[libc++] Forward std::all_of and std::none_of to std::any_of

[philnik777]

This allows propagating optimizations to different algorithms by just optimizing the lowest one. This is especially relevant now that we start optimizing how we're iterating through ranges (e.g. the segmented iterator optimizations) and adding assumptions so the compier can better leverage semantics guaranteed by the standard (e.g. __builtin_assume_dereferenceable).

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

This allows propagating optimizations to different algorithms by just optimizing the lowest one. This is especially relevant now that we start optimizing how we're iterating through ranges (e.g. the segmented iterator optimizations) and adding assumptions so the compier can better leverage semantics guaranteed by the standard (e.g. __builtin_assume_dereferenceable).

---

Full diff: https://github.com/llvm/llvm-project/pull/167670.diff

2 Files Affected:

• (modified) libcxx/include/__algorithm/all_of.h (+5-5)
• (modified) libcxx/include/__algorithm/none_of.h (+2-4)

diff --git a/libcxx/include/__algorithm/all_of.h b/libcxx/include/__algorithm/all_of.h
index 6acc117fc47bc..bed6fdb073f80 100644
--- a/libcxx/include/__algorithm/all_of.h
+++ b/libcxx/include/__algorithm/all_of.h
@@ -10,9 +10,11 @@
 #ifndef _LIBCPP___ALGORITHM_ALL_OF_H
 #define _LIBCPP___ALGORITHM_ALL_OF_H
 
+#include <__algorithm/any_of.h>
 #include <__config>
 #include <__functional/identity.h>
 #include <__type_traits/invoke.h>
+#include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -23,11 +25,9 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 template <class _Iter, class _Sent, class _Proj, class _Pred>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
 __all_of(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
-  for (; __first != __last; ++__first) {
-    if (!std::__invoke(__pred, std::__invoke(__proj, *__first)))
-      return false;
-  }
-  return true;
+  using _Ref          = decltype(std::__invoke(__proj, *__first));
+  auto __wrapped_pred = [&__pred](_Ref __arg) { return !std::__invoke(__pred, std::forward<_Ref>(__arg)); };
+  return !std::__any_of(std::move(__first), std::move(__last), __wrapped_pred, __proj);
 }
 
 template <class _InputIterator, class _Predicate>
diff --git a/libcxx/include/__algorithm/none_of.h b/libcxx/include/__algorithm/none_of.h
index e6bd197622292..0ccdb4e0b0ec0 100644
--- a/libcxx/include/__algorithm/none_of.h
+++ b/libcxx/include/__algorithm/none_of.h
@@ -10,6 +10,7 @@
 #ifndef _LIBCPP___ALGORITHM_NONE_OF_H
 #define _LIBCPP___ALGORITHM_NONE_OF_H
 
+#include <__algorithm/any_of.h>
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -21,10 +22,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 template <class _InputIterator, class _Predicate>
 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
-  for (; __first != __last; ++__first)
-    if (__pred(*__first))
-      return false;
-  return true;
+  return !std::any_of(__first, __last, __pred);
 }
 
 _LIBCPP_END_NAMESPACE_STD

[ldionne]

I think this makes sense, have a few comments.

[huixie90]

I wonder if there is any benefit to spell _Ref out, rather than just taking a forwarding reference? is the bahaviour same if the _Ref is a PR value?

[philnik777]

Yes, there is: the compiler doesn't crash. (See #145881)

[github-actions]

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