Fix bugs and improve that about HPX_HAVE_CXX11_AUTO_RETURN_VALUE of CMake.

CMakeLists.txt

@@ -7,6 +7,7 @@
 # Copyright (c) 2014-2016 Andreas Schaefer
 # Copyright (c) 2017      Abhimanyu Rawat
 # Copyright (c) 2017      Google
+# Copyright (c) 2017      Taeguk Kwon
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -1100,27 +1101,39 @@ if(HPX_WITH_CUDA)
   endif()
 endif()
 
-# Set default for enabling auto-return type workaround to ON for non-clang CUDA
-# only
-set(HPX_CXX11_AUTO_RETURN_VALUE_VALUE_DEFAULT ON)
-if(HPX_WITH_CUDA AND NOT HPX_WITH_CUDA_CLANG)
-  set(HPX_CXX11_AUTO_RETURN_VALUE_VALUE_DEFAULT OFF)
-endif()
-
-hpx_option(HPX_WITH_CXX11_AUTO_RETURN_VALUE BOOL
-  "Enable the use of auto as a return value in some places. Overriding this flag is only necessary if the C++ compiler is not standard compliant, e.g. nvcc."
-  ${HPX_CXX11_AUTO_RETURN_VALUE_VALUE_DEFAULT} ADVANCED)
-if(HPX_WITH_CXX11_AUTO_RETURN_VALUE)
-  hpx_add_config_define(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+# Store option value passed by an user for HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION.
+if(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION)
+  set(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION_ADVANCED )
+  set(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION_GIVEN ON)
+else()
+  set(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION_ADVANCED ADVANCED)
+  set(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION_GIVEN OFF)
 endif()
 
 ################################################################################
 # C++ feature tests
 ################################################################################
-
 include(HPX_PerformCxxFeatureTests)
 hpx_perform_cxx_feature_tests()
 
+# Exceptional handling for non-clang CUDA.
+if(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION)
+  if(HPX_WITH_CUDA AND NOT HPX_WITH_CUDA_CLANG)
+    # means using default value (given value).
+    unset(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION)
+  endif()
+endif()
+
+# HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION
+# Default value is used only when HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION is not defined.
+hpx_option(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION BOOL
+  "Enable the use of auto as a return value in some places. Overriding this flag is only necessary if the C++ compiler is not standard compliant, e.g. nvcc."
+  ${HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION_GIVEN}
+  ${HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION_ADVANCED})
+if(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION)
+  hpx_add_config_define(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
+endif()
+
 # HPX_WITH_THREAD_COMPATIBILITY
 hpx_option(HPX_WITH_THREAD_COMPATIBILITY BOOL
     "Use a compatibility implementation of std::thread, i.e. fall back to Boost.Thread (default: OFF)"

cmake/HPX_AddConfigTest.cmake

@@ -2,6 +2,7 @@
 # Copyright (c) 2014 Thomas Heller
 # Copyright (c) 2017 Denis Blank
 # Copyright (c) 2017 Google
+# Copyright (c) 2017 Taeguk Kwon
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -572,6 +573,14 @@ macro(hpx_check_for_cxx14_deprecated_attribute)
     FILE ${ARGN})
 endmacro()
 
+###############################################################################
+macro(hpx_check_for_cxx14_return_type_deduction)
+  add_hpx_config_test(HPX_WITH_CXX14_RETURN_TYPE_DEDUCTION
+    SOURCE cmake/tests/cxx14_return_type_deduction.cpp
+    FILE ${ARGN}
+    CMAKECXXFEATURE cxx_return_type_deduction)
+endmacro()
+
 ###############################################################################
 macro(hpx_check_for_libfun_std_experimental_optional)
   add_hpx_config_test(HPX_WITH_LIBFUN_EXPERIMENTAL_OPTIONAL

cmake/HPX_PerformCxxFeatureTests.cmake

@@ -1,6 +1,7 @@
 # Copyright (c) 2007-2017 Hartmut Kaiser
 # Copyright (c) 2011-2014 Thomas Heller
 # Copyright (c) 2013-2016 Agustin Berge
+# Copyright (c)      2017 Taeguk Kwon
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -162,6 +163,8 @@ macro(hpx_perform_cxx_feature_tests)
 
     hpx_check_for_cxx14_deprecated_attribute(
       DEFINITIONS HPX_HAVE_CXX14_DEPRECATED_ATTRIBUTE)
+
+    hpx_check_for_cxx14_return_type_deduction()
 
