[PATCH] 2/2 Remove debug/array

[PATCH] 2/2 Remove debug/array

[François Dumont]

[-- Attachment #1: Type: text/plain, Size: 2800 bytes --]

Following a recent fix on std::array this test started to fail in 
_GLIBCXX_DEBUG mode.

FAIL: 23_containers/array/comparison_operators/96851.cc (test for excess 
errors)

Rather than fixing it and now that __glibcxx_assert is constexpr 
compatible I would like to propose to simply remove __gnu_debug::array.

The only code we are losing with this change are the 
_Array_check_nonempty/_Array_check_subscript types. I am not sure about 
the purpose of this code as I saw no impact on tests. Maybe it was to 
avoid assertion in constexpr where the value of the expression is not 
use but there is a test doing that and it does produce an assertion.

Note that I am also moving std::array in versioned namespace. It is just 
for consistency so no problem to remove it.

I also manually edited include/Makefile.in cause I do not have the 
proper autoreconf version. Can you regenerate it on your side once patch 
is in ?

     libstdc++: Remove <debug/array>

     Add _GLIBCXX_ASSERTIONS assert in normal std::array and remove 
__gnu_debug::array
     implementation.

     libstdc++-v3/ChangeLog:

             * include/debug/array: Remove.
             * include/Makefile.am: Remove <debug/array>.
             * include/Makefile.in: Regenerate.
             * include/experimental/functional: Adapt.
             * include/std/array: Move to _GLIBCXX_INLINE_VERSION namespace.
             * include/std/functional: Adapt.
             * include/std/span: Adapt.
             * testsuite/23_containers/array/debug/back1_neg.cc:
             Remove dg-require-debug-mode. Add -D_GLIBCXX_ASSERTIONS option.
             * testsuite/23_containers/array/debug/back2_neg.cc: Likewise.
             * testsuite/23_containers/array/debug/front1_neg.cc: Likewise.
             * testsuite/23_containers/array/debug/front2_neg.cc: Likewise.
             * 
testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc:
             Likewise.
             * 
testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc:
             Likewise.
             * testsuite/23_containers/array/element_access/60497.cc
             * 
testsuite/23_containers/array/tuple_interface/get_debug_neg.cc:
             Remove.
             * testsuite/23_containers/array/tuple_interface/get_neg.cc
             * 
testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc
             * 
testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc

Tested under Linux x86_64 normal and debug modes.

Ok to commit ?

