Fix brace init of unions with unnamed struct members

The check for unnamed members was intended to skip unnamed bitfields,
but it ended up skipping unnamed structs. This lead to an assertion in
IRGen.

llvm-svn: 221818

2 files changed, 14 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index d1e51de6210..39d6a575aa2 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -1555,10 +1555,11 @@ void InitListChecker::CheckStructUnionTypes(const InitializedEntity &Entity,
       }
     }
 
-    // Value-initialize the first named member of the union.
+    // Value-initialize the first member of the union that isn't an unnamed
+    // bitfield.
     for (RecordDecl::field_iterator FieldEnd = RD->field_end();
          Field != FieldEnd; ++Field) {
-      if (Field->getDeclName()) {
+      if (!Field->isUnnamedBitfield()) {
         if (VerifyOnly)
           CheckEmptyInitializable(
               InitializedEntity::InitializeMember(*Field, &Entity),
diff --git a/clang/test/CodeGenCXX/cxx1y-initializer-aggregate.cpp b/clang/test/CodeGenCXX/cxx1y-initializer-aggregate.cpp
index 8bdf8633d61..098a4b945e0 100644
--- a/clang/test/CodeGenCXX/cxx1y-initializer-aggregate.cpp
+++ b/clang/test/CodeGenCXX/cxx1y-initializer-aggregate.cpp
@@ -36,6 +36,17 @@ B y {};
 B z { 1 };
 // CHECK: @z = global {{.*}} { i32 1 }
 
+// Brace initialization should initialize the first field even though it is
+// unnamed.
+union C {
+  struct {
+    int C::*memptr;
+  };
+};
+
+C n{};
+// CHECK: @n = global %union.C { %struct.anon { i64 -1 } }, align 8
+
 // Initialization of 'a':
 
 // CHECK: store i32 0, i32* getelementptr inbounds ({{.*}} @a, i32 0, i32 0)