From 1bae23e32ba1f1af7c7d1488a69a351ec96dc98d Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 16 Dec 2020 11:07:40 -0800 Subject: Export of internal Abseil changes -- dab5caab05d89d03066ef92584660688595a3aaf by Mark Barolak : Add absl::Status and absl::StatusOr to absl/README.md Import of https://github.com/abseil/abseil-cpp/pull/863 PiperOrigin-RevId: 347857368 -- 1ca3c7a96417cd6e6d62f4dc36fd5ddaa61cfa20 by Chris Kennelly : Leverage integer power-of-2 functions and bit counting library in Abseil. PiperOrigin-RevId: 347816486 -- e5cbe05879fd65dce7875e2e0105331a1615d89b by Chris Kennelly : Mitigate narrowing warning on MSVC. If sizeof(x) <= sizeof(uint32_t), no truncation occurs when casting to uint32_t, but the compiler cannot always determine this. PiperOrigin-RevId: 347696526 -- 079dff64cb175d282d9e22dfb4a522199ffdae2e by Benjamin Barenblat : Avoid libgcc -NaN narrowing bug When testing -NaN parsing, avoid narrowing -NaN from double to float. This avoids a bug in libgcc (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98251). PiperOrigin-RevId: 347654751 -- 2e78a7634865aeef6765e1f447e96cf8d9985059 by Chris Kennelly : Mark popcount helpers as inline. These are conditionally constexpr, so we need to add inline to cover the non-constexpr builds to avoid ODR violations. PiperOrigin-RevId: 347620138 -- 437fbb363aea1654179f102dcdd607ec33c1af1e by Chris Kennelly : Use explicit narrowing cast. This is never invoked in practice, but compilers with -Wimplicit-int-conversion may trigger when sizeof(T) > sizeof(uint16_t) prior to determining this never runs. PiperOrigin-RevId: 347609857 GitOrigin-RevId: dab5caab05d89d03066ef92584660688595a3aaf Change-Id: I6296ddffe7ec646f8ce121138f21e1e85a2cff4b --- absl/container/internal/raw_hash_set.h | 29 ++++++++--------------------- 1 file changed, 8 insertions(+), 21 deletions(-) (limited to 'absl/container/internal') diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h index a958daaf..4477f7dc 100644 --- a/absl/container/internal/raw_hash_set.h +++ b/absl/container/internal/raw_hash_set.h @@ -102,7 +102,6 @@ #include #include -#include "absl/base/internal/bits.h" #include "absl/base/internal/endian.h" #include "absl/base/optimization.h" #include "absl/base/port.h" @@ -116,6 +115,7 @@ #include "absl/container/internal/layout.h" #include "absl/memory/memory.h" #include "absl/meta/type_traits.h" +#include "absl/numeric/bits.h" #include "absl/utility/utility.h" namespace absl { @@ -190,17 +190,8 @@ constexpr bool IsNoThrowSwappable(std::false_type /* is_swappable */) { template int TrailingZeros(T x) { - return sizeof(T) == 8 ? base_internal::CountTrailingZerosNonZero64( - static_cast(x)) - : base_internal::CountTrailingZerosNonZero32( - static_cast(x)); -} - -template -int LeadingZeros(T x) { - return sizeof(T) == 8 - ? base_internal::CountLeadingZeros64(static_cast(x)) - : base_internal::CountLeadingZeros32(static_cast(x)); + ABSL_INTERNAL_ASSUME(x != 0); + return countr_zero(x); } // An abstraction over a bitmask. It provides an easy way to iterate through the @@ -233,11 +224,7 @@ class BitMask { int LowestBitSet() const { return container_internal::TrailingZeros(mask_) >> Shift; } - int HighestBitSet() const { - return (sizeof(T) * CHAR_BIT - container_internal::LeadingZeros(mask_) - - 1) >> - Shift; - } + int HighestBitSet() const { return (bit_width(mask_) - 1) >> Shift; } BitMask begin() const { return *this; } BitMask end() const { return BitMask(0); } @@ -249,7 +236,7 @@ class BitMask { int LeadingZeros() const { constexpr int total_significant_bits = SignificantBits << Shift; constexpr int extra_bits = sizeof(T) * 8 - total_significant_bits; - return container_internal::LeadingZeros(mask_ << extra_bits) >> Shift; + return countl_zero(mask_ << extra_bits) >> Shift; } private: @@ -380,8 +367,8 @@ struct GroupSse2Impl { // Returns the number of trailing empty or deleted elements in the group. uint32_t CountLeadingEmptyOrDeleted() const { auto special = _mm_set1_epi8(kSentinel); - return TrailingZeros( - _mm_movemask_epi8(_mm_cmpgt_epi8_fixed(special, ctrl)) + 1); + return TrailingZeros(static_cast( + _mm_movemask_epi8(_mm_cmpgt_epi8_fixed(special, ctrl)) + 1)); } void ConvertSpecialToEmptyAndFullToDeleted(ctrl_t* dst) const { @@ -476,7 +463,7 @@ void ConvertDeletedToEmptyAndFullToDeleted(ctrl_t* ctrl, size_t capacity); // Rounds up the capacity to the next power of 2 minus 1, with a minimum of 1. inline size_t NormalizeCapacity(size_t n) { - return n ? ~size_t{} >> LeadingZeros(n) : 1; + return n ? ~size_t{} >> countl_zero(n) : 1; } // We use 7/8th as maximum load factor. -- cgit v1.2.3