[libcxx-commits] [libcxx] [libc++] Slightly simplify max_size and add new tests for vector (PR #119990)

[Peng Liu via libcxx-commits]

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@@ -0,0 +1,106 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <vector>
+
+// size_type max_size() const;
+
+#include <algorithm>
+#include <cassert>
+#include <climits>
+#include <cstdint>
+#include <limits>
+#include <memory>
+#include <type_traits>
+#include <vector>
+
+#include "min_allocator.h"
+#include "sized_allocator.h"
+#include "test_allocator.h"
+#include "test_macros.h"
+
+#if TEST_STD_VER >= 11
+
+template <typename Alloc>
+TEST_CONSTEXPR_CXX20 void test(const std::vector<bool, Alloc>& v) {
+  using Vector              = std::vector<bool, Alloc>;
+  using size_type           = typename Vector::size_type;
+  using difference_type     = typename Vector::difference_type;
+  using storage_type        = typename Vector::__storage_type;
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winner245 wrote:

Another reason why this test is not fully portable to other standard implementations is that libc++, libstdc++, and MSVC-STL all use different word types for vector<bool> underlying storage:

| Compiler   | Size Type                      |
|------------|--------------------------------|
| MSVC       | `unsigned int` (fixed)           |
| libstdc++  | `unsigned long` (fixed)          |
| libc++     | `alloc_traits::size_type` (configurable through custom allocator) |


https://github.com/llvm/llvm-project/pull/119990