François


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diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index 8652b921274..292d89da8ba 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -856,7 +856,6 @@ endif
 debug_srcdir = ${glibcxx_srcdir}/include/debug
 debug_builddir = ./debug
 debug_headers = \
-	${debug_srcdir}/array \
 	${debug_srcdir}/assertions.h \
 	${debug_srcdir}/bitset \
 	${debug_srcdir}/debug.h \
diff --git a/libstdc++-v3/include/Makefile.in b/libstdc++-v3/include/Makefile.in
index 4eb6b2b480a..fff444c69e8 100644
--- a/libstdc++-v3/include/Makefile.in
+++ b/libstdc++-v3/include/Makefile.in
@@ -1195,7 +1195,6 @@ c_compatibility_builddir = .
 debug_srcdir = ${glibcxx_srcdir}/include/debug
 debug_builddir = ./debug
 debug_headers = \
-	${debug_srcdir}/array \
 	${debug_srcdir}/assertions.h \
 	${debug_srcdir}/bitset \
 	${debug_srcdir}/debug.h \
diff --git a/libstdc++-v3/include/debug/array b/libstdc++-v3/include/debug/array
deleted file mode 100644
index dd4044c9c7b..00000000000
--- a/libstdc++-v3/include/debug/array
+++ /dev/null
@@ -1,408 +0,0 @@
-// Debugging array implementation -*- C++ -*-
-
-// Copyright (C) 2012-2020 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// Under Section 7 of GPL version 3, you are granted additional
-// permissions described in the GCC Runtime Library Exception, version
-// 3.1, as published by the Free Software Foundation.
-
-// You should have received a copy of the GNU General Public License and
-// a copy of the GCC Runtime Library Exception along with this program;
-// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
-// <http://www.gnu.org/licenses/>.
-
-/** @file debug/array
- *  This is a Standard C++ Library header.
- */
-
-#ifndef _GLIBCXX_DEBUG_ARRAY
-#define _GLIBCXX_DEBUG_ARRAY 1
-
-#pragma GCC system_header
-
-#include <array>
-
-#include <debug/formatter.h>
-#include <debug/macros.h>
-
-namespace std _GLIBCXX_VISIBILITY(default)
-{
-namespace __debug
-{
-  template<typename _Tp, std::size_t _Nm>
-    struct array
-    {
-      typedef _Tp 	    			      value_type;
-      typedef value_type*			      pointer;
-      typedef const value_type*                       const_pointer;
-      typedef value_type&                   	      reference;
-      typedef const value_type&             	      const_reference;
-      typedef value_type*                             iterator;
-      typedef const value_type*                       const_iterator;
-      typedef std::size_t                    	      size_type;
-      typedef std::ptrdiff_t                   	      difference_type;
-      typedef std::reverse_iterator<iterator>	      reverse_iterator;
-      typedef std::reverse_iterator<const_iterator>   const_reverse_iterator;
-
-      // Support for zero-sized arrays mandatory.
-      typedef _GLIBCXX_STD_C::__array_traits<_Tp, _Nm> _AT_Type;
-      typename _AT_Type::_Type                         _M_elems;
-
-      template<std::size_t _Size>
-	struct _Array_check_subscript
- 	{
-	  std::size_t size() { return _Size; }
-
-	  _Array_check_subscript(std::size_t __index)
-	  { __glibcxx_check_subscript(__index); }
-        };
-
-      template<std::size_t _Size>
-	struct _Array_check_nonempty
- 	{
-	  _GLIBCXX_NODISCARD bool empty() { return _Size == 0; }
-
-	  _Array_check_nonempty()
-	  { __glibcxx_check_nonempty(); }
-        };
-
-      // No explicit construct/copy/destroy for aggregate type.
-
-      // DR 776.
-      _GLIBCXX20_CONSTEXPR void
-      fill(const value_type& __u)
-      { std::fill_n(begin(), size(), __u); }
-
-      _GLIBCXX20_CONSTEXPR void
-      swap(array& __other)
-      noexcept(_AT_Type::_Is_nothrow_swappable::value)
-      { std::swap_ranges(begin(), end(), __other.begin()); }
-
-      // Iterators.
-      _GLIBCXX17_CONSTEXPR iterator
-      begin() noexcept
-      { return iterator(data()); }
-
-      _GLIBCXX17_CONSTEXPR const_iterator
-      begin() const noexcept
-      { return const_iterator(data()); }
-
-      _GLIBCXX17_CONSTEXPR iterator
-      end() noexcept
-      { return iterator(data() + _Nm); }
-
-      _GLIBCXX17_CONSTEXPR const_iterator
-      end() const noexcept
-      { return const_iterator(data() + _Nm); }
-
-      _GLIBCXX17_CONSTEXPR reverse_iterator
-      rbegin() noexcept
-      { return reverse_iterator(end()); }
-
-      _GLIBCXX17_CONSTEXPR const_reverse_iterator
-      rbegin() const noexcept
-      { return const_reverse_iterator(end()); }
-
-      _GLIBCXX17_CONSTEXPR reverse_iterator
-      rend() noexcept
-      { return reverse_iterator(begin()); }
-
-      _GLIBCXX17_CONSTEXPR const_reverse_iterator
-      rend() const noexcept
-      { return const_reverse_iterator(begin()); }
-
-      _GLIBCXX17_CONSTEXPR const_iterator
-      cbegin() const noexcept
-      { return const_iterator(data()); }
-
-      _GLIBCXX17_CONSTEXPR const_iterator
-      cend() const noexcept
-      { return const_iterator(data() + _Nm); }
-
-      _GLIBCXX17_CONSTEXPR const_reverse_iterator
-      crbegin() const noexcept
-      { return const_reverse_iterator(end()); }
-
-      _GLIBCXX17_CONSTEXPR const_reverse_iterator
-      crend() const noexcept
-      { return const_reverse_iterator(begin()); }
-
-      // Capacity.
-      constexpr size_type
-      size() const noexcept { return _Nm; }
-
-      constexpr size_type
-      max_size() const noexcept { return _Nm; }
-
-      _GLIBCXX_NODISCARD constexpr bool
-      empty() const noexcept { return size() == 0; }
-
-      // Element access.
-      _GLIBCXX17_CONSTEXPR reference
-      operator[](size_type __n) noexcept
-      {
-	__glibcxx_check_subscript(__n);
-	return _AT_Type::_S_ref(_M_elems, __n);
-      }
-
-      constexpr const_reference
-      operator[](size_type __n) const noexcept
-      {
-	return __n < _Nm ? _AT_Type::_S_ref(_M_elems, __n)
-	 : (_GLIBCXX_THROW_OR_ABORT(_Array_check_subscript<_Nm>(__n)),
-	    _AT_Type::_S_ref(_M_elems, 0));
-      }
-
-      _GLIBCXX17_CONSTEXPR reference
-      at(size_type __n)
-      {
-	if (__n >= _Nm)
-	  std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
-					    ">= _Nm (which is %zu)"),
-					__n, _Nm);
-	return _AT_Type::_S_ref(_M_elems, __n);
-      }
-
-      constexpr const_reference
-      at(size_type __n) const
-      {
-	// Result of conditional expression must be an lvalue so use
-	// boolean ? lvalue : (throw-expr, lvalue)
-	return __n < _Nm ? _AT_Type::_S_ref(_M_elems, __n)
-	  : (std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
-					       ">= _Nm (which is %zu)"),
-					   __n, _Nm),
-	     _AT_Type::_S_ref(_M_elems, 0));
-      }
-
-      _GLIBCXX17_CONSTEXPR reference
-      front() noexcept
-      {
-	__glibcxx_check_nonempty();
-	return *begin();
-      }
-
-      constexpr const_reference
-      front() const noexcept
-      {
-	return _Nm ? _AT_Type::_S_ref(_M_elems, 0)
-	  : (_GLIBCXX_THROW_OR_ABORT(_Array_check_nonempty<_Nm>()),
-	     _AT_Type::_S_ref(_M_elems, 0));
-      }
-
-      _GLIBCXX17_CONSTEXPR reference
