if inline call is only return subexpression

js/js.inliner/src/org/jetbrains/kotlin/js/inline/FunctionInlineMutator.kt

@@ -94,6 +94,11 @@ class FunctionInlineMutator private (private val call: JsInvocation, private val
     }
 
     private fun processReturns() {
+        if (currentStatement is JsReturn && currentStatement.getExpression() === call) {
+            inliningContext.statementContext.removeMe()
+            return
+        }
+
         val returnCount = collectInstances(javaClass<JsReturn>(), body).size()
         if (returnCount == 0) {
             // TODO return Unit (KT-5647)

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

@@ -41,6 +41,12 @@ public class InlineSizeReductionTestGenerated extends AbstractInlineSizeReductio
         doTest(fileName);
     }
 
+    @TestMetadata("returnInlineCall.kt")
+    public void testReturnInlineCall() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("js/js.translator/testData/inlineSizeReduction/cases/returnInlineCall.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("simpleReturnFunction.kt")
     public void testSimpleReturnFunction() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("js/js.translator/testData/inlineSizeReduction/cases/simpleReturnFunction.kt");

js/js.translator/testData/inlineSizeReduction/cases/returnInlineCall.kt

@@ -0,0 +1,30 @@
+package foo
+
+// CHECK_CONTAINS_NO_CALLS: test
+// CHECK_VARS_COUNT: function=test count=0
+
+inline fun sign(x: Int): Int {
+    if (x < 0) return -1
+
+    if (x == 0) return 0
+
+    return 1
+}
+
+fun test(x: Int, y: Int): Int {
+    if (x != 0) {
+        return sign(x)
+    }
+
+    return sign(y)
+}
+
+fun box(): String {
+    assertEquals(-1, test(-2, 2))
+    assertEquals(1, test(2, -2))
+    assertEquals(-1, test(0, -2))
+    assertEquals(1, test(0, 2))
+    assertEquals(0, test(0, 0))
+
+    return "OK"
+}