Index: flang/lib/Optimizer/Dialect/FIRType.cpp
===================================================================
--- flang/lib/Optimizer/Dialect/FIRType.cpp
+++ flang/lib/Optimizer/Dialect/FIRType.cpp
@@ -948,10 +948,6 @@
   if (ty.getNumResults() == 0)
     return false;
   auto resultType = ty.getResult(0);
-  // FIXME: The interoperable derived type needs more investigations and tests.
-  // The derived type without BIND attribute may also not be abstract result.
-  if (fir::isa_builtin_cptr_type(resultType))
-    return false;
   return resultType.isa<fir::SequenceType, fir::BoxType, fir::RecordType>();
 }
 
Index: flang/lib/Optimizer/Transforms/AbstractResult.cpp
===================================================================
--- flang/lib/Optimizer/Transforms/AbstractResult.cpp
+++ flang/lib/Optimizer/Transforms/AbstractResult.cpp
@@ -6,10 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "flang/Optimizer/Builder/FIRBuilder.h"
 #include "flang/Optimizer/Builder/Todo.h"
 #include "flang/Optimizer/Dialect/FIRDialect.h"
 #include "flang/Optimizer/Dialect/FIROps.h"
 #include "flang/Optimizer/Dialect/FIRType.h"
+#include "flang/Optimizer/Support/FIRContext.h"
 #include "flang/Optimizer/Transforms/Passes.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"
 #include "mlir/IR/Diagnostics.h"
@@ -56,6 +58,20 @@
                                  /*resultTypes=*/{});
 }
 
+/// This is for derived type in function result. The derived type is translated
+/// according to ABI of interoperability with C.
+static mlir::FunctionType getNewFuncResultType(mlir::FunctionType funcTy) {
+  auto resultType = funcTy.getResult(0);
+  assert(fir::isa_derived(resultType));
+  llvm::SmallVector<mlir::Type> outputTypes;
+  if (fir::isa_builtin_cptr_type(resultType)) {
+    auto recTy = resultType.dyn_cast<fir::RecordType>();
+    outputTypes.emplace_back(recTy.getTypeList()[0].second);
+  }
+  return mlir::FunctionType::get(funcTy.getContext(), funcTy.getInputs(),
+                                 outputTypes);
+}
+
 static bool mustEmboxResult(mlir::Type resultType, bool shouldBoxResult) {
   return resultType.isa<fir::SequenceType, fir::RecordType>() &&
          shouldBoxResult;
@@ -92,28 +108,54 @@
           saveResult.getTypeparams());
 
     llvm::SmallVector<mlir::Type> newResultTypes;
+    // TODO: This should be generalized for derived type, and it is
+    // architecture and OS dependent.
+    bool isResultBuiltinCPtr = fir::isa_builtin_cptr_type(result.getType());
+    fir::CallOp newCallOp;
+    if (isResultBuiltinCPtr) {
+      auto recTy = result.getType().dyn_cast<fir::RecordType>();
+      newResultTypes.emplace_back(recTy.getTypeList()[0].second);
+    }
     if (callOp.getCallee()) {
-      llvm::SmallVector<mlir::Value> newOperands = {arg};
+      llvm::SmallVector<mlir::Value> newOperands;
+      if (!isResultBuiltinCPtr)
+        newOperands.emplace_back(arg);
       newOperands.append(callOp.getOperands().begin(),
                          callOp.getOperands().end());
-      rewriter.create<fir::CallOp>(loc, *callOp.getCallee(), newResultTypes,
-                                   newOperands);
+      newCallOp = rewriter.create<fir::CallOp>(loc, *callOp.getCallee(),
+                                               newResultTypes, newOperands);
     } else {
       // Indirect calls.
-      llvm::SmallVector<mlir::Type> newInputTypes = {argType};
+      llvm::SmallVector<mlir::Type> newInputTypes;
+      if (!isResultBuiltinCPtr)
+        newInputTypes.emplace_back(argType);
       for (auto operand : callOp.getOperands().drop_front())
         newInputTypes.push_back(operand.getType());
-      auto funTy = mlir::FunctionType::get(callOp.getContext(), newInputTypes,
-                                           newResultTypes);
+      auto newFuncTy = mlir::FunctionType::get(callOp.getContext(),
+                                               newInputTypes, newResultTypes);
 
