[libc++] Complete overhaul of constexpr support in std::array
This commit adds missing support for constexpr in std::array under all
standard modes up to and including C++20. It also transforms the <array>
tests to check for constexpr-friendliness under the right standard modes.
Fixes https://llvm.org/PR40124
Fixes rdar://57522096
Supersedes https://reviews.llvm.org/D60666
Differential Revision: https://reviews.llvm.org/D80452
diff --git a/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp b/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp
index 41a7153..9589e63 100644
--- a/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/contiguous.pass.cpp
@@ -15,20 +15,33 @@
#include "test_macros.h"
-template <class C>
-void test_contiguous ( const C &c )
+template <class Container>
+TEST_CONSTEXPR_CXX14 void assert_contiguous(Container const& c)
{
- for ( size_t i = 0; i < c.size(); ++i )
- assert ( *(c.begin() + i) == *(std::addressof(*c.begin()) + i));
+ for (size_t i = 0; i < c.size(); ++i)
+ assert(*(c.begin() + i) == *(std::addressof(*c.begin()) + i));
+}
+
+TEST_CONSTEXPR_CXX17 bool tests()
+{
+ assert_contiguous(std::array<double, 0>());
+ assert_contiguous(std::array<double, 1>());
+ assert_contiguous(std::array<double, 2>());
+ assert_contiguous(std::array<double, 3>());
+
+ assert_contiguous(std::array<char, 0>());
+ assert_contiguous(std::array<char, 1>());
+ assert_contiguous(std::array<char, 2>());
+ assert_contiguous(std::array<char, 3>());
+
+ return true;
}
int main(int, char**)
{
- {
- typedef double T;
- typedef std::array<T, 3> C;
- test_contiguous (C());
- }
-
- return 0;
+ tests();
+#if TEST_STD_VER >= 17 // begin() & friends are constexpr in >= C++17 only
+ static_assert(tests(), "");
+#endif
+ return 0;
}