diff -r b156fd0a4607 -r 675d857f5ee3 src/hotspot/share/opto/regmask.cpp
--- a/src/hotspot/share/opto/regmask.cpp	Wed Jan 23 10:23:05 2019 +0100
+++ b/src/hotspot/share/opto/regmask.cpp	Wed Jan 23 10:01:21 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,7 @@
 #include "opto/matcher.hpp"
 #include "opto/node.hpp"
 #include "opto/regmask.hpp"
+#include "utilities/population_count.hpp"
 
 #define RM_SIZE _RM_SIZE /* a constant private to the class RegMask */
 
@@ -62,7 +63,7 @@
 }
 
 // Find highest 1, or return 32 if empty
-int find_hihghest_bit( uint32_t mask ) {
+int find_highest_bit( uint32_t mask ) {
   int n = 0;
   if( mask > 0xffff ) {
     mask >>= 16;
@@ -140,21 +141,6 @@
     return 1;
 }
 
-//------------------------------find_first_pair--------------------------------
-// Find the lowest-numbered register pair in the mask.  Return the
-// HIGHEST register number in the pair, or BAD if no pairs.
-OptoReg::Name RegMask::find_first_pair() const {
-  verify_pairs();
-  for( int i = 0; i < RM_SIZE; i++ ) {
-    if( _A[i] ) {               // Found some bits
-      int bit = _A[i] & -_A[i]; // Extract low bit
-      // Convert to bit number, return hi bit in pair
-      return OptoReg::Name((i<<_LogWordBits)+find_lowest_bit(bit)+1);
-    }
-  }
-  return OptoReg::Bad;
-}
-
 //------------------------------ClearToPairs-----------------------------------
 // Clear out partial bits; leave only bit pairs
 void RegMask::clear_to_pairs() {
@@ -167,18 +153,6 @@
   verify_pairs();
 }
 
-//------------------------------SmearToPairs-----------------------------------
-// Smear out partial bits; leave only bit pairs
-void RegMask::smear_to_pairs() {
-  for( int i = 0; i < RM_SIZE; i++ ) {
-    int bits = _A[i];
-    bits |= ((bits & 0x55555555)<<1); // Smear lo bit hi per pair
-    bits |= ((bits & 0xAAAAAAAA)>>1); // Smear hi bit lo per pair
-    _A[i] = bits;
-  }
-  verify_pairs();
-}
-
 //------------------------------is_aligned_pairs-------------------------------
 bool RegMask::is_aligned_pairs() const {
   // Assert that the register mask contains only bit pairs.
@@ -389,14 +363,10 @@
 //------------------------------Size-------------------------------------------
 // Compute size of register mask in bits
 uint RegMask::Size() const {
-  extern uint8_t bitsInByte[BITS_IN_BYTE_ARRAY_SIZE];
   uint sum = 0;
-  for( int i = 0; i < RM_SIZE; i++ )
-    sum +=
-      bitsInByte[(_A[i]>>24) & 0xff] +
-      bitsInByte[(_A[i]>>16) & 0xff] +
-      bitsInByte[(_A[i]>> 8) & 0xff] +
-      bitsInByte[ _A[i]      & 0xff];
+  for (int i = 0; i < RM_SIZE; i++) {
+    sum += population_count(_A[i]);
+  }
   return sum;
 }