SubclassID is really a small field. Split it into half and let subclasses

play with the unused part.

llvm-svn: 20043

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/include/llvm/Value.h b/llvm/include/llvm/Value.h
index 46257cc7a34..267b9eb1b3e 100644
--- a/llvm/include/llvm/Value.h
+++ b/llvm/include/llvm/Value.h
@@ -41,7 +41,13 @@ class SymbolTable;
 /// as operands to other values.
 ///
 class Value {
-  unsigned SubclassID;               // Subclass identifier (for isa/dyn_cast)
+  unsigned short SubclassID;         // Subclass identifier (for isa/dyn_cast)
+protected:
+  /// SubclassData - This member is defined by this class, but is not used for
+  /// anything.  Subclasses can use it to hold whatever state they find useful.
+  /// This field is initialized to zero by the ctor.
+  unsigned short SubclassData;
+private:
   PATypeHolder Ty;
   Use *UseList;
   std::string Name;