Implement the missing constexpr stuff in <array>. Fixes PR#31645.

llvm-svn: 292091

3 files changed, 53 insertions, 3 deletions

diff --git a/libcxx/test/std/containers/sequences/array/at.pass.cpp b/libcxx/test/std/containers/sequences/array/at.pass.cpp
index 29483153d4a..8e7ff6dff70 100644
--- a/libcxx/test/std/containers/sequences/array/at.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/at.pass.cpp
@@ -23,6 +23,14 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
+#if TEST_STD_VER > 14
+constexpr bool check_idx( size_t idx, double val )
+{ 
+    std::array<double, 3> arr = {1, 2, 3.5};
+	return arr.at(idx) == val;
+}
+#endif
+
 int main()
 {
     {
@@ -82,4 +90,11 @@ int main()
     }
 #endif
 
+#if TEST_STD_VER > 14
+    {
+        static_assert (check_idx(0, 1), "");
+        static_assert (check_idx(1, 2), "");
+        static_assert (check_idx(2, 3.5), "");
+    }
+#endif
 }
diff --git a/libcxx/test/std/containers/sequences/array/front_back.pass.cpp b/libcxx/test/std/containers/sequences/array/front_back.pass.cpp
index 7d53b8265e9..239fda5c99d 100644
--- a/libcxx/test/std/containers/sequences/array/front_back.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/front_back.pass.cpp
@@ -9,10 +9,10 @@
 
 // <array>
 
-// reference front();
-// reference back();
+// reference front();       // constexpr in C++17
+// reference back();        // constexpr in C++17
 // const_reference front(); // constexpr in C++14
-// const_reference back(); // constexpr in C++14
+// const_reference back();  // constexpr in C++14
 
 #include <array>
 #include <cassert>
@@ -23,6 +23,20 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
+#if TEST_STD_VER > 14
+constexpr bool check_front( double val )
+{ 
+    std::array<double, 3> arr = {1, 2, 3.5};
+	return arr.front() == val;
+}
+
+constexpr bool check_back( double val )
+{ 
+    std::array<double, 3> arr = {1, 2, 3.5};
+	return arr.back() == val;
+}
+#endif
+
 int main()
 {
     {
@@ -65,4 +79,10 @@ int main()
     }
 #endif
 
+#if TEST_STD_VER > 14
+    {
+        static_assert (check_front(1),   "");
+        static_assert (check_back (3.5), "");
+    }
+#endif
 }
diff --git a/libcxx/test/std/containers/sequences/array/indexing.pass.cpp b/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
index 64d2716a759..6cb7941d92c 100644
--- a/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
@@ -23,6 +23,14 @@
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
+#if TEST_STD_VER > 14
+constexpr bool check_idx( size_t idx, double val )
+{ 
+    std::array<double, 3> arr = {1, 2, 3.5};
+	return arr[idx] == val;
+}
+#endif
+
 int main()
 {
     {
@@ -63,4 +71,11 @@ int main()
     }
 #endif
 
+#if TEST_STD_VER > 14
+    {
+        static_assert (check_idx(0, 1), "");
+        static_assert (check_idx(1, 2), "");
+        static_assert (check_idx(2, 3.5), "");
+    }
+#endif
 }