Optimize the implementation of std::find_first_of to use any_of #129319 #129574
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@llvm/pr-subscribers-libcxx Author: Ali Raeisdanaei (aliraeisdanaei) ChangesFull diff: https://github.com/llvm/llvm-project/pull/129574.diff 1 Files Affected:
diff --git a/libcxx/include/__algorithm/find_first_of.h b/libcxx/include/__algorithm/find_first_of.h
index 45ec133154371..54c0dbd103ddb 100644
--- a/libcxx/include/__algorithm/find_first_of.h
+++ b/libcxx/include/__algorithm/find_first_of.h
@@ -26,11 +26,9 @@ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator1 __find_fir
_ForwardIterator2 __first2,
_ForwardIterator2 __last2,
_BinaryPredicate&& __pred) {
- for (; __first1 != __last1; ++__first1)
- for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
- if (__pred(*__first1, *__j))
- return __first1;
- return __last1;
+ return std::find_if(first1, last1, [&](const auto& x) {
+ return std::any_of(first2, last2, [&](const auto& y) { return x == y; });
+ });
}
template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
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aliraeisdanaei
changed the title
| return __first1; | ||
| return __last1; | ||
| return std::find_if(first1, last1, [&](const auto& x) { | ||
| return std::any_of(first2, last2, [&](const auto& y) { return x == y; }); |
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Isn't this just std::find?
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No std::find would returns only for the first value; whereas, this one returns where any of the values in the needle are found
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I'm talking about that std::any_of call.
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You are right std::find and std::any_of have the same function; however, std::find returns an iterator, and std::any_of returns a predicate which is needed in the std::find_any.
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Additionally std::find does not work for custom predicates. (I may be totally wrong).
Sure, but this may take me a few days. |
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It seems the failing checks are due to regex checks. I haven't touched it and keep my implementation within libc++. |
Can you provide me some resources on how to build the benchmarks? |
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