[libc++] Tidy-up instances of __STDCPP_DEFAULT_NEW_ALIGNMENT__ in the tests

[ldionne]

Summary

See https://reviews.llvm.org/D105905 for context.

[• Quuxplusone]

LGTM % comments. Requesting changes, but I don't really need to see it again.

libcxx/test/std/containers/sequences/array/size_and_alignment.pass.cpp

47

Since this is >= 11, do we even need TEST_ALIGNXX, or could this be straightforwardly alignas(2 * alignof(std::max_align_t))?

libcxx/test/std/language.support/support.types/max_align_t.compile.pass.cpp

22–23

I believe it's safe to test these two traits in all modes. Just don't test is_pod unless TEST_STD_VER <= 17.

30

Since this is UNSUPPORTED: c++03, I think it's safe to use alignof(std::max_align_t) throughout instead of std::alignment_of<std::max_align_t>::value. std::alignment_of is at least en route to deprecation, if not there yet, and it'll be one less thing to worry about in the future.

[ldionne]

Address review feedback.

libcxx/test/std/containers/sequences/array/size_and_alignment.pass.cpp

 
 template <class T>
 void test_type() {
   test<T, 1>();
   test<T, 42>();
   test<T, 0>();
 }
 
-#ifdef __STDCPP_DEFAULT_NEW_ALIGNMENT__
-struct TEST_ALIGNAS(__STDCPP_DEFAULT_NEW_ALIGNMENT__ * 2) TestType1 {
+#if TEST_STD_VER >= 11
+struct TEST_ALIGNAS(TEST_ALIGNOF(std::max_align_t) * 2) TestType1 {
 
 };
 
-struct TEST_ALIGNAS(__STDCPP_DEFAULT_NEW_ALIGNMENT__ * 2) TestType2 {
+struct TEST_ALIGNAS(TEST_ALIGNOF(std::max_align_t) * 2) TestType2 {
   char data[1000];
 };
-#else
-struct TEST_ALIGNAS(TEST_ALIGNOF(std::max_align_t) * 2) TestType1 {
 
-};
-
-struct TEST_ALIGNAS(TEST_ALIGNOF(std::max_align_t) * 2) TestType2 {
+struct TEST_ALIGNAS(TEST_ALIGNOF(std::max_align_t)) TestType3 {
   char data[1000];
 };
 #endif
 
 int main(int, char**) {
   test_type<char>();
   test_type<int>();
   test_type<double>();
   test_type<long double>();
 
 #if TEST_STD_VER >= 11
   test_type<std::max_align_t>();
-#endif
   test_type<TestType1>();
   test_type<TestType2>();
+  test_type<TestType3>();
+#endif
 
   return 0;
 }

libcxx/test/std/language.support/support.types/max_align_t.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+#include <cstddef>
+#include <type_traits>
+
+// max_align_t is a trivial standard-layout type whose alignment requirement
+//   is at least as great as that of every scalar type
+
+#include <stdio.h>
+#include "test_macros.h"
+
+#if TEST_STD_VER > 17
+  // P0767
+  static_assert(std::is_trivial<std::max_align_t>::value, "");
+  static_assert(std::is_standard_layout<std::max_align_t>::value, "");
+#else
+  static_assert(std::is_pod<std::max_align_t>::value, "");
+#endif
+static_assert(std::alignment_of<std::max_align_t>::value >= std::alignment_of<long long>::value, "");
+static_assert(std::alignment_of<std::max_align_t>::value >= std::alignment_of<long double>::value, "");
+static_assert(std::alignment_of<std::max_align_t>::value >= std::alignment_of<void*>::value,"");
+static_assert(std::alignment_of<std::max_align_t>::value <= __STDCPP_DEFAULT_NEW_ALIGNMENT__,
+              "max_align_t alignment should be no larger than operator new's alignment");

libcxx/test/std/language.support/support.types/max_align_t.pass.cpp

-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03
-
-#include <cstddef>
-#include <type_traits>
-
-// max_align_t is a trivial standard-layout type whose alignment requirement
-//   is at least as great as that of every scalar type
-
-#include <stdio.h>
-#include "test_macros.h"
-
-int main(int, char**)
-{
-
-#if TEST_STD_VER > 17
-//  P0767
-    static_assert(std::is_trivial<std::max_align_t>::value,
-                  "std::is_trivial<std::max_align_t>::value");
-    static_assert(std::is_standard_layout<std::max_align_t>::value,
-                  "std::is_standard_layout<std::max_align_t>::value");
-#else
-    static_assert(std::is_pod<std::max_align_t>::value,
-                  "std::is_pod<std::max_align_t>::value");
-#endif
-    static_assert((std::alignment_of<std::max_align_t>::value >=
-                  std::alignment_of<long long>::value),
-                  "std::alignment_of<std::max_align_t>::value >= "
-                  "std::alignment_of<long long>::value");
-    static_assert(std::alignment_of<std::max_align_t>::value >=
-                  std::alignment_of<long double>::value,
-                  "std::alignment_of<std::max_align_t>::value >= "
-                  "std::alignment_of<long double>::value");
-    static_assert(std::alignment_of<std::max_align_t>::value >=
-                  std::alignment_of<void*>::value,
-                  "std::alignment_of<std::max_align_t>::value >= "
-                  "std::alignment_of<void*>::value");
-
-#ifdef __STDCPP_DEFAULT_NEW_ALIGNMENT__
-    static_assert(std::alignment_of<std::max_align_t>::value <=
-                  __STDCPP_DEFAULT_NEW_ALIGNMENT__,
-                  "max_align_t alignment is no larger than new alignment");
-#endif
-
-  return 0;
-}