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Remove unused functions from bit_details. Replace some with stl <bit> #22

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Merged
merged 1 commit into from
Jul 11, 2025
Merged

Remove unused functions from bit_details. Replace some with stl <bit> #22

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70 changes: 34 additions & 36 deletions include/bitlib/bit-algorithms/count.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ count(

if (first.position() != 0) {
word_type first_value = lsr(*first.base(), first.position());
result = _popcnt(first_value);
result = std::popcount(static_cast<std::make_unsigned_t<word_type>>(first_value));
++it;
}
// The SIMD implementation here is actually slower than the standard
Expand All @@ -67,46 +67,44 @@ count(
//{
//// Align to boundary
//for (; it != last.base() && !is_aligned(&(*it), 64); ++it) {
//result += _popcnt(*it);
//}

//// SIMD
//hn::ScalableTag<word_type> d;
//for (; std::distance(it, last.base()) >= hn::Lanes(d); it += hn::Lanes(d))
//{
//const auto popcntV = hn::PopulationCount(hn::Load(d, &*it));
//result += hn::ReduceSum(d, popcntV);
//}

//// Remaining
//for (; it != last.base(); ++it) {
//result += _popcnt(*it);
//}
//} else
//#endif
{
// std:: version
//result += std::transform_reduce(
//it,
//last.base(),
//0,
//std::plus{},
//[](word_type word) {return _popcnt(word); }
//);

// libpopcnt
result += popcnt(&*it, (digits / 8) * std::distance(it, last.base()));
}
//result += std::popcount(*it);
//}

//// SIMD
//hn::ScalableTag<word_type> d;
//for (; std::distance(it, last.base()) >= hn::Lanes(d); it += hn::Lanes(d))
//{
//const auto popcntV = hn::PopulationCount(hn::Load(d, &*it));
//result += hn::ReduceSum(d, popcntV);
//}

//// Remaining
//for (; it != last.base(); ++it) {
//result += std::popcount(*it);
//}
//} else
//#endif
{
// std:: version
//result += std::transform_reduce(
//it,
//last.base(),
//0,
//std::plus{},
//[](word_type word) {return std::popcount(word); }
//);

// libpopcnt
result += popcnt(&*it, (digits / 8) * std::distance(it, last.base()));
}
if (last.position() != 0) {
word_type last_value = *last.base() << (digits - last.position());
result += _popcnt(last_value);
result += std::popcount(static_cast<std::make_unsigned_t<word_type>>(last_value));
}
// Computation when bits belong to the same underlying word
} else {
result = _popcnt(
_bextr<word_type>(*first.base(), first.position(), last.position()
- first.position())
);
result = std::popcount(static_cast<std::make_unsigned_t<word_type>>(
_bextr<word_type>(*first.base(), first.position(), last.position() - first.position())));
}

// Negates when the number of zero bits is requested
Expand Down
30 changes: 16 additions & 14 deletions include/bitlib/bit-algorithms/find.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@

// ============================== PREAMBLE ================================== //
// C++ standard library
#include <bit>
#include <iterator>
// Project sources
#include "bitlib/bit-iterator/bit.hpp"
Expand Down Expand Up @@ -37,6 +38,7 @@ constexpr bit_iterator<RandomAccessIt> find(
) {

using word_type = typename bit_iterator<RandomAccessIt>::word_type;
using uword_type = std::make_unsigned_t<word_type>;
using size_type = typename bit_iterator<RandomAccessIt>::size_type;
const std::size_t digits = binary_digits<word_type>::value;

Expand All @@ -48,8 +50,8 @@ constexpr bit_iterator<RandomAccessIt> find(
if (!is_first_aligned) {
word_type shifted_first = lsr(*first.base(), first.position());
size_type num_trailing_complementary_bits = (bv == bit0)
? _tzcnt(static_cast<word_type>(~shifted_first))
: _tzcnt(static_cast<word_type>(shifted_first));
? std::countr_zero(static_cast<uword_type>(~shifted_first))
: std::countr_zero(static_cast<uword_type>(shifted_first));
if (std::next(first.base(), is_last_aligned) == last.base()) {
return first + std::min(num_trailing_complementary_bits, static_cast<size_type>(distance(first, last)));
} else if (num_trailing_complementary_bits + first.position() < digits) {
Expand All @@ -72,8 +74,8 @@ constexpr bit_iterator<RandomAccessIt> find(
}

size_type num_trailing_complementary_bits = (bv == bit0)
? _tzcnt(static_cast<word_type>(~*it))
: _tzcnt(static_cast<word_type>(*it));
? std::countr_zero(static_cast<uword_type>(~*it))
: std::countr_zero(static_cast<uword_type>(*it));
return bit_iterator(it, (size_type) num_trailing_complementary_bits);
}

Expand All @@ -92,8 +94,8 @@ constexpr bit_iterator<RandomAccessIt> find(
{
it += hn::FindKnownFirstTrue(d, found);
size_type num_trailing_complementary_bits = (bv == bit0)
? _tzcnt(static_cast<word_type>(~*it))
: _tzcnt(static_cast<word_type>(*it));
? std::countr_zero(static_cast<uword_type>(~*it))
: std::countr_zero(static_cast<uword_type>(*it));
return bit_iterator(it, (size_type) num_trailing_complementary_bits);
}
}
Expand All @@ -106,18 +108,18 @@ constexpr bit_iterator<RandomAccessIt> find(
}

if (it != last.base()) {
size_type num_trailing_complementary_bits = (bv == bit0)
? _tzcnt(static_cast<word_type>(~*it))
: _tzcnt(static_cast<word_type>(*it));
return bit_iterator(it, static_cast<size_type>(num_trailing_complementary_bits));
size_type num_trailing_complementary_bits = (bv == bit0)
? std::countr_zero(static_cast<uword_type>(~*it))
: std::countr_zero(static_cast<uword_type>(*it));
return bit_iterator(it, static_cast<size_type>(num_trailing_complementary_bits));
}

// Deal with any unaligned boundaries
if (!is_last_aligned) {
size_type num_trailing_complementary_bits = (bv == bit0)
? _tzcnt(static_cast<word_type>(~*it))
: _tzcnt(static_cast<word_type>(*it));
return bit_iterator(it, static_cast<size_type>(std::min(num_trailing_complementary_bits, last.position())));
size_type num_trailing_complementary_bits = (bv == bit0)
? std::countr_zero(static_cast<uword_type>(~*it))
: std::countr_zero(static_cast<uword_type>(*it));
return bit_iterator(it, static_cast<size_type>(std::min(num_trailing_complementary_bits, last.position())));
}
return last;
}
Expand Down
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