diff --git a/util/test/demos/d3d12/d3d12_subgroup_zoo.cpp b/util/test/demos/d3d12/d3d12_subgroup_zoo.cpp
index e27bf58af..b4acf17fe 100644
--- a/util/test/demos/d3d12/d3d12_subgroup_zoo.cpp
+++ b/util/test/demos/d3d12/d3d12_subgroup_zoo.cpp
@@ -356,6 +356,13 @@ void main(uint3 inTid : SV_DispatchThreadID)
       data.z = WavePrefixSum(data.x);
       data.w = WavePrefixProduct(1 + data.y);
     }
+    else
+    {
+      data.x = WavePrefixCountBits(id > 23);
+      data.y = WavePrefixCountBits(id < 1);
+      data.z = WavePrefixSum(data.x);
+      data.w = WavePrefixSum(data.y);
+    }
   }
   else if(IsTest(13))
   {
diff --git a/util/test/demos/vk/vk_subgroup_zoo.cpp b/util/test/demos/vk/vk_subgroup_zoo.cpp
index ba99808f5..b48064ee4 100644
--- a/util/test/demos/vk/vk_subgroup_zoo.cpp
+++ b/util/test/demos/vk/vk_subgroup_zoo.cpp
@@ -336,6 +336,15 @@ void main()
       data.z = subgroupExclusiveAdd(data.x);
       data.w = subgroupExclusiveMul(1 + data.y);
     }
+    else
+    {
+      uvec4 bits = subgroupBallot(id > 23);
+      data.x = subgroupBallotExclusiveBitCount(bits);
+      bits = subgroupBallot(id < 1);
+      data.y = subgroupBallotExclusiveBitCount(bits);
+      data.z = subgroupExclusiveAdd(data.x);
+      data.w = subgroupExclusiveAdd(data.y);
+    }
   }
   else if(IsTest(13))
   {