| // -*- 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___BITS |
| #define _LIBCPP___BITS |
| |
| #include <__config> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_ctz(unsigned __x) _NOEXCEPT { return __builtin_ctz(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_ctz(unsigned long __x) _NOEXCEPT { return __builtin_ctzl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); } |
| |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(unsigned __x) _NOEXCEPT { return __builtin_clz(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(unsigned long __x) _NOEXCEPT { return __builtin_clzl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(unsigned long long __x) _NOEXCEPT { return __builtin_clzll(__x); } |
| |
| # ifndef _LIBCPP_HAS_NO_INT128 |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(__uint128_t __x) _NOEXCEPT { |
| // The function is written in this form due to C++ constexpr limitations. |
| // The algorithm: |
| // - Test whether any bit in the high 64-bits is set |
| // - No bits set: |
| // - The high 64-bits contain 64 leading zeros, |
| // - Add the result of the low 64-bits. |
| // - Any bits set: |
| // - The number of leading zeros of the input is the number of leading |
| // zeros in the high 64-bits. |
| return ((__x >> 64) == 0) |
| ? (64 + __builtin_clzll(static_cast<unsigned long long>(__x))) |
| : __builtin_clzll(static_cast<unsigned long long>(__x >> 64)); |
| } |
| # endif |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_popcount(unsigned __x) _NOEXCEPT { return __builtin_popcount(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_popcount(unsigned long __x) _NOEXCEPT { return __builtin_popcountl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { return __builtin_popcountll(__x); } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___BITS |
