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* [gcc r12-1976] libstdc++: Revert changes to std::unique_ptr<T[]>::operator[] [PR 101271]
@ 2021-07-02 11:15 Jonathan Wakely
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From: Jonathan Wakely @ 2021-07-02 11:15 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:bc8f0ed7042280282035168428f6afc839997cf0
commit r12-1976-gbc8f0ed7042280282035168428f6afc839997cf0
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Jul 2 08:46:18 2021 +0100
libstdc++: Revert changes to std::unique_ptr<T[]>::operator[] [PR 101271]
This reverts the changes in r12-1778 which added a noexcept-specifier to
std::unique_ptr<T[]>::operator[], and the changes in r12-1844 which
tried to make it work with incomplete types (for PR 101236).
The noexcept-specifier is not required by the standard, and is causing
regressions, so just remove it.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
PR libstdc++/101271
* include/bits/unique_ptr.h (unique_ptr<T[],D>::operator[]):
Remove noexcept-specifier.
(unique_ptr<T[],D>::_S_nothrow_deref): Remove.
* testsuite/20_util/unique_ptr/lwg2762.cc: Remove checks for
operator[].
Diff:
---
libstdc++-v3/include/bits/unique_ptr.h | 15 ---------------
libstdc++-v3/testsuite/20_util/unique_ptr/lwg2762.cc | 18 ------------------
2 files changed, 33 deletions(-)
diff --git a/libstdc++-v3/include/bits/unique_ptr.h b/libstdc++-v3/include/bits/unique_ptr.h
index e478056c755..d483f13f2b0 100644
--- a/libstdc++-v3/include/bits/unique_ptr.h
+++ b/libstdc++-v3/include/bits/unique_ptr.h
@@ -491,20 +491,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
= __and_< is_base_of<_Tp, _Up>,
__not_<is_same<__remove_cv<_Tp>, __remove_cv<_Up>>> >;
- // This checks whether p[n] is noexcept, but fails gracefully when
- // element_type is incomplete. The standard requires a complete type
- // for unique_ptr<T[], D>, but we try to support it anyway (PR 101236).
- template<typename _Ptr, typename _Elt>
- static constexpr auto
- _S_nothrow_deref(size_t __n)
- -> decltype(sizeof(_Elt) != 0) // PR c++/101239
- { return noexcept(std::declval<_Ptr>()[__n]); }
-
- template<typename _Ptr, typename _Elt>
- static constexpr bool
- _S_nothrow_deref(...)
- { return false; }
-
public:
using pointer = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
using element_type = _Tp;
@@ -669,7 +655,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/// Access an element of owned array.
typename std::add_lvalue_reference<element_type>::type
operator[](size_t __i) const
- noexcept(_S_nothrow_deref<pointer, element_type>(0))
{
__glibcxx_assert(get() != pointer());
return get()[__i];
diff --git a/libstdc++-v3/testsuite/20_util/unique_ptr/lwg2762.cc b/libstdc++-v3/testsuite/20_util/unique_ptr/lwg2762.cc
index c88237dd9ea..ea067eb3af3 100644
--- a/libstdc++-v3/testsuite/20_util/unique_ptr/lwg2762.cc
+++ b/libstdc++-v3/testsuite/20_util/unique_ptr/lwg2762.cc
@@ -12,11 +12,6 @@ struct deleter
int& operator*() && noexcept(B); // this is used by unique_ptr
int& operator*() const& = delete; // this should not be
- int& operator[](std::size_t) && noexcept(B); // this is used by unique_ptr
- int& operator[](std::size_t) const& = delete; // should not be used
- int& operator[](int) && = delete; // should not be used
- int& operator[](double) && = delete; // should not be used
-
int* operator->() noexcept(false); // noexcept here doesn't affect anything
// Needed for NullablePointer requirements
@@ -40,16 +35,3 @@ static_assert( noexcept(std::declval<std::unique_ptr<long>>().operator->()),
"operator-> is always noexcept" );
static_assert( noexcept(std::declval<UPtr<int, false>&>().operator->()),
"operator-> is always noexcept" );
-
-// This is not required by the standard, but we make it depend on the pointer.
-static_assert( noexcept(std::declval<std::unique_ptr<long[]>>()[0]), "QoI" );
-static_assert( noexcept(std::declval<UPtr<int[], true>&>()[0]), "QoI" );
-static_assert( ! noexcept(std::declval<UPtr<int[], false>&>()[0]), "QoI" );
-
-// This is forbidden by the standard ("T shall be a complete type")
-// but we try to support it anyway, see PR libstdc++/101236.
-struct Incomplete;
-static_assert( ! noexcept(std::declval<UPtr<Incomplete[], true>>()[0]),
- "this would be noexcept if the type was complete");
-static_assert( ! noexcept(std::declval<UPtr<Incomplete[], false>>()[0]),
- "this would still be noexcept(false) if the type was complete");
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