-      back() noexcept
-      {
-	__glibcxx_check_nonempty();
-	return _Nm ? *(end() - 1) : *end();
-      }
-
-      constexpr const_reference
-      back() const noexcept
-      {
-	return _Nm ? _AT_Type::_S_ref(_M_elems, _Nm - 1)
-	  : (_GLIBCXX_THROW_OR_ABORT(_Array_check_nonempty<_Nm>()),
-	     _AT_Type::_S_ref(_M_elems, 0));
-      }
-
-      _GLIBCXX17_CONSTEXPR pointer
-      data() noexcept
-      { return _AT_Type::_S_ptr(_M_elems); }
-
-      _GLIBCXX17_CONSTEXPR const_pointer
-      data() const noexcept
-      { return _AT_Type::_S_ptr(_M_elems); }
-    };
-
-#if __cpp_deduction_guides >= 201606
-  template<typename _Tp, typename... _Up>
-    array(_Tp, _Up...)
-      -> array<std::enable_if_t<(std::is_same_v<_Tp, _Up> && ...), _Tp>,
-	       1 + sizeof...(_Up)>;
-#endif
-
-  // Array comparisons.
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline bool
-    operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
-    { return std::equal(__one.begin(), __one.end(), __two.begin()); }
-
-#if __cpp_lib_three_way_comparison && __cpp_lib_concepts
-  template<typename _Tp, size_t _Nm>
-    constexpr __detail::__synth3way_t<_Tp>
-    operator<=>(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
-    {
-      if constexpr (_Nm && __is_byte<_Tp>::__value)
-	return __builtin_memcmp(__a.data(), __b.data(), _Nm) <=> 0;
-      else
-	{
-	  for (size_t __i = 0; __i < _Nm; ++__i)
-	    {
-	      auto __c = __detail::__synth3way(__a[__i], __b[__i]);
-	      if (__c != 0)
-		return __c;
-	    }
-	}
-      return strong_ordering::equal;
-    }
-#else
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline bool
-    operator!=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
-    { return !(__one == __two); }
-
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline bool
-    operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
-    {
-      return std::lexicographical_compare(__a.begin(), __a.end(),
-					  __b.begin(), __b.end());
-    }
-
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline bool
-    operator>(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
-    { return __two < __one; }
-
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline bool
-    operator<=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
-    { return !(__one > __two); }
-
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline bool
-    operator>=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
-    { return !(__one < __two); }
-#endif // three_way_comparison && concepts
-
-  // Specialized algorithms.
-
-#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
-  template<typename _Tp, size_t _Nm>
-    typename enable_if<
-      !_GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::_Is_swappable::value>::type
-    swap(array<_Tp, _Nm>&, array<_Tp, _Nm>&) = delete;
-#endif
-
-  template<typename _Tp, std::size_t _Nm>
-    _GLIBCXX20_CONSTEXPR
-    inline void
-    swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
-    noexcept(noexcept(__one.swap(__two)))
-    { __one.swap(__two); }
-
-  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
-    constexpr _Tp&
-    get(array<_Tp, _Nm>& __arr) noexcept
-    {
-      static_assert(_Int < _Nm, "index is out of bounds");
-      return _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::
-	_S_ref(__arr._M_elems, _Int);
-    }
-
-  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
-    constexpr _Tp&&
-    get(array<_Tp, _Nm>&& __arr) noexcept
-    {
-      static_assert(_Int < _Nm, "index is out of bounds");
-      return std::move(__debug::get<_Int>(__arr));
-    }
-
-  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
-    constexpr const _Tp&
-    get(const array<_Tp, _Nm>& __arr) noexcept
-    {
-      static_assert(_Int < _Nm, "index is out of bounds");
-      return _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::
-	_S_ref(__arr._M_elems, _Int);
-    }
-
-  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
-    constexpr const _Tp&&
-    get(const array<_Tp, _Nm>&& __arr) noexcept
-    {
-      static_assert(_Int < _Nm, "index is out of bounds");
-      return std::move(__debug::get<_Int>(__arr));
-    }
-
-#if __cplusplus > 201703L
-#define __cpp_lib_to_array 201907L
-
-  template<bool _Move = false, typename _Tp, size_t... _Idx>
-    constexpr array<remove_cv_t<_Tp>, sizeof...(_Idx)>
-    __to_array(_Tp (&__a)[sizeof...(_Idx)], index_sequence<_Idx...>)
-    {
-      if constexpr (_Move)
-	return {{std::move(__a[_Idx])...}};
-      else
-	return {{__a[_Idx]...}};
-    }
-
-  template<typename _Tp, size_t _Nm>
-    constexpr array<remove_cv_t<_Tp>, _Nm>
-    to_array(_Tp (&__a)[_Nm])
-    noexcept(is_nothrow_constructible_v<_Tp, _Tp&>)
-    {
-      static_assert(!is_array_v<_Tp>);
-      static_assert(is_constructible_v<_Tp, _Tp&>);
-      if constexpr (is_constructible_v<_Tp, _Tp&>)
-	return __debug::__to_array(__a, make_index_sequence<_Nm>{});
-      __builtin_unreachable(); // FIXME: see PR c++/91388
-    }
-
-  template<typename _Tp, size_t _Nm>
-    constexpr array<remove_cv_t<_Tp>, _Nm>
-    to_array(_Tp (&&__a)[_Nm])
-    noexcept(is_nothrow_move_constructible_v<_Tp>)
-    {
-      static_assert(!is_array_v<_Tp>);
-      static_assert(is_move_constructible_v<_Tp>);
-      if constexpr (is_move_constructible_v<_Tp>)
-	return __debug::__to_array<1>(__a, make_index_sequence<_Nm>{});
-      __builtin_unreachable(); // FIXME: see PR c++/91388
-    }
-#endif // C++20
-
-} // namespace __debug
-
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-  // Tuple interface to class template array.
-
-  /// tuple_size
-  template<typename _Tp, std::size_t _Nm>
-    struct tuple_size<std::__debug::array<_Tp, _Nm>>
-    : public integral_constant<std::size_t, _Nm> { };
-
-  /// tuple_element
-  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
-    struct tuple_element<_Int, std::__debug::array<_Tp, _Nm>>
-    {
-      static_assert(_Int < _Nm, "index is out of bounds");
-      typedef _Tp type;
-    };
-
-  template<typename _Tp, std::size_t _Nm>
-    struct __is_tuple_like_impl<std::__debug::array<_Tp, _Nm>> : true_type
-    { };
-
-_GLIBCXX_END_NAMESPACE_VERSION
-} // namespace std
-
-#endif // _GLIBCXX_DEBUG_ARRAY
diff --git a/libstdc++-v3/include/experimental/functional b/libstdc++-v3/include/experimental/functional
index fe9b3b738d8..df3bb9a618b 100644
--- a/libstdc++-v3/include/experimental/functional
+++ b/libstdc++-v3/include/experimental/functional
@@ -127,7 +127,7 @@ inline namespace fundamentals_v1
       template<typename _RAIter, typename _Unused>
 	__boyer_moore_array_base(_RAIter __pat, size_t __patlen,
 				 _Unused&&, _Pred&& __pred)
-	: _M_bad_char{ _GLIBCXX_STD_C::array<_Tp, _Len>{}, std::move(__pred) }
+	: _M_bad_char{ std::array<_Tp, _Len>{}, std::move(__pred) }
 	{
 	  std::get<0>(_M_bad_char).fill(__patlen);
 	  if (__patlen > 0)
@@ -155,7 +155,7 @@ inline namespace fundamentals_v1
       const _Pred&
       _M_pred() const { return std::get<1>(_M_bad_char); }
 
