Add note that this is for old bytecode files.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17991 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index bbf6952..e086568 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -1449,7 +1449,7 @@
     return Result;
   }
 
-  case Type::PointerTyID: {  // ConstantPointerRef value...
+  case Type::PointerTyID: {  // ConstantPointerRef value (backwards compat).
     const PointerType *PT = cast<PointerType>(Ty);
     unsigned Slot = read_vbr_uint();