diff --git a/Source/kwsys/CMakeLists.txt b/Source/kwsys/CMakeLists.txt
index 3ad5c2e8d..977d57bec 100644
--- a/Source/kwsys/CMakeLists.txt
+++ b/Source/kwsys/CMakeLists.txt
@@ -1228,6 +1228,9 @@ IF(KWSYS_STANDALONE OR CMake_SOURCE_DIR)
     # Some Apple compilers produce bad optimizations in this source.
     IF(APPLE AND "${CMAKE_C_COMPILER_ID}" MATCHES "^(GNU|LLVM)$")
       SET_SOURCE_FILES_PROPERTIES(testProcess.c PROPERTIES COMPILE_FLAGS -O0)
+    ELSEIF(CMAKE_C_COMPILER_ID STREQUAL "XL")
+      # Tell IBM XL not to warn about our test infinite loop
+      SET_PROPERTY(SOURCE testProcess.c PROPERTY COMPILE_FLAGS -qsuppress=1500-010)
     ENDIF()
 
     # Test SharedForward