[gcc/devel/ranger] libstdc++: Implement LWG 3324 for [cmp.alg] function objects (LWG 3324)
Aldy Hernandez
aldyh@gcc.gnu.org
Wed Jun 17 20:20:54 GMT 2020
https://gcc.gnu.org/g:3fd1c229ad10fda68318882329568f400a38fb6d
commit 3fd1c229ad10fda68318882329568f400a38fb6d
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Apr 9 22:24:57 2020 +0100
libstdc++: Implement LWG 3324 for [cmp.alg] function objects (LWG 3324)
LWG 3324 changed the [cmp.alg] types to use std::compare_three_way
instead of the <=> operator, but we were still using the old
specification. In order to make the existing tests pass the N::X type
needs to be equality comparable, so that three_way_comparable is
satisfied and compare_three_way can be used.
As part of this change I noticed that the compare_three_way call
operator was unconditionally noexcept, which is incorrect.
* libsupc++/compare (compare_three_way): Fix noexcept-specifier.
(strong_order, weak_order, partial_order): Replace uses of <=> with
compare_three_way function object (LWG 3324).
* testsuite/18_support/comparisons/algorithms/partial_order.cc: Add
equality operator so that X satisfies three_way_comparable.
* testsuite/18_support/comparisons/algorithms/strong_order.cc:
Likewise.
* testsuite/18_support/comparisons/algorithms/weak_order.cc: Likewise.
Diff:
---
libstdc++-v3/ChangeLog | 9 ++++
libstdc++-v3/libsupc++/compare | 49 +++++++++++++---------
.../comparisons/algorithms/partial_order.cc | 4 ++
.../comparisons/algorithms/strong_order.cc | 4 ++
.../comparisons/algorithms/weak_order.cc | 4 ++
5 files changed, 50 insertions(+), 20 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 98812f0faae..3ca7a0e7165 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,14 @@
2020-04-09 Jonathan Wakely <jwakely@redhat.com>
+ * libsupc++/compare (compare_three_way): Fix noexcept-specifier.
+ (strong_order, weak_order, partial_order): Replace uses of <=> with
+ compare_three_way function object (LWG 3324).
+ * testsuite/18_support/comparisons/algorithms/partial_order.cc: Add
+ equality operator so that X satisfies three_way_comparable.
+ * testsuite/18_support/comparisons/algorithms/strong_order.cc:
+ Likewise.
+ * testsuite/18_support/comparisons/algorithms/weak_order.cc: Likewise.
+
* include/bits/unique_ptr.h (operator<=>): Define for C++20.
* testsuite/20_util/default_delete/48631_neg.cc: Adjust dg-error line.
* testsuite/20_util/default_delete/void_neg.cc: Likewise.
diff --git a/libstdc++-v3/libsupc++/compare b/libstdc++-v3/libsupc++/compare
index b88b691b9e1..37601d32648 100644
--- a/libstdc++-v3/libsupc++/compare
+++ b/libstdc++-v3/libsupc++/compare
@@ -419,7 +419,8 @@ namespace std
= __detail::__weakly_eq_cmp_with<_Tp, _Tp>
&& __detail::__partially_ordered_with<_Tp, _Tp>
&& requires(const remove_reference_t<_Tp>& __a,
- const remove_reference_t<_Tp>& __b) {
+ const remove_reference_t<_Tp>& __b)
+ {
{ __a <=> __b } -> __detail::__compares_as<_Cat>;
};
@@ -435,7 +436,8 @@ namespace std
&& __detail::__weakly_eq_cmp_with<_Tp, _Up>
&& __detail::__partially_ordered_with<_Tp, _Up>
&& requires(const remove_reference_t<_Tp>& __t,
- const remove_reference_t<_Up>& __u) {
+ const remove_reference_t<_Up>& __u)
+ {
