Additional comments and whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136892 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 89b6ce9..7bed507 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1970,7 +1970,8 @@
       UseZeroLengthBitfieldAlignment = true;
 
       /// gcc forces the alignment to 4 bytes, regardless of the type of the
-      /// zero length bitfield.
+      /// zero length bitfield.  This corresponds to EMPTY_FIELD_BOUNDARY in
+      /// gcc.
       ZeroLengthBitfieldBoundary = 32;
 
       if (IsThumb) {