GCC fails if there is a trailing colon but no clobbers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@44265 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Parser/asm.c b/test/Parser/asm.c
new file mode 100644
index 0000000..a09b545
--- /dev/null
+++ b/test/Parser/asm.c
@@ -0,0 +1,5 @@
+// RUN: clang -fsyntax-only -verify %s
+
+void f1() {
+  asm ("ret" : : :); // expected-error {{expected string literal}}
+}