C++/Darwin/x86: Teach IRgen it can pass reference types in registers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@103761 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGenCXX/x86_32-arguments.cpp b/test/CodeGenCXX/x86_32-arguments.cpp
index 3af2746..a92ba78 100644
--- a/test/CodeGenCXX/x86_32-arguments.cpp
+++ b/test/CodeGenCXX/x86_32-arguments.cpp
@@ -83,3 +83,7 @@
 struct s4_1 { float x; };
 struct s4_2 : s4_0, s4_1 { };
 s4_2 f4() { return s4_2(); }
+
+// CHECK: define i32 @_Z2f5v()
+struct s5 { s5(); int &x; };
+s5 f5() { return s5(); }