Skip to content

<mdspan>: layout_stride improvements #3673

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
StephanTLavavej merged 1 commit into from
Apr 26, 2023
Merged

<mdspan>: layout_stride improvements #3673

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
154 changes: 90 additions & 64 deletions stl/inc/mdspan
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -601,9 +601,34 @@ public:
"If Extents::rank_dynamic() == 0 is true, then the size of the multidimensional index space Extents() must be "
"representable as a value of type typename Extents::index_type (N4944 [mdspan.layout.stride.overview]/4).");

constexpr mapping() noexcept = default;
#pragma warning(push) // TRANSITION, "/analyze:only" BUG?
#pragma warning(disable : 28020) // The expression '0<=_Param_(1)&&_Param_(1)<=1-1' is not true at this call
constexpr mapping() noexcept : _Exts(extents_type{}) {
if constexpr (extents_type::rank() != 0) {
_Strides.back() = 1;
for (rank_type _Idx = extents_type::rank() - 1; _Idx-- > 0;) {
// TRANSITION USE `_Multiply_with_overflow_check` IN DEBUG MODE
_Strides[_Idx] = _Strides[_Idx + 1] * _Exts.extent(_Idx + 1);
}
}
}
#pragma warning(pop) // TRANSITION, "/analyze:only" BUG?

constexpr mapping(const mapping&) noexcept = default;

template <class _OtherIndexType, size_t... _Indices>
requires is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&>
constexpr mapping(const extents_type& _Exts_, span<_OtherIndexType, extents_type::rank()> _Strides_,
index_sequence<_Indices...>) noexcept
: _Exts(_Exts_), _Strides{static_cast<index_type>(_STD as_const(_Strides_[_Indices]))...} {
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
// TRANSITION CHECK [mdspan.layout.stride.cons]/4.2 (REQUIRES `_Multiply_with_overflow_check`)
_STL_VERIFY(_Strides[_Idx] > 0, "Value of s[i] must be greater than 0 for all i in the range [0, rank_) "
"(N4944 [mdspan.layout.stride.cons]/4.1).");
}
}

#ifndef __clang__ // TRANSITION, MSVC messes up CTAD when concepts are used here (needs further investigation)
template <class _OtherIndexType, enable_if_t<is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&>,
Expand All @@ -613,12 +638,9 @@ public:
requires is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&>
#endif // ^^^ no workaround ^^^
constexpr mapping(const extents_type& _Exts_, const span<_OtherIndexType, extents_type::rank()> _Strides_) noexcept
: _Exts(_Exts_) {
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
_Strides[_Idx] = _Strides_[_Idx];
}
};
constexpr mapping(const extents_type& _Exts_, span<_OtherIndexType, extents_type::rank()> _Strides_) noexcept
: mapping(_Exts_, _Strides_, make_index_sequence<extents_type::rank()>{}) {
}

#ifndef __clang__ // TRANSITION, MSVC messes up CTAD when concepts are used here (needs further investigation)
template <class _OtherIndexType, enable_if_t<is_convertible_v<const _OtherIndexType&, index_type>
Expand All @@ -631,11 +653,8 @@ public:
#endif // ^^^ no workaround ^^^
constexpr mapping(
const extents_type& _Exts_, const array<_OtherIndexType, extents_type::rank()>& _Strides_) noexcept
: _Exts(_Exts_) {
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
_Strides[_Idx] = _Strides_[_Idx];
}
};
: mapping(_Exts_, span{_Strides_}, make_index_sequence<extents_type::rank()>{}) {
}

template <class _StridedLayoutMapping>
requires _Layout_mapping_alike<_StridedLayoutMapping>
Expand All @@ -647,8 +666,16 @@ public:
|| _Is_mapping_of<layout_stride, _StridedLayoutMapping>) ))
mapping(const _StridedLayoutMapping& _Other) noexcept
: _Exts(_Other.extents()) {
for (rank_type _Dim = 0; _Dim < extents_type::rank(); ++_Dim) {
_Strides[_Dim] = _Other.stride(_Dim);
_STL_VERIFY(_STD in_range<index_type>(_Other.required_span_size()),
"Value of other.required_span_size() must be representable as a value of type index_type (N4944 "
"[mdspan.layout.stride.cons]/7.3).");
_STL_VERIFY(
_Offset(_Other) == 0, "Value of OFFSET(other) must be equal to 0 (N4944 [mdspan.layout.stride.cons]/7.4).");
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
const auto _Stride = _Other.stride(_Idx);
_STL_VERIFY(_Stride > 0, "Value of other.stride(r) must be greater than 0 for every rank index r of "
"extents() (N4944 [mdspan.layout.stride.cons]/7.2).");
_Strides[_Idx] = static_cast<index_type>(_Stride);
}
}

Expand All @@ -662,30 +689,32 @@ public:
return _Strides;
}

#pragma warning(push) // TRANSITION, "/analyze:only" BUG?
#pragma warning(disable : 28020) // The expression '0<=_Param_(1)&&_Param_(1)<=1-1' is not true at this call
_NODISCARD constexpr index_type required_span_size() const noexcept {
if (extents_type::rank() > 0) {
if constexpr (extents_type::rank() == 0) {
return 1;
} else {
index_type _Result = 1;
for (rank_type _Dim = 0; _Dim < extents_type::rank(); ++_Dim) {
const auto _Ext = _Exts.extent(_Dim);
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
const index_type _Ext = _Exts.extent(_Idx);
if (_Ext == 0) {
return 0;
}

