Changed an order of processing loops in ForLoopsLowering

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt

@@ -332,9 +332,9 @@ abstract class Symbols<out T : CommonBackendContext>(val context: T, irBuiltIns:
 
     open val unsafeCoerceIntrinsic: IrSimpleFunctionSymbol? = null
 
-    open val getWithoutBCName: Name? = null
+    open val getWithoutBoundCheckName: Name? = null
 
-    open val setWithoutBCName: Name? = null
+    open val setWithoutBoundCheckName: Name? = null
 
     companion object {
         fun isLateinitIsInitializedPropertyGetter(symbol: IrFunctionSymbol): Boolean =

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

@@ -118,35 +118,14 @@ class ForLoopsLowering(val context: CommonBackendContext, val loopBodyTransforme
  * Abstract class for additional for-loop bodies transformations.
  */
 abstract class ForLoopBodyTransformer : IrElementTransformerVoid() {
-    protected lateinit var mainLoopVariable: IrVariable
-    protected lateinit var loopHeader: ForLoopHeader
-    protected lateinit var loopVariableComponents: Map<Int, IrVariable>
-    protected lateinit var context: CommonBackendContext
 
-    open fun initialize(
-        context: CommonBackendContext,
-        loopVariable: IrVariable,
-        forLoopHeader: ForLoopHeader,
-        loopComponents: Map<Int, IrVariable>
-    ) {
-        this.context = context
-        mainLoopVariable = loopVariable
-        loopHeader = forLoopHeader
-        loopVariableComponents = loopComponents
-    }
-
-    fun transform(
+    abstract fun transform(
         context: CommonBackendContext,
         irExpression: IrExpression,
         loopVariable: IrVariable,
         forLoopHeader: ForLoopHeader,
         loopComponents: Map<Int, IrVariable>
-    ) {
-        initialize(context, loopVariable, forLoopHeader, loopComponents)
-        irExpression.transformChildrenVoid(this)
-    }
-
-    open fun shouldTransform(context: CommonBackendContext) = true
+    )
 }
 
 private class RangeLoopTransformer(
@@ -162,6 +141,7 @@ private class RangeLoopTransformer(
     fun getScopeOwnerSymbol() = currentScope?.scope?.scopeOwnerSymbol ?: container.symbol
 
     override fun visitBlock(expression: IrBlock): IrExpression {
+        val returnExpression = super.visitBlock(expression) as IrBlock
         // LoopExpressionGenerator in psi2ir lowers `for (loopVar in <someIterable>) { // Loop body }` into an IrBlock with origin FOR_LOOP.
         // This block has 2 statements:
         //
@@ -178,21 +158,21 @@ private class RangeLoopTransformer(
         // `withIndex()` call, a progression such as `10 downTo 1`). However in some cases (e.g., for `withIndex()`), we also need to
         // examine the while loop to determine if we CAN optimize the loop.
         if (expression.origin != IrStatementOrigin.FOR_LOOP) {
-            return super.visitBlock(expression)  // Not a for-loop block.
+            return returnExpression  // Not a for-loop block.
         }
 
-        with(expression.statements) {
-            assert(size == 2) { "Expected 2 statements in for-loop block, was:\n${expression.dump()}" }
+        with(returnExpression.statements) {
+            assert(size == 2) { "Expected 2 statements in for-loop block, was:\n${returnExpression.dump()}" }
             val iteratorVariable = get(0) as IrVariable
             assert(iteratorVariable.origin == IrDeclarationOrigin.FOR_LOOP_ITERATOR) { "Expected FOR_LOOP_ITERATOR origin for iterator variable, was:\n${iteratorVariable.dump()}" }
             val loopHeader = headerProcessor.extractHeader(iteratorVariable)
-                ?: return super.visitBlock(expression)  // The iterable in the header is not supported.
+                ?: return returnExpression // The iterable in the header is not supported.
             val loweredHeader = lowerHeader(iteratorVariable, loopHeader)
 
             val oldLoop = get(1) as IrWhileLoop
             assert(oldLoop.origin == IrStatementOrigin.FOR_LOOP_INNER_WHILE) { "Expected FOR_LOOP_INNER_WHILE origin for while loop, was:\n${oldLoop.dump()}" }
             val (newLoop, loopReplacementExpression) = lowerWhileLoop(oldLoop, loopHeader)
-                ?: return super.visitBlock(expression)  // Cannot lower the loop.
+                ?: return returnExpression  // Cannot lower the loop.
 
