[libc++] Fix PR35491 - std::array of zero-size doesn't work with non-default constructible types.
Summary:
This patch fixes llvm.org/PR35491 and LWG2157 (https://cplusplus.github.io/LWG/issue2157)
The fix attempts to maintain ABI compatibility by replacing the array with a instance of `aligned_storage`.
Reviewers: mclow.lists, EricWF
Reviewed By: EricWF
Subscribers: lichray, cfe-commits
Differential Revision: https://reviews.llvm.org/D41223
llvm-svn: 324526
diff --git a/libcxx/test/std/containers/sequences/array/compare.pass.cpp b/libcxx/test/std/containers/sequences/array/compare.pass.cpp
new file mode 100644
index 0000000..c8bcf75
--- /dev/null
+++ b/libcxx/test/std/containers/sequences/array/compare.pass.cpp
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+
+// bool operator==(array<T, N> const&, array<T, N> const&);
+// bool operator!=(array<T, N> const&, array<T, N> const&);
+// bool operator<(array<T, N> const&, array<T, N> const&);
+// bool operator<=(array<T, N> const&, array<T, N> const&);
+// bool operator>(array<T, N> const&, array<T, N> const&);
+// bool operator>=(array<T, N> const&, array<T, N> const&);
+
+
+#include <array>
+#include <vector>
+#include <cassert>
+
+#include "test_macros.h"
+
+// std::array is explicitly allowed to be initialized with A a = { init-list };.
+// Disable the missing braces warning for this reason.
+#include "disable_missing_braces_warning.h"
+
+template <class Array>
+void test_compare(const Array& LHS, const Array& RHS) {
+ typedef std::vector<typename Array::value_type> Vector;
+ const Vector LHSV(LHS.begin(), LHS.end());
+ const Vector RHSV(RHS.begin(), RHS.end());
+ assert((LHS == RHS) == (LHSV == RHSV));
+ assert((LHS != RHS) == (LHSV != RHSV));
+ assert((LHS < RHS) == (LHSV < RHSV));
+ assert((LHS <= RHS) == (LHSV <= RHSV));
+ assert((LHS > RHS) == (LHSV > RHSV));
+ assert((LHS >= RHS) == (LHSV >= RHSV));
+}
+
+int main()
+{
+ {
+ typedef int T;
+ typedef std::array<T, 3> C;
+ C c1 = {1, 2, 3};
+ C c2 = {1, 2, 3};
+ C c3 = {3, 2, 1};
+ C c4 = {1, 2, 1};
+ test_compare(c1, c2);
+ test_compare(c1, c3);
+ test_compare(c1, c4);
+ }
+ {
+ typedef int T;
+ typedef std::array<T, 0> C;
+ C c1 = {};
+ C c2 = {};
+ test_compare(c1, c2);
+ }
+}