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* [gcc r12-4824] libstdc++: Fix range access for empty std::valarray [PR103022]
@ 2021-11-01 13:26 Jonathan Wakely
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From: Jonathan Wakely @ 2021-11-01 13:26 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:91bac9fed5d082f0b180834110ebc0f46f97599a
commit r12-4824-g91bac9fed5d082f0b180834110ebc0f46f97599a
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Mon Nov 1 11:06:51 2021 +0000
libstdc++: Fix range access for empty std::valarray [PR103022]
The std::begin and std::end overloads for std::valarray are defined in
terms of std::addressof(v[0]) which is undefined for an empty valarray.
libstdc++-v3/ChangeLog:
PR libstdc++/103022
* include/std/valarray (begin, end): Do not dereference an empty
valarray. Add noexcept and [[nodiscard]].
* testsuite/26_numerics/valarray/range_access.cc: Check empty
valarray. Check iterator properties. Run as well as compiling.
* testsuite/26_numerics/valarray/range_access2.cc: Likewise.
* testsuite/26_numerics/valarray/103022.cc: New test.
Diff:
---
libstdc++-v3/include/std/valarray | 30 +++++++++----
.../testsuite/26_numerics/valarray/103022.cc | 15 +++++++
.../testsuite/26_numerics/valarray/range_access.cc | 49 +++++++++++++++++++---
.../26_numerics/valarray/range_access2.cc | 22 +++++++++-
4 files changed, 100 insertions(+), 16 deletions(-)
diff --git a/libstdc++-v3/include/std/valarray b/libstdc++-v3/include/std/valarray
index 5adc94282ee..c6242eb4db9 100644
--- a/libstdc++-v3/include/std/valarray
+++ b/libstdc++-v3/include/std/valarray
@@ -1210,9 +1210,10 @@ _DEFINE_BINARY_OPERATOR(>=, __greater_equal)
* @param __va valarray.
*/
template<class _Tp>
+ [[__nodiscard__]]
inline _Tp*
- begin(valarray<_Tp>& __va)
- { return std::__addressof(__va[0]); }
+ begin(valarray<_Tp>& __va) noexcept
+ { return __va.size() ? std::__addressof(__va[0]) : nullptr; }
/**
* @brief Return an iterator pointing to the first element of
@@ -1220,9 +1221,10 @@ _DEFINE_BINARY_OPERATOR(>=, __greater_equal)
* @param __va valarray.
*/
template<class _Tp>
+ [[__nodiscard__]]
inline const _Tp*
- begin(const valarray<_Tp>& __va)
- { return std::__addressof(__va[0]); }
+ begin(const valarray<_Tp>& __va) noexcept
+ { return __va.size() ? std::__addressof(__va[0]) : nullptr; }
/**
* @brief Return an iterator pointing to one past the last element of
@@ -1230,9 +1232,15 @@ _DEFINE_BINARY_OPERATOR(>=, __greater_equal)
* @param __va valarray.
*/
template<class _Tp>
+ [[__nodiscard__]]
inline _Tp*
- end(valarray<_Tp>& __va)
- { return std::__addressof(__va[0]) + __va.size(); }
+ end(valarray<_Tp>& __va) noexcept
+ {
+ if (auto __n = __va.size())
+ return std::__addressof(__va[0]) + __n;
+ else
+ return nullptr;
+ }
/**
* @brief Return an iterator pointing to one past the last element of
@@ -1240,9 +1248,15 @@ _DEFINE_BINARY_OPERATOR(>=, __greater_equal)
* @param __va valarray.
