diff --git a/mlir/include/mlir-c/Dialect/Func.h b/mlir/include/mlir-c/Dialect/Func.h
--- a/mlir/include/mlir-c/Dialect/Func.h
+++ b/mlir/include/mlir-c/Dialect/Func.h
@@ -18,7 +18,10 @@
 #ifndef MLIR_C_DIALECT_FUNC_H
 #define MLIR_C_DIALECT_FUNC_H
 
+#include <stdint.h>
+
 #include "mlir-c/IR.h"
+#include "mlir-c/Support.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -26,6 +29,12 @@
 
 MLIR_DECLARE_CAPI_DIALECT_REGISTRATION(Func, func);
 
+/// Sets the argument attribute 'name' of an argument at index 'pos'.
+/// Asserts that the operation is a FuncOp.
+MLIR_CAPI_EXPORTED void mlirFuncSetArgAttr(MlirOperation op, intptr_t pos,
+                                           MlirStringRef name,
+                                           MlirAttribute attr);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/mlir/include/mlir-c/IR.h b/mlir/include/mlir-c/IR.h
--- a/mlir/include/mlir-c/IR.h
+++ b/mlir/include/mlir-c/IR.h
@@ -533,6 +533,11 @@
 MLIR_CAPI_EXPORTED void mlirOperationSetOperand(MlirOperation op, intptr_t pos,
                                                 MlirValue newValue);
 
+/// Replaces the operands of the operation.
+MLIR_CAPI_EXPORTED void mlirOperationSetOperands(MlirOperation op,
+                                                 intptr_t nOperands,
+                                                 MlirValue const *operands);
+
 /// Returns the number of results of the operation.
 MLIR_CAPI_EXPORTED intptr_t mlirOperationGetNumResults(MlirOperation op);
 
@@ -664,6 +669,10 @@
 /// operation.
 MLIR_CAPI_EXPORTED MlirRegion mlirRegionGetNextInOperation(MlirRegion region);
 
+/// Moves the entire content of the source region to the target region.
+MLIR_CAPI_EXPORTED void mlirRegionTakeBody(MlirRegion target,
+                                           MlirRegion source);
+
 //===----------------------------------------------------------------------===//
 // Block API.
 //===----------------------------------------------------------------------===//
@@ -737,6 +746,13 @@
                                                   MlirType type,
                                                   MlirLocation loc);
 
+/// Inserts an argument of the specified type at a specified index to the block.
+/// Returns the newly added argument.
+MLIR_CAPI_EXPORTED MlirValue mlirBlockInsertArgument(MlirBlock block,
+                                                     intptr_t pos,
+                                                     MlirType type,
+                                                     MlirLocation loc);
+
 /// Returns `pos`-th argument of the block.
 MLIR_CAPI_EXPORTED MlirValue mlirBlockGetArgument(MlirBlock block,
                                                   intptr_t pos);
diff --git a/mlir/lib/CAPI/Dialect/Func.cpp b/mlir/lib/CAPI/Dialect/Func.cpp
--- a/mlir/lib/CAPI/Dialect/Func.cpp
+++ b/mlir/lib/CAPI/Dialect/Func.cpp
@@ -7,7 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "mlir-c/Dialect/Func.h"
+#include "mlir-c/IR.h"
+#include "mlir-c/Support.h"
 #include "mlir/CAPI/Registration.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"
 
 MLIR_DEFINE_CAPI_DIALECT_REGISTRATION(Func, func, mlir::func::FuncDialect)
+
+void mlirFuncSetArgAttr(MlirOperation op, intptr_t pos, MlirStringRef name,
+                        MlirAttribute attr) {
+  llvm::cast<mlir::func::FuncOp>(unwrap(op))
+      .setArgAttr(pos, unwrap(name), unwrap(attr));
+}
diff --git a/mlir/lib/CAPI/IR/IR.cpp b/mlir/lib/CAPI/IR/IR.cpp
--- a/mlir/lib/CAPI/IR/IR.cpp
+++ b/mlir/lib/CAPI/IR/IR.cpp
@@ -497,6 +497,12 @@
   unwrap(op)->setOperand(static_cast<unsigned>(pos), unwrap(newValue));
 }
 
+void mlirOperationSetOperands(MlirOperation op, intptr_t nOperands,
+                              MlirValue const *operands) {
+  SmallVector<Value> ops;
+  unwrap(op)->setOperands(unwrapList(nOperands, operands, ops));
+}
+
 intptr_t mlirOperationGetNumResults(MlirOperation op) {
   return static_cast<intptr_t>(unwrap(op)->getNumResults());
 }
@@ -632,6 +638,10 @@
   delete static_cast<Region *>(region.ptr);
 }
 
+void mlirRegionTakeBody(MlirRegion target, MlirRegion source) {
+  unwrap(target)->takeBody(*unwrap(source));
+}
+
 //===----------------------------------------------------------------------===//
 // Block API.
 //===----------------------------------------------------------------------===//
@@ -730,6 +740,11 @@
   return wrap(unwrap(block)->addArgument(unwrap(type), unwrap(loc)));
 }
 
+MlirValue mlirBlockInsertArgument(MlirBlock block, intptr_t pos, MlirType type,
+                                  MlirLocation loc) {
+  return wrap(unwrap(block)->insertArgument(pos, unwrap(type), unwrap(loc)));
+}
+
 MlirValue mlirBlockGetArgument(MlirBlock block, intptr_t pos) {
   return wrap(unwrap(block)->getArgument(static_cast<unsigned>(pos)));
 }