_Result += (_Ext - 1) * _Strides[_Dim];
_Result += (_Ext - 1) * _Strides[_Idx];
}

return _Result;
} else {
return 1;
}
}
#pragma warning(pop) // TRANSITION, "/analyze:only" BUG?

template <class... _Indices>
requires (sizeof...(_Indices) == extents_type::rank()) && (is_convertible_v<_Indices, index_type> && ...)
&& (is_nothrow_constructible_v<index_type, _Indices> && ...)
_NODISCARD constexpr index_type operator()(_Indices... _Idx) const noexcept {
return _Index_impl<conditional_t<true, index_type, _Indices>...>(
static_cast<index_type>(_Idx)..., make_index_sequence<extents_type::rank()>{});
template <class... _IndexTypes>
requires (sizeof...(_IndexTypes) == extents_type::rank()) && (is_convertible_v<_IndexTypes, index_type> && ...)
&& (is_nothrow_constructible_v<index_type, _IndexTypes> && ...)
_NODISCARD constexpr index_type operator()(_IndexTypes... _Indices) const noexcept {
return _Index_impl(make_index_sequence<extents_type::rank()>{}, static_cast<index_type>(_Indices)...);
}

_NODISCARD static constexpr bool is_always_unique() noexcept {
Expand All @@ -700,20 +729,19 @@ public:
return true;
}

_NODISCARD constexpr bool is_unique() const noexcept {
_NODISCARD static constexpr bool is_unique() noexcept {
return true;
}

_NODISCARD constexpr bool is_exhaustive() const noexcept {
index_type _Ext_size = 1;
for (rank_type _Dim = 0; _Dim < extents_type::rank(); ++_Dim) {
_Ext_size *= _Exts.extent(_Dim);
if constexpr (extents_type::rank() == 0) {
return true;
} else {
return required_span_size() == _Exts._Fwd_prod_of_extents(extents_type::rank());
}

return required_span_size() == _Ext_size;
}

_NODISCARD constexpr bool is_strided() const noexcept {
_NODISCARD static constexpr bool is_strided() noexcept {
return true;
}

Expand All @@ -725,49 +753,47 @@ public:
requires _Layout_mapping_alike<_OtherMapping> && (extents_type::rank() == _OtherMapping::extents_type::rank())
&& (_OtherMapping::is_always_strided())
_NODISCARD_FRIEND constexpr bool operator==(const mapping& _Left, const _OtherMapping& _Right) noexcept {
if (_Left.extents() != _Right.extents()) {
return false;
}

constexpr rank_type _Rank = extents_type::rank();
for (rank_type _Dim = 0; _Dim < _Rank; ++_Dim) {
if (_Left.stride(_Dim) != _Right.stride(_Dim)) {
if constexpr (extents_type::rank() != 0) {
if (_Left.extents() != _Right.extents()) {
return false;
}
}

index_type _Offset;
if constexpr (_Rank == 0) {
_Offset = _Right();
} else {
bool _Is_empty = false;
for (rank_type _Dim = 0; _Dim < _Rank; ++_Dim) {
if (_Left.extents().extent(_Dim) == 0) {
_Is_empty = true;
break;
}
}

if (_Is_empty) {
_Offset = 0;
} else {
_Offset = [&_Right]<size_t... _Idx>(index_sequence<_Idx...>) {
return _Right(((void) _Idx, 0)...);
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
if (_Left.stride(_Idx) != _Right.stride(_Idx)) {
return false;
}
(make_index_sequence<_Rank>{});
}

return _Offset == 0;
}

return _Offset(_Right) == 0;
}

private:
extents_type _Exts{};
array<index_type, extents_type::rank()> _Strides{};

template <class... _IndexType, size_t... _Seq>
constexpr index_type _Index_impl(_IndexType... _Idx, index_sequence<_Seq...>) const noexcept {
return ((_Idx * _Strides[_Seq]) + ...);
template <class _OtherMapping>
_NODISCARD static constexpr typename _OtherMapping::index_type _Offset(_OtherMapping& _Mapping) noexcept {
if constexpr (extents_type::rank() == 0) {
return _Mapping();
} else {
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
if (_Mapping.extents().extent(_Idx) == 0) {
return 0;
}
}

return [&]<size_t... _Indices>(index_sequence<_Indices...>) {
return _Mapping(((void) _Indices, 0)...);
}
(make_index_sequence<extents_type::rank()>{});
}
}

template <class... _IndexTypes, size_t... _Seq>
_NODISCARD constexpr index_type _Index_impl(index_sequence<_Seq...>, _IndexTypes... _Indices) const noexcept {
_STL_INTERNAL_STATIC_ASSERT((same_as<_IndexTypes, index_type> && ...));
return ((_Indices * _Strides[_Seq]) + ... + 0);
}
};

Expand Down
2 changes: 2 additions & 0 deletions tests/std/test.lst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -238,6 +238,8 @@ tests\P0009R18_mdspan_layout_left
tests\P0009R18_mdspan_layout_left_death
tests\P0009R18_mdspan_layout_right
tests\P0009R18_mdspan_layout_right_death
tests\P0009R18_mdspan_layout_stride
tests\P0009R18_mdspan_layout_stride_death
tests\P0019R8_atomic_ref
tests\P0024R2_parallel_algorithms_adjacent_difference
tests\P0024R2_parallel_algorithms_adjacent_find
Expand Down
4 changes: 4 additions & 0 deletions tests/std/tests/P0009R18_mdspan_layout_stride/env.lst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
# Copyright (c) Microsoft Corporation.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

RUNALL_INCLUDE ..\concepts_latest_matrix.lst
Loading