Some refactoring of my ms_struct patch.
// rdar://8823265 related.

llvm-svn: 130311
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index c4a156f..4076557 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -1261,10 +1261,8 @@
       // Zero-length bitfields following non-bitfield members are
       // ignored:
       const FieldDecl *FD =  (*Field);
-      if (FD->isBitField() && LastFD && !LastFD->isBitField() &&
-          FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue() == 0) {
+      if (Context.ZeroBitfieldFollowsNonBitfield(FD, LastFD))
         continue;
-      }
       LastFD = FD;
     }
     LayoutField(*Field);