diff --git a/CMakeLists.txt b/CMakeLists.txt
index a4b012c00..26fd972ae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,7 +19,7 @@ if(CMAKE_COMPILER_IS_CLANG)
   set(CMAKE_C_FLAGS_DEBUG "-g3 -O0")
   set(CMAKE_C_FLAGS_COVERAGE "-g3 -O0 --coverage")
   set(CMAKE_C_FLAGS_ASAN "-fsanitize=address -fno-omit-frame-pointer -g3 -O1")
-  set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS} -Werror -Wpointer-arith -Wwrite-strings -Wdocumentation")
+  set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS} -Werror -Wpointer-arith -Wwrite-strings -Wdocumentation -Wunreachable-code")
 endif(CMAKE_COMPILER_IS_CLANG)
 
 set(CMAKE_BUILD_TYPE ${CMAKE_BUILD_TYPE}
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 00e15e531..74ec5d511 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -31,6 +31,9 @@ endfunction(add_test_suite)
 
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-function -Wno-unused-value")
 set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS_CHECK} -Wno-unused-function -Wno-unused-value")
+if(CMAKE_COMPILER_IS_CLANG)
+    set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS_CHECK} -Wno-unreachable-code")
+endif(CMAKE_COMPILER_IS_CLANG)
 
 add_test_suite(aes aes.ecb)
 add_test_suite(aes aes.cbc)