--- jsr166/src/main/java/util/HashMap.java	2018/03/28 02:50:41	1.4
+++ jsr166/src/main/java/util/HashMap.java	2018/05/22 16:16:57	1.5
@@ -376,12 +376,7 @@ public class HashMap<K,V> extends Abstra
      * Returns a power of two size for the given target capacity.
      */
     static final int tableSizeFor(int cap) {
-        int n = cap - 1;
-        n |= n >>> 1;
-        n |= n >>> 2;
-        n |= n >>> 4;
-        n |= n >>> 8;
-        n |= n >>> 16;
+        int n = -1 >>> Integer.numberOfLeadingZeros(cap - 1);
         return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
     }