-      std::tuple<_GLIBCXX_STD_C::array<_Tp, _Len>, _Pred> _M_bad_char;
+      std::tuple<std::array<_Tp, _Len>, _Pred> _M_bad_char;
     };
 
   // Use __boyer_moore_array_base when pattern consists of narrow characters
diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array
index 3bb6f48c432..3c4c88a536e 100644
--- a/libstdc++-v3/include/std/array
+++ b/libstdc++-v3/include/std/array
@@ -39,10 +39,11 @@
 #include <bits/functexcept.h>
 #include <bits/stl_algobase.h>
 #include <bits/range_access.h>
+#include <debug/assertions.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
-_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   template<typename _Tp, std::size_t _Nm>
     struct __array_traits
@@ -106,7 +107,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       typedef std::reverse_iterator<const_iterator>   const_reverse_iterator;
 
       // Support for zero-sized arrays mandatory.
-      typedef _GLIBCXX_STD_C::__array_traits<_Tp, _Nm> _AT_Type;
+      typedef __array_traits<_Tp, _Nm> _AT_Type;
       typename _AT_Type::_Type                         _M_elems;
 
       // No explicit construct/copy/destroy for aggregate type.
@@ -183,11 +184,17 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       // Element access.
       _GLIBCXX17_CONSTEXPR reference
       operator[](size_type __n) noexcept
-      { return _AT_Type::_S_ref(_M_elems, __n); }
+      {
+	__glibcxx_requires_subscript(__n);
+	return _AT_Type::_S_ref(_M_elems, __n);
+      }
 
       constexpr const_reference
       operator[](size_type __n) const noexcept
-      { return _AT_Type::_S_ref(_M_elems, __n); }
+      {
+	__glibcxx_requires_subscript(__n);
+	return _AT_Type::_S_ref(_M_elems, __n);
+      }
 
       _GLIBCXX17_CONSTEXPR reference
       at(size_type __n)
@@ -213,19 +220,29 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       _GLIBCXX17_CONSTEXPR reference
       front() noexcept
-      { return *begin(); }
+      {
+	__glibcxx_requires_nonempty();
+	return *begin();
+      }
 
       constexpr const_reference
       front() const noexcept
-      { return _AT_Type::_S_ref(_M_elems, 0); }
+      {
+	__glibcxx_requires_nonempty();
+	return _AT_Type::_S_ref(_M_elems, 0);
+      }
 
       _GLIBCXX17_CONSTEXPR reference
       back() noexcept
-      { return _Nm ? *(end() - 1) : *end(); }
+      {
+	__glibcxx_requires_nonempty();
+	return _Nm ? *(end() - 1) : *end();
+      }
 
       constexpr const_reference
       back() const noexcept
       {
+	__glibcxx_requires_nonempty();
 	return _Nm ? _AT_Type::_S_ref(_M_elems, _Nm - 1)
  	           : _AT_Type::_S_ref(_M_elems, 0);
       }
@@ -317,7 +334,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
     // Constrained free swap overload, see p0185r1
     typename enable_if<
-      _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::_Is_swappable::value
+      __array_traits<_Tp, _Nm>::_Is_swappable::value
     >::type
 #else
     void
@@ -329,7 +346,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
   template<typename _Tp, std::size_t _Nm>
     typename enable_if<
-      !_GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::_Is_swappable::value>::type
+      !__array_traits<_Tp, _Nm>::_Is_swappable::value>::type
     swap(array<_Tp, _Nm>&, array<_Tp, _Nm>&) = delete;
 #endif
 
