diff --git a/redo-ifcreate.py b/redo-ifcreate.py
index 473f61e..1091ba6 100755
--- a/redo-ifcreate.py
+++ b/redo-ifcreate.py
@@ -11,6 +11,7 @@ if not vars.TARGET:
 for t in sys.argv[1:]:
     mkdirp('%s/.redo' % vars.BASE)
     if os.path.exists(t):
-        add_dep(vars.TARGET, 'm', t)
+        err('redo-ifcreate: error: %r already exists\n' % t)
+        sys.exit(1)
     else:
         add_dep(vars.TARGET, 'c', t)
diff --git a/t/hello.o.do b/t/hello.o.do
index 543adfa..543bf85 100644
--- a/t/hello.o.do
+++ b/t/hello.o.do
@@ -1,2 +1,3 @@
 redo-ifchange CC hello.c /usr/include/stdio.h
+redo-ifcreate stdio.h
 ./CC hello.c