diff --git a/mlir/include/mlir/IR/FunctionSupport.h b/mlir/include/mlir/IR/FunctionSupport.h
--- a/mlir/include/mlir/IR/FunctionSupport.h
+++ b/mlir/include/mlir/IR/FunctionSupport.h
@@ -206,6 +206,7 @@
   //===--------------------------------------------------------------------===//
   // Argument Handling
   //===--------------------------------------------------------------------===//
+  using BlockArgListType = Region::BlockArgListType;
 
   unsigned getNumArguments() {
     return static_cast<ConcreteType *>(this)->getNumFuncArguments();
@@ -218,12 +219,19 @@
   /// Gets argument.
   BlockArgument getArgument(unsigned idx) { return getBody().getArgument(idx); }
 
+  /// Add one value to the argument list.
+  BlockArgument addArgument(Type type) { return getBody().addArgument(type); }
+
   /// Support argument iteration.
   using args_iterator = Region::args_iterator;
   args_iterator args_begin() { return getBody().args_begin(); }
   args_iterator args_end() { return getBody().args_end(); }
   Block::BlockArgListType getArguments() { return getBody().getArguments(); }
 
+  ValueTypeRange<BlockArgListType> getArgumentTypes() {
+    return getBody().getArgumentTypes();
+  }
+
   //===--------------------------------------------------------------------===//
   // Argument Attributes
   //===--------------------------------------------------------------------===//