diff --git a/runtime/src/main/kotlin/kotlin/collections/HashMap.kt b/runtime/src/main/kotlin/kotlin/collections/HashMap.kt
index 63893db0d85..4757343ccd1 100644
--- a/runtime/src/main/kotlin/kotlin/collections/HashMap.kt
+++ b/runtime/src/main/kotlin/kotlin/collections/HashMap.kt
@@ -511,9 +511,11 @@ actual class HashMap<K, V> private constructor(
         const val INITIAL_MAX_PROBE_DISTANCE = 2
         const val TOMBSTONE = -1
 
-        fun computeHashSize(capacity: Int): Int = (capacity.coerceAtLeast(1) * 3).highestOneBit()
+        @UseExperimental(ExperimentalStdlibApi::class)
+        fun computeHashSize(capacity: Int): Int = (capacity.coerceAtLeast(1) * 3).takeHighestOneBit()
 
-        fun computeShift(hashSize: Int): Int = hashSize.numberOfLeadingZeros() + 1
+        @UseExperimental(ExperimentalStdlibApi::class)
+        fun computeShift(hashSize: Int): Int = hashSize.countLeadingZeroBits() + 1
     }
 
     internal open class Itr<K, V>(
diff --git a/runtime/src/main/kotlin/kotlin/collections/IntUtil.kt b/runtime/src/main/kotlin/kotlin/collections/IntUtil.kt
deleted file mode 100644
index d2d901fa059..00000000000
--- a/runtime/src/main/kotlin/kotlin/collections/IntUtil.kt
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright 2010-2018 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 kotlin.collections
-
-internal fun Int.highestOneBit() : Int {
-    var index = 31
-
-    while (index >= 0) {
-        var mask = (1 shl index)
-        if ((mask and this) != 0) {
-            return mask
-        }
-        index--
-    }
-    return 0
-}
-
-internal fun Int.numberOfLeadingZeros() : Int {
-    var index = 31
-
-    while (index >= 0) {
-        var mask = (1 shl index)
-        if ((mask and this) != 0) {
-            return 31 - index
-        }
-        index--
-    }
-    return 0
-}
\ No newline at end of file