             // We can lower both the header and while loop.
             // Update mapping from old to new loop so we can later update references in break/continue.
@@ -202,7 +182,7 @@ private class RangeLoopTransformer(
             set(1, loopReplacementExpression)
         }
 
-        return super.visitBlock(expression)
+        return returnExpression
     }
 
     /**
@@ -296,7 +276,7 @@ private class RangeLoopTransformer(
                 it
             }
         }
-        if (newBody != null && loopBodyTransformer != null && loopBodyTransformer.shouldTransform(context)) {
+        if (newBody != null && loopBodyTransformer != null) {
             loopBodyTransformer.transform(context, newBody, mainLoopVariable, loopHeader, loopVariableComponents)
         }
 

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

@@ -81,7 +81,7 @@ internal class ArrayIterationHandler(context: CommonBackendContext) : IndexedGet
         get() = getClass()!!.getPropertyGetter("size")!!.owner
 
     private val getFunctionName: Name
-        get() = context.ir.symbols.getWithoutBCName ?: OperatorNameConventions.GET
+        get() = context.ir.symbols.getWithoutBoundCheckName ?: OperatorNameConventions.GET
 
     override val IrType.getFunction
         get() = getClass()!!.functions.single {

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

@@ -10,7 +10,7 @@ import org.jetbrains.kotlin.backend.common.lower.loops.ForLoopsLowering
 import org.jetbrains.kotlin.backend.common.lower.optimizations.FoldConstantLowering
 import org.jetbrains.kotlin.backend.common.lower.optimizations.PropertyAccessorInlineLowering
 import org.jetbrains.kotlin.backend.common.phaser.*
-import org.jetbrains.kotlin.backend.konan.ir.FunctionsWithoutBCGenerator
+import org.jetbrains.kotlin.backend.konan.ir.FunctionsWithoutBoundCheckGenerator
 import org.jetbrains.kotlin.backend.konan.lower.*
 import org.jetbrains.kotlin.backend.konan.lower.FinallyBlocksLowering
 import org.jetbrains.kotlin.backend.konan.lower.InitializersLowering
@@ -258,12 +258,21 @@ internal val rangeContainsLoweringPhase = makeKonanFileLoweringPhase(
         description = "Optimizes calls to contains() for ClosedRanges"
 )
 
+internal val functionsWithoutBoundCheck = makeKonanModuleOpPhase(
+        name = "FunctionsWithoutBoundCheckGenerator",
+        description = "Functions without bounds check generation",
+        op = { context, _ ->
+            FunctionsWithoutBoundCheckGenerator(context).generate()
+        }
+)
+
 internal val forLoopsPhase = makeKonanFileOpPhase(
         { context, irFile ->
             ForLoopsLowering(context, KonanBCEForLoopBodyTransformer()).lower(irFile)
         },
         name = "ForLoops",
-        description = "For loops lowering"
+        description = "For loops lowering",
+        prerequisite = setOf(functionsWithoutBoundCheck)
 )
 
 internal val dataClassesPhase = makeKonanFileLoweringPhase(
@@ -341,19 +350,11 @@ internal val interopPhase = makeKonanFileLoweringPhase(
         prerequisite = setOf(inlinePhase, localFunctionsPhase, functionReferencePhase)
 )
 
-internal val functionsWithoutBC = makeKonanModuleOpPhase(
-        name = "FunctionsWithoutBCGenerator",
-        description = "Functions without bounds check generation",
-        op = { context, _ ->
-            FunctionsWithoutBCGenerator(context).generate()
-        }
-)
-
 internal val varargPhase = makeKonanFileLoweringPhase(
         ::VarargInjectionLowering,
         name = "Vararg",
         description = "Vararg lowering",
-        prerequisite = setOf(functionReferencePhase, defaultParameterExtentPhase, interopPhase, functionsWithoutBC)
+        prerequisite = setOf(functionReferencePhase, defaultParameterExtentPhase, interopPhase, functionsWithoutBoundCheck)
 )
 
 internal val compileTimeEvaluatePhase = makeKonanFileLoweringPhase(

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

@@ -393,7 +393,7 @@ private val backendCodegen = namedUnitPhase(
         name = "Backend codegen",
         description = "Backend code generation",
         lower = takeFromContext<Context, Unit, IrModuleFragment> { it.irModule!! } then
-                functionsWithoutBC then
+                functionsWithoutBoundCheck then
                 allLoweringsPhase then // Lower current module first.
                 dependenciesLowerPhase then // Then lower all libraries in topological order.
                                             // With that we guarantee that inline functions are unlowered while being inlined.

