diff --git a/src/util/bitfield.h b/src/util/bitfield.h
index a580da7b..202232b6 100644
--- a/src/util/bitfield.h
+++ b/src/util/bitfield.h
@@ -189,10 +189,7 @@ public:
         size_t sum = 0;
         size_t i = 0;
         for (; i + 4 <= num_blocks; i += 4) {
-            sum += popcount64(bits[i]);
-            sum += popcount64(bits[i + 1]);
-            sum += popcount64(bits[i + 2]);
-            sum += popcount64(bits[i + 3]);
+            sum += popcount64x4(&bits[i]);
         }
         for (; i < num_blocks; i++) {
             sum += popcount64(bits[i]);
diff --git a/src/util/popcount.h b/src/util/popcount.h
index c7a69d46..d90a0d50 100644
--- a/src/util/popcount.h
+++ b/src/util/popcount.h
@@ -52,6 +52,15 @@ u32 popcount32(u32 x) {
 // #endif
 }
 
+static really_inline
+u32 popcount32x4(u32 const *x) {
+    u32 sum = popcount32(x[0]);
+    sum += popcount32(x[1]);
+    sum += popcount32(x[2]);
+    sum += popcount32(x[3]);
+    return sum;
+}
+
 static really_inline
 u32 popcount64(u64a x) {
     return __builtin_popcountll(x);
@@ -73,5 +82,14 @@ u32 popcount64(u64a x) {
 // #endif
 }
 
+static really_inline
+u32 popcount64x4(u64a const *x) {
+    volatile u32 sum = popcount64(x[0]);
+    sum += popcount64(x[1]);
+    sum += popcount64(x[2]);
+    sum += popcount64(x[3]);
+    return sum;
+}
+
 #endif /* UTIL_POPCOUNT_H_ */