*/
template<class _Tp>
+ [[__nodiscard__]]
inline const _Tp*
- end(const valarray<_Tp>& __va)
- { return std::__addressof(__va[0]) + __va.size(); }
+ end(const valarray<_Tp>& __va) noexcept
+ {
+ if (auto __n = __va.size())
+ return std::__addressof(__va[0]) + __n;
+ else
+ return nullptr;
+ }
#endif // C++11
/// @} group numeric_arrays
diff --git a/libstdc++-v3/testsuite/26_numerics/valarray/103022.cc b/libstdc++-v3/testsuite/26_numerics/valarray/103022.cc
new file mode 100644
index 00000000000..d2e346760dd
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/valarray/103022.cc
@@ -0,0 +1,15 @@
+// { dg-options "-D_GLIBCXX_DEBUG" }
+// { dg-do compile { target c++11 } }
+
+#include <valarray>
+
+int main()
+{
+ // PR libstdc++/103022
+ std::valarray<double> va;
+ (void) std::begin(va);
+ (void) std::end(va);
+ const auto& cva = va;
+ (void) std::begin(cva);
+ (void) std::end(cva);
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/valarray/range_access.cc b/libstdc++-v3/testsuite/26_numerics/valarray/range_access.cc
index c015d1890b6..c49c2c52f47 100644
--- a/libstdc++-v3/testsuite/26_numerics/valarray/range_access.cc
+++ b/libstdc++-v3/testsuite/26_numerics/valarray/range_access.cc
@@ -1,4 +1,4 @@
-// { dg-do compile { target c++11 } }
+// { dg-do run { target c++11 } }
// Copyright (C) 2010-2021 Free Software Foundation, Inc.
//
@@ -17,7 +17,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
-// 26.6.10 valarray range access: [valarray.range]
+// C++11 26.6.10 valarray range access: [valarray.range]
#include <valarray>
@@ -25,9 +25,46 @@ void
test01()
{
std::valarray<double> va{1.0, 2.0, 3.0};
- std::begin(va);
- std::end(va);
+ (void) std::begin(va);
+ (void) std::end(va);
const auto& cva = va;
- std::begin(cva);
- std::end(cva);
+ (void) std::begin(cva);
+ (void) std::end(cva);
+
+ using Iter = decltype(std::begin(va));
+ using IterTraits = std::iterator_traits<Iter>;
+ static_assert( std::is_same<Iter, decltype(std::end(va))>::value, "" );
+ static_assert( std::is_same<IterTraits::iterator_category,
+ std::random_access_iterator_tag>::value, "" );
+ static_assert( std::is_same<IterTraits::value_type, double>::value, "" );
+ static_assert( std::is_same<IterTraits::reference, double&>::value, "" );
+ using CIter = decltype(std::begin(cva));
+ using CIterTraits = std::iterator_traits<CIter>;
+ static_assert( std::is_same<CIter, decltype(std::end(cva))>::value, "" );
+ static_assert( std::is_same<CIterTraits::iterator_category,
+ std::random_access_iterator_tag>::value, "" );
+ static_assert( std::is_same<CIterTraits::value_type, double>::value, "" );
+ static_assert( std::is_same<CIterTraits::reference, const double&>::value, "" );
+#if __cplusplus >= 202002L
+ static_assert( std::contiguous_iterator<Iter> );
+ static_assert( std::contiguous_iterator<CIter> );
+#endif
+}
+
+// PR libstdc++/103022
+void
+test02()
+{
+ std::valarray<double> va;
+ (void) std::begin(va);
+ (void) std::end(va);
+ const auto& cva = va;
+ (void) std::begin(cva);
+ (void) std::end(cva);
+}
+
+int main()
+{
+ test01();
+ test02();
}
diff --git a/libstdc++-v3/testsuite/26_numerics/valarray/range_access2.cc b/libstdc++-v3/testsuite/26_numerics/valarray/range_access2.cc
index cf5418a61d1..4217367cf22 100644
--- a/libstdc++-v3/testsuite/26_numerics/valarray/range_access2.cc
+++ b/libstdc++-v3/testsuite/26_numerics/valarray/range_access2.cc
@@ -1,4 +1,4 @@
-// { dg-do compile { target c++14 } }
+// { dg-do run { target c++14 } }
// Copyright (C) 2015-2021 Free Software Foundation, Inc.
//
@@ -17,7 +17,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
-// 26.6.10 valarray range access: [valarray.range]
+// C++11 26.6.10 valarray range access: [valarray.range]
#include <iterator>
#include <valarray>
@@ -33,3 +33,21 @@ test01()
(void) std::cbegin(cva);
(void) std::cend(cva);
}
+
+// PR libstdc++/103022
+void
+test02()
+{
+ std::valarray<double> va;
+ (void) std::cbegin(va);
+ (void) std::cend(va);
+ const auto& cva = va;
+ (void) std::cbegin(cva);
+ (void) std::cend(cva);
+}
+
+int main()
+{
+ test01();
+ test02();
+}
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