Propagate lvalue alignment into bitfields.  Per report on cfe-dev.

llvm-svn: 159295
diff --git a/clang/lib/CodeGen/CGRecordLayout.h b/clang/lib/CodeGen/CGRecordLayout.h
index 25a0a50..94c822f 100644
--- a/clang/lib/CodeGen/CGRecordLayout.h
+++ b/clang/lib/CodeGen/CGRecordLayout.h
@@ -64,12 +64,7 @@
     /// Bit width of the memory access to perform.
     unsigned AccessWidth;
 
-    /// The alignment of the memory access, or 0 if the default alignment should
-    /// be used.
-    //
-    // FIXME: Remove use of 0 to encode default, instead have IRgen do the right
-    // thing when it generates the code, if avoiding align directives is
-    // desired.
+    /// The alignment of the memory access, assuming the parent is aligned.
     CharUnits AccessAlignment;
 
     /// Offset for the target value.