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

@@ -27,7 +27,7 @@ import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.util.OperatorNameConventions
 
 // Generate additional functions for array set and get operators without bounds checking.
-internal class FunctionsWithoutBCGenerator(val context: KonanBackendContext) {
+internal class FunctionsWithoutBoundCheckGenerator(val context: KonanBackendContext) {
     private val symbols = context.ir.symbols
 
     private fun generateFunction(baseFunction: IrSimpleFunction, functionName: Name) =
@@ -55,7 +55,7 @@ internal class FunctionsWithoutBCGenerator(val context: KonanBackendContext) {
                 val setWithoutBEAnnotations = baseFunction.annotations.map { annotation ->
                     annotation.deepCopyWithSymbols().also { copy ->
                         if (copy.isAnnotationWithEqualFqName(KonanFqNames.gcUnsafeCall)) {
-                            val value = "${annotation.getAnnotationStringValue("callee")}_without_BC"
+                            val value = "${annotation.getAnnotationStringValue("callee")}_without_BoundCheck"
                             copy.putValueArgument(0,
                                     IrConstImpl.string(UNDEFINED_OFFSET, UNDEFINED_OFFSET, context.irBuiltIns.stringType, value))
                         }
@@ -69,10 +69,10 @@ internal class FunctionsWithoutBCGenerator(val context: KonanBackendContext) {
         val arraysClasses = symbols.primitiveArrays.values + symbols.array
         arraysClasses.forEach { classSymbol ->
             val setFunction = classSymbol.owner.functions.single { it.name == OperatorNameConventions.SET }
-            classSymbol.owner.addMember(generateFunction(setFunction, KonanNameConventions.setWithoutBC))
+            classSymbol.owner.addMember(generateFunction(setFunction, KonanNameConventions.setWithoutBoundCheck))
 
             val getFunction = classSymbol.owner.functions.single { it.descriptor.name == OperatorNameConventions.GET }
-            classSymbol.owner.addMember(generateFunction(getFunction, KonanNameConventions.getWithoutBC))
+            classSymbol.owner.addMember(generateFunction(getFunction, KonanNameConventions.getWithoutBoundCheck))
         }
     }
 }

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

@@ -43,8 +43,8 @@ import org.jetbrains.kotlin.types.Variance
 import kotlin.properties.Delegates
 
 object KonanNameConventions {
-    val setWithoutBC = Name.special("<setWithoutBC>")
-    val getWithoutBC = Name.special("<getWithoutBC>")
+    val setWithoutBoundCheck = Name.special("<setWithoutBoundCheck>")
+    val getWithoutBoundCheck = Name.special("<getWithoutBoundCheck>")
 }
 
 // This is what Context collects about IR.
@@ -575,9 +575,9 @@ internal class KonanSymbols(
     val topLevelSuite    = getKonanTestClass("TopLevelSuite")
     val testFunctionKind = getKonanTestClass("TestFunctionKind")
 
-    override val getWithoutBCName: Name? = KonanNameConventions.getWithoutBC
+    override val getWithoutBoundCheckName: Name? = KonanNameConventions.getWithoutBoundCheck
 
-    override val setWithoutBCName: Name? = KonanNameConventions.setWithoutBC
+    override val setWithoutBoundCheckName: Name? = KonanNameConventions.setWithoutBoundCheck
 
     private val testFunctionKindCache = TestProcessor.FunctionKind.values().associate {
         val symbol = if (it.runtimeKindString.isEmpty())

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/VarargLowering.kt

@@ -208,7 +208,7 @@ internal class VarargInjectionLowering constructor(val context: KonanBackendCont
     abstract inner class ArrayHandle(val arraySymbol: IrClassSymbol) {
         val setMethodSymbol = with(arraySymbol.owner.functions) {
             // For unsigned types use set method.
-            singleOrNull { it.name == KonanNameConventions.setWithoutBC } ?: single { it.name == OperatorNameConventions.SET }
+            singleOrNull { it.name == KonanNameConventions.setWithoutBoundCheck } ?: single { it.name == OperatorNameConventions.SET }
         }
         val sizeGetterSymbol = arraySymbol.getPropertyGetter("size")!!
         val copyIntoSymbol = symbols.copyInto[arraySymbol.descriptor]!!

