[libcxx-commits] [libcxx] [libc++] Added segmented iterator for std::fill (PR #104680)

[Nikolas Klauser via libcxx-commits]

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@@ -21,23 +24,37 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 // fill isn't specialized for std::memset, because the compiler already optimizes the loop to a call to std::memset.
 
-template <class _ForwardIterator, class _Tp>
+template < class _ForwardIterator,
+           class _Tp,
+           __enable_if_t<!__has_random_access_iterator_category<_ForwardIterator>::value, int> = 0>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
-__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, forward_iterator_tag) {
+__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
   for (; __first != __last; ++__first)
     *__first = __value;
 }
 
-template <class _RandomAccessIterator, class _Tp>
+template <class _RandomAccessIterator,
+          class _Tp,
+          __enable_if_t<__has_random_access_iterator_category<_RandomAccessIterator>::value &&
+                            !__is_segmented_iterator<_RandomAccessIterator>::value,
+                        int> = 0>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
-__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value, random_access_iterator_tag) {
+__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value) {
   std::fill_n(__first, __last - __first, __value);
 }
 
+template <class _SegmentedIterator,
+          class _Tp,
+          __enable_if_t<__is_segmented_iterator<_SegmentedIterator>::value, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
+__fill(_SegmentedIterator __first, _SegmentedIterator __last, const _Tp& __value) {
+  std::for_each(__first, __last, [__value](_Tp& __val) { __val = __value; });
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philnik777 wrote:

We should be able to call `for_each` unconditionally. No need to only do it for segmented iterators.

https://github.com/llvm/llvm-project/pull/104680