@@ -338,8 +355,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     get(array<_Tp, _Nm>& __arr) noexcept
     {
       static_assert(_Int < _Nm, "array index is within bounds");
-      return _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::
-	_S_ref(__arr._M_elems, _Int);
+      return __array_traits<_Tp, _Nm>::_S_ref(__arr._M_elems, _Int);
     }
 
   template<std::size_t _Int, typename _Tp, std::size_t _Nm>
@@ -347,7 +363,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     get(array<_Tp, _Nm>&& __arr) noexcept
     {
       static_assert(_Int < _Nm, "array index is within bounds");
-      return std::move(_GLIBCXX_STD_C::get<_Int>(__arr));
+      return std::move(std::get<_Int>(__arr));
     }
 
   template<std::size_t _Int, typename _Tp, std::size_t _Nm>
@@ -355,8 +371,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     get(const array<_Tp, _Nm>& __arr) noexcept
     {
       static_assert(_Int < _Nm, "array index is within bounds");
-      return _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::
-	_S_ref(__arr._M_elems, _Int);
+      return __array_traits<_Tp, _Nm>::_S_ref(__arr._M_elems, _Int);
     }
 
   template<std::size_t _Int, typename _Tp, std::size_t _Nm>
@@ -364,7 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     get(const array<_Tp, _Nm>&& __arr) noexcept
     {
       static_assert(_Int < _Nm, "array index is within bounds");
-      return std::move(_GLIBCXX_STD_C::get<_Int>(__arr));
+      return std::move(std::get<_Int>(__arr));
     }
 
 #if __cplusplus > 201703L
@@ -388,7 +403,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       static_assert(!is_array_v<_Tp>);
       static_assert(is_constructible_v<_Tp, _Tp&>);
       if constexpr (is_constructible_v<_Tp, _Tp&>)
-	return _GLIBCXX_STD_C::__to_array(__a, make_index_sequence<_Nm>{});
+	return __to_array(__a, make_index_sequence<_Nm>{});
       __builtin_unreachable(); // FIXME: see PR c++/91388
     }
 
@@ -400,18 +415,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       static_assert(!is_array_v<_Tp>);
       static_assert(is_move_constructible_v<_Tp>);
       if constexpr (is_move_constructible_v<_Tp>)
-	return _GLIBCXX_STD_C::__to_array<1>(__a, make_index_sequence<_Nm>{});
+	return __to_array<1>(__a, make_index_sequence<_Nm>{});
       __builtin_unreachable(); // FIXME: see PR c++/91388
     }
 #endif // C++20
 
-_GLIBCXX_END_NAMESPACE_CONTAINER
-} // namespace std
-
-namespace std _GLIBCXX_VISIBILITY(default)
-{
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-
   // Tuple interface to class template array.
 
   /// tuple_size
@@ -420,7 +428,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   /// Partial specialization for std::array
   template<typename _Tp, std::size_t _Nm>
-    struct tuple_size<_GLIBCXX_STD_C::array<_Tp, _Nm>>
+    struct tuple_size<array<_Tp, _Nm>>
     : public integral_constant<std::size_t, _Nm> { };
 
   /// tuple_element
@@ -429,23 +437,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   /// Partial specialization for std::array
   template<std::size_t _Int, typename _Tp, std::size_t _Nm>
-    struct tuple_element<_Int, _GLIBCXX_STD_C::array<_Tp, _Nm>>
+    struct tuple_element<_Int, array<_Tp, _Nm>>
     {
       static_assert(_Int < _Nm, "index is out of bounds");
       typedef _Tp type;
     };
 
   template<typename _Tp, std::size_t _Nm>
-    struct __is_tuple_like_impl<_GLIBCXX_STD_C::array<_Tp, _Nm>> : true_type
+    struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
     { };
 
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
-#ifdef _GLIBCXX_DEBUG
-# include <debug/array>
-#endif
-
 #endif // C++11
 
 #endif // _GLIBCXX_ARRAY
diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 4e2d053f778..06dcf948248 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -1066,7 +1066,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       template<typename _RAIter, typename _Unused>
 	__boyer_moore_array_base(_RAIter __pat, size_t __patlen,
 				 _Unused&&, _Pred&& __pred)
-	: _M_bad_char{ _GLIBCXX_STD_C::array<_Tp, _Len>{}, std::move(__pred) }
+	: _M_bad_char{ array<_Tp, _Len>{}, std::move(__pred) }
 	{
 	  std::get<0>(_M_bad_char).fill(__patlen);
 	  if (__patlen > 0)
@@ -1094,7 +1094,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       const _Pred&
       _M_pred() const { return std::get<1>(_M_bad_char); }
 
-      tuple<_GLIBCXX_STD_C::array<_Tp, _Len>, _Pred> _M_bad_char;
+      tuple<array<_Tp, _Len>, _Pred> _M_bad_char;
     };
 
   // Use __boyer_moore_array_base when pattern consists of narrow characters
diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span
index 24c61ba4172..3d996fa0a1b 100644
--- a/libstdc++-v3/include/std/span
+++ b/libstdc++-v3/include/std/span
@@ -67,12 +67,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       struct __is_std_array : false_type { };
 
     template<typename _Tp, size_t _Num>
-      struct __is_std_array<_GLIBCXX_STD_C::array<_Tp, _Num>> : true_type { };
-
-#ifdef _GLIBCXX_DEBUG
-    template<typename _Tp, size_t _Num>
-      struct __is_std_array<__debug::array<_Tp, _Num>> : true_type { };
-#endif
+      struct __is_std_array<std::array<_Tp, _Num>> : true_type { };
 
     template<size_t _Extent>
       class __extent_storage
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/back1_neg.cc b/libstdc++-v3/testsuite/23_containers/array/debug/back1_neg.cc
index 8062f989066..8216dea3cfb 100644
--- a/libstdc++-v3/testsuite/23_containers/array/debug/back1_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/back1_neg.cc
@@ -15,8 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do run { target c++11 xfail *-*-* } }
-// { dg-require-debug-mode "" }
 
 #include <array>
 
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/back2_neg.cc b/libstdc++-v3/testsuite/23_containers/array/debug/back2_neg.cc
index 0fafb517e80..b14a3ec8c04 100644
--- a/libstdc++-v3/testsuite/23_containers/array/debug/back2_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/back2_neg.cc
@@ -15,8 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do run { target c++11 xfail *-*-* } }
-// { dg-require-debug-mode "" }
 
