Support const-bound counter loop generation for 'downTo'

compiler/backend/src/org/jetbrains/kotlin/codegen/codegenUtil.kt

@@ -47,6 +47,7 @@ import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.DescriptorUtils.isSubclass
 import org.jetbrains.kotlin.resolve.annotations.hasJvmStaticAnnotation
 import org.jetbrains.kotlin.resolve.bindingContextUtil.getDataFlowInfoBefore
+import org.jetbrains.kotlin.resolve.calls.callUtil.getFirstArgumentExpression
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
@@ -420,11 +421,11 @@ fun extractReificationArgument(type: KotlinType): Pair<TypeParameterDescriptor,
 fun unwrapInitialSignatureDescriptor(function: FunctionDescriptor): FunctionDescriptor =
         function.initialSignatureDescriptor ?: function
 
-fun ExpressionCodegen.generateCallReceiver(rangeCall: ResolvedCall<out CallableDescriptor>): StackValue =
-        generateReceiverValue(rangeCall.extensionReceiver ?: rangeCall.dispatchReceiver!!, false)
+fun ExpressionCodegen.generateCallReceiver(call: ResolvedCall<out CallableDescriptor>): StackValue =
+        generateReceiverValue(call.extensionReceiver ?: call.dispatchReceiver!!, false)
 
-fun ExpressionCodegen.generateCallSingleArgument(rangeCall: ResolvedCall<out CallableDescriptor>): StackValue =
-        gen(ExpressionCodegen.getSingleArgumentExpression(rangeCall)!!)
+fun ExpressionCodegen.generateCallSingleArgument(call: ResolvedCall<out CallableDescriptor>): StackValue =
+        gen(call.getFirstArgumentExpression()!!)
 
 fun ClassDescriptor.isPossiblyUninitializedSingleton() =
         DescriptorUtils.isEnumEntry(this) ||

compiler/backend/src/org/jetbrains/kotlin/codegen/range/DownToProgressionRangeValue.kt

@@ -20,8 +20,11 @@ import org.jetbrains.kotlin.codegen.ExpressionCodegen
 import org.jetbrains.kotlin.codegen.generateCallReceiver
 import org.jetbrains.kotlin.codegen.generateCallSingleArgument
 import org.jetbrains.kotlin.codegen.range.forLoop.ForInSimpleProgressionLoopGenerator
+import org.jetbrains.kotlin.codegen.range.forLoop.ForLoopGenerator
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.psi.KtForExpression
+import org.jetbrains.kotlin.resolve.calls.callUtil.getFirstArgumentExpression
+import org.jetbrains.kotlin.resolve.calls.callUtil.getReceiverExpression
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 
 class DownToProgressionRangeValue(rangeCall: ResolvedCall<out CallableDescriptor>) :
@@ -35,8 +38,36 @@ class DownToProgressionRangeValue(rangeCall: ResolvedCall<out CallableDescriptor
             )
 
     override fun createForLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression) =
+            createConstBoundedForInDownToGenerator(codegen, forExpression) ?:
             ForInSimpleProgressionLoopGenerator.fromBoundedValueWithStepMinus1(codegen, forExpression, getBoundedValue(codegen))
 
     override fun createForInReversedLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression) =
+            createConstBoundedForInReversedDownToGenerator(codegen, forExpression) ?:
             ForInSimpleProgressionLoopGenerator.fromBoundedValueWithStep1(codegen, forExpression, getBoundedValue(codegen))
+
+    private fun createConstBoundedForInDownToGenerator(
+            codegen: ExpressionCodegen,
+            forExpression: KtForExpression
+    ): ForLoopGenerator? {
+        val endExpression = rangeCall.getFirstArgumentExpression() ?: return null
+        return createConstBoundedForLoopGeneratorOrNull(
+                codegen, forExpression,
+                codegen.generateCallReceiver(rangeCall),
+                endExpression,
+                -1
+        )
+    }
+
+    private fun createConstBoundedForInReversedDownToGenerator(
+            codegen: ExpressionCodegen,
+            forExpression: KtForExpression
+    ): ForLoopGenerator? {
+        val endExpression = rangeCall.getReceiverExpression() ?: return null
+        return createConstBoundedForLoopGeneratorOrNull(
+                codegen, forExpression,
+                codegen.generateCallSingleArgument(rangeCall),
+                endExpression,
+                1
+        )
+    }
 }

compiler/backend/src/org/jetbrains/kotlin/codegen/range/PrimitiveNumberRangeLiteralRangeValue.kt

@@ -23,9 +23,9 @@ import org.jetbrains.kotlin.codegen.range.forLoop.ForInSimpleProgressionLoopGene
 import org.jetbrains.kotlin.codegen.range.forLoop.ForLoopGenerator
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.psi.KtForExpression
+import org.jetbrains.kotlin.resolve.calls.callUtil.getReceiverExpression
+import org.jetbrains.kotlin.resolve.calls.callUtil.getFirstArgumentExpression
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
-import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class PrimitiveNumberRangeLiteralRangeValue(
         rangeCall: ResolvedCall<out CallableDescriptor>
@@ -47,7 +47,7 @@ class PrimitiveNumberRangeLiteralRangeValue(
             codegen: ExpressionCodegen,
             forExpression: KtForExpression
     ): ForLoopGenerator? {
-        val endExpression = rangeCall.valueArgumentsByIndex?.run { get(0).arguments[0].getArgumentExpression() } ?: return null
+        val endExpression = rangeCall.getFirstArgumentExpression() ?: return null
         return createConstBoundedForLoopGeneratorOrNull(
                 codegen, forExpression,
                 codegen.generateCallReceiver(rangeCall),
@@ -60,7 +60,7 @@ class PrimitiveNumberRangeLiteralRangeValue(
             codegen: ExpressionCodegen,
             forExpression: KtForExpression
     ): ForLoopGenerator? {
-        val endExpression = rangeCall.extensionReceiver.safeAs<ExpressionReceiver>()?.expression ?: return null
+        val endExpression = rangeCall.getReceiverExpression() ?: return null
         return createConstBoundedForLoopGeneratorOrNull(
                 codegen, forExpression,
                 codegen.generateCallSingleArgument(rangeCall),