diff --git a/runtime/src/kmp_affinity.cpp b/runtime/src/kmp_affinity.cpp
index 0161aca..a94dbd1 100644
--- a/runtime/src/kmp_affinity.cpp
+++ b/runtime/src/kmp_affinity.cpp
@@ -109,8 +109,8 @@
     }
     bool radix1 = true;
     bool all_same = true;
-    int id1 = addrP[0].first.labels[top_index1];
-    int id2 = addrP[0].first.labels[top_index2];
+    unsigned id1 = addrP[0].first.labels[top_index1];
+    unsigned id2 = addrP[0].first.labels[top_index2];
     int pref1 = preference[type1];
     int pref2 = preference[type2];
     for (int hwidx = 1; hwidx < nTh; ++hwidx) {