Implement PR4175, catching some questionable comparisons.  Patch by
David Majnemer!

llvm-svn: 74513
diff --git a/clang/test/Sema/compare.c b/clang/test/Sema/compare.c
index 4b44bf5..51f7731 100644
--- a/clang/test/Sema/compare.c
+++ b/clang/test/Sema/compare.c
@@ -15,3 +15,17 @@
   int d = (a == c);
   return a == b; // expected-warning {{comparison of distinct pointer types}}
 }
+
+int pointers(int *a)
+{
+  return a > 0; // expected-warning {{ordered comparison between pointer and integer}}
+  return a > (void *)0; // expected-warning {{comparison of distinct pointer types}}
+}
+
+int function_pointers(int (*a)(int), int (*b)(int))
+{
+  return a > b; // expected-warning {{ordered comparison of function pointers}}
+  return function_pointers > function_pointers; // expected-warning {{ordered comparison of function pointers}}
+  return a == (void *) 0;
+  return a == (void *) 1; // expected-warning {{comparison of distinct pointer types}}
+}