diff --git a/runtime/test/tasking/hidden_helper_task/capacity_mix_threads.cpp b/runtime/test/tasking/hidden_helper_task/capacity_mix_threads.cpp
index 776aee9..3f2ceef 100644
--- a/runtime/test/tasking/hidden_helper_task/capacity_mix_threads.cpp
+++ b/runtime/test/tasking/hidden_helper_task/capacity_mix_threads.cpp
@@ -1,4 +1,7 @@
 // RUN: %libomp-cxx-compile-and-run
+//
+// AIX runs out of resource in 32-bit with 4*omp_get_max_threads() threads.
+// XFAIL: aix && ppc
 
 #include <omp.h>
 
diff --git a/runtime/test/tasking/hidden_helper_task/capacity_nthreads.cpp b/runtime/test/tasking/hidden_helper_task/capacity_nthreads.cpp
index b551318..f7405d0 100644
--- a/runtime/test/tasking/hidden_helper_task/capacity_nthreads.cpp
+++ b/runtime/test/tasking/hidden_helper_task/capacity_nthreads.cpp
@@ -1,4 +1,7 @@
 // RUN: %libomp-cxx-compile-and-run
+//
+// AIX runs out of resource in 32-bit with 4*omp_get_max_threads() threads.
+// XFAIL: aix && ppc
 
 #include <omp.h>