2009-10-31 Paolo Carlini <paolo.carlini@oracle.com>

	* include/std/chrono (struct __common_rep_type): New.
	(duration_cast(const duration<>&),
	duration<>::duration(const _Rep2&),
	duration<>::duration(const duration<>&),
	operator*(const duration<>&, const _Rep2&),
	operator*(const _Rep1&, const duration<>&),
	operator/(const duration<>&, const _Rep2&),
	time_point_cast(const time_point<>&)): Implement resolution of
	DR 1177 ([Ready] in Santa Cruz), change to not participate to
	overload resolution if the constraints are not met. 
	* testsuite/20_util/duration/cons/1_neg.cc: Adjust dg-errors.
	* testsuite/20_util/duration/cons/dr974.cc: Likewise.
	* testsuite/20_util/duration/requirements/typedefs_neg1.cc: Adjust
	dg-error line numbers.
	* testsuite/20_util/duration/requirements/typedefs_neg2.cc: Likewise.
	* testsuite/20_util/duration/requirements/typedefs_neg3.cc: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@153787 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 38 insertions, 33 deletions

diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono
index 300c13ce97e..e80ec13c093 100644
--- a/libstdc++-v3/include/std/chrono
+++ b/libstdc++-v3/include/std/chrono
@@ -138,9 +138,20 @@ namespace std
           }
       };
 
+    template<typename _Tp>
+      struct __is_duration
+      : std::false_type
+      { };
+
+    template<typename _Rep, typename _Period>
+      struct __is_duration<duration<_Rep, _Period>>
+      : std::true_type
+      { };
+
     /// duration_cast
     template<typename _ToDuration, typename _Rep, typename _Period>
-      inline _ToDuration
+      inline typename enable_if<__is_duration<_ToDuration>::value,
+				_ToDuration>::type
       duration_cast(const duration<_Rep, _Period>& __d)
       {
         typedef typename
@@ -175,16 +186,6 @@ namespace std
         { return numeric_limits<_Rep>::min(); }
       };
 
-    template<typename _Tp>
-      struct __is_duration
-      : std::false_type
-      { };
-
-    template<typename _Rep, typename _Period>
-      struct __is_duration<duration<_Rep, _Period>>
-      : std::true_type
-      { };
-
     template<typename T>
       struct __is_ratio
       : std::false_type
@@ -210,25 +211,19 @@ namespace std
         // 20.8.3.1 construction / copy / destroy
 	duration() = default;
 
-        template<typename _Rep2>
+        template<typename _Rep2, typename = typename
+	       enable_if<is_convertible<_Rep2, rep>::value
+			 && (treat_as_floating_point<rep>::value
+			     || !treat_as_floating_point<_Rep2>::value)>::type>
           explicit duration(const _Rep2& __rep)
-          : __r(static_cast<rep>(__rep))
-          {
-            static_assert(is_convertible<_Rep2,rep>::value 
-			  && (treat_as_floating_point<rep>::value 
-			      || !treat_as_floating_point<_Rep2>::value),
-	      "cannot construct integral duration with floating point type");
-          }
+          : __r(static_cast<rep>(__rep)) { }
 
-        template<typename _Rep2, typename _Period2>
+        template<typename _Rep2, typename _Period2, typename = typename
+	       enable_if<treat_as_floating_point<rep>::value 
+			 || (ratio_divide<_Period2, period>::type::den == 1
+			     && !treat_as_floating_point<_Rep2>::value)>::type>
           duration(const duration<_Rep2, _Period2>& __d)
-          : __r(duration_cast<duration>(__d).count())
-          {
-            static_assert(treat_as_floating_point<rep>::value == true 
-			  || (ratio_divide<_Period2, period>::type::den == 1
-			      && !treat_as_floating_point<_Rep2>::value), 
-              "the resulting duration is not exactly representable");
-          }
+          : __r(duration_cast<duration>(__d).count()) { }
 
 	~duration() = default;
 	duration(const duration&) = default;
@@ -359,8 +354,17 @@ namespace std
         return __ct(__lhs) -= __rhs;
       }
 
+    template<typename _Rep1, typename _Rep2, bool =
+	     is_convertible<_Rep2,
+			    typename common_type<_Rep1, _Rep2>::type>::value>
+      struct __common_rep_type { };
+
+    template<typename _Rep1, typename _Rep2>
+      struct __common_rep_type<_Rep1, _Rep2, true>
+      { typedef typename common_type<_Rep1, _Rep2>::type type; };     
+
     template<typename _Rep1, typename _Period, typename _Rep2>
-      inline duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+      inline duration<typename __common_rep_type<_Rep1, _Rep2>::type, _Period>
       operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
       {
         typedef typename common_type<_Rep1, _Rep2>::type __cr;
@@ -368,12 +372,12 @@ namespace std
       }
 
     template<typename _Rep1, typename _Period, typename _Rep2>
-      inline duration<typename common_type<_Rep1, _Rep2>::type, _Period>
-      operator*(const _Rep2& __s, const duration<_Rep1, _Period>& __d)
+      inline duration<typename __common_rep_type<_Rep2, _Rep1>::type, _Period>
+      operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
       { return __d * __s; }
  
     template<typename _Rep1, typename _Period, typename _Rep2>
-      inline duration<typename common_type<_Rep1, typename
+      inline duration<typename __common_rep_type<_Rep1, typename
 	enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
       operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
       {
@@ -394,7 +398,7 @@ namespace std
 
     // DR 934.
     template<typename _Rep1, typename _Period, typename _Rep2>
-      inline duration<typename common_type<_Rep1, typename
+      inline duration<typename __common_rep_type<_Rep1, typename
 	enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
       operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
       {
@@ -541,7 +545,8 @@ namespace std
   
     /// time_point_cast
     template<typename _ToDuration, typename _Clock, typename _Duration>
-      inline time_point<_Clock, _ToDuration> 
+      inline typename enable_if<__is_duration<_ToDuration>::value,
+				time_point<_Clock, _ToDuration>>::type
       time_point_cast(const time_point<_Clock, _Duration>& __t)
       {
         return time_point<_Clock, _ToDuration>(