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Merged
StephanTLavavej merged 4 commits into from
Apr 27, 2023
Merged

<mdspan>: Reduce amount of function calls in non-optimized debug mode #3674

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f4cc153
Improve debug experience a little bit
JMazurkiewicz Apr 26, 2023
e56dc01
Merge branch 'mdspan/main' into mdspan/debug-experience
JMazurkiewicz Apr 26, 2023
a0c173a
Use even more _Rank
JMazurkiewicz Apr 26, 2023
f60bbc8
Address comments from previous PR
JMazurkiewicz Apr 26, 2023
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113 changes: 53 additions & 60 deletions stl/inc/mdspan
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Original file line number Diff line number Diff line change
Expand Up @@ -32,45 +32,38 @@ public:
using size_type = make_unsigned_t<index_type>;
using rank_type = size_t;

_NODISCARD static constexpr rank_type rank() noexcept {
return sizeof...(_Extents);
}

static_assert(_Is_standard_integer<index_type>,
"IndexType must be a signed or unsigned integer type (N4944 [mdspan.extents.overview]/1.1).");
static_assert(((_Extents == dynamic_extent || _STD in_range<index_type>(_Extents)) && ...),
"Each element of Extents must be either equal to dynamic_extent, or must be representable as a value of type "
"IndexType (N4944 [mdspan.extents.overview]/1.2).");

static constexpr rank_type _Rank = sizeof...(_Extents);
static constexpr rank_type _Rank_dynamic = (static_cast<rank_type>(_Extents == dynamic_extent) + ... + 0);

private:
static constexpr array<rank_type, _Rank> _Static_extents = {_Extents...};

_NODISCARD static _CONSTEVAL auto _Make_dynamic_indices() noexcept {
#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
array<rank_type, rank() + 1> _Result{};
array<rank_type, _Rank + 1> _Result{};
rank_type _Counter = 0;
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < _Rank; ++_Idx) {
_Result[_Idx] = _Counter;
if (_Static_extents[_Idx] == dynamic_extent) {
++_Counter;
}
}
_Result[rank()] = _Counter;
_Result[_Rank] = _Counter;
return _Result;
#pragma warning(pop) // TRANSITION, "/analyze:only" BUG?
}

static constexpr array<rank_type, rank()> _Static_extents = {_Extents...};
static constexpr array<rank_type, rank() + 1> _Dynamic_indices = _Make_dynamic_indices();

_NODISCARD static constexpr rank_type _Dynamic_index(rank_type _Idx) noexcept {
return _Dynamic_indices[_Idx];
}
static constexpr array<rank_type, _Rank + 1> _Dynamic_indices = _Make_dynamic_indices();

_NODISCARD static _CONSTEVAL auto _Make_dynamic_indices_inv() noexcept {
array<rank_type, rank()> _Result{};
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
for (rank_type _Idx_inv = 0; _Idx_inv < rank(); ++_Idx_inv) {
if (_Dynamic_index(_Idx_inv + 1) == _Idx + 1) {
array<rank_type, _Rank> _Result{};
for (rank_type _Idx = 0; _Idx < _Rank; ++_Idx) {
for (rank_type _Idx_inv = 0; _Idx_inv < _Rank; ++_Idx_inv) {
if (_Dynamic_indices[_Idx_inv + 1] == _Idx + 1) {
_Result[_Idx] = _Idx_inv;
break;
}
Expand All @@ -79,11 +72,7 @@ private:
return _Result;
}

static constexpr array<rank_type, rank()> _Dynamic_indices_inv = _Make_dynamic_indices_inv();

_NODISCARD static constexpr rank_type _Dynamic_index_inv(rank_type _Idx) noexcept {
return _Dynamic_indices_inv[_Idx];
}
static constexpr array<rank_type, _Rank> _Dynamic_indices_inv = _Make_dynamic_indices_inv();

struct _Static_extents_only {
constexpr explicit _Static_extents_only() noexcept = default;
Expand All @@ -96,30 +85,33 @@ private:
}
};

static constexpr rank_type _Rank_dynamic = _Dynamic_index(rank());
conditional_t<_Rank_dynamic != 0, array<index_type, _Rank_dynamic>, _Static_extents_only> _Dynamic_extents{};

public:
_NODISCARD static constexpr rank_type rank() noexcept {
return _Rank;
}

_NODISCARD static constexpr rank_type rank_dynamic() noexcept {
return _Rank_dynamic;
}

_NODISCARD static constexpr size_t static_extent(const rank_type _Idx) noexcept {
_STL_VERIFY(_Idx < rank(), "Index must be less than rank() (N4944 [mdspan.extents.obs]/1)");
_STL_VERIFY(_Idx < _Rank, "Index must be less than rank() (N4944 [mdspan.extents.obs]/1)");
return _Static_extents[_Idx];
}