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/KonanBCEForLoopBodyTransformer.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.ir.util.functions
 import org.jetbrains.kotlin.ir.util.getPropertyGetter
 import org.jetbrains.kotlin.ir.util.isPrimitiveArray
+import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.util.OperatorNameConventions
 
 // Class contains information about analyzed loop.
@@ -30,16 +31,22 @@ internal data class BoundsCheckAnalysisResult(val boundsAreSafe: Boolean, val ar
  * Transformer for for loops bodies replacing get/set operators on analogs without bounds check where it's possible.
  */
 class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
+    lateinit var mainLoopVariable: IrVariable
+    lateinit var loopHeader: ForLoopHeader
+    lateinit var loopVariableComponents: Map<Int, IrVariable>
+    lateinit var context: CommonBackendContext
+
     private var analysisResult: BoundsCheckAnalysisResult = BoundsCheckAnalysisResult(false, null)
 
-    override fun shouldTransform(context: CommonBackendContext): Boolean {
-        return context is Context && context.shouldOptimize()
-    }
-
-    override fun initialize(context: CommonBackendContext, loopVariable: IrVariable,
-                            forLoopHeader: ForLoopHeader, loopComponents: Map<Int, IrVariable>) {
-        super.initialize(context, loopVariable, forLoopHeader, loopComponents)
+    override fun transform(context: CommonBackendContext, irExpression: IrExpression, loopVariable: IrVariable,
+                           forLoopHeader: ForLoopHeader, loopComponents: Map<Int, IrVariable>) {
+        this.context = context
+        mainLoopVariable = loopVariable
+        loopHeader = forLoopHeader
+        loopVariableComponents = loopComponents
         analysisResult = analyzeLoopHeader(loopHeader)
+        if (analysisResult.boundsAreSafe && analysisResult.arrayInLoop != null)
+            irExpression.transformChildrenVoid(this)
     }
 
     private fun IrExpression.compareIntegerNumericConst(compare: (Long) -> Boolean): Boolean {
@@ -60,46 +67,45 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
     private fun IrCall.dispatchReceiverIsGetSizeCall() = (dispatchReceiver as? IrCall)?.let { it.isGetSizeCall() } ?: false
 
     private fun lessThanSize(functionCall: IrCall): BoundsCheckAnalysisResult {
-        var result = false
-        when (functionCall.symbol.owner.name) {
+        val boundsAreSafe = when (functionCall.symbol.owner.name) {
             OperatorNameConventions.DEC ->
-                if (functionCall.dispatchReceiverIsGetSizeCall()) {
-                    result = true
-                }
+                functionCall.dispatchReceiverIsGetSizeCall()
             OperatorNameConventions.MINUS -> {
                 val value = functionCall.getValueArgument(0)
-                result = functionCall.dispatchReceiverIsGetSizeCall() &&
+                functionCall.dispatchReceiverIsGetSizeCall() &&
                         value?.compareIntegerNumericConst { it > 0 } == true
             }
-            OperatorNameConventions.DIV-> {
+            OperatorNameConventions.DIV -> {
                 val value = functionCall.getValueArgument(0)
-                result = functionCall.dispatchReceiverIsGetSizeCall() &&
+                functionCall.dispatchReceiverIsGetSizeCall() &&
                         value?.compareFloatNumericConst { it > 1 } == true
             }
+            else -> false
         }
         val array = ((functionCall.dispatchReceiver as? IrCall)?.dispatchReceiver as? IrGetValue)?.symbol
-        return BoundsCheckAnalysisResult(result, array)
+        return BoundsCheckAnalysisResult(boundsAreSafe, array)
     }
 
     private fun checkLastElement(last: IrExpression, loopHeader: ProgressionLoopHeader): BoundsCheckAnalysisResult {
-        var result = BoundsCheckAnalysisResult(false, null)
-        if (last is IrCall) {
-            result = lessThanSize(last)
+        return if (last is IrCall) {
             if (last.isGetSizeCall() && !loopHeader.headerInfo.isLastInclusive) {
-                result = BoundsCheckAnalysisResult(true, (last.dispatchReceiver as? IrGetValue)?.symbol)
+                BoundsCheckAnalysisResult(true, (last.dispatchReceiver as? IrGetValue)?.symbol)
+            } else {
+                lessThanSize(last)
             }
+        } else {
+            BoundsCheckAnalysisResult(false, null)
         }
-        return result
     }
 
