[libcxx-commits] [libcxx] [libc++] Use __integer_pack to implement integer_sequence on GCC (PR #82983)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Feb 26 03:03:49 PST 2024
https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/82983
None
>From 12125f7c846ba85ef0081bdc5782ba387069aa26 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Mon, 26 Feb 2024 12:01:35 +0100
Subject: [PATCH] [libc++] Use __integer_pack to implement integer_sequence on
GCC
---
libcxx/include/__utility/integer_sequence.h | 87 +++----------------
.../make_integer_seq_fallback.pass.cpp | 19 ----
2 files changed, 12 insertions(+), 94 deletions(-)
delete mode 100644 libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq_fallback.pass.cpp
diff --git a/libcxx/include/__utility/integer_sequence.h b/libcxx/include/__utility/integer_sequence.h
index e63f3f265b7d5e..ccce9433e7a801 100644
--- a/libcxx/include/__utility/integer_sequence.h
+++ b/libcxx/include/__utility/integer_sequence.h
@@ -31,65 +31,16 @@ struct __integer_sequence {
using __to_tuple_indices = __tuple_indices<(_Values + _Sp)...>;
};
-#if !__has_builtin(__make_integer_seq) || defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
-
-namespace __detail {
-
-template <typename _Tp, size_t... _Extra>
-struct __repeat;
-template <typename _Tp, _Tp... _Np, size_t... _Extra>
-struct __repeat<__integer_sequence<_Tp, _Np...>, _Extra...> {
- typedef _LIBCPP_NODEBUG __integer_sequence<
- _Tp,
- _Np...,
- sizeof...(_Np) + _Np...,
- 2 * sizeof...(_Np) + _Np...,
- 3 * sizeof...(_Np) + _Np...,
- 4 * sizeof...(_Np) + _Np...,
- 5 * sizeof...(_Np) + _Np...,
- 6 * sizeof...(_Np) + _Np...,
- 7 * sizeof...(_Np) + _Np...,
- _Extra...>
- type;
-};
-
-template <size_t _Np>
-struct __parity;
-template <size_t _Np>
-struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
-
-// clang-format off
-template<> struct __make<0> { typedef __integer_sequence<size_t> type; };
-template<> struct __make<1> { typedef __integer_sequence<size_t, 0> type; };
-template<> struct __make<2> { typedef __integer_sequence<size_t, 0, 1> type; };
-template<> struct __make<3> { typedef __integer_sequence<size_t, 0, 1, 2> type; };
-template<> struct __make<4> { typedef __integer_sequence<size_t, 0, 1, 2, 3> type; };
-template<> struct __make<5> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
-template<> struct __make<6> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
-template<> struct __make<7> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
-
-template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
-template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
-template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
-template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
-template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
-template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
-template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
-template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
-// clang-format on
-
-} // namespace __detail
-
-#endif
-
#if __has_builtin(__make_integer_seq)
template <size_t _Ep, size_t _Sp>
using __make_indices_imp =
typename __make_integer_seq<__integer_sequence, size_t, _Ep - _Sp>::template __to_tuple_indices<_Sp>;
-#else
+#elif __has_builtin(__integer_pack)
template <size_t _Ep, size_t _Sp>
-using __make_indices_imp = typename __detail::__make<_Ep - _Sp>::type::template __to_tuple_indices<_Sp>;
-
+using __make_indices_imp =
+ typename __integer_sequence<size_t, __integer_pack(_Ep - _Sp)...>::template __to_tuple_indices<_Sp>;
+#else
+# error "No known way to get an integer pack from the compiler"
#endif
#if _LIBCPP_STD_VER >= 14
@@ -104,34 +55,20 @@ struct _LIBCPP_TEMPLATE_VIS integer_sequence {
template <size_t... _Ip>
using index_sequence = integer_sequence<size_t, _Ip...>;
-# if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
+# if __has_builtin(__make_integer_seq)
template <class _Tp, _Tp _Ep>
-using __make_integer_sequence _LIBCPP_NODEBUG = __make_integer_seq<integer_sequence, _Tp, _Ep>;
-
-# else
+using make_integer_sequence _LIBCPP_NODEBUG = __make_integer_seq<integer_sequence, _Tp, _Ep>;
-template <typename _Tp, _Tp _Np>
-using __make_integer_sequence_unchecked _LIBCPP_NODEBUG =
- typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
+# elif __has_builtin(__integer_pack)
-template <class _Tp, _Tp _Ep>
-struct __make_integer_sequence_checked {
- static_assert(is_integral<_Tp>::value, "std::make_integer_sequence can only be instantiated with an integral type");
- static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
- // Workaround GCC bug by preventing bad installations when 0 <= _Ep
- // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
- typedef _LIBCPP_NODEBUG __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
-};
-
-template <class _Tp, _Tp _Ep>
-using __make_integer_sequence _LIBCPP_NODEBUG = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
+template <class _Tp, _Tp _SequenceSize>
+using make_integer_sequence _LIBCPP_NODEBUG = integer_sequence<_Tp, __integer_pack(_SequenceSize)...>;
+# else
+# error "No known way to get an integer pack from the compiler"
# endif
-template <class _Tp, _Tp _Np>
-using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
-
template <size_t _Np>
using make_index_sequence = make_integer_sequence<size_t, _Np>;
diff --git a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq_fallback.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq_fallback.pass.cpp
deleted file mode 100644
index ceeb4dd3eeec41..00000000000000
--- a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq_fallback.pass.cpp
+++ /dev/null
@@ -1,19 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// <utility>
-
-// template<class T, T N>
-// using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
-
-// UNSUPPORTED: c++03, c++11
-
-#define _LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE
-#include "make_integer_seq.pass.cpp"
-
-#include "test_macros.h"
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