`<algorithm>`: unused `__find_end` implementation details

[hewillk]

The two functions named __find_end in find_end.h are not called from anywhere, they are useless and should be removed.

llvm-project/libcxx/include/__algorithm/find_end.h

Lines 83 to 184 in a79db96

	template < class _IterOps,
	class _Pred,
	class _Iter1,
	class _Sent1,
	class _Iter2,
	class _Sent2,
	class _Proj1,
	class _Proj2>
	_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter1 __find_end(
	_Iter1 __first1,
	_Sent1 __sent1,
	_Iter2 __first2,
	_Sent2 __sent2,
	_Pred& __pred,
	_Proj1& __proj1,
	_Proj2& __proj2,
	bidirectional_iterator_tag,
	bidirectional_iterator_tag) {
	auto __last1 = _IterOps::next(__first1, __sent1);
	auto __last2 = _IterOps::next(__first2, __sent2);
	// modeled after search algorithm (in reverse)
	if (__first2 == __last2)
	return __last1; // Everything matches an empty sequence
	_Iter1 __l1 = __last1;
	_Iter2 __l2 = __last2;
	--__l2;
	while (true) {
	// Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
	while (true) {
	if (__first1 == __l1) // return __last1 if no element matches *__first2
	return __last1;
	if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
	break;
	}
	// *__l1 matches *__l2, now match elements before here
	_Iter1 __m1 = __l1;
	_Iter2 __m2 = __l2;
	while (true) {
	if (__m2 == __first2) // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
	return __m1;
	if (__m1 == __first1) // Otherwise if source exhaused, pattern not found
	return __last1;
	// if there is a mismatch, restart with a new __l1
	if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(__proj2, *--__m2))) {
	break;
	} // else there is a match, check next elements
	}
	}
	}
	template < class _AlgPolicy,
	class _Pred,
	class _Iter1,
	class _Sent1,
	class _Iter2,
	class _Sent2,
	class _Proj1,
	class _Proj2>
	_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iter1 __find_end(
	_Iter1 __first1,
	_Sent1 __sent1,
	_Iter2 __first2,
	_Sent2 __sent2,
	_Pred& __pred,
	_Proj1& __proj1,
	_Proj2& __proj2,
	random_access_iterator_tag,
	random_access_iterator_tag) {
	typedef typename iterator_traits<_Iter1>::difference_type _D1;
	auto __last1 = _IterOps<_AlgPolicy>::next(__first1, __sent1);
	auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __sent2);
	// Take advantage of knowing source and pattern lengths. Stop short when source is smaller than pattern
	auto __len2 = __last2 - __first2;
	if (__len2 == 0)
	return __last1;
	auto __len1 = __last1 - __first1;
	if (__len1 < __len2)
	return __last1;
	const _Iter1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here
	_Iter1 __l1 = __last1;
	_Iter2 __l2 = __last2;
	--__l2;
	while (true) {
	while (true) {
	if (__s == __l1)
	return __last1;
	if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
	break;
	}
	_Iter1 __m1 = __l1;
	_Iter2 __m2 = __l2;
	while (true) {
	if (__m2 == __first2)
	return __m1;
	// no need to check range on __m1 because __s guarantees we have enough source
	if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(*--__m2))) {
	break;
	}
	}
	}
	}

[hewillk]

Note that there is a typo in line 179, namely std::__invoke(*--__m2). But since this is dead code, we should just remove the whole function.

[frederick-vs-ja]

Would you like to kill this __find_end yourself? This seems to be NFC.