     private fun IrExpression.isProgressionPropertyGetter(propertyName: String) =
             this is IrCall && symbol.owner.origin == IrDeclarationOrigin.DEFAULT_PROPERTY_ACCESSOR &&
                     (symbol.signature as? IdSignature.AccessorSignature)?.propertySignature?.asPublic()?.shortName == propertyName &&
-                        dispatchReceiver?.type?.getClass()?.symbol in context.ir.symbols.progressionClasses
+                    dispatchReceiver?.type?.getClass()?.symbol in context.ir.symbols.progressionClasses
 
     private fun analyzeLoopHeader(loopHeader: ForLoopHeader): BoundsCheckAnalysisResult {
-        analysisResult = BoundsCheckAnalysisResult(false, null)
-        when(loopHeader) {
+        var analysisResult = BoundsCheckAnalysisResult(false, null)
+        when (loopHeader) {
             is ProgressionLoopHeader ->
                 when (loopHeader.headerInfo.direction) {
                     ProgressionDirection.INCREASING -> {
@@ -112,6 +118,8 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
                         if (loopHeader.headerInfo.last is IrCall) {
                             val functionCall = (loopHeader.headerInfo.last as IrCall)
                             // Case of range with step - `for (i in 0..array.size - 1 step n)`.
+                            // There is a temporary variable `val nestedLast = array.size - 1`
+                            // and `last` is computed as `getProgressionLastElement(0, nestedLast, n)`
                             if (loopHeader.headerInfo.progressionType.getProgressionLastElementFunction == functionCall.symbol) {
                                 val nestedLastVariable = functionCall.getValueArgument(1)
                                 if (nestedLastVariable is IrGetValue && nestedLastVariable.symbol.owner is IrVariable) {
@@ -130,6 +138,8 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
                         if (loopHeader.headerInfo.last is IrCall) {
                             val functionCall = (loopHeader.headerInfo.last as IrCall)
                             // Case of range with step - for (i in array.size - 1 downTo 0 step n).
+                            // There is a temporary variable `val nestedFirst = array.size - 1`
+                            // and `last` is computed as `getProgressionLastElement(nestedFirst, 0, n)`
                             if (loopHeader.headerInfo.progressionType.getProgressionLastElementFunction == functionCall.symbol) {
                                 if (functionCall.getValueArgument(1)?.compareIntegerNumericConst { it >= valueToCompare } == true) {
                                     boundsAreSafe = true
@@ -140,16 +150,13 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
                         }
                         if (!boundsAreSafe)
                             return analysisResult
-                        when (loopHeader.headerInfo.first) {
-                            is IrCall -> {
-                                val functionCall = (loopHeader.headerInfo.first as IrCall)
-                                analysisResult = lessThanSize(functionCall)
-                            }
-                            is IrGetValue -> {
-                                (((loopHeader.headerInfo.first as IrGetValue).symbol.owner as? IrVariable)?.initializer as? IrCall)?.let {
+                        when (val first = loopHeader.headerInfo.first) {
+                            is IrCall ->
+                                analysisResult = lessThanSize(first)
+                            is IrGetValue ->
+                                ((first.symbol.owner as? IrVariable)?.initializer as? IrCall)?.let {
                                     analysisResult = lessThanSize(it)
                                 }
-                            }
                         }
                     }
                     ProgressionDirection.UNKNOWN ->
@@ -177,7 +184,7 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
                 }
 
             is WithIndexLoopHeader ->
-                when(loopHeader.nestedLoopHeader) {
+                when (loopHeader.nestedLoopHeader) {
                     is IndexedGetLoopHeader -> {
                         analysisResult = BoundsCheckAnalysisResult(true,
                                 ((loopHeader.loopInitStatements[0] as? IrVariable)?.initializer as? IrGetValue)?.symbol)
@@ -190,14 +197,14 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
 
     private fun replaceOperators(expression: IrCall, index: IrExpression, safeIndexVariables: List<IrVariable>): IrExpression {
         if (index is IrGetValue && index.symbol.owner in safeIndexVariables) {
-            val operatorWithoutBC = expression.dispatchReceiver!!.type.getClass()!!.functions.singleOrNull {
+            val operatorWithoutBoundCheck = expression.dispatchReceiver!!.type.getClass()!!.functions.singleOrNull {
                 if (expression.symbol.owner.name == OperatorNameConventions.SET)
-                    it.name == KonanNameConventions.setWithoutBC
+                    it.name == KonanNameConventions.setWithoutBoundCheck
                 else
-                    it.name == KonanNameConventions.getWithoutBC
+                    it.name == KonanNameConventions.getWithoutBoundCheck
             } ?: return expression
             return IrCallImpl(
-                    expression.startOffset, expression.endOffset, expression.type, operatorWithoutBC.symbol,
+                    expression.startOffset, expression.endOffset, expression.type, operatorWithoutBoundCheck.symbol,
                     typeArgumentsCount = expression.typeArgumentsCount,
                     valueArgumentsCount = expression.valueArgumentsCount).apply {
                 dispatchReceiver = expression.dispatchReceiver
@@ -210,28 +217,28 @@ class KonanBCEForLoopBodyTransformer : ForLoopBodyTransformer() {
     }
 
