diff --git a/contrib/kyua/engine/atf.cpp b/contrib/kyua/engine/atf.cpp
--- a/contrib/kyua/engine/atf.cpp
+++ b/contrib/kyua/engine/atf.cpp
@@ -196,6 +196,7 @@
     auto e = execenv::get(test_program, test_case_name);
     e->init();
     e->exec(args);
+    __builtin_unreachable();
 }
 
 
@@ -227,6 +228,7 @@
 
     auto e = execenv::get(test_program, test_case_name);
     e->exec(args);
+    __builtin_unreachable();
 }
 
 
diff --git a/contrib/kyua/engine/plain.cpp b/contrib/kyua/engine/plain.cpp
--- a/contrib/kyua/engine/plain.cpp
+++ b/contrib/kyua/engine/plain.cpp
@@ -110,6 +110,7 @@
     auto e = execenv::get(test_program, test_case_name);
     e->init();
     e->exec(args);
+    __builtin_unreachable();
 }
 
 
diff --git a/contrib/kyua/engine/tap.cpp b/contrib/kyua/engine/tap.cpp
--- a/contrib/kyua/engine/tap.cpp
+++ b/contrib/kyua/engine/tap.cpp
@@ -157,6 +157,7 @@
     auto e = execenv::get(test_program, test_case_name);
     e->init();
     e->exec(args);
+    __builtin_unreachable();
 }