From 29d2fd56b5eeeb52f7fdbdd232229e570c30d62b Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 28 Apr 2010 22:43:14 +0000
Subject: [PATCH] Fix template instantiation for __builtin_offfsetof
 expressions that refer to members of anonymous structs/unions

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@102551 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/TreeTransform.h                 |  3 +++
 test/SemaTemplate/instantiate-expr-5.cpp | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 17f6553d0d..4e32897df6 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -4219,6 +4219,9 @@ TreeTransform<Derived>::TransformOffsetOfExpr(OffsetOfExpr *E) {
     case Node::Identifier:
       Comp.isBrackets = false;
       Comp.U.IdentInfo = ON.getFieldName();
+      if (!Comp.U.IdentInfo)
+        continue;
+        
       break;
     }
     
diff --git a/test/SemaTemplate/instantiate-expr-5.cpp b/test/SemaTemplate/instantiate-expr-5.cpp
index 916c4f9493..6cdedda4d8 100644
--- a/test/SemaTemplate/instantiate-expr-5.cpp
+++ b/test/SemaTemplate/instantiate-expr-5.cpp
@@ -19,4 +19,20 @@ namespace PR5880 {
   struct B { ArrayOfHasM a; };
   A<B> x;
   A<HasM> x2; // expected-note{{in instantiation of}}
+
+  template<typename T>
+  struct AnonymousUnion {
+    union {
+      int i;
+      float f;
+    };
+  };
+
+  template<typename T>
+  void test_anon_union() {
+    int array1[__builtin_offsetof(AnonymousUnion<T>, f) == 0? 1 : -1];
+    int array2[__builtin_offsetof(AnonymousUnion<int>, f) == 0? 1 : -1];
+  }
+
+  template void test_anon_union<int>();
 }
-- 
2.40.0