_NODISCARD constexpr index_type extent(const rank_type _Idx) const noexcept {
_STL_VERIFY(_Idx < rank(), "Index must be less than rank() (N4944 [mdspan.extents.obs]/3)");
_STL_VERIFY(_Idx < _Rank, "Index must be less than rank() (N4944 [mdspan.extents.obs]/3)");
if constexpr (rank_dynamic() == 0) {
return static_cast<index_type>(static_extent(_Idx));
return static_cast<index_type>(_Static_extents[_Idx]);
} else if constexpr (rank_dynamic() == rank()) {
return _Dynamic_extents[_Idx];
} else {
if (static_extent(_Idx) == dynamic_extent) {
return _Dynamic_extents[_Dynamic_index(_Idx)];
if (_Static_extents[_Idx] == dynamic_extent) {
return _Dynamic_extents[_Dynamic_indices[_Idx]];
} else {
return static_cast<index_type>(static_extent(_Idx));
return static_cast<index_type>(_Static_extents[_Idx]);
}
}
}
Expand All @@ -133,16 +125,16 @@ public:
|| (numeric_limits<index_type>::max)() < (numeric_limits<_OtherIndexType>::max)())
extents(const extents<_OtherIndexType, _OtherExtents...>& _Other) noexcept {
auto _It = _Dynamic_extents.begin();
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < _Rank; ++_Idx) {
_STL_VERIFY(
static_extent(_Idx) == dynamic_extent || _STD cmp_equal(static_extent(_Idx), _Other.extent(_Idx)),
_Static_extents[_Idx] == dynamic_extent || _STD cmp_equal(_Static_extents[_Idx], _Other.extent(_Idx)),
"Value of other.extent(r) must be equal to extent(r) for each r for which extent(r) is a static extent "
"(N4944 [mdspan.extents.cons]/2.1)");
_STL_VERIFY(_STD in_range<index_type>(_Other.extent(_Idx)),
"Value of other.extent(r) must be representable as a value of type index_type for every rank index r "
"(N4944 [mdspan.extents.cons]/2.2)");

if (static_extent(_Idx) == dynamic_extent) {
if (_Static_extents[_Idx] == dynamic_extent) {
*_It = static_cast<index_type>(_Other.extent(_Idx));
++_It;
}
Expand All @@ -167,12 +159,12 @@ public:
} else {
array<index_type, sizeof...(_Exts)> _Exts_arr{static_cast<index_type>(_STD move(_Exts))...};
auto _It = _Dynamic_extents.begin();
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < _Rank; ++_Idx) {
_STL_VERIFY(
static_extent(_Idx) == dynamic_extent || _STD cmp_equal(static_extent(_Idx), _Exts_arr[_Idx]),
_Static_extents[_Idx] == dynamic_extent || _STD cmp_equal(_Static_extents[_Idx], _Exts_arr[_Idx]),
"Value of exts_arr[r] must be equal to extent(r) for each r for which extent(r) is a static extent "
"(N4944 [mdspan.extents.cons]/7.1)");
if (static_extent(_Idx) == dynamic_extent) {
if (_Static_extents[_Idx] == dynamic_extent) {
*_It = _Exts_arr[_Idx];
++_It;
}
Expand All @@ -199,10 +191,11 @@ public:
requires is_convertible_v<const _OtherIndexType&, index_type>
&& is_nothrow_constructible_v<index_type, const _OtherIndexType&> && (_Size == rank())
constexpr explicit extents(span<_OtherIndexType, _Size> _Exts, index_sequence<_Indices...>) noexcept
: _Dynamic_extents{static_cast<index_type>(_STD as_const(_Exts[_Dynamic_index_inv(_Indices)]))...} {
: _Dynamic_extents{static_cast<index_type>(_STD as_const(_Exts[_Dynamic_indices_inv[_Indices]]))...} {
if constexpr (_Is_standard_integer<_OtherIndexType>) {
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
_STL_VERIFY(static_extent(_Idx) == dynamic_extent || _STD cmp_equal(static_extent(_Idx), _Exts[_Idx]),
for (rank_type _Idx = 0; _Idx < _Rank; ++_Idx) {
_STL_VERIFY(
_Static_extents[_Idx] == dynamic_extent || _STD cmp_equal(_Static_extents[_Idx], _Exts[_Idx]),
"Value of exts[r] must be equal to extent(r) for each r for which extent(r) is a static extent "
"(N4944 [mdspan.extents.cons]/10.1)");
_STL_VERIFY(_Exts[_Idx] >= 0 && _STD in_range<index_type>(_Exts[_Idx]),
Expand Down Expand Up @@ -232,7 +225,7 @@ public:
if constexpr (rank() != sizeof...(_OtherExtents)) {
return false;
} else {
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < _Rank; ++_Idx) {
if (_STD cmp_not_equal(_Left.extent(_Idx), _Right.extent(_Idx))) {
return false;
}
Expand All @@ -253,7 +246,7 @@ public:
// TRANSITION, LWG ISSUE? I believe that this function should return 'index_type'
_NODISCARD constexpr index_type _Rev_prod_of_extents(const rank_type _Idx) const noexcept {
index_type _Result = 1;
for (rank_type _Dim = _Idx + 1; _Dim < rank(); ++_Dim) {
for (rank_type _Dim = _Idx + 1; _Dim < _Rank; ++_Dim) {
_Result *= extent(_Dim);
}
return _Result;
Expand Down Expand Up @@ -361,7 +354,7 @@ public:
const bool _Verify = [&]<size_t... _Indices>(index_sequence<_Indices...>) {
index_type _Prod = 1;
return ((_Other.stride(_Indices)
== (_Indices == extents_type::rank() - 1
== (_Indices == extents_type::_Rank - 1
? _Prod
: _STD exchange(_Prod, static_cast<index_type>(_Prod * _Exts.extent(_Indices)))))
&& ...);
Expand All @@ -382,7 +375,7 @@ public:
}