     # check for experimental facilities
 

cmake/tests/cxx14_return_type_deduction.cpp

@@ -0,0 +1,30 @@
+////////////////////////////////////////////////////////////////////////////////
+//  Copyright (c) 2017 Taeguk Kwon
+//
+//  Distributed under the Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+////////////////////////////////////////////////////////////////////////////////
+
+auto check(int a, int b)
+{
+    int c = a + b;
+    return c;
+}
+
+template <typename T>
+auto check2(T num);
+
+template <typename T>
+auto check2(T num)
+{
+    return num * num;
+}
+
+int main()
+{
+    int a = 10;
+    int b = 20;
+    check(a, b);
+    double c = check2(30.0);
+}
+

hpx/parallel/executors/execution_fwd.hpp

@@ -73,7 +73,7 @@ namespace hpx { namespace parallel { namespace execution
             }
         };
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         // forward declare customization point implementations
         template <>
         struct customization_point<post_tag>
@@ -315,7 +315,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // async_execute customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<async_execute_tag>::
         operator()(Executor&& exec, F&& f, Ts&&... ts) const
@@ -342,7 +342,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // sync_execute customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<sync_execute_tag>::
         operator()(Executor&& exec, F&& f, Ts&&... ts) const
@@ -369,7 +369,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // then_execute customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename Future,
             typename... Ts>
         HPX_FORCEINLINE auto customization_point<then_execute_tag>::
@@ -402,7 +402,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // post customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<post_tag>::operator()(
             Executor&& exec, F&& f, Ts&&... ts) const
@@ -429,7 +429,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // bulk_async_execute customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename Shape,
             typename... Ts>
         HPX_FORCEINLINE auto customization_point<bulk_async_execute_tag>::
@@ -459,7 +459,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // bulk_sync_execute customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename Shape,
             typename... Ts>
         HPX_FORCEINLINE auto customization_point<bulk_sync_execute_tag>::
@@ -489,7 +489,7 @@ namespace hpx { namespace parallel { namespace execution
 
         ///////////////////////////////////////////////////////////////////////
         // bulk_then_execute customization point
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename Shape,
             typename Future, typename... Ts>
         HPX_FORCEINLINE auto customization_point<bulk_then_execute_tag>::

hpx/parallel/executors/execution_information_fwd.hpp

@@ -30,7 +30,7 @@ namespace hpx { namespace parallel { namespace execution
         struct get_pu_mask_tag {};
         struct set_scheduler_mode_tag {};
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         // forward declare customization point implementations
         template <>
         struct customization_point<processing_units_count_tag>
@@ -106,7 +106,7 @@ namespace hpx { namespace parallel { namespace execution
                 >::call(0, std::forward<Executor>(exec), params);
         }
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename Parameters>
         HPX_FORCEINLINE auto customization_point<processing_units_count_tag>::
         operator()(Executor&& exec, Parameters& params) const
@@ -145,7 +145,7 @@ namespace hpx { namespace parallel { namespace execution
                 >::call(0, std::forward<Executor>(exec));
         }
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor>
         HPX_FORCEINLINE auto customization_point<has_pending_closures_tag>::
         operator()(Executor&& exec) const
@@ -182,7 +182,7 @@ namespace hpx { namespace parallel { namespace execution
                 >::call(0, std::forward<Executor>(exec), topo, thread_num);
         }
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor>
         HPX_FORCEINLINE auto customization_point<get_pu_mask_tag>::operator()(
             Executor&& exec, threads::topology& topo,
@@ -221,7 +221,7 @@ namespace hpx { namespace parallel { namespace execution
                 >::call(0, std::forward<Executor>(exec), mode);
         }
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename Mode>
         HPX_FORCEINLINE auto customization_point<set_scheduler_mode_tag>::
         operator()(Executor&& exec, Mode const& mode) const

hpx/parallel/executors/timed_execution_fwd.hpp

@@ -97,7 +97,7 @@ namespace hpx { namespace parallel { namespace execution
         struct async_execute_at_tag {};
         struct async_execute_after_tag {};
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         // forward declare customization point implementations
         template <>
         struct customization_point<post_at_tag>
@@ -268,7 +268,7 @@ namespace hpx { namespace parallel { namespace execution
                     std::forward<F>(f), std::forward<Ts>(ts)...);
         }
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<post_after_tag>::operator()(
             Executor&& exec, hpx::util::steady_duration const& rel_time, F&& f,
@@ -294,7 +294,7 @@ namespace hpx { namespace parallel { namespace execution
         };
 #endif
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<post_at_tag>::operator()(
             Executor&& exec, hpx::util::steady_time_point const& abs_time,
@@ -320,7 +320,7 @@ namespace hpx { namespace parallel { namespace execution
         };
 #endif
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<sync_execute_after_tag>::
         operator()(Executor&& exec, hpx::util::steady_duration const& rel_time,
@@ -346,7 +346,7 @@ namespace hpx { namespace parallel { namespace execution
         };
 #endif
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<sync_execute_at_tag>::
         operator()(Executor&& exec,
@@ -373,7 +373,7 @@ namespace hpx { namespace parallel { namespace execution
         };
 #endif
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<async_execute_at_tag>::
         operator()(Executor&& exec,
@@ -400,7 +400,7 @@ namespace hpx { namespace parallel { namespace execution
         };
 #endif
 
-#if defined(HPX_HAVE_CXX11_AUTO_RETURN_VALUE)
+#if defined(HPX_HAVE_CXX14_RETURN_TYPE_DEDUCTION)
         template <typename Executor, typename F, typename... Ts>
         HPX_FORCEINLINE auto customization_point<async_execute_after_tag>::
         operator()(Executor&& exec, hpx::util::steady_duration const& rel_time,