diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt
index 3591f8787dc..717437d6271 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt
@@ -157,6 +157,7 @@ class WasmSymbols(
     val refIsNull = getInternalFunction("wasm_ref_is_null")
     val refTest = getInternalFunction("wasm_ref_test")
     val refCast = getInternalFunction("wasm_ref_cast")
+    val wasmArrayCopy = getInternalFunction("wasm_array_copy")
 
     val intToLong = getInternalFunction("wasm_i64_extend_i32_s")
 
diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/dce/WasmUsefulDeclarationProcessor.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/dce/WasmUsefulDeclarationProcessor.kt
index c773ecc83fe..8b206e43aef 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/dce/WasmUsefulDeclarationProcessor.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/dce/WasmUsefulDeclarationProcessor.kt
@@ -48,7 +48,8 @@ internal class WasmUsefulDeclarationProcessor(
             context.wasmSymbols.wasmInterfaceId,
             context.wasmSymbols.refCast,
             context.wasmSymbols.refTest,
-            context.wasmSymbols.boxIntrinsic -> {
+            context.wasmSymbols.boxIntrinsic,
+            context.wasmSymbols.wasmArrayCopy -> {
                 call.getTypeArgument(0)?.enqueueRuntimeClassOrAny(from, "intrinsic ${call.symbol.owner.name}")
                 true
             }
diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
index 142d91fdfe6..6053bb45b4e 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
@@ -475,6 +475,13 @@ class BodyGenerator(
                 body.buildConstI32Symbol(WasmSymbol(context.scratchMemSizeInBytes))
             }
 
+            wasmSymbols.wasmArrayCopy -> {
+                val immediate = WasmImmediate.GcType(
+                    context.referenceGcType(call.getTypeArgument(0)!!.getRuntimeClass(irBuiltIns).symbol)
+                )
+                body.buildInstr(WasmOp.ARRAY_COPY, immediate, immediate)
+            }
+
             else -> {
                 return false
             }
diff --git a/generators/wasm/WasmIntrinsicGenerator.kt b/generators/wasm/WasmIntrinsicGenerator.kt
index 358befbfb60..aa5e6836c9f 100644
--- a/generators/wasm/WasmIntrinsicGenerator.kt
+++ b/generators/wasm/WasmIntrinsicGenerator.kt
@@ -104,7 +104,11 @@ fun wasmArrayForType(
     
                 @WasmOp(WasmOp.ARRAY_LEN)
                 fun len(): Int =
-                    implementedAsIntrinsic
+                    implementedAsIntrinsic                    
+            }
+            
+            internal inline fun $name.copyTo(destination: $name, sourceIndex: Int, destinationIndex: Int, length: Int) {
+                wasm_array_copy<$name>(destination, destinationIndex, this, sourceIndex, length)
             }
     
             internal inline fun $name.fill(size: Int, init: (Int) -> $type) {
@@ -113,8 +117,7 @@ fun wasmArrayForType(
                     set(i, init(i))
                     i++
                 }
-            }
-            
+            }            
             """.trimIndent()
 }
 
diff --git a/libraries/stdlib/wasm/builtins/kotlin/Array.kt b/libraries/stdlib/wasm/builtins/kotlin/Array.kt
index 31c6f07af3e..00bdbf45547 100644
--- a/libraries/stdlib/wasm/builtins/kotlin/Array.kt
+++ b/libraries/stdlib/wasm/builtins/kotlin/Array.kt
@@ -15,7 +15,7 @@ import kotlin.wasm.internal.*
  * for more information on arrays.
  */
 public class Array<T> constructor(size: Int) {
-    private var storage: WasmAnyArray = WasmAnyArray(size)
+    internal val storage: WasmAnyArray = WasmAnyArray(size)
 
