JS/Inlining: in temporary variable elimination improve moving of some expressions which are provably pure

js/js.inliner/src/org/jetbrains/kotlin/js/inline/clean/TemporaryVariableElimination.kt

@@ -17,8 +17,8 @@
 package org.jetbrains.kotlin.js.inline.clean
 
 import com.google.dart.compiler.backend.js.ast.*
-import com.google.dart.compiler.backend.js.ast.metadata.synthetic
 import com.google.dart.compiler.backend.js.ast.metadata.sideEffects
+import com.google.dart.compiler.backend.js.ast.metadata.synthetic
 import org.jetbrains.kotlin.js.inline.util.collectDefinedNames
 import org.jetbrains.kotlin.js.inline.util.collectFreeVariables
 import org.jetbrains.kotlin.js.translate.utils.JsAstUtils
@@ -545,13 +545,25 @@ internal class TemporaryVariableElimination(private val root: JsStatement) {
         is JsNameRef -> {
             val qualifier = expr.qualifier
             if (qualifier == null) {
-                !expr.sideEffects || (expr.name?.let { definitions[it] ?: 0 <= 1 } ?: false)
+                if (!expr.sideEffects) {
+                    true
+                }
+                else {
+                    val name = expr.name
+                    name != null && when (definitions[name] ?: 0) {
+                        0 -> true
+                        1 -> name !in namesToSubstitute || definedValues[name]?.let { isTrivial(it) } ?: false
+                        else -> false
+                    }
+                }
             }
             else {
                 !expr.sideEffects && isTrivial(qualifier)
             }
         }
         is JsLiteral.JsValueLiteral -> true
+        is JsInvocation -> !expr.sideEffects && isTrivial(expr.qualifier) && expr.arguments.all { isTrivial(it) }
+        is JsArrayAccess -> isTrivial(expr.arrayExpression) && isTrivial(expr.indexExpression)
         else -> false
     }
 }

js/js.translator/testData/js-optimizer/temporary-variable/transitiveNotConsideredTrivial.optimized.js

@@ -0,0 +1,13 @@
+var global = 1;
+
+function se() {
+    return global++;
+}
+
+function box() {
+    var $b = se();
+    var result = $b + $b;
+    if (result != 2) return "fail: " + result;
+
+    return "OK";
+}

js/js.translator/testData/js-optimizer/temporary-variable/transitiveNotConsideredTrivial.original.js

@@ -0,0 +1,14 @@
+var global = 1;
+
+function se() {
+    return global++;
+}
+
+function box() {
+    var $a = se();
+    var $b = $a;
+    var result = $b + $b;
+    if (result != 2) return "fail: " + result;
+
+    return "OK";
+}