{ __t <=> __u } -> __detail::__compares_as<_Cat>;
{ __u <=> __t } -> __detail::__compares_as<_Cat>;
};
@@ -494,7 +496,8 @@ namespace std
template<typename _Tp, typename _Up>
requires three_way_comparable_with<_Tp, _Up>
constexpr auto
- operator()(_Tp&& __t, _Up&& __u) const noexcept
+ operator()(_Tp&& __t, _Up&& __u) const
+ noexcept(noexcept(std::declval<_Tp>() <=> std::declval<_Up>()))
{
if constexpr (__detail::__3way_builtin_ptr_cmp<_Tp, _Up>)
{
@@ -579,16 +582,16 @@ namespace std
};
template<typename _Ord, typename _Tp, typename _Up>
- concept __op_cmp = requires(_Tp&& __t, _Up&& __u)
+ concept __cmp3way = requires(_Tp&& __t, _Up&& __u, compare_three_way __c)
{
- _Ord(static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u));
+ _Ord(__c(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)));
};
template<typename _Tp, typename _Up>
concept __strongly_ordered
= __adl_strong<_Tp, _Up>
// FIXME: || floating_point<remove_reference_t<_Tp>>
- || __op_cmp<strong_ordering, _Tp, _Up>;
+ || __cmp3way<strong_ordering, _Tp, _Up>;
class _Strong_order
{
@@ -601,8 +604,9 @@ namespace std
else if constexpr (__adl_strong<_Tp, _Up>)
return noexcept(strong_ordering(strong_order(std::declval<_Tp>(),
std::declval<_Up>())));
- else if constexpr (__op_cmp<strong_ordering, _Tp, _Up>)
- return noexcept(std::declval<_Tp>() <=> std::declval<_Up>());
+ else if constexpr (__cmp3way<strong_ordering, _Tp, _Up>)
+ return noexcept(compare_three_way()(std::declval<_Tp>(),
+ std::declval<_Up>()));
}
friend class _Weak_order;
@@ -623,8 +627,9 @@ namespace std
else */ if constexpr (__adl_strong<_Tp, _Up>)
return strong_ordering(strong_order(static_cast<_Tp&&>(__e),
static_cast<_Up&&>(__f)));
- else if constexpr (__op_cmp<strong_ordering, _Tp, _Up>)
- return static_cast<_Tp&&>(__e) <=> static_cast<_Up&&>(__f);
+ else if constexpr (__cmp3way<strong_ordering, _Tp, _Up>)
+ return compare_three_way()(static_cast<_Tp&&>(__e),
+ static_cast<_Up&&>(__f));
}
};
@@ -632,7 +637,7 @@ namespace std
concept __weakly_ordered
= floating_point<remove_reference_t<_Tp>>
|| __adl_weak<_Tp, _Up>
- || __op_cmp<weak_ordering, _Tp, _Up>
+ || __cmp3way<weak_ordering, _Tp, _Up>
|| __strongly_ordered<_Tp, _Up>;
class _Weak_order
@@ -646,8 +651,9 @@ namespace std
else if constexpr (__adl_weak<_Tp, _Up>)
return noexcept(weak_ordering(weak_order(std::declval<_Tp>(),
std::declval<_Up>())));
- else if constexpr (__op_cmp<weak_ordering, _Tp, _Up>)
- return noexcept(std::declval<_Tp>() <=> std::declval<_Up>());
+ else if constexpr (__cmp3way<weak_ordering, _Tp, _Up>)
+ return noexcept(compare_three_way()(std::declval<_Tp>(),
+ std::declval<_Up>()));
else if constexpr (__strongly_ordered<_Tp, _Up>)
return _Strong_order::_S_noexcept<_Tp, _Up>();
}
@@ -669,8 +675,9 @@ namespace std
else if constexpr (__adl_weak<_Tp, _Up>)
return weak_ordering(weak_order(static_cast<_Tp&&>(__e),
static_cast<_Up&&>(__f)));
- else if constexpr (__op_cmp<weak_ordering, _Tp, _Up>)
- return static_cast<_Tp&&>(__e) <=> static_cast<_Up&&>(__f);
+ else if constexpr (__cmp3way<weak_ordering, _Tp, _Up>)
+ return compare_three_way()(static_cast<_Tp&&>(__e),
+ static_cast<_Up&&>(__f));
else if constexpr (__strongly_ordered<_Tp, _Up>)
