diff --git a/tests/atomics-13.ispc b/tests/atomics-13.ispc
index dd9c316c..5ca59c30 100644
--- a/tests/atomics-13.ispc
+++ b/tests/atomics-13.ispc
@@ -8,7 +8,7 @@ export void f_f(uniform float RET[], uniform float aFOO[]) {
     float b = 0;
     if (programIndex & 1)
         b = atomic_or_global(s, (1 << programIndex));
-    RET[programIndex] = popcnt(reduce_add((int32)b));
+    RET[programIndex] = popcnt(reduce_max((int32)b));
 }
 
 export void result(uniform float RET[]) {