     /**
      * Creates a new array with the specified [size], where each element is calculated by calling the specified
diff --git a/libraries/stdlib/wasm/builtins/kotlin/Arrays.kt b/libraries/stdlib/wasm/builtins/kotlin/Arrays.kt
index 28a8c955a9d..c662ac9374c 100644
--- a/libraries/stdlib/wasm/builtins/kotlin/Arrays.kt
+++ b/libraries/stdlib/wasm/builtins/kotlin/Arrays.kt
@@ -8,7 +8,7 @@ package kotlin
 import kotlin.wasm.internal.*
 
 public class ByteArray(size: Int) {
-    private var storage = WasmByteArray(size)
+    internal val storage = WasmByteArray(size)
 
     public constructor(size: Int, init: (Int) -> Byte) : this(size) {
         storage.fill(size, init)
@@ -38,7 +38,7 @@ internal fun byteArrayIterator(array: ByteArray) = object : ByteIterator() {
 
 
 public class CharArray(size: Int) {
-    private var storage = WasmCharArray(size)
+    internal val storage = WasmCharArray(size)
 
     public constructor(size: Int, init: (Int) -> Char) : this(size) {
         storage.fill(size) { init(it) }
@@ -69,7 +69,7 @@ internal fun charArrayIterator(array: CharArray) = object : CharIterator() {
 
 
 public class ShortArray(size: Int) {
-    private var storage = WasmShortArray(size)
+    internal val storage = WasmShortArray(size)
 
     public constructor(size: Int, init: (Int) -> Short) : this(size) {
         storage.fill(size, init)
@@ -100,7 +100,7 @@ internal fun shortArrayIterator(array: ShortArray) = object : ShortIterator() {
 
 
 public class IntArray(size: Int) {
-    private var storage = WasmIntArray(size)
+    internal val storage = WasmIntArray(size)
 
     public constructor(size: Int, init: (Int) -> Int) : this(size) {
         storage.fill(size, init)
@@ -131,7 +131,7 @@ internal fun intArrayIterator(array: IntArray) = object : IntIterator() {
 
 
 public class LongArray(size: Int) {
-    private var storage = WasmLongArray (size)
+    internal val storage = WasmLongArray (size)
 
     public constructor(size: Int, init: (Int) -> Long) : this(size) {
         storage.fill(size, init)
@@ -161,7 +161,7 @@ internal fun longArrayIterator(array: LongArray) = object : LongIterator() {
 
 
 public class FloatArray(size: Int) {
-    private var storage = WasmFloatArray(size)
+    internal val storage = WasmFloatArray(size)
 
     public constructor(size: Int, init: (Int) -> Float) : this(size) {
         storage.fill(size, init)
@@ -191,7 +191,7 @@ internal fun floatArrayIterator(array: FloatArray) = object : FloatIterator() {
 
 
 public class DoubleArray(size: Int) {
-    private var storage = WasmDoubleArray(size)
+    internal val storage = WasmDoubleArray(size)
 
     public constructor(size: Int, init: (Int) -> Double) : this(size) {
         storage.fill(size, init)
@@ -221,7 +221,7 @@ internal fun doubleArrayIterator(array: DoubleArray) = object : DoubleIterator()
 
 
 public class BooleanArray(size: Int) {
-    private var storage = WasmByteArray(size)
+    internal val storage = WasmByteArray(size)
 
     public constructor(size: Int, init: (Int) -> Boolean) : this(size) {
         storage.fill(size) { init(it).toInt().reinterpretAsByte() }
diff --git a/libraries/stdlib/wasm/builtins/kotlin/String.kt b/libraries/stdlib/wasm/builtins/kotlin/String.kt
index 2b45996ce9b..b119532473a 100644
--- a/libraries/stdlib/wasm/builtins/kotlin/String.kt
+++ b/libraries/stdlib/wasm/builtins/kotlin/String.kt
@@ -22,12 +22,15 @@ public class String private constructor(internal val chars: WasmCharArray) : Com
      * Returns a string obtained by concatenating this string with the string representation of the given [other] object.
      */
     public operator fun plus(other: Any?): String {
+        val thisChars = chars
         val otherChars = if (other is String) other.chars else other.toString().chars
-        val newCharsLen = chars.len() + otherChars.len()
-        val newChars = WasmCharArray(newCharsLen)
-        newChars.fill(newCharsLen) { i ->
-            if (i < chars.len()) chars.get(i) else otherChars.get(i - chars.len())
-        }
+        val thisLen = thisChars.len()
+        val otherLen = otherChars.len()
+        if (otherLen == 0) return String(thisChars)
+
+        val newChars = WasmCharArray(thisLen + otherLen)
+        thisChars.copyTo(newChars, 0, 0, thisLen)
+        otherChars.copyTo(newChars, 0, thisLen, otherLen)
         return String(newChars)
     }
 