_NODISCARD constexpr index_type required_span_size() const noexcept {
return _Exts._Fwd_prod_of_extents(extents_type::rank());
return _Exts._Fwd_prod_of_extents(extents_type::_Rank);
}

template <class... _IndexTypes>
Expand Down Expand Up @@ -419,7 +412,7 @@ public:
_NODISCARD constexpr index_type stride(const rank_type _Idx) const noexcept
requires (extents_type::rank() > 0)
{
_STL_VERIFY(_Idx < extents_type::rank(),
_STL_VERIFY(_Idx < extents_type::_Rank,
"Value of i must be less than extents_type::rank() (N4944 [mdspan.layout.left.obs]/6).");
return _Exts._Fwd_prod_of_extents(_Idx);
}
Expand Down Expand Up @@ -494,7 +487,7 @@ public:
index_type _Prod = stride(0);
return (
(_Other.stride(_Indices)
== (_Indices == extents_type::rank() - 1
== (_Indices == extents_type::_Rank - 1
? _Prod
: _STD exchange(_Prod, static_cast<index_type>(_Prod / _Exts.extent(_Indices + 1)))))
&& ...);
Expand All @@ -515,7 +508,7 @@ public:
}

_NODISCARD constexpr index_type required_span_size() const noexcept {
return _Exts._Fwd_prod_of_extents(extents_type::rank());
return _Exts._Fwd_prod_of_extents(extents_type::_Rank);
}

template <class... _IndexTypes>
Expand Down Expand Up @@ -552,7 +545,7 @@ public:
_NODISCARD constexpr index_type stride(const rank_type _Idx) const noexcept
requires (extents_type::rank() > 0)
{
_STL_VERIFY(_Idx < extents_type::rank(),
_STL_VERIFY(_Idx < extents_type::_Rank,
"Value of i must be less than extents_type::rank() (N4944 [mdspan.layout.right.obs]/6).");
return _Exts._Rev_prod_of_extents(_Idx);
}
Expand Down Expand Up @@ -606,7 +599,7 @@ public:
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;) {
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);
}
Expand All @@ -622,7 +615,7 @@ public:
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) {
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).");
Expand Down Expand Up @@ -671,7 +664,7 @@ public:
"[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) {
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).");
Expand All @@ -696,7 +689,7 @@ public:
return 1;
} else {
index_type _Result = 1;
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < extents_type::_Rank; ++_Idx) {
const index_type _Ext = _Exts.extent(_Idx);
if (_Ext == 0) {
return 0;
Expand Down Expand Up @@ -737,7 +730,7 @@ public:
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() == _Exts._Fwd_prod_of_extents(extents_type::_Rank);
}
}

Expand All @@ -758,7 +751,7 @@ public:
return false;
}

for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < extents_type::_Rank; ++_Idx) {
if (_Left.stride(_Idx) != _Right.stride(_Idx)) {
return false;
}
Expand All @@ -777,7 +770,7 @@ private:
if constexpr (extents_type::rank() == 0) {
return _Mapping();
} else {
for (rank_type _Idx = 0; _Idx < extents_type::rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < extents_type::_Rank; ++_Idx) {
if (_Mapping.extents().extent(_Idx) == 0) {
return 0;
}
Expand Down Expand Up @@ -855,11 +848,11 @@ public:
"[mdspan.mdspan.overview]/2.3).");

_NODISCARD static constexpr rank_type rank() noexcept {
return extents_type::rank();
return extents_type::_Rank;
}

_NODISCARD static constexpr rank_type rank_dynamic() noexcept {
return extents_type::rank_dynamic();
return extents_type::_Rank_dynamic;
}

_NODISCARD static constexpr size_t static_extent(const rank_type _Idx) noexcept {
Expand Down Expand Up @@ -956,11 