[libcxx-commits] [libcxx] [libc++] Fix UB in bitwise logic of {std, ranges}::{fill, fill_n} algorithms (PR #122410)

[Louis Dionne via libcxx-commits]

================
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TEST_SUPPORT_SIZED_ALLOCATOR_H
+#define TEST_SUPPORT_SIZED_ALLOCATOR_H
+
+#include <cstddef>
+#include <limits>
+#include <memory>
+#include <new>
+
+#include "test_macros.h"
+
+template <typename T, typename Size = std::size_t, typename Difference = std::ptrdiff_t>
+class sized_allocator {
----------------
ldionne wrote:

```suggestion
// Allocator with a provided size_type and difference_type, used to test corner
// cases like arithmetic on Allocator::size_type in generic code.
template <typename T, typename Size = std::size_t, typename Difference = std::ptrdiff_t>
class sized_allocator {
```

https://github.com/llvm/llvm-project/pull/122410