commit 9b07c6cfd553566a3ebdbab72b12e007d4912bf1
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Oct 1 20:33:08 2019 +0100
Make some parallel mode algorithms usable in constexpr contexts
This makes the __parallel::equal and __parallel:lexicographical_compare
algorithms usable in constant expressions, by dispatching to the
sequential algorithm when calling during constant evaluation.
* include/parallel/algobase.h (equal, lexicographical_compare): Add
_GLIBCXX20_CONSTEXPR and dispatch to sequential algorithm when being
constant evaluated.
* include/parallel/algorithmfwd.h (equal, lexicographical_compare):
Add _GLIBCXX20_CONSTEXPR.
@@ -214,19 +214,31 @@ namespace __parallel
// Public interface
template<typename _IIter1, typename _IIter2>
+ _GLIBCXX20_CONSTEXPR
inline bool
equal(_IIter1 __begin1, _IIter1 __end1, _IIter2 __begin2)
{
+#if __cplusplus > 201703L
+ if (std::is_constant_evaluated())
+ return _GLIBCXX_STD_A::equal(__begin1, __end1, __begin2);
+#endif
+
return __gnu_parallel::mismatch(__begin1, __end1, __begin2).first
== __end1;
}
// Public interface
template<typename _IIter1, typename _IIter2, typename _Predicate>
+ _GLIBCXX20_CONSTEXPR
inline bool
equal(_IIter1 __begin1, _IIter1 __end1, _IIter2 __begin2,
_Predicate __pred)
{
+#if __cplusplus > 201703L
+ if (std::is_constant_evaluated())
+ return _GLIBCXX_STD_A::equal(__begin1, __end1, __begin2, __pred);
+#endif
+
return __gnu_parallel::mismatch(__begin1, __end1, __begin2, __pred).first
== __end1;
}
@@ -286,9 +298,15 @@ namespace __parallel
}
template<typename _IIter1, typename _IIter2>
+ _GLIBCXX20_CONSTEXPR
inline bool
equal(_IIter1 __begin1, _IIter1 __end1, _IIter2 __begin2, _IIter2 __end2)
{
+#if __cplusplus > 201703L
+ if (std::is_constant_evaluated())
+ return _GLIBCXX_STD_A::equal(__begin1, __end1, __begin2, __end2);
+#endif
+
typedef __gnu_parallel::_EqualTo<
typename std::iterator_traits<_IIter1>::value_type,
typename std::iterator_traits<_IIter2>::value_type> _EqualTo;
@@ -299,15 +317,22 @@ namespace __parallel
}
template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
+ _GLIBCXX20_CONSTEXPR
inline bool
equal(_IIter1 __begin1, _IIter1 __end1,
_IIter2 __begin2, _IIter2 __end2, _BinaryPredicate __binary_pred)
{
+#if __cplusplus > 201703L
+ if (std::is_constant_evaluated())
+ return _GLIBCXX_STD_A::equal(__begin1, __end1, __begin2, __end2,
+ __binary_pred);
+#endif
+
return __equal_switch(__begin1, __end1, __begin2, __end2, __binary_pred,
std::__iterator_category(__begin1),
std::__iterator_category(__begin2));
}
-#endif
+#endif // C++14
// Sequential fallback
template<typename _IIter1, typename _IIter2>
@@ -391,10 +416,17 @@ namespace __parallel
// Public interface
template<typename _IIter1, typename _IIter2>
+ _GLIBCXX20_CONSTEXPR
inline bool
lexicographical_compare(_IIter1 __begin1, _IIter1 __end1,
_IIter2 __begin2, _IIter2 __end2)
{
+#if __cplusplus > 201703L
+ if (std::is_constant_evaluated())
+ return _GLIBCXX_STD_A::lexicographical_compare(__begin1, __end1,
+ __begin2, __end2);
+#endif
+
typedef iterator_traits<_IIter1> _TraitsType1;
typedef typename _TraitsType1::value_type _ValueType1;
typedef typename _TraitsType1::iterator_category _IteratorCategory1;
@@ -411,11 +443,19 @@ namespace __parallel
// Public interface
template<typename _IIter1, typename _IIter2, typename _Predicate>
+ _GLIBCXX20_CONSTEXPR
inline bool
lexicographical_compare(_IIter1 __begin1, _IIter1 __end1,
_IIter2 __begin2, _IIter2 __end2,
_Predicate __pred)
{
+#if __cplusplus > 201703L
+ if (std::is_constant_evaluated())
+ return _GLIBCXX_STD_A::lexicographical_compare(__begin1, __end1,
+ __begin2, __end2,
+ __pred);
+#endif
+
typedef iterator_traits<_IIter1> _TraitsType1;
typedef typename _TraitsType1::iterator_category _IteratorCategory1;
@@ -130,10 +130,12 @@ namespace __parallel
__gnu_parallel::sequential_tag);
template<typename _IIter1, typename _IIter2>
+ _GLIBCXX20_CONSTEXPR
bool
equal(_IIter1, _IIter1, _IIter2);
template<typename _IIter1, typename _IIter2, typename _Predicate>
+ _GLIBCXX20_CONSTEXPR
bool
equal(_IIter1, _IIter1, _IIter2, _Predicate);
@@ -285,10 +287,12 @@ namespace __parallel
__gnu_parallel::sequential_tag);
template<typename _IIter1, typename _IIter2>
+ _GLIBCXX20_CONSTEXPR
bool
lexicographical_compare(_IIter1, _IIter1, _IIter2, _IIter2);
template<typename _IIter1, typename _IIter2, typename _Predicate>
+ _GLIBCXX20_CONSTEXPR
bool
lexicographical_compare(_IIter1, _IIter1, _IIter2, _IIter2, _Predicate);