Prevent a code gen. crash on empty unions - pr5408.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86287 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 7baf69d876..8e0864b8dd 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -208,7 +208,11 @@ void CGRecordLayoutBuilder::LayoutUnion(const RecordDecl *D) {
       Align = 1;
     }
   }
-
+  if (!Align) {
+    assert((D->field_begin() == D->field_end()) && "LayoutUnion - Align 0");
+    Align = 1;
+  }
+  
   // Append tail padding.
   if (Layout.getSize() / 8 > Size)
     AppendPadding(Layout.getSize() / 8, Align);