       llvm::SmallVector<mlir::Value> newOperands;
-      newOperands.push_back(
-          rewriter.create<fir::ConvertOp>(loc, funTy, callOp.getOperand(0)));
-      newOperands.push_back(arg);
-      newOperands.append(callOp.getOperands().begin() + 1,
-                         callOp.getOperands().end());
-      rewriter.create<fir::CallOp>(loc, mlir::SymbolRefAttr{}, newResultTypes,
-                                   newOperands);
+      newOperands.push_back(rewriter.create<fir::ConvertOp>(
+          loc, newFuncTy, callOp.getOperand(0)));
+      if (!isResultBuiltinCPtr) {
+        newOperands.push_back(arg);
+        newOperands.append(callOp.getOperands().begin() + 1,
+                           callOp.getOperands().end());
+      } else {
+        newOperands.append(callOp.getOperands().begin(),
+                           callOp.getOperands().end());
+      }
+      newCallOp = rewriter.create<fir::CallOp>(loc, mlir::SymbolRefAttr{},
+                                               newResultTypes, newOperands);
+    }
+    if (isResultBuiltinCPtr) {
+      mlir::Value save = saveResult.getMemref();
+      auto module = callOp->getParentOfType<mlir::ModuleOp>();
+      fir::KindMapping kindMap = fir::getKindMapping(module);
+      FirOpBuilder builder(rewriter, kindMap);
+      mlir::Value saveAddr = fir::factory::genCPtrOrCFunptrAddr(
+          builder, loc, save, result.getType());
+      rewriter.create<fir::StoreOp>(loc, newCallOp->getResult(0), saveAddr);
     }
     callOp->dropAllReferences();
     rewriter.eraseOp(callOp);
@@ -146,12 +188,28 @@
   mlir::LogicalResult
   matchAndRewrite(mlir::func::ReturnOp ret,
                   mlir::PatternRewriter &rewriter) const override {
+    auto loc = ret.getLoc();
     rewriter.setInsertionPoint(ret);
     auto returnedValue = ret.getOperand(0);
     bool replacedStorage = false;
     if (auto *op = returnedValue.getDefiningOp())
       if (auto load = mlir::dyn_cast<fir::LoadOp>(op)) {
         auto resultStorage = load.getMemref();
+        // TODO: This should be generalized for derived type, and it is
+        // architecture and OS dependent.
+        if (fir::isa_builtin_cptr_type(returnedValue.getType())) {
+          rewriter.eraseOp(load);
+          auto module = ret->getParentOfType<mlir::ModuleOp>();
+          fir::KindMapping kindMap = fir::getKindMapping(module);
+          FirOpBuilder builder(rewriter, kindMap);
+          mlir::Value retAddr = fir::factory::genCPtrOrCFunptrAddr(
+              builder, loc, resultStorage, returnedValue.getType());
+          mlir::Value retValue = rewriter.create<fir::LoadOp>(
+              loc, fir::unwrapRefType(retAddr.getType()), retAddr);
+          rewriter.replaceOpWithNewOp<mlir::func::ReturnOp>(
+              ret, mlir::ValueRange{retValue});
+          return mlir::success();
+        }
         load.getMemref().replaceAllUsesWith(newArg);
         replacedStorage = true;
         if (auto *alloc = resultStorage.getDefiningOp())
@@ -163,7 +221,7 @@
     // with no length parameters. Simply store the result in the result storage.
     // at the return point.
     if (!replacedStorage)
-      rewriter.create<fir::StoreOp>(ret.getLoc(), returnedValue, newArg);
+      rewriter.create<fir::StoreOp>(loc, returnedValue, newArg);
     rewriter.replaceOpWithNewOp<mlir::func::ReturnOp>(ret);
     return mlir::success();
   }
@@ -263,6 +321,18 @@
     // Convert function type itself if it has an abstract result.
     auto funcTy = func.getFunctionType().cast<mlir::FunctionType>();
     if (hasAbstractResult(funcTy)) {
+      // TODO: This should be generalized for derived type, and it is
+      // architecture and OS dependent.
+      if (fir::isa_builtin_cptr_type(funcTy.getResult(0))) {
+        func.setType(getNewFuncResultType(funcTy));
+        patterns.insert<ReturnOpConversion>(context, mlir::Value{});
+        target.addDynamicallyLegalOp<mlir::func::ReturnOp>(
+            [](mlir::func::ReturnOp ret) {
+              mlir::Type retTy = ret.getOperand(0).getType();
+              return !fir::isa_builtin_cptr_type(retTy);
+            });
+        return;
+      }
       func.setType(getNewFunctionType(funcTy, shouldBoxResult));
       if (!func.empty()) {
         // Insert new argument.
Index: flang/test/Fir/abstract-results.fir
===================================================================
--- flang/test/Fir/abstract-results.fir
+++ flang/test/Fir/abstract-results.fir
@@ -87,6 +87,26 @@
   // FUNC-BOX: return
 }
 
+// FUNC-REF-LABEL: func @retcptr() -> i64
+// FUNC-BOX-LABEL: func @retcptr() -> i64
+func.func @retcptr() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {
+  %0 = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = "rec", uniq_name = "_QFrecErec"}
+  %1 = fir.load %0 : !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>
+  return %1 : !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+
+  // FUNC-REF: %[[ALLOC:.*]] = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = "rec", uniq_name = "_QFrecErec"}
+  // FUNC-REF: %[[FIELD:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  // FUNC-REF: %[[ADDR:.*]] = fir.coordinate_of %[[ALLOC]], %[[FIELD]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  // FUNC-REF: %[[VAL:.*]] = fir.load %[[ADDR]] : !fir.ref<i64>
+  // FUNC-REF: return %[[VAL]] : i64
+  // FUNC-BOX: %[[ALLOC:.*]] = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = "rec", uniq_name = "_QFrecErec"}
+  // FUNC-BOX: %[[FIELD:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  // FUNC-BOX: %[[ADDR:.*]] = fir.coordinate_of %[[ALLOC]], %[[FIELD]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  // FUNC-BOX: %[[VAL:.*]] = fir.load %[[ADDR]] : !fir.ref<i64>
+  // FUNC-BOX: return %[[VAL]] : i64
+}
+
+
 // ------------------------ Test caller rewrite --------------------------------
 
