In mergeVisibilityWithMin, let an implicit hidden symbol take precedence over
an explicit default one. This means that with -fvisibility hidden we
now produce a hidden symbol for

template <typename T>
class DEFAULT foo {
  void bar() {}
};
class zed {};
template class foo<zed>;

This matches the behaviour of gcc 4.7.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155102 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 0bf4615..026be08 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -281,9 +281,10 @@
       if (visibility() < V)
         return;
 
-      // If this visibility is explicit, keep it.
-      if (visibilityExplicit() && !E)
+      // Don't lose the explicit bit for nothing
+      if (visibility() == V && visibilityExplicit())
         return;
+
       setVisibility(V, E);
     }
     void mergeVisibility(LinkageInfo Other) {
diff --git a/test/CodeGenCXX/visibility.cpp b/test/CodeGenCXX/visibility.cpp
index 59fd7c2..59d02d6 100644
--- a/test/CodeGenCXX/visibility.cpp
+++ b/test/CodeGenCXX/visibility.cpp
@@ -510,7 +510,7 @@
   };
   template class foo::bar<zed>;
   // CHECK: define weak_odr void @_ZN7PR101133foo3barINS_3zedEE3zedEv
-  // CHECK-HIDDEN: define weak_odr void @_ZN7PR101133foo3barINS_3zedEE3zedEv
+  // CHECK-HIDDEN: define weak_odr hidden void @_ZN7PR101133foo3barINS_3zedEE3zedEv
 }
 
 namespace PR11690 {
@@ -541,7 +541,7 @@
   };
   template class foo::zed<baz>;
   // CHECK: define weak_odr void @_ZN9PR11690_23foo3zedINS_3bazENS0_3barEE3barEv
-  // CHECK-HIDDEN: define weak_odr void @_ZN9PR11690_23foo3zedINS_3bazENS0_3barEE3barEv
+  // CHECK-HIDDEN: define weak_odr hidden void @_ZN9PR11690_23foo3zedINS_3bazENS0_3barEE3barEv
 }
 
 namespace test23 {