@@ -47,42 +50,48 @@ public class String private constructor(internal val chars: WasmCharArray) : Com
 
     public override fun subSequence(startIndex: Int, endIndex: Int): CharSequence {
         val actualStartIndex = startIndex.coerceAtLeast(0)
-        val actualEndIndex = endIndex.coerceAtMost(chars.len())
+        val thisChars = chars
+        val actualEndIndex = endIndex.coerceAtMost(thisChars.len())
         val newCharsLen = actualEndIndex - actualStartIndex
         val newChars = WasmCharArray(newCharsLen)
-        newChars.fill(newCharsLen) { i ->
-            chars.get(actualStartIndex + i)
-        }
+        thisChars.copyTo(newChars, actualStartIndex, 0, newCharsLen)
         return String(newChars)
     }
 
     public override fun compareTo(other: String): Int {
-        val len = min(this.length, other.length)
+        val thisChars = this.chars
+        val otherChars = other.chars
+
+        val thisLength = thisChars.len()
+        val otherLength = otherChars.len()
+        val len = min(thisLength, otherLength)
 
         for (i in 0 until len) {
-            val l = this[i]
-            val r = other[i]
+            val l = thisChars.get(i)
+            val r = otherChars.get(i)
             if (l != r)
                 return l - r
         }
-        return this.length - other.length
+        return thisLength - otherLength
     }
 
-    public override fun equals(other: Any?): Boolean {
-        if (other is String)
-            return this.compareTo(other) == 0
-        return false
-    }
+    public override fun equals(other: Any?): Boolean =
+        other != null &&
+        other is String &&
+        (this.length == other.length) &&
+        this.compareTo(other) == 0
 
     public override fun toString(): String = this
 
     public override fun hashCode(): Int {
-        if (_hashCode != 0 || this.isEmpty())
+        val thisLength = length
+
+        if (_hashCode != 0 || thisLength == null)
             return _hashCode
 
         var hash = 0
         var i = 0
-        while (i < chars.len()) {
+        while (i < thisLength) {
             hash = 31 * hash + chars.get(i).toInt()
             i++
         }
diff --git a/libraries/stdlib/wasm/internal/kotlin/wasm/internal/WasmInstructions.kt b/libraries/stdlib/wasm/internal/kotlin/wasm/internal/WasmInstructions.kt
index 69bbc71cafe..328f0d6a7e4 100644
--- a/libraries/stdlib/wasm/internal/kotlin/wasm/internal/WasmInstructions.kt
+++ b/libraries/stdlib/wasm/internal/kotlin/wasm/internal/WasmInstructions.kt
@@ -24,6 +24,9 @@ internal fun <To> wasm_ref_cast(a: Any?): To =
 internal fun <To> wasm_ref_test(a: Any?): Boolean =
     implementedAsIntrinsic
 
+internal fun <T> wasm_array_copy(destination: T, destinationIndex: Int, source: T, sourceIndex: Int, length: Int): Unit =
+    implementedAsIntrinsic
+
 @WasmOp(WasmOp.I32_EQ)
 public external fun wasm_i32_eq(a: Int, b: Int): Boolean
 