     override fun visitCall(expression: IrCall): IrExpression {
-        if (!analysisResult.boundsAreSafe || analysisResult.arrayInLoop == null)
-            return expression
-        if (expression.symbol.owner.name != OperatorNameConventions.SET && expression.symbol.owner.name != OperatorNameConventions.GET) {
-            expression.transformChildrenVoid()
-            return expression
-        }
+        if (expression.symbol.owner.name != OperatorNameConventions.SET && expression.symbol.owner.name != OperatorNameConventions.GET)
+            return super.visitCall(expression)
         if (expression.dispatchReceiver?.type?.isBasicArray() != true ||
                 (expression.dispatchReceiver as? IrGetValue)?.symbol != analysisResult.arrayInLoop)
-            return expression
+            return super.visitCall(expression)
         // Analyze arguments of set/get operator.
-        val index = expression.getValueArgument(0)
-        return when(loopHeader) {
+        val index = expression.getValueArgument(0)!!
+        return when (loopHeader) {
             is ProgressionLoopHeader -> with(loopHeader as ProgressionLoopHeader) {
-                replaceOperators(expression, index!!, listOf(mainLoopVariable, inductionVariable))
+                replaceOperators(expression, index, listOf(mainLoopVariable, inductionVariable))
             }
 
             is WithIndexLoopHeader -> with(loopHeader as WithIndexLoopHeader) {
-                when(nestedLoopHeader) {
+                when (nestedLoopHeader) {
                     is IndexedGetLoopHeader ->
-                        replaceOperators(expression, index!!, listOfNotNull(indexVariable, loopVariableComponents[1]))
+                        replaceOperators(expression, index, listOfNotNull(indexVariable, loopVariableComponents[1]))
                     is ProgressionLoopHeader ->
-                        replaceOperators(expression, index!!,
+                        // Case of `for ((index, value) in (0..array.size - 1 step n).withIndex())`.
+                        // Both `index` (progression size less than array size)
+                        // and `value` (progression start and end element are inside bounds)
+                        // are safe variables if use them in get/set operators.
+                        replaceOperators(expression, index,
                                 listOfNotNull(indexVariable, loopVariableComponents[1], loopVariableComponents[2])
                         )
                     else -> expression

kotlin-native/backend.native/tests/codegen/bce/arraysForLoops.kt

@@ -2,6 +2,8 @@
  * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
  * that can be found in the LICENSE file.
  */
+package codegen.bce.arraysForLoops
+
 import kotlin.test.*
 
 @Test fun forEachIndexedTest() {
@@ -159,7 +161,7 @@ import kotlin.test.*
 @Test fun forRangeToWithStep() {
     val array = Array(10) { 0L }
     val array1 = Array(3) { 0L }
-    var j = 4
+    var j = 8
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for (i in 0..array.size - 1 step 2) {
@@ -202,7 +204,7 @@ import kotlin.test.*
 @Test fun forUntilWithStep() {
     val array = CharArray(10) { '0' }
     val array1 = CharArray(3) { '0' }
-    var j = 4
+    var j = 8
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for (i in 0 until array.size step 2) {
@@ -213,7 +215,7 @@ import kotlin.test.*
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for (i in 0 until array.size step 2) {
-            array[i + 1] = '6'
+            array[i + 3] = '6'
         }
     }
 