 // FUNC-REF-LABEL: func @call_arrayfunc() {
@@ -202,15 +222,26 @@
   // FUNC-BOX-NOT: fir.save_result
 }
 
-func.func private @rettcptr() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> attributes {fir.bindc_name = "rettcptr"}
-
-// FUNC-REF-LABEL: func @_QPtest_return_cptr() {
-// FUNC-BOX-LABEL: func @_QPtest_return_cptr() {
+// FUNC-REF-LABEL: func @_QPtest_return_cptr
+// FUNC-BOX-LABEL: func @_QPtest_return_cptr
 func.func @_QPtest_return_cptr() {
-  // FUNC-REF: [[VAL:.*]] = fir.call @rettcptr() : () -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
-  // FUNC-BOX: [[VAL:.*]] = fir.call @rettcptr() : () -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
-  %1 = fir.call @rettcptr() : () -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  %0 = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = ".result"}
+  %1 = fir.call @retcptr() : () -> i64
+  %2 = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  %3 = fir.coordinate_of %0, %2 : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  fir.store %1 to %3 : !fir.ref<i64>
   return
+
+  // FUNC-REF: %[[ALLOC:.*]] = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = ".result"}
+  // FUNC-REF: %[[VAL:.*]] = fir.call @retcptr() : () -> i64
+  // FUNC-REF: %[[FIELD:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  // FUNC-REF: %[[ADDR:.*]] = fir.coordinate_of %[[ALLOC]], %[[FIELD]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  // FUNC-REF: fir.store %[[VAL]] to %[[ADDR]] : !fir.ref<i64>
+  // FUNC-BOX: %[[ALLOC:.*]] = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = ".result"}
+  // FUNC-BOX: %[[VAL:.*]] = fir.call @retcptr() : () -> i64
+  // FUNC-BOX: %[[FIELD:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  // FUNC-BOX: %[[ADDR:.*]] = fir.coordinate_of %[[ALLOC]], %[[FIELD]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  // FUNC-BOX: fir.store %[[VAL]] to %[[ADDR]] : !fir.ref<i64>
 }
 
 // ------------------------ Test fir.address_of rewrite ------------------------
@@ -267,6 +298,33 @@
   // FUNC-BOX-NOT: fir.save_result
 }
 
+// FUNC-REF-LABEL: func @test_indirect_calls_return_cptr(
+// FUNC-REF-SAME: %[[ARG0:.*]]: () -> ())
+// FUNC-BOX-LABEL: func @test_indirect_calls_return_cptr(
+// FUNC-BOX-SAME: %[[ARG0:.*]]: () -> ())
+func.func @test_indirect_calls_return_cptr(%arg0: () -> ()) {
+  %0 = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = ".result"}
+  %1 = fir.convert %arg0 : (() -> ()) -> (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>)
+  %2 = fir.call %1() : () -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  fir.save_result %2 to %0 : !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>, !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>
+  return
+
+  // FUNC-REF: %[[VAL_0:.*]] = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = ".result"}
+  // FUNC-REF: %[[VAL_1:.*]] = fir.convert %[[ARG0]] : (() -> ()) -> (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>)
+  // FUNC-REF: %[[VAL_2:.*]] = fir.convert %[[VAL_1]] : (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>) -> (() -> i64)
+  // FUNC-REF: %[[VAL_3:.*]] = fir.call %[[VAL_2]](%[[VAL_1]]) : (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>) -> i64
+  // FUNC-REF: %[[VAL_4:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  // FUNC-REF: %[[VAL_5:.*]] = fir.coordinate_of %[[VAL_0]], %[[VAL_4]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  // FUNC-REF: fir.store %[[VAL_3]] to %[[VAL_5]] : !fir.ref<i64>
+  // FUNC-BOX: %[[VAL_0:.*]] = fir.alloca !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}> {bindc_name = ".result"}
+  // FUNC-BOX: %[[VAL_1:.*]] = fir.convert %[[ARG0]] : (() -> ()) -> (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>)
+  // FUNC-BOX: %[[VAL_2:.*]] = fir.convert %[[VAL_1]] : (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>) -> (() -> i64)
+  // FUNC-BOX: %[[VAL_3:.*]] = fir.call %[[VAL_2]](%[[VAL_1]]) : (() -> !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>) -> i64
+  // FUNC-BOX: %[[VAL_4:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>
+  // FUNC-BOX: %[[VAL_5:.*]] = fir.coordinate_of %[[VAL_0]], %[[VAL_4]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+  // FUNC-BOX: fir.store %[[VAL_3]] to %[[VAL_5]] : !fir.ref<i64>
+}
+
 // ----------------------- Test GlobalOp rewrite ------------------------
 
 // This is needed to separate GlobalOp tests from FuncOp tests for FileCheck