Don't warn about extraneous '()' around a comparison if it occurs within a macro.

Macros frequently contain extra '()' to make instantiation less error prone.
This warning was flagging a ton of times on postgresql because of its use of macros.

llvm-svn: 124695
diff --git a/clang/test/SemaCXX/warn-assignment-condition.cpp b/clang/test/SemaCXX/warn-assignment-condition.cpp
index 7596bb2..ab9d2ad 100644
--- a/clang/test/SemaCXX/warn-assignment-condition.cpp
+++ b/clang/test/SemaCXX/warn-assignment-condition.cpp
@@ -124,3 +124,13 @@
                           // expected-note {{remove extraneous parentheses around the comparison to silence this warning}}
     if ((test2 == fn)) {}
 }
+
+// Do not warn about extra '()' used within a macro.  This pattern
+// occurs frequently.
+#define COMPARE(x,y) (x == y)
+int test3(int x, int y) {
+  if (COMPARE(x, y)) // no-warning
+    return 0;
+  return 1;
+}
+