diff --git a/polly/CMakeLists.txt b/polly/CMakeLists.txt
index 11e842011bfd..dba7ef06c737 100644
--- a/polly/CMakeLists.txt
+++ b/polly/CMakeLists.txt
@@ -165,7 +165,7 @@ configure_file( ${CMAKE_CURRENT_SOURCE_DIR}/include/polly/Config/config.h.cmake
                 ${POLLY_BINARY_DIR}/include/polly/Config/config.h )
 
 # Add target to check formatting of polly files
-file( GLOB_RECURSE files *.h *.cpp *.c)
+file( GLOB_RECURSE files *.h lib/**/*.cpp lib/**/*.c)
 file( GLOB_RECURSE wwwfiles www/*)
 file( GLOB_RECURSE jsonfiles lib/JSON/*.h lib/JSON/*.cpp)
 file( GLOB_RECURSE islfiles lib/External/isl/*.h lib/External/isl/*.c