diff options
author | Derek Mauro <dmauro@google.com> | 2023-08-16 11:59:48 -0700 |
---|---|---|
committer | Copybara-Service <copybara-worker@google.com> | 2023-08-16 12:01:08 -0700 |
commit | 9a6d9c6eae90f4a5ddb162b8ef49af1e321c9769 (patch) | |
tree | 8cceabaee3b9fb3245d3574ce8f4c3bfbbd6dd12 /absl/numeric/bits.h | |
parent | 17a3ac4bcc9b16aa1ae020a2f7067008d627ad88 (diff) |
Use Abseil's implementation of absl::rotl and absl::rotr for libc++
prior to 18.0 to workaround libc++ having the wrong signature for
these functions.
Upstream issue: https://github.com/llvm/llvm-project/issues/64544
The preprocessor conditions were inverted for readability as the
conditions became more complex.
PiperOrigin-RevId: 557559472
Change-Id: Ibf7a2651e13a0d2a91846bc0d72ba3a44f56747b
Diffstat (limited to 'absl/numeric/bits.h')
-rw-r--r-- | absl/numeric/bits.h | 58 |
1 files changed, 40 insertions, 18 deletions
diff --git a/absl/numeric/bits.h b/absl/numeric/bits.h index 5ed36f52..4b90d3fa 100644 --- a/absl/numeric/bits.h +++ b/absl/numeric/bits.h @@ -49,9 +49,22 @@ namespace absl { ABSL_NAMESPACE_BEGIN -#if !(defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L) -// rotating +// https://github.com/llvm/llvm-project/issues/64544 +// libc++ had the wrong signature for std::rotl and std::rotr +// prior to libc++ 18.0. +// +// b/289016048 requires a workaround for _LIBCPP_GOOGLE3. +#if (defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L) && \ + (!defined(_LIBCPP_VERSION) || _LIBCPP_VERSION >= 180000) && \ + !defined(_LIBCPP_GOOGLE3) + +using std::rotl; +using std::rotr; + +#else + +// Rotating functions template <class T> ABSL_MUST_USE_RESULT constexpr typename std::enable_if<std::is_unsigned<T>::value, T>::type @@ -66,6 +79,20 @@ ABSL_MUST_USE_RESULT constexpr return numeric_internal::RotateRight(x, s); } +#endif + +// b/289016048 requires a workaround for _LIBCPP_GOOGLE3. +#if (defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L) && \ + !defined(_LIBCPP_GOOGLE3) + +using std::countl_one; +using std::countl_zero; +using std::countr_one; +using std::countr_zero; +using std::popcount; + +#else + // Counting functions // // While these functions are typically constexpr, on some platforms, they may @@ -107,19 +134,20 @@ ABSL_INTERNAL_CONSTEXPR_POPCOUNT inline popcount(T x) noexcept { return numeric_internal::Popcount(x); } -#else // defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L - -using std::countl_one; -using std::countl_zero; -using std::countr_one; -using std::countr_zero; -using std::popcount; -using std::rotl; -using std::rotr; #endif -#if !(defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L) +// b/289016048 requires a workaround for _LIBCPP_GOOGLE3. +#if (defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L) && \ + !defined(_LIBCPP_GOOGLE3) + +using std::bit_ceil; +using std::bit_floor; +using std::bit_width; +using std::has_single_bit; + +#else + // Returns: true if x is an integral power of two; false otherwise. template <class T> constexpr inline typename std::enable_if<std::is_unsigned<T>::value, bool>::type @@ -162,12 +190,6 @@ ABSL_INTERNAL_CONSTEXPR_CLZ inline return has_single_bit(x) ? T{1} << (bit_width(x) - 1) : numeric_internal::BitCeilNonPowerOf2(x); } -#else // defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L - -using std::bit_ceil; -using std::bit_floor; -using std::bit_width; -using std::has_single_bit; #endif |