diff --git a/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp
index 8e4898ba..84aabfde 100644
--- a/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp
@@ -17,7 +17,7 @@ namespace boost { namespace fusion
     }
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::iter_fold<
         Seq
       , State const
@@ -26,7 +26,7 @@ namespace boost { namespace fusion
     iter_fold(Seq& seq, State const& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::iter_fold<
         Seq const
       , State const
@@ -35,7 +35,7 @@ namespace boost { namespace fusion
     iter_fold(Seq const& seq, State const& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::iter_fold<
         Seq
       , State const
@@ -44,7 +44,7 @@ namespace boost { namespace fusion
     iter_fold(Seq& seq, State& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::iter_fold<
         Seq const
       , State const
diff --git a/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp
index c5596e79..82fad70a 100644
--- a/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp
@@ -17,7 +17,7 @@ namespace boost { namespace fusion
     }
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_fold<
         Seq
       , State const
@@ -26,7 +26,7 @@ namespace boost { namespace fusion
     reverse_fold(Seq& seq, State const& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_fold<
         Seq const
       , State const
@@ -35,7 +35,7 @@ namespace boost { namespace fusion
     reverse_fold(Seq const& seq, State const& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_fold<
         Seq
       , State const
@@ -44,7 +44,7 @@ namespace boost { namespace fusion
     reverse_fold(Seq& seq, State& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_fold<
         Seq const
       , State const
diff --git a/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp
index 7b49ea69..9f002419 100644
--- a/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp
@@ -17,7 +17,7 @@ namespace boost { namespace fusion
     }
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_iter_fold<
         Seq
       , State const
@@ -26,7 +26,7 @@ namespace boost { namespace fusion
     reverse_iter_fold(Seq& seq, State const& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_iter_fold<
         Seq const
       , State const
@@ -35,7 +35,7 @@ namespace boost { namespace fusion
     reverse_iter_fold(Seq const& seq, State const& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_iter_fold<
         Seq
       , State const
@@ -44,7 +44,7 @@ namespace boost { namespace fusion
     reverse_iter_fold(Seq& seq, State& state, F f);
 
     template<typename Seq, typename State, typename F>
-    BOOST_FUSION_GPU_ENABLED
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
     typename result_of::reverse_iter_fold<
         Seq const
       , State const