@@ -239,7 +241,7 @@ import kotlin.test.*
 @Test fun forDownToWithStep() {
     val array = Array(10) { 0L }
     val array1 = Array(3) { 0L }
-    var j = 4
+    var j = 8
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for (i in array.size - 1 downTo 0 step 2) {
@@ -282,7 +284,7 @@ import kotlin.test.*
 @Test fun forIndiciesWithStep() {
     val array = Array(10) { 0L }
     val array1 = Array(3) { 0L }
-    var j = 4
+    var j = 8
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for (i in array.indices step 2) {
@@ -307,7 +309,7 @@ import kotlin.test.*
 @Test fun forWithIndex() {
     val array = Array(10) { 100 }
     val array1 = Array(3) { 0 }
-    var j = 4
+    var j = 8
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for ((index, value) in array.withIndex()) {
@@ -329,7 +331,7 @@ import kotlin.test.*
     }
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
-        for ((i, v) in (0..array.size + 1 step 2).withIndex()) {
+        for ((i, v) in (0..array.size + 30 step 2).withIndex()) {
             array[i] = 6
         }
     }
@@ -344,7 +346,7 @@ import kotlin.test.*
 @Test fun forReversed() {
     val array = Array(10) { 100 }
     val array1 = Array(3) { 0 }
-    var j = 4
+    var j = 8
 
     assertFailsWith<ArrayIndexOutOfBoundsException> {
         for (i in (0..array.size-1).reversed()) {

kotlin-native/runtime/src/main/cpp/Arrays.cpp

@@ -136,7 +136,7 @@ OBJ_GETTER(Kotlin_Array_get, KConstRef thiz, KInt index) {
   RETURN_OBJ(*Kotlin_Array_get_value(thiz, index));
 }
 
-OBJ_GETTER(Kotlin_Array_get_without_BC, KConstRef thiz, KInt index){
+OBJ_GETTER(Kotlin_Array_get_without_BoundCheck, KConstRef thiz, KInt index){
   RETURN_OBJ(*Kotlin_Array_get_value<false>(thiz, index));
 }
 
@@ -144,7 +144,7 @@ void Kotlin_Array_set(KRef thiz, KInt index, KConstRef value) {
   Kotlin_Array_set_value(thiz, index, value);
 }
 
-void Kotlin_Array_set_without_BC(KRef thiz, KInt index, KConstRef value) {
+void Kotlin_Array_set_without_BoundCheck(KRef thiz, KInt index, KConstRef value) {
   Kotlin_Array_set_value<false>(thiz, index, value);
 }
 
@@ -199,7 +199,7 @@ KByte Kotlin_ByteArray_get(KConstRef thiz, KInt index) {
   return Kotlin_ByteArray_get_value(thiz, index);
 }
 
-KByte Kotlin_ByteArray_get_without_BC(KConstRef thiz, KInt index) {
+KByte Kotlin_ByteArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return Kotlin_ByteArray_get_value<false>(thiz, index);
 }
 
@@ -207,7 +207,7 @@ void Kotlin_ByteArray_set(KRef thiz, KInt index, KByte value) {
   Kotlin_ByteArray_set_value(thiz, index, value);
 }
 
-void Kotlin_ByteArray_set_without_BC(KRef thiz, KInt index, KByte value) {
+void Kotlin_ByteArray_set_without_BoundCheck(KRef thiz, KInt index, KByte value) {
   Kotlin_ByteArray_set_value<false>(thiz, index, value);
 }
 
@@ -489,7 +489,7 @@ KChar Kotlin_CharArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KChar>(thiz, index);
 }
 
-KChar Kotlin_CharArray_get_without_BC(KConstRef thiz, KInt index) {
+KChar Kotlin_CharArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KChar, false>(thiz, index);
 }
 
@@ -497,7 +497,7 @@ void Kotlin_CharArray_set(KRef thiz, KInt index, KChar value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_CharArray_set_without_BC(KRef thiz, KInt index, KChar value) {
+void Kotlin_CharArray_set_without_BoundCheck(KRef thiz, KInt index, KChar value) {
   PrimitiveArraySet<KChar, false>(thiz, index, value);
 }
 
@@ -524,7 +524,7 @@ KShort Kotlin_ShortArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KShort>(thiz, index);
 }
 
-KShort Kotlin_ShortArray_get_without_BC(KConstRef thiz, KInt index) {
+KShort Kotlin_ShortArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KShort, false>(thiz, index);
 }
 
@@ -532,7 +532,7 @@ void Kotlin_ShortArray_set(KRef thiz, KInt index, KShort value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_ShortArray_set_without_BC(KRef thiz, KInt index, KShort value) {
+void Kotlin_ShortArray_set_without_BoundCheck(KRef thiz, KInt index, KShort value) {
   PrimitiveArraySet<KShort, false>(thiz, index, value);
 }
 
@@ -545,7 +545,7 @@ KInt Kotlin_IntArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KInt>(thiz, index);
 }
 
