Make optimized loop over unsigned array, indices, withIndex JVM-specific

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

@@ -61,4 +61,7 @@ interface CommonBackendContext : BackendContext, LoggingContext {
 
     val inductionVariableOrigin: IrDeclarationOrigin
         get() = IrDeclarationOrigin.IR_TEMPORARY_VARIABLE
+
+    val optimizeLoopsOverUnsignedArrays: Boolean
+        get() = false
 }

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

@@ -72,7 +72,10 @@ abstract class IndexedGetIterationHandler(
 
 /** Builds a [HeaderInfo] for arrays. */
 internal class ArrayIterationHandler(context: CommonBackendContext) : IndexedGetIterationHandler(context, canCacheLast = true) {
-    override fun matchIterable(expression: IrExpression) = expression.type.run { isArray() || isPrimitiveArray() || isUnsignedArray() }
+    private val supportsUnsignedArrays = context.optimizeLoopsOverUnsignedArrays
+
+    override fun matchIterable(expression: IrExpression) =
+        expression.type.run { isArray() || isPrimitiveArray() || (supportsUnsignedArrays && isUnsignedArray()) }
 
     override val IrType.sizePropertyGetter
         get() = getClass()!!.getPropertyGetter("size")!!.owner

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

@@ -76,9 +76,14 @@ internal class CollectionIndicesHandler(context: CommonBackendContext) : Indices
 }
 
 internal class ArrayIndicesHandler(context: CommonBackendContext) : IndicesHandler(context) {
+    private val supportsUnsignedArrays = context.optimizeLoopsOverUnsignedArrays
 
     override val matcher = SimpleCalleeMatcher {
-        extensionReceiver { it != null && it.type.run { isArray() || isPrimitiveArray() || isUnsignedArray() } }
+        extensionReceiver {
+            it != null && it.type.run {
+                isArray() || isPrimitiveArray() || (supportsUnsignedArrays && isUnsignedArray())
+            }
+        }
         fqName { it == FqName("kotlin.collections.<get-indices>") }
         parameterCount { it == 0 }
     }

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

@@ -26,12 +26,19 @@ import org.jetbrains.kotlin.name.FqName
 internal class WithIndexHandler(context: CommonBackendContext, private val visitor: NestedHeaderInfoBuilderForWithIndex) :
     HeaderInfoFromCallHandler<Nothing?> {
 
+    private val supportsUnsignedArrays = context.optimizeLoopsOverUnsignedArrays
+
     // Use Quantifier.ANY so we can handle all `withIndex()` calls in the same manner.
     override val matcher =
         createIrCallMatcher(Quantifier.ANY) {
             callee {
                 fqName { it == FqName("kotlin.collections.withIndex") }
-                extensionReceiver { it != null && it.type.run { isArray() || isPrimitiveArray() || isUnsignedArray() || isIterable() } }
+                extensionReceiver {
+                    it != null && it.type.run {
+                        isArray() || isPrimitiveArray() || isIterable() ||
+                                (supportsUnsignedArrays && isUnsignedArray())
+                    }
+                }
                 parameterCount { it == 0 }
             }
             callee {

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt

@@ -215,6 +215,9 @@ class JvmBackendContext(
     override val preferJavaLikeCounterLoop: Boolean
         get() = true
 
+    override val optimizeLoopsOverUnsignedArrays: Boolean
+        get() = true
+
     override val doWhileCounterLoopOrigin: IrStatementOrigin
         get() = JvmLoweredStatementOrigin.DO_WHILE_COUNTER_LOOP