Turn the mixed-sign-comparison diagnostic into a runtime behavior
diagnostic, from Eitan Adler!

llvm-svn: 155876
diff --git a/clang/test/Sema/compare.c b/clang/test/Sema/compare.c
index 03aebb3..406ade8 100644
--- a/clang/test/Sema/compare.c
+++ b/clang/test/Sema/compare.c
@@ -333,3 +333,10 @@
 int test11(unsigned y, struct test11S *p) {
   return y > (p->x >> 24); // no-warning
 }
+
+typedef char one_char[1];
+typedef char two_chars[2];
+
+void test12(unsigned a) {
+  if (0 && -1 > a) { }
+}