diff --git a/libraries/stdlib/wasm/src/generated/_ArraysWasm.kt b/libraries/stdlib/wasm/src/generated/_ArraysWasm.kt
index c2dd04aff36..322f4152c6a 100644
--- a/libraries/stdlib/wasm/src/generated/_ArraysWasm.kt
+++ b/libraries/stdlib/wasm/src/generated/_ArraysWasm.kt
@@ -1017,18 +1017,8 @@ public actual fun CharArray?.contentToString(): String {
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun <T> Array<out T>.copyInto(destination: Array<T>, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): Array<T> {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    @Suppress("UNCHECKED_CAST")
+    arrayCopy(this as Array<Any?>, startIndex, destination as Array<Any?>, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1051,18 +1041,7 @@ public actual fun <T> Array<out T>.copyInto(destination: Array<T>, destinationOf
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun ByteArray.copyInto(destination: ByteArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): ByteArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1085,18 +1064,7 @@ public actual fun ByteArray.copyInto(destination: ByteArray, destinationOffset:
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun ShortArray.copyInto(destination: ShortArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): ShortArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1119,18 +1087,7 @@ public actual fun ShortArray.copyInto(destination: ShortArray, destinationOffset
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun IntArray.copyInto(destination: IntArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): IntArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1153,18 +1110,7 @@ public actual fun IntArray.copyInto(destination: IntArray, destinationOffset: In
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun LongArray.copyInto(destination: LongArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): LongArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1187,18 +1133,7 @@ public actual fun LongArray.copyInto(destination: LongArray, destinationOffset:
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun FloatArray.copyInto(destination: FloatArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): FloatArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1221,18 +1156,7 @@ public actual fun FloatArray.copyInto(destination: FloatArray, destinationOffset
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun DoubleArray.copyInto(destination: DoubleArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): DoubleArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1255,18 +1179,7 @@ public actual fun DoubleArray.copyInto(destination: DoubleArray, destinationOffs
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun BooleanArray.copyInto(destination: BooleanArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): BooleanArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
@@ -1289,18 +1202,7 @@ public actual fun BooleanArray.copyInto(destination: BooleanArray, destinationOf
 @SinceKotlin("1.3")
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun CharArray.copyInto(destination: CharArray, destinationOffset: Int = 0, startIndex: Int = 0, endIndex: Int = size): CharArray {
-    AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-    val rangeSize = endIndex - startIndex
-    AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-    if (this !== destination || destinationOffset <= startIndex) {
-        for (index in 0 until rangeSize) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    } else {
-        for (index in rangeSize - 1 downTo 0) {
-            destination[destinationOffset + index] = this[startIndex + index]
-        }
-    }
+    arrayCopy(this, startIndex, destination, destinationOffset, endIndex - startIndex)
     return destination
 }
 
diff --git a/libraries/stdlib/wasm/src/generated/_WasmArrays.kt b/libraries/stdlib/wasm/src/generated/_WasmArrays.kt
index 1e1d41b23a7..3db1676adf2 100644
--- a/libraries/stdlib/wasm/src/generated/_WasmArrays.kt
+++ b/libraries/stdlib/wasm/src/generated/_WasmArrays.kt
@@ -32,7 +32,11 @@ internal class WasmAnyArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmAnyArray.copyTo(destination: WasmAnyArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmAnyArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmAnyArray.fill(size: Int, init: (Int) -> Any?) {
@@ -41,8 +45,7 @@ internal inline fun WasmAnyArray.fill(size: Int, init: (Int) -> Any?) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Byte::class, isNullable = false)
 internal class WasmByteArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET_S)
@@ -55,7 +58,11 @@ internal class WasmByteArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmByteArray.copyTo(destination: WasmByteArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmByteArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmByteArray.fill(size: Int, init: (Int) -> Byte) {
@@ -64,8 +71,7 @@ internal inline fun WasmByteArray.fill(size: Int, init: (Int) -> Byte) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Char::class, isNullable = false)
 internal class WasmCharArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET_U)
@@ -78,7 +84,11 @@ internal class WasmCharArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmCharArray.copyTo(destination: WasmCharArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmCharArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmCharArray.fill(size: Int, init: (Int) -> Char) {
@@ -87,8 +97,7 @@ internal inline fun WasmCharArray.fill(size: Int, init: (Int) -> Char) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Short::class, isNullable = false)
 internal class WasmShortArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET_S)
@@ -101,7 +110,11 @@ internal class WasmShortArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmShortArray.copyTo(destination: WasmShortArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmShortArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmShortArray.fill(size: Int, init: (Int) -> Short) {
@@ -110,8 +123,7 @@ internal inline fun WasmShortArray.fill(size: Int, init: (Int) -> Short) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Int::class, isNullable = false)
 internal class WasmIntArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET)
@@ -124,7 +136,11 @@ internal class WasmIntArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmIntArray.copyTo(destination: WasmIntArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmIntArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmIntArray.fill(size: Int, init: (Int) -> Int) {
@@ -133,8 +149,7 @@ internal inline fun WasmIntArray.fill(size: Int, init: (Int) -> Int) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Long::class, isNullable = false)
 internal class WasmLongArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET)
@@ -147,7 +162,11 @@ internal class WasmLongArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmLongArray.copyTo(destination: WasmLongArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmLongArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmLongArray.fill(size: Int, init: (Int) -> Long) {
@@ -156,8 +175,7 @@ internal inline fun WasmLongArray.fill(size: Int, init: (Int) -> Long) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Float::class, isNullable = false)
 internal class WasmFloatArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET)
@@ -170,7 +188,11 @@ internal class WasmFloatArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmFloatArray.copyTo(destination: WasmFloatArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmFloatArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmFloatArray.fill(size: Int, init: (Int) -> Float) {
@@ -179,8 +201,7 @@ internal inline fun WasmFloatArray.fill(size: Int, init: (Int) -> Float) {
         set(i, init(i))
         i++
     }
-}
-
+}            
 @WasmArrayOf(Double::class, isNullable = false)
 internal class WasmDoubleArray(size: Int) {
     @WasmOp(WasmOp.ARRAY_GET)
@@ -193,7 +214,11 @@ internal class WasmDoubleArray(size: Int) {
 
