[libcxx-commits] [libcxx] [libc++][NFC] Simplify copy and move lowering to memmove a bit (PR #83574)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Fri Mar 1 06:24:01 PST 2024
https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/83574
We've introduced `__constexpr_memmove` a while ago, which simplified the implementation of the copy and move lowering a bit. This allows us to remove some of the boilerplate.
>From 384e0f1c922fdb4dbb91079659dbd75aa55b1e1c Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Fri, 1 Mar 2024 15:22:10 +0100
Subject: [PATCH] [libc++][NFC] Simplify copy and move lowering to memmove a
bit
---
libcxx/include/__algorithm/copy.h | 4 +--
libcxx/include/__algorithm/copy_backward.h | 4 +--
libcxx/include/__algorithm/copy_move_common.h | 33 +++----------------
libcxx/include/__algorithm/move.h | 4 +--
libcxx/include/__algorithm/move_backward.h | 4 +--
5 files changed, 8 insertions(+), 41 deletions(-)
diff --git a/libcxx/include/__algorithm/copy.h b/libcxx/include/__algorithm/copy.h
index 4c3815405af0cf..caa11df645122b 100644
--- a/libcxx/include/__algorithm/copy.h
+++ b/libcxx/include/__algorithm/copy.h
@@ -94,9 +94,7 @@ struct __copy_loop {
__local_first = _Traits::__begin(++__segment_iterator);
}
}
-};
-struct __copy_trivial {
// At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
@@ -108,7 +106,7 @@ struct __copy_trivial {
template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
__copy(_InIter __first, _Sent __last, _OutIter __result) {
- return std::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
+ return std::__dispatch_copy_or_move<__copy_loop<_AlgPolicy> >(
std::move(__first), std::move(__last), std::move(__result));
}
diff --git a/libcxx/include/__algorithm/copy_backward.h b/libcxx/include/__algorithm/copy_backward.h
index 3ec88d8bd5cc3a..cc4701db842bbb 100644
--- a/libcxx/include/__algorithm/copy_backward.h
+++ b/libcxx/include/__algorithm/copy_backward.h
@@ -104,9 +104,7 @@ struct __copy_backward_loop {
__local_last = _Traits::__end(__segment_iterator);
}
}
-};
-struct __copy_backward_trivial {
// At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
@@ -118,7 +116,7 @@ struct __copy_backward_trivial {
template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
__copy_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result) {
- return std::__dispatch_copy_or_move<_AlgPolicy, __copy_backward_loop<_AlgPolicy>, __copy_backward_trivial>(
+ return std::__dispatch_copy_or_move<__copy_backward_loop<_AlgPolicy> >(
std::move(__first), std::move(__last), std::move(__result));
}
diff --git a/libcxx/include/__algorithm/copy_move_common.h b/libcxx/include/__algorithm/copy_move_common.h
index 0fc7a5e3cee700..baca6ccace4ce7 100644
--- a/libcxx/include/__algorithm/copy_move_common.h
+++ b/libcxx/include/__algorithm/copy_move_common.h
@@ -81,22 +81,9 @@ __copy_backward_trivial_impl(_In* __first, _In* __last, _Out* __result) {
// Iterator unwrapping and dispatching to the correct overload.
-template <class _F1, class _F2>
-struct __overload : _F1, _F2 {
- using _F1::operator();
- using _F2::operator();
-};
-
template <class _InIter, class _Sent, class _OutIter, class = void>
-struct __can_rewrap : false_type {};
-
-template <class _InIter, class _Sent, class _OutIter>
-struct __can_rewrap<_InIter,
- _Sent,
- _OutIter,
- // Note that sentinels are always copy-constructible.
- __enable_if_t< is_copy_constructible<_InIter>::value && is_copy_constructible<_OutIter>::value > >
- : true_type {};
+struct __can_rewrap
+ : integral_constant<bool, is_copy_constructible<_InIter>::value && is_copy_constructible<_OutIter>::value> {};
template <class _Algorithm,
class _InIter,
@@ -104,7 +91,7 @@ template <class _Algorithm,
class _OutIter,
__enable_if_t<__can_rewrap<_InIter, _Sent, _OutIter>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
-__unwrap_and_dispatch(_InIter __first, _Sent __last, _OutIter __out_first) {
+__dispatch_copy_or_move(_InIter __first, _Sent __last, _OutIter __out_first) {
auto __range = std::__unwrap_range(__first, std::move(__last));
auto __result = _Algorithm()(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__out_first));
return std::make_pair(std::__rewrap_range<_Sent>(std::move(__first), std::move(__result.first)),
@@ -117,20 +104,8 @@ template <class _Algorithm,
class _OutIter,
__enable_if_t<!__can_rewrap<_InIter, _Sent, _OutIter>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
-__unwrap_and_dispatch(_InIter __first, _Sent __last, _OutIter __out_first) {
- return _Algorithm()(std::move(__first), std::move(__last), std::move(__out_first));
-}
-
-template <class _AlgPolicy,
- class _NaiveAlgorithm,
- class _OptimizedAlgorithm,
- class _InIter,
- class _Sent,
- class _OutIter>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
__dispatch_copy_or_move(_InIter __first, _Sent __last, _OutIter __out_first) {
- using _Algorithm = __overload<_NaiveAlgorithm, _OptimizedAlgorithm>;
- return std::__unwrap_and_dispatch<_Algorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+ return _Algorithm()(std::move(__first), std::move(__last), std::move(__out_first));
}
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__algorithm/move.h b/libcxx/include/__algorithm/move.h
index dba6d487fff77e..baefb5b53314e8 100644
--- a/libcxx/include/__algorithm/move.h
+++ b/libcxx/include/__algorithm/move.h
@@ -95,9 +95,7 @@ struct __move_loop {
__local_first = _Traits::__begin(++__segment_iterator);
}
}
-};
-struct __move_trivial {
// At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
template <class _In, class _Out, __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
@@ -109,7 +107,7 @@ struct __move_trivial {
template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
__move(_InIter __first, _Sent __last, _OutIter __result) {
- return std::__dispatch_copy_or_move<_AlgPolicy, __move_loop<_AlgPolicy>, __move_trivial>(
+ return std::__dispatch_copy_or_move<__move_loop<_AlgPolicy> >(
std::move(__first), std::move(__last), std::move(__result));
}
diff --git a/libcxx/include/__algorithm/move_backward.h b/libcxx/include/__algorithm/move_backward.h
index aeedf4241dce9c..4f5f2470147830 100644
--- a/libcxx/include/__algorithm/move_backward.h
+++ b/libcxx/include/__algorithm/move_backward.h
@@ -104,9 +104,7 @@ struct __move_backward_loop {
__local_last = _Traits::__end(--__segment_iterator);
}
}
-};
-struct __move_backward_trivial {
// At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
template <class _In, class _Out, __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
@@ -122,7 +120,7 @@ __move_backward(_BidirectionalIterator1 __first, _Sentinel __last, _Bidirectiona
std::is_copy_constructible<_BidirectionalIterator1>::value,
"Iterators must be copy constructible.");
- return std::__dispatch_copy_or_move<_AlgPolicy, __move_backward_loop<_AlgPolicy>, __move_backward_trivial>(
+ return std::__dispatch_copy_or_move<__move_backward_loop<_AlgPolicy> >(
std::move(__first), std::move(__last), std::move(__result));
}
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