diff -r 6ecaa8f42f36 -r 40bef246bc7a src/mem/ruby/common/Set.hh
--- a/src/mem/ruby/common/Set.hh	Mon Apr 27 10:36:05 2015 -0500
+++ b/src/mem/ruby/common/Set.hh	Mon Apr 27 14:18:37 2015 -0500
@@ -62,10 +62,11 @@
     // 64 bits if the -m64 parameter is passed to g++, which it is
     // for an AMD opteron under our configuration
 
-    long *m_p_nArray;      // an word array to hold the bits in the set
-    long m_p_nArray_Static[NUMBER_WORDS_PER_SET];
+    // an word array to hold the bits in the set
+    unsigned long *m_p_nArray;
+    unsigned long m_p_nArray_Static[NUMBER_WORDS_PER_SET];
 
-    static const int LONG_BITS = std::numeric_limits<long>::digits + 1;
+    static const int LONG_BITS = std::numeric_limits<unsigned long>::digits + 1;
     static const int INDEX_SHIFT = LONG_BITS == 64 ? 6 : 5;
     static const int INDEX_MASK = (1 << INDEX_SHIFT) - 1;
 
diff -r 6ecaa8f42f36 -r 40bef246bc7a src/mem/ruby/common/Set.cc
--- a/src/mem/ruby/common/Set.cc	Mon Apr 27 10:36:05 2015 -0500
+++ b/src/mem/ruby/common/Set.cc	Mon Apr 27 14:18:37 2015 -0500
@@ -73,9 +73,9 @@
 {
     // now just ensure that no bits over the maximum size were set
 #ifdef _LP64
-    long mask = 0x7FFFFFFFFFFFFFFF;
+    unsigned long mask = 0x7FFFFFFFFFFFFFFF;
 #else
-    long mask = 0x7FFFFFFF;
+    unsigned long mask = 0x7FFFFFFF;
 #endif
 
     // the number of populated spaces in the higest-order array slot
@@ -132,10 +132,9 @@
 Set::count() const
 {
     int counter = 0;
-    long mask;
 
     for (int i = 0; i < m_nArrayLen; i++) {
-        mask = (long)0x01;
+        unsigned long mask = 0x01;
 
         for (int j = 0; j < LONG_BITS; j++) {
             // FIXME - significant performance loss when array
@@ -172,14 +171,13 @@
 Set::smallestElement() const
 {
     assert(count() > 0);
-    long x;
     for (int i = 0; i < m_nArrayLen; i++) {
         if (m_p_nArray[i] != 0) {
             // the least-set bit must be in here
-            x = m_p_nArray[i];
+            unsigned long x = m_p_nArray[i];
 
             for (int j = 0; j < LONG_BITS; j++) {
-                if (x & (unsigned long)1) {
+                if (x & 1) {
                     return LONG_BITS * i + j;
                 }
 
@@ -212,7 +210,7 @@
     }
 
     // now check the last word, which may not be fully loaded
-    long mask = 1;
+    unsigned long mask = 1;
     for (int j = 0; j < (m_nSize % LONG_BITS); j++) {
         if ((mask & m_p_nArray[m_nArrayLen-1]) == 0) {
             return false;
@@ -306,7 +304,7 @@
         if (m_p_nArray && m_p_nArray != &m_p_nArray_Static[0])
             delete [] m_p_nArray;
 
-        m_p_nArray = new long[m_nArrayLen];
+        m_p_nArray = new unsigned long[m_nArrayLen];
     }
 
     clear();