[libcxx-commits] [libcxx] [libc++] Implement hardware_interference_size even on Clang (PR #83603)

[Mark de Wever via libcxx-commits]

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@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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 _LIBCPP___NEW_HARDWARE_INTERFERENCE_SIZE_H
+#define _LIBCPP___NEW_HARDWARE_INTERFERENCE_SIZE_H
+
+#include <__config>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+
+#  if defined(__GCC_DESTRUCTIVE_SIZE) && defined(__GCC_CONSTRUCTIVE_SIZE)
+
+inline constexpr size_t hardware_destructive_interference_size  = __GCC_DESTRUCTIVE_SIZE;
+inline constexpr size_t hardware_constructive_interference_size = __GCC_CONSTRUCTIVE_SIZE;
+
+#  elif defined(__APPLE__) && defined(__arm64__)
+
+inline constexpr size_t hardware_destructive_interference_size  = 128;
+inline constexpr size_t hardware_constructive_interference_size = 128;
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mordante wrote:

Is this only true for Apple 64-bit ARM platforms of for all 64-bit ARM platforms?

https://github.com/llvm/llvm-project/pull/83603