     @WasmOp(WasmOp.ARRAY_LEN)
     fun len(): Int =
-        implementedAsIntrinsic
+        implementedAsIntrinsic                    
+}
+
+internal inline fun WasmDoubleArray.copyTo(destination: WasmDoubleArray, sourceIndex: Int, destinationIndex: Int, length: Int) {
+    wasm_array_copy<WasmDoubleArray>(destination, destinationIndex, this, sourceIndex, length)
 }
 
 internal inline fun WasmDoubleArray.fill(size: Int, init: (Int) -> Double) {
@@ -202,5 +227,4 @@ internal inline fun WasmDoubleArray.fill(size: Int, init: (Int) -> Double) {
         set(i, init(i))
         i++
     }
-}
-
+}            
diff --git a/libraries/stdlib/wasm/src/generated/_WasmOp.kt b/libraries/stdlib/wasm/src/generated/_WasmOp.kt
index c1bdf9d20b3..753e781b453 100644
--- a/libraries/stdlib/wasm/src/generated/_WasmOp.kt
+++ b/libraries/stdlib/wasm/src/generated/_WasmOp.kt
@@ -252,6 +252,7 @@ internal annotation class WasmOp(val name: String) {
         const val ARRAY_GET_U = "ARRAY_GET_U"
         const val ARRAY_SET = "ARRAY_SET"
         const val ARRAY_LEN = "ARRAY_LEN"
+        const val ARRAY_COPY = "ARRAY_COPY"
         const val I31_NEW = "I31_NEW"
         const val I31_GET_S = "I31_GET_S"
         const val I31_GET_U = "I31_GET_U"
diff --git a/libraries/stdlib/wasm/src/kotlin/collections/ArraysWasm.kt b/libraries/stdlib/wasm/src/kotlin/collections/ArraysWasm.kt
index 7143e735332..862b4c5df44 100644
--- a/libraries/stdlib/wasm/src/kotlin/collections/ArraysWasm.kt
+++ b/libraries/stdlib/wasm/src/kotlin/collections/ArraysWasm.kt
@@ -5,6 +5,84 @@
 
