finish off codegen support for sub of pointer to functions, 
finishing off rdar://6520707


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64295 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/exprs.c b/test/CodeGen/exprs.c
index 07a9158..8174267 100644
--- a/test/CodeGen/exprs.c
+++ b/test/CodeGen/exprs.c
@@ -52,3 +52,10 @@
 	if (*t)
 		return;
 }
+
+// rdar://6520707
+void f0(void (*fp)(void), void (*fp2)(void)) {
+  int x = fp - fp2;
+}
+
+