 #include <array>
 
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/front1_neg.cc b/libstdc++-v3/testsuite/23_containers/array/debug/front1_neg.cc
index 4d8534183e7..c6871093d2a 100644
--- a/libstdc++-v3/testsuite/23_containers/array/debug/front1_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/front1_neg.cc
@@ -15,8 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do run { target c++11 xfail *-*-* } }
-// { dg-require-debug-mode "" }
 
 #include <array>
 
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/front2_neg.cc b/libstdc++-v3/testsuite/23_containers/array/debug/front2_neg.cc
index ee8c04d0be8..e099e6eb46b 100644
--- a/libstdc++-v3/testsuite/23_containers/array/debug/front2_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/front2_neg.cc
@@ -15,8 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do run { target c++11 xfail *-*-* } }
-// { dg-require-debug-mode "" }
 
 #include <array>
 
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc b/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc
index eb099d6a14b..3f1ea128902 100644
--- a/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc
@@ -15,8 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do run { target c++11  xfail *-*-* } }
-// { dg-require-debug-mode "" }
 
 #include <array>
 
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc b/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc
index 1f425af94c3..4e93c8a7d68 100644
--- a/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc
@@ -15,8 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do run { target c++11 xfail *-*-* } }
-// { dg-require-debug-mode "" }
 
 #include <array>
 
diff --git a/libstdc++-v3/testsuite/23_containers/array/element_access/60497.cc b/libstdc++-v3/testsuite/23_containers/array/element_access/60497.cc
index 31471147d70..ff62427c6d7 100644
--- a/libstdc++-v3/testsuite/23_containers/array/element_access/60497.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/element_access/60497.cc
@@ -20,7 +20,6 @@
 // libstdc++/60497
 
 #include <array>
-#include <debug/array>
 #include <memory>
 
 struct A;
@@ -28,6 +27,3 @@ template<typename T> struct B { T t; };
 
 std::array<B<A>*, 1> a;
 auto b = std::get<0>(std::move(a));
-
-std::__debug::array<B<A>*, 1> c;
-auto d = std::__debug::get<0>(std::move(c));
diff --git a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_debug_neg.cc b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_debug_neg.cc
deleted file mode 100644
index 0a9525e9654..00000000000
--- a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_debug_neg.cc
+++ /dev/null
@@ -1,32 +0,0 @@
-// { dg-do compile { target c++11 } }
-// { dg-require-debug-mode "" }
-
-// Copyright (C) 2012-2020 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#include <array>
-
-std::array<int, 1> a{};
-const std::array<int, 1> ca{};
-
-int n1 = std::get<1>(a);
-int n2 = std::get<1>(std::move(a));
-int n3 = std::get<1>(ca);
-
-// { dg-error "static assertion failed" "" { target *-*-* } 315 }
-// { dg-error "static assertion failed" "" { target *-*-* } 324 }
-// { dg-error "static assertion failed" "" { target *-*-* } 332 }
diff --git a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc
index a2640318617..88416cc661c 100644
--- a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc
@@ -1,5 +1,4 @@
 // { dg-do compile { target c++11 } }
-// { dg-require-normal-mode "" }
 
 // Copyright (C) 2012-2020 Free Software Foundation, Inc.
 //
@@ -27,6 +26,6 @@ int n1 = std::get<1>(a);
 int n2 = std::get<1>(std::move(a));
 int n3 = std::get<1>(ca);
 
-// { dg-error "static assertion failed" "" { target *-*-* } 340 }
-// { dg-error "static assertion failed" "" { target *-*-* } 349 }
 // { dg-error "static assertion failed" "" { target *-*-* } 357 }
+// { dg-error "static assertion failed" "" { target *-*-* } 365 }
+// { dg-error "static assertion failed" "" { target *-*-* } 373 }
diff --git a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc
deleted file mode 100644
index 0bd5989c04a..00000000000
--- a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc
+++ /dev/null
@@ -1,25 +0,0 @@
-// { dg-do compile { target c++11 } }
-// { dg-require-debug-mode "" }
-
-// Copyright (C) 2012-2020 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#include <array>
-
-typedef std::tuple_element<1, std::array<int, 1>>::type type;
-
-// { dg-error "static assertion failed" "" { target *-*-* } 397 }
diff --git a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc
index 977727be120..61c277c375d 100644
--- a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc
@@ -1,5 +1,4 @@
 // { dg-do compile { target c++11 } }
-// { dg-require-normal-mode "" }
 
 // Copyright (C) 2012-2020 Free Software Foundation, Inc.
 //

Re: [PATCH] 2/2 Remove debug/array

[Jonathan Wakely]