 package kotlin.collections
 
+import kotlin.wasm.internal.copyTo
+
+private inline fun rangeCheck(index: Int, count: Int, arraySize: Int) {
+    if (index < 0 || count < 0 || index + count > arraySize) throw IndexOutOfBoundsException()
+}
+
+internal inline fun arrayCopy(array: ByteArray, fromIndex: Int, destination: ByteArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: ShortArray, fromIndex: Int, destination: ShortArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: CharArray, fromIndex: Int, destination: CharArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: IntArray, fromIndex: Int, destination: IntArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: LongArray, fromIndex: Int, destination: LongArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: FloatArray, fromIndex: Int, destination: FloatArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: DoubleArray, fromIndex: Int, destination: DoubleArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: BooleanArray, fromIndex: Int, destination: BooleanArray, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
+internal inline fun arrayCopy(array: Array<Any?>, fromIndex: Int, destination: Array<Any?>, toIndex: Int, count: Int) {
+    val srcStorage = array.storage
+    rangeCheck(fromIndex, count, srcStorage.len())
+    val dstStorage = destination.storage
+    rangeCheck(toIndex, count, dstStorage.len())
+    srcStorage.copyTo(dstStorage, fromIndex, toIndex, count)
+}
+
 /**
  * Returns a *typed* array containing all of the elements of this collection.
  *
diff --git a/libraries/stdlib/wasm/src/kotlin/text/StringBuilderWasm.kt b/libraries/stdlib/wasm/src/kotlin/text/StringBuilderWasm.kt
index b5477b0bf4c..771d4dc50c3 100644
--- a/libraries/stdlib/wasm/src/kotlin/text/StringBuilderWasm.kt
+++ b/libraries/stdlib/wasm/src/kotlin/text/StringBuilderWasm.kt
@@ -7,18 +7,14 @@ package kotlin.text
 
 import kotlin.wasm.internal.*
 
-internal fun insertString(array: CharArray, distIndex: Int, value: String, sourceIndex: Int, count: Int): Int {
-    var arrayIdx = distIndex
-    var stringIdx = sourceIndex
-    repeat(count) {
-        array[arrayIdx++] = value[stringIdx++]
-    }
+internal fun insertString(array: CharArray, destinationIndex: Int, value: String, sourceIndex: Int, count: Int): Int {
+    value.chars.copyTo(array.storage, sourceIndex, destinationIndex, count)
     return count
 }
 
 internal fun unsafeStringFromCharArray(array: CharArray, start: Int, size: Int): String {
     val copy = WasmCharArray(size)
-    copy.fill(size) { array[it + start] }
+    array.storage.copyTo(copy, start, 0, size)
     return String.unsafeFromCharArray(copy)
 }
 
diff --git a/libraries/stdlib/wasm/src/kotlin/text/StringsWasm.kt b/libraries/stdlib/wasm/src/kotlin/text/StringsWasm.kt
index a5703862013..89fde9f7886 100644
--- a/libraries/stdlib/wasm/src/kotlin/text/StringsWasm.kt
+++ b/libraries/stdlib/wasm/src/kotlin/text/StringsWasm.kt
@@ -74,7 +74,7 @@ public actual fun String(chars: CharArray, offset: Int, length: Int): String {
         throw IndexOutOfBoundsException()
 
     val copy = WasmCharArray(length)
-    copy.fill(length) { chars[it + offset] }
+    chars.storage.copyTo(copy, offset, 0, length)
     return String.unsafeFromCharArray(copy)
 }
 
@@ -84,8 +84,10 @@ public actual fun String(chars: CharArray, offset: Int, length: Int): String {
 @SinceKotlin("1.4")
 @WasExperimental(ExperimentalStdlibApi::class)
 public actual fun CharArray.concatToString(): String {
-    val copy = WasmCharArray(this.size)
-    copy.fill(this.size) { this[it] }
+    val thisStorage = this.storage
+    val thisLength = thisStorage.len()
+    val copy = WasmCharArray(thisLength)
+    this.storage.copyTo(copy, 0, 0, thisLength)
     return String.unsafeFromCharArray(copy)
 }
 
@@ -106,7 +108,7 @@ public actual fun CharArray.concatToString(startIndex: Int = 0, endIndex: Int =
 
     val length = endIndex - startIndex
     val copy = WasmCharArray(length)
-    copy.fill(length) { this[it + startIndex] }
+    this.storage.copyTo(copy, startIndex, 0, length)
     return String.unsafeFromCharArray(copy)
 }
 