return _Strong_order{}(static_cast<_Tp&&>(__e),
static_cast<_Up&&>(__f));
@@ -680,7 +687,7 @@ namespace std
template<typename _Tp, typename _Up>
concept __partially_ordered
= __adl_partial<_Tp, _Up>
- || __op_cmp<partial_ordering, _Tp, _Up>
+ || __cmp3way<partial_ordering, _Tp, _Up>
|| __weakly_ordered<_Tp, _Up>;
class _Partial_order
@@ -692,8 +699,9 @@ namespace std
if constexpr (__adl_partial<_Tp, _Up>)
return noexcept(partial_ordering(partial_order(std::declval<_Tp>(),
std::declval<_Up>())));
- else if constexpr (__op_cmp<partial_ordering, _Tp, _Up>)
- return noexcept(std::declval<_Tp>() <=> std::declval<_Up>());
+ else if constexpr (__cmp3way<partial_ordering, _Tp, _Up>)
+ return noexcept(compare_three_way()(std::declval<_Tp>(),
+ std::declval<_Up>()));
else if constexpr (__weakly_ordered<_Tp, _Up>)
return _Weak_order::_S_noexcept<_Tp, _Up>();
}
@@ -712,8 +720,9 @@ namespace std
if constexpr (__adl_partial<_Tp, _Up>)
return partial_ordering(partial_order(static_cast<_Tp&&>(__e),
static_cast<_Up&&>(__f)));
- else if constexpr (__op_cmp<partial_ordering, _Tp, _Up>)
- return static_cast<_Tp&&>(__e) <=> static_cast<_Up&&>(__f);
+ else if constexpr (__cmp3way<partial_ordering, _Tp, _Up>)
+ return compare_three_way()(static_cast<_Tp&&>(__e),
+ static_cast<_Up&&>(__f));
else if constexpr (__weakly_ordered<_Tp, _Up>)
return _Weak_order{}(static_cast<_Tp&&>(__e),
static_cast<_Up&&>(__f));
diff --git a/libstdc++-v3/testsuite/18_support/comparisons/algorithms/partial_order.cc b/libstdc++-v3/testsuite/18_support/comparisons/algorithms/partial_order.cc
index aef738d538a..0806eabf74a 100644
--- a/libstdc++-v3/testsuite/18_support/comparisons/algorithms/partial_order.cc
+++ b/libstdc++-v3/testsuite/18_support/comparisons/algorithms/partial_order.cc
@@ -94,6 +94,10 @@ namespace N
return partial_ordering::equivalent;
return r.i <=> l.i;
}
+
+ constexpr bool operator==(X l, X r) { return std::is_eq(l <=> r); }
+
+ static_assert(std::three_way_comparable<X>);
}
void
diff --git a/libstdc++-v3/testsuite/18_support/comparisons/algorithms/strong_order.cc b/libstdc++-v3/testsuite/18_support/comparisons/algorithms/strong_order.cc
index fd0a10c1f56..edbcc9f1acb 100644
--- a/libstdc++-v3/testsuite/18_support/comparisons/algorithms/strong_order.cc
+++ b/libstdc++-v3/testsuite/18_support/comparisons/algorithms/strong_order.cc
@@ -47,6 +47,10 @@ namespace N
return strong_ordering::equivalent;
return r.i <=> l.i;
}
+
+ constexpr bool operator==(X l, X r) { return std::is_eq(l <=> r); }
+
+ static_assert(std::three_way_comparable<X>);
}
using N::X;
diff --git a/libstdc++-v3/testsuite/18_support/comparisons/algorithms/weak_order.cc b/libstdc++-v3/testsuite/18_support/comparisons/algorithms/weak_order.cc
index a5405dbc377..d7d43ade8d2 100644
--- a/libstdc++-v3/testsuite/18_support/comparisons/algorithms/weak_order.cc
+++ b/libstdc++-v3/testsuite/18_support/comparisons/algorithms/weak_order.cc
@@ -95,6 +95,10 @@ namespace N
return weak_ordering::equivalent;
return r.i <=> l.i;
}
+
+ constexpr bool operator==(X l, X r) { return std::is_eq(l <=> r); }
+
+ static_assert(std::three_way_comparable<X>);
}
void
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