mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-28 08:16:05 +00:00
e78f53d1e8
This reverts commit 68c04b0ae62d8431d72d8b47fc13008002ee4387. This disables the IWYU mapping that caused the failure, since the headers aren't reachable for now. This is the first part of the "Freezing C++03 headers" proposal explained in https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc/77319/58. This patch mechanically copies the headers as of the LLVM 19.1 release into a subdirectory of libc++ so that we can start using these headers when building in C++03 mode. We are going to be backporting important changes to that copy of the headers until the LLVM 21 release. After the LLVM 21 release, only critical bugfixes will be fixed in the C++03 copy of the headers. This patch only performs a copy of the headers -- these headers are still unused by the rest of the codebase.
73 lines
2.2 KiB
C++
73 lines
2.2 KiB
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___BIT_ROTATE_H
|
|
#define _LIBCPP___BIT_ROTATE_H
|
|
|
|
#include <__concepts/arithmetic.h>
|
|
#include <__config>
|
|
#include <__type_traits/is_unsigned_integer.h>
|
|
#include <limits>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
// Writing two full functions for rotl and rotr makes it easier for the compiler
|
|
// to optimize the code. On x86 this function becomes the ROL instruction and
|
|
// the rotr function becomes the ROR instruction.
|
|
template <class _Tp>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotl(_Tp __x, int __s) _NOEXCEPT {
|
|
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotl requires an unsigned integer type");
|
|
const int __N = numeric_limits<_Tp>::digits;
|
|
int __r = __s % __N;
|
|
|
|
if (__r == 0)
|
|
return __x;
|
|
|
|
if (__r > 0)
|
|
return (__x << __r) | (__x >> (__N - __r));
|
|
|
|
return (__x >> -__r) | (__x << (__N + __r));
|
|
}
|
|
|
|
template <class _Tp>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotr(_Tp __x, int __s) _NOEXCEPT {
|
|
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type");
|
|
const int __N = numeric_limits<_Tp>::digits;
|
|
int __r = __s % __N;
|
|
|
|
if (__r == 0)
|
|
return __x;
|
|
|
|
if (__r > 0)
|
|
return (__x >> __r) | (__x << (__N - __r));
|
|
|
|
return (__x << -__r) | (__x >> (__N + __r));
|
|
}
|
|
|
|
#if _LIBCPP_STD_VER >= 20
|
|
|
|
template <__libcpp_unsigned_integer _Tp>
|
|
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotl(_Tp __t, int __cnt) noexcept {
|
|
return std::__rotl(__t, __cnt);
|
|
}
|
|
|
|
template <__libcpp_unsigned_integer _Tp>
|
|
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotr(_Tp __t, int __cnt) noexcept {
|
|
return std::__rotr(__t, __cnt);
|
|
}
|
|
|
|
#endif // _LIBCPP_STD_VER >= 20
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___BIT_ROTATE_H
|