-// Returns a pass which converts all instances of ConstantExpression
-// into regular LLVM instructions.
-FunctionPass* createLowerConstantExpressionsPass();
-
+//
+// PredicateSimplifier - This pass collapses duplicate variables into one
+// canonical form, and tries to simplify expressions along the way.
+//
+FunctionPass *createPredicateSimplifierPass();
+
+//===----------------------------------------------------------------------===//
+//
+// GVN-PRE - This pass performs global value numbering and partial redundancy
+// elimination.
+//
+FunctionPass *createGVNPREPass();
+
+//===----------------------------------------------------------------------===//
+//
+// GVN - This pass performs global value numbering and redundant load
+// elimination cotemporaneously.
+//
+FunctionPass *createGVNPass();