[mlir][bufferize] Fix dropped return type in ModuleBufferization

[springerm]

Summary

Depends On D123191

[springerm]

add test case

mlir/lib/Dialect/Linalg/ComprehensiveBufferize/ModuleBufferization.cpp

static LogicalResult bufferizeFuncOpBoundary(FuncOp funcOp,
   // The body of such functions is assumed opaque and we can't know the
   // bufferization contract they want to enforce atm.
   // As a consequence, only support functions that don't return any tensor atm.
   if (funcOp.getBody().empty()) {
     if (llvm::any_of(funcOp.getFunctionType().getResults(), isaTensor))
       return funcOp->emitError() << "cannot bufferize bodiless function that "
                                  << "returns a tensor";
     FunctionType bufferizedFuncType = getBufferizedFunctionType(
-        funcOp.getContext(), funcOp.getFunctionType().getInputs(), TypeRange{},
-        state.getOptions());
+        funcOp.getContext(), funcOp.getFunctionType().getInputs(),
+        funcOp.getFunctionType().getResults(), state.getOptions());
     funcOp.setType(bufferizedFuncType);
     return success();
   }
 
   // Support only single return-terminated block in the function.
   func::ReturnOp returnOp = getAssumedUniqueReturnOp(funcOp);
   assert(returnOp && "expected func with single return op");
 

mlir/test/Dialect/Linalg/comprehensive-module-bufferize.mlir

//      CHECK:   call @some_external_func_within_scf_execute(%[[B]]) : (memref<4xi32, #[[$DYN_1D_MAP]]>) -> ()
   }
 
 //      CHECK:   memref.dealloc %[[alloc]]
   return
 }
 
 // -----
 
+// CHECK: func private @external_func_with_return_val(memref<4xi32, #{{.*}}>) -> f32
+func private @external_func_with_return_val(tensor<4xi32>) -> f32
+
+// -----
+
 // CHECK-LABEL: func @execute_region_test(
 //  CHECK-SAME:     %[[m1:.*]]: memref<?xf32
 func @execute_region_test(%t1 : tensor<?xf32> {linalg.inplaceable = "true"})
     -> (f32, tensor<?xf32>, f32)
 {
   %f1 = arith.constant 0.0 : f32
   %f2 = arith.constant 1.0 : f32
   %idx = arith.constant 7 : index