Add bytecode tests for array for-loop iteration.

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionHandlers.kt

@@ -212,22 +212,19 @@ internal class ArrayIterationHandler(private val context: CommonBackendContext)
         with(context.createIrBuilder(call.symbol, call.startOffset, call.endOffset)) {
             // Consider the case like:
             //
-            // ```
+            //   for (elem in A) { f(elem) }`
-            // for (elem in A) { f(elem) }`
-            // ```
             //
             // If we lower it to:
             //
-            // ```
+            //   for (i in A.indices) { f(A[i]) }
-            // for (i in A.indices) { f(A[i]) }
-            // ```
             //
             // ...then we will break program behaviour if `A` is an expression with side-effect. Instead, we lower it to:
             //
-            // ```
+            //   val a = A
-            // val a = A
+            //   for (i in a.indices) { f(a[i]) }
-            // for (i in a.indices) { f(a[i]) }
+            //
-            // ```
+            // This also ensures that the semantics of re-assignment of array variables used in the loop is consistent with the semantics
+            // proposed in https://youtrack.jetbrains.com/issue/KT-21354.
             val arrayReference = scope.createTemporaryVariable(
                 call.dispatchReceiver!!, nameHint = "array",
                 origin = IrDeclarationOrigin.FOR_LOOP_IMPLICIT_VARIABLE

compiler/testData/codegen/bytecodeText/forLoop/forInObjectArray.kt

@@ -0,0 +1,11 @@
+fun array() = arrayOfNulls<Any>(4)
+
+fun f() {
+    for (i in array()) {
+    }
+}
+
+// 0 iterator
+// 1 INVOKESTATIC .*\.array \(\)
+// 1 ARRAYLENGTH
+// 1 IF_ICMP

compiler/testData/codegen/bytecodeText/forLoop/forInPrimitiveArray.kt

@@ -0,0 +1,16 @@
+fun intArray() = intArrayOf(0, 0, 0, 0)
+fun longArray() = longArrayOf(0, 0, 0, 0)
+
+fun f() {
+    for (i in intArray()) {
+    }
+
+    for (i in longArray()) {
+    }
+}
+
+// 0 iterator
+// 1 INVOKESTATIC .*\.intArray \(\)
+// 1 INVOKESTATIC .*\.longArray \(\)
+// 2 ARRAYLENGTH
+// 2 IF_ICMP

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -1627,11 +1627,21 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/forLoop/forInCharSequence.kt");
         }
 
+        @TestMetadata("forInObjectArray.kt")
+        public void testForInObjectArray() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/forLoop/forInObjectArray.kt");
+        }
+
         @TestMetadata("forInOptimizableUnsignedRange.kt")
         public void testForInOptimizableUnsignedRange() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/forLoop/forInOptimizableUnsignedRange.kt");
         }
 
+        @TestMetadata("forInPrimitiveArray.kt")
+        public void testForInPrimitiveArray() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/forLoop/forInPrimitiveArray.kt");
+        }
+
         @TestMetadata("forInRangeSpecializedToUntil.kt")
         public void testForInRangeSpecializedToUntil() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/forLoop/forInRangeSpecializedToUntil.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBytecodeTextTestGenerated.java

@@ -1637,11 +1637,21 @@ public class IrBytecodeTextTestGenerated extends AbstractIrBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/forLoop/forInCharSequence.kt");
         }
 
+        @TestMetadata("forInObjectArray.kt")
+        public void testForInObjectArray() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/forLoop/forInObjectArray.kt");
+        }
+
         @TestMetadata("forInOptimizableUnsignedRange.kt")
         public void testForInOptimizableUnsignedRange() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/forLoop/forInOptimizableUnsignedRange.kt");
         }
 
+        @TestMetadata("forInPrimitiveArray.kt")
+        public void testForInPrimitiveArray() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/forLoop/forInPrimitiveArray.kt");
+        }
+
         @TestMetadata("forInRangeSpecializedToUntil.kt")
         public void testForInRangeSpecializedToUntil() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/forLoop/forInRangeSpecializedToUntil.kt");