@@ -116,7 +118,11 @@ public actual fun CharArray.concatToString(startIndex: Int = 0, endIndex: Int =
 @SinceKotlin("1.4")
 @WasExperimental(ExperimentalStdlibApi::class)
 public actual fun String.toCharArray(): CharArray {
-    return CharArray(length) { get(it) }
+    val thisChars = this.chars
+    val thisLength = thisChars.len()
+    val newArray = CharArray(thisLength)
+    thisChars.copyTo(newArray.storage, 0, 0, thisLength)
+    return newArray
 }
 
 /**
@@ -133,7 +139,10 @@ public actual fun String.toCharArray(): CharArray {
 @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
 public actual fun String.toCharArray(startIndex: Int = 0, endIndex: Int = this.length): CharArray {
     AbstractList.checkBoundsIndexes(startIndex, endIndex, length)
-    return CharArray(endIndex - startIndex) { get(startIndex + it) }
+    val newLength = endIndex - startIndex
+    val newArray = CharArray(newLength)
+    this.chars.copyTo(newArray.storage, startIndex, 0, newLength)
+    return newArray
 }
 
 /**
diff --git a/libraries/stdlib/wasm/src/kotlin/text/regex/DecompositionValues.kt b/libraries/stdlib/wasm/src/kotlin/text/regex/DecompositionValues.kt
index 8051d863bdc..6fa169a9a95 100644
--- a/libraries/stdlib/wasm/src/kotlin/text/regex/DecompositionValues.kt
+++ b/libraries/stdlib/wasm/src/kotlin/text/regex/DecompositionValues.kt
@@ -350,9 +350,9 @@ private val decompositionValueIndex = shortArrayOf(
 )
 
 internal fun getDecompositionByIndex(index: Int): IntArray {
-    val valueIndex = decompositionValueIndex[index]
-    val size = decompositionValueIndex[index + 1] - valueIndex
-    return IntArray(size) { shift ->
-        decompositionValues[valueIndex + shift]
-    }
+    val startIndex = decompositionValueIndex[index].toInt()
+    val endIndex = decompositionValueIndex[index + 1].toInt()
+    val result = IntArray(endIndex - startIndex)
+    decompositionValues.copyInto(result, startIndex = startIndex, endIndex = endIndex)
+    return result
 }
\ No newline at end of file
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/Arrays.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/Arrays.kt
index 04c797f6db5..96755d3791f 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/Arrays.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/Arrays.kt
@@ -919,26 +919,6 @@ object ArrayOps : TemplateGroupBase() {
                         """
                     }
                 }
-                on(Backend.Wasm) {
-                    body {
-                        """
-                        AbstractList.checkRangeIndexes(startIndex, endIndex, this.size)
-                        val rangeSize = endIndex - startIndex
-                        AbstractList.checkRangeIndexes(destinationOffset, destinationOffset + rangeSize, destination.size)
-                        
-                        if (this !== destination || destinationOffset <= startIndex) {
-                            for (index in 0 until rangeSize) {
-                                destination[destinationOffset + index] = this[startIndex + index]
-                            }
-                        } else {
-                            for (index in rangeSize - 1 downTo 0) {
-                                destination[destinationOffset + index] = this[startIndex + index]
-                            }
-                        }
-                        return destination
-                        """
-                    }
-                }
             }
         }
     }
diff --git a/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt b/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt
index 65270c5cb2d..eb3c31d6032 100644
--- a/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt
+++ b/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt
@@ -354,6 +354,7 @@ enum class WasmOp(
     ARRAY_GET_U("array.get_u", 0xFB_15, listOf(STRUCT_TYPE_IDX)),
     ARRAY_SET("array.set", 0xFB_16, listOf(STRUCT_TYPE_IDX)),
     ARRAY_LEN("array.len", 0xFB_17, listOf(STRUCT_TYPE_IDX)),
+    ARRAY_COPY("array.copy", 0xFB_18, listOf(STRUCT_TYPE_IDX, STRUCT_TYPE_IDX)),
 
     I31_NEW("i31.new", 0xFB_20),
     I31_GET_S("i31.get_s", 0xFB_21),