not is a keyword in ansi C++, avoid it

llvm-svn: 763
diff --git a/llvm/lib/VMCore/ConstantHandling.cpp b/llvm/lib/VMCore/ConstantHandling.cpp
index c899d7d..67a598c 100644
--- a/llvm/lib/VMCore/ConstantHandling.cpp
+++ b/llvm/lib/VMCore/ConstantHandling.cpp
@@ -30,7 +30,7 @@
   // Redirecting functions that cast to the appropriate types
   //===--------------------------------------------------------------------===//
 
-  virtual ConstPoolVal *not(const ConstPoolVal *V) const {
+  virtual ConstPoolVal *op_not(const ConstPoolVal *V) const {
     return SubClassName::Not((const ArgType *)V);
   }