diff --git a/source/blender/functions/intern/multi_function_procedure_executor.cc b/source/blender/functions/intern/multi_function_procedure_executor.cc
index e0f26ee427c..dd781dbdb27 100644
--- a/source/blender/functions/intern/multi_function_procedure_executor.cc
+++ b/source/blender/functions/intern/multi_function_procedure_executor.cc
@@ -782,7 +782,8 @@ class VariableState : NonCopyable, NonMovable {
         BLI_assert(value_typed->is_initialized);
         const bool condition = *static_cast<const bool *>(value_typed->data);
         Vector<int64_t> &indices = r_indices[condition];
-        mask.foreach_index([&](const int64_t i) { indices.append(i); });
+        indices.reserve(indices.size() + mask.size());
+        mask.foreach_index_optimized<int64_t>([&](const int64_t i) { indices.append(i); });
         break;
       }
       case ValueType::GVVectorArray: