[libc++] [P0202] constexpr set_union, set_difference, set_symmetric_difference, merge
These had been waiting on the ability to use `std::copy` from
constexpr code (which in turn had been waiting on the ability to
use `is_constant_evaluated()` to switch between `memmove` and non-`memmove`
implementations of `std::copy`). That work landed a while ago,
so these algorithms can all be constexpr in C++20 now.
Simultaneously, update the tests for the set algorithms.
- Use an element type with "equivalent but not identical" values.
- The custom-comparator tests now pass something different from `operator<`.
- Make the constexpr coverage match the non-constexpr coverage.
Differential Revision: https://reviews.llvm.org/D92255
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 2a854e7..7ad8ff9 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -415,12 +415,12 @@
binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
template <class InputIterator1, class InputIterator2, class OutputIterator>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
merge(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result);
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
merge(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
@@ -441,12 +441,12 @@
includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
template <class InputIterator1, class InputIterator2, class OutputIterator>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
set_union(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result);
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
set_union(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
@@ -461,22 +461,22 @@
InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
template <class InputIterator1, class InputIterator2, class OutputIterator>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
set_difference(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result);
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
set_difference(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
template <class InputIterator1, class InputIterator2, class OutputIterator>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result);
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
- OutputIterator
+ constexpr OutputIterator // constexpr in C++20
set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
@@ -5401,7 +5401,7 @@
// set_union
template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
-_OutputIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
{
@@ -5426,7 +5426,7 @@
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
set_union(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
@@ -5436,7 +5436,7 @@
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
set_union(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
@@ -5495,7 +5495,7 @@
// set_difference
template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
-_OutputIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
{
@@ -5520,7 +5520,7 @@
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
@@ -5530,7 +5530,7 @@
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
@@ -5543,7 +5543,7 @@
// set_symmetric_difference
template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
-_OutputIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
{
@@ -5573,7 +5573,7 @@
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
@@ -5583,7 +5583,7 @@
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