On 08/11/20 15:27 +0100, François Dumont via Libstdc++ wrote:
>Following a recent fix on std::array this test started to fail in 
>_GLIBCXX_DEBUG mode.
>
>FAIL: 23_containers/array/comparison_operators/96851.cc (test for 
>excess errors)
>
>Rather than fixing it and now that __glibcxx_assert is constexpr 
>compatible I would like to propose to simply remove 
>__gnu_debug::array.
>
>The only code we are losing with this change are the 
>_Array_check_nonempty/_Array_check_subscript types. I am not sure 
>about the purpose of this code as I saw no impact on tests. Maybe it 
>was to avoid assertion in constexpr where the value of the expression 
>is not use but there is a test doing that and it does produce an 
>assertion.
>
>Note that I am also moving std::array in versioned namespace. It is 
>just for consistency so no problem to remove it.
>
>I also manually edited include/Makefile.in cause I do not have the 
>proper autoreconf version. Can you regenerate it on your side once 
>patch is in ?
>
>    libstdc++: Remove <debug/array>
>
>    Add _GLIBCXX_ASSERTIONS assert in normal std::array and remove 
>__gnu_debug::array
>    implementation.
>
>    libstdc++-v3/ChangeLog:
>
>            * include/debug/array: Remove.
>            * include/Makefile.am: Remove <debug/array>.
>            * include/Makefile.in: Regenerate.
>            * include/experimental/functional: Adapt.
>            * include/std/array: Move to _GLIBCXX_INLINE_VERSION namespace.
>            * include/std/functional: Adapt.
>            * include/std/span: Adapt.
>            * testsuite/23_containers/array/debug/back1_neg.cc:
>            Remove dg-require-debug-mode. Add -D_GLIBCXX_ASSERTIONS option.
>            * testsuite/23_containers/array/debug/back2_neg.cc: Likewise.
>            * testsuite/23_containers/array/debug/front1_neg.cc: Likewise.
>            * testsuite/23_containers/array/debug/front2_neg.cc: Likewise.
>            * 
>testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc:
>            Likewise.
>            * 
>testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc:
>            Likewise.
>            * testsuite/23_containers/array/element_access/60497.cc
>            * 
>testsuite/23_containers/array/tuple_interface/get_debug_neg.cc:
>            Remove.
>            * testsuite/23_containers/array/tuple_interface/get_neg.cc
>            * testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc
>            * 
>testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc
>
>Tested under Linux x86_64 normal and debug modes.
>
>Ok to commit ?

Yes, this is a nice simplification, thanks.

Re: [PATCH] 2/2 Remove debug/array

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 3167 bytes --]

On 09/11/20 13:07 +0000, Jonathan Wakely wrote:
>On 08/11/20 15:27 +0100, François Dumont via Libstdc++ wrote:
>>Following a recent fix on std::array this test started to fail in 
>>_GLIBCXX_DEBUG mode.
>>
>>FAIL: 23_containers/array/comparison_operators/96851.cc (test for 
>>excess errors)
>>
>>Rather than fixing it and now that __glibcxx_assert is constexpr 
>>compatible I would like to propose to simply remove 
>>__gnu_debug::array.
>>
>>The only code we are losing with this change are the 
>>_Array_check_nonempty/_Array_check_subscript types. I am not sure 
>>about the purpose of this code as I saw no impact on tests. Maybe it 
>>was to avoid assertion in constexpr where the value of the 
>>expression is not use but there is a test doing that and it does 
>>produce an assertion.
>>
>>Note that I am also moving std::array in versioned namespace. It is 
>>just for consistency so no problem to remove it.
>>
>>I also manually edited include/Makefile.in cause I do not have the 
>>proper autoreconf version. Can you regenerate it on your side once 
>>patch is in ?
>>
>>    libstdc++: Remove <debug/array>
>>
>>    Add _GLIBCXX_ASSERTIONS assert in normal std::array and remove 
>>__gnu_debug::array
>>    implementation.
>>
>>    libstdc++-v3/ChangeLog:
>>
>>            * include/debug/array: Remove.
>>            * include/Makefile.am: Remove <debug/array>.
>>            * include/Makefile.in: Regenerate.
>>            * include/experimental/functional: Adapt.
>>            * include/std/array: Move to _GLIBCXX_INLINE_VERSION namespace.
>>            * include/std/functional: Adapt.
>>            * include/std/span: Adapt.
>>            * testsuite/23_containers/array/debug/back1_neg.cc:
>>            Remove dg-require-debug-mode. Add -D_GLIBCXX_ASSERTIONS option.
>>            * testsuite/23_containers/array/debug/back2_neg.cc: Likewise.
>>            * testsuite/23_containers/array/debug/front1_neg.cc: Likewise.
>>            * testsuite/23_containers/array/debug/front2_neg.cc: Likewise.
>>            * 
>>testsuite/23_containers/array/debug/square_brackets_operator1_neg.cc:
>>            Likewise.
>>            * 
>>testsuite/23_containers/array/debug/square_brackets_operator2_neg.cc:
>>            Likewise.
>>            * testsuite/23_containers/array/element_access/60497.cc
>>            * 
>>testsuite/23_containers/array/tuple_interface/get_debug_neg.cc:
>>            Remove.
>>            * testsuite/23_containers/array/tuple_interface/get_neg.cc
>>            * testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc
>>            * 
>>testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc
>>
>>Tested under Linux x86_64 normal and debug modes.
>>
>>Ok to commit ?
>
>Yes, this is a nice simplification, thanks.

This broke the C++11 constexpr support in std::array. Fixed with this
patch. Tested x86_64-linux, committed to trunk.



[-- Attachment #2: patch.txt --]
[-- Type: text/x-patch, Size: 5502 bytes --]

commit 91cfacc4b5d317b12a3bdcd798273a581568f645
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Dec 3 17:08:01 2020

    libstdc++: Disable std::array assertions for C++11 constexpr
    
    The recent changes to add assertions to std::array broke the functions
    that need to be constexpr in C++11, because of the restrictive rules for
    constexpr functions in C++11.
    