-KInt Kotlin_IntArray_get_without_BC(KConstRef thiz, KInt index) {
+KInt Kotlin_IntArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KInt, false>(thiz, index);
 }
 
@@ -553,7 +553,7 @@ void Kotlin_IntArray_set(KRef thiz, KInt index, KInt value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_IntArray_set_without_BC(KRef thiz, KInt index, KInt value) {
+void Kotlin_IntArray_set_without_BoundCheck(KRef thiz, KInt index, KInt value) {
   PrimitiveArraySet<KInt, false>(thiz, index, value);
 }
 
@@ -638,7 +638,7 @@ KLong Kotlin_LongArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KLong>(thiz, index);
 }
 
-KLong Kotlin_LongArray_get_without_BC(KConstRef thiz, KInt index) {
+KLong Kotlin_LongArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KLong, false>(thiz, index);
 }
 
@@ -646,7 +646,7 @@ void Kotlin_LongArray_set(KRef thiz, KInt index, KLong value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_LongArray_set_without_BC(KRef thiz, KInt index, KLong value) {
+void Kotlin_LongArray_set_without_BoundCheck(KRef thiz, KInt index, KLong value) {
   PrimitiveArraySet<KLong, false>(thiz, index, value);
 }
 
@@ -659,7 +659,7 @@ KFloat Kotlin_FloatArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KFloat>(thiz, index);
 }
 
-KFloat Kotlin_FloatArray_get_without_BC(KConstRef thiz, KInt index) {
+KFloat Kotlin_FloatArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KFloat, false>(thiz, index);
 }
 
@@ -667,7 +667,7 @@ void Kotlin_FloatArray_set(KRef thiz, KInt index, KFloat value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_FloatArray_set_without_BC(KRef thiz, KInt index, KFloat value) {
+void Kotlin_FloatArray_set_without_BoundCheck(KRef thiz, KInt index, KFloat value) {
   PrimitiveArraySet<KFloat, false>(thiz, index, value);
 }
 
@@ -680,7 +680,7 @@ KDouble Kotlin_DoubleArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KDouble>(thiz, index);
 }
 
-KDouble Kotlin_DoubleArray_get_without_BC(KConstRef thiz, KInt index) {
+KDouble Kotlin_DoubleArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KDouble, false>(thiz, index);
 }
 
@@ -688,7 +688,7 @@ void Kotlin_DoubleArray_set(KRef thiz, KInt index, KDouble value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_DoubleArray_set_without_BC(KRef thiz, KInt index, KDouble value) {
+void Kotlin_DoubleArray_set_without_BoundCheck(KRef thiz, KInt index, KDouble value) {
   PrimitiveArraySet<KDouble, false>(thiz, index, value);
 }
 
@@ -701,7 +701,7 @@ KBoolean Kotlin_BooleanArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KBoolean>(thiz, index);
 }
 
-KBoolean Kotlin_BooleanArray_get_without_BC(KConstRef thiz, KInt index) {
+KBoolean Kotlin_BooleanArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KBoolean, false>(thiz, index);
 }
 
@@ -709,7 +709,7 @@ void Kotlin_BooleanArray_set(KRef thiz, KInt index, KBoolean value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_BooleanArray_set_without_BC(KRef thiz, KInt index, KBoolean value) {
+void Kotlin_BooleanArray_set_without_BoundCheck(KRef thiz, KInt index, KBoolean value) {
   PrimitiveArraySet<KBoolean, false>(thiz, index, value);
 }
 
@@ -722,7 +722,7 @@ KNativePtr Kotlin_NativePtrArray_get(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KNativePtr>(thiz, index);
 }
 
-KNativePtr Kotlin_NativePtrArray_get_without_BC(KConstRef thiz, KInt index) {
+KNativePtr Kotlin_NativePtrArray_get_without_BoundCheck(KConstRef thiz, KInt index) {
   return PrimitiveArrayGet<KNativePtr, false>(thiz, index);
 }
 
@@ -730,7 +730,7 @@ void Kotlin_NativePtrArray_set(KRef thiz, KInt index, KNativePtr value) {
   PrimitiveArraySet(thiz, index, value);
 }
 
-void Kotlin_NativePtrArray_set_without_BC(KRef thiz, KInt index, KNativePtr value) {
+void Kotlin_NativePtrArray_set_without_BoundCheck(KRef thiz, KInt index, KNativePtr value) {
   PrimitiveArraySet<KNativePtr, false>(thiz, index, value);
 }