    This simply disables the assertions for C++11 mode, so the functions can
    be constexpr again.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/array (array::operator[](size_t) const, array::front() const)
            (array::back() const) [__cplusplus == 201103]: Disable
            assertions.
            * testsuite/23_containers/array/element_access/constexpr_element_access.cc:
            Check for correct values.
            * testsuite/23_containers/array/tuple_interface/get_neg.cc:
            Adjust dg-error line numbers.
            * testsuite/23_containers/array/debug/constexpr_c++11.cc: New test.

diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array
index 3c4c88a536e..80750994058 100644
--- a/libstdc++-v3/include/std/array
+++ b/libstdc++-v3/include/std/array
@@ -192,7 +192,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr const_reference
       operator[](size_type __n) const noexcept
       {
+#if __cplusplus >= 201402L
 	__glibcxx_requires_subscript(__n);
+#endif
 	return _AT_Type::_S_ref(_M_elems, __n);
       }
 
@@ -228,7 +230,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr const_reference
       front() const noexcept
       {
+#if __cplusplus >= 201402L
 	__glibcxx_requires_nonempty();
+#endif
 	return _AT_Type::_S_ref(_M_elems, 0);
       }
 
@@ -242,7 +246,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr const_reference
       back() const noexcept
       {
+#if __cplusplus >= 201402L
 	__glibcxx_requires_nonempty();
+#endif
 	return _Nm ? _AT_Type::_S_ref(_M_elems, _Nm - 1)
  	           : _AT_Type::_S_ref(_M_elems, 0);
       }
diff --git a/libstdc++-v3/testsuite/23_containers/array/debug/constexpr_c++11.cc b/libstdc++-v3/testsuite/23_containers/array/debug/constexpr_c++11.cc
new file mode 100644
index 00000000000..c8b35994102
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/array/debug/constexpr_c++11.cc
@@ -0,0 +1,32 @@
+// { dg-options "-std=gnu++11 -D_GLIBCXX_DEBUG" }
+// { dg-do compile { target c++11 } }
+
+// Copyright (C) 2011-2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <array>
+
+void test01()
+{
+  // array
+  constexpr std::array<std::size_t, 6> a = { { 0, 55, 66, 99, 4115, 2 } };
+  constexpr auto v1 = a[1];
+  constexpr auto v2 = a.at(2);
+  constexpr auto v3 = a.front();
+  constexpr auto v4 = a.back();
+  static_assert( (v1 + v2 + v3 + v4) == (55 + 66 + 0 + 2), "" );
+}
diff --git a/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_element_access.cc b/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_element_access.cc
index c1dd9054606..037f6ea4223 100644
--- a/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_element_access.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_element_access.cc
@@ -19,14 +19,13 @@
 
 #include <array>
 
-int main()
+void test01()
 {
   // array
-  typedef std::array<std::size_t, 6> array_type;
-  constexpr array_type a = { { 0, 55, 66, 99, 4115, 2 } };
-  constexpr auto v1 __attribute__((unused)) = a[1];
-  constexpr auto v2 __attribute__((unused)) = a.at(2);
-  constexpr auto v3 __attribute__((unused)) = a.front();
-  constexpr auto v4 __attribute__((unused)) = a.back();
-  return 0;
+  constexpr std::array<std::size_t, 6> a = { { 0, 55, 66, 99, 4115, 2 } };
+  constexpr auto v1 = a[1];
+  constexpr auto v2 = a.at(2);
+  constexpr auto v3 = a.front();
+  constexpr auto v4 = a.back();
+  static_assert( (v1 + v2 + v3 + v4) == (55 + 66 + 0 + 2), "" );
 }
diff --git a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc
index 88416cc661c..e287eef2f61 100644
--- a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/get_neg.cc
@@ -26,6 +26,6 @@ int n1 = std::get<1>(a);
 int n2 = std::get<1>(std::move(a));
 int n3 = std::get<1>(ca);
 
-// { dg-error "static assertion failed" "" { target *-*-* } 357 }
-// { dg-error "static assertion failed" "" { target *-*-* } 365 }
-// { dg-error "static assertion failed" "" { target *-*-* } 373 }
+// { dg-error "static assertion failed" "" { target *-*-* } 363 }
+// { dg-error "static assertion failed" "" { target *-*-* } 371 }
+// { dg-error "static assertion failed" "" { target *-*-* } 379 }

Re: [PATCH] 2/2 Remove debug/array

[Daniel Krügler]

Am Do., 3. Dez. 2020 um 18:10 Uhr schrieb Jonathan Wakely via
Libstdc++ <libstdc++@gcc.gnu.org>:
>
[..]
> >>Ok to commit ?
> >
> >Yes, this is a nice simplification, thanks.
>
> This broke the C++11 constexpr support in std::array. Fixed with this
> patch. Tested x86_64-linux, committed to trunk.

Wouldn't a transformation into a comma expression, such as

return __glibcxx_requires_subscript(__n), _AT_Type::_S_ref(_M_elems, __n);

realize the same thing but would still keep the assertion-like thing?
(Untested, just out of my head)

- Daniel

Re: [PATCH] 2/2 Remove debug/array

[Jonathan Wakely]

On 03/12/20 18:14 +0100, Daniel Krügler via Libstdc++ wrote:
>Am Do., 3. Dez. 2020 um 18:10 Uhr schrieb Jonathan Wakely via
>Libstdc++ <libstdc++@gcc.gnu.org>:
>>
>[..]
>> >>Ok to commit ?
>> >
>> >Yes, this is a nice simplification, thanks.
>>
>> This broke the C++11 constexpr support in std::array. Fixed with this
>> patch. Tested x86_64-linux, committed to trunk.
>
>Wouldn't a transformation into a comma expression, such as
>
>return __glibcxx_requires_subscript(__n), _AT_Type::_S_ref(_M_elems, __n);
>
>realize the same thing but would still keep the assertion-like thing?

No, because the assertion is defined as  do { ... } while(false) so
can't be used in C++11 constexpr functions.

We could change that, or introduce new assertion macros just for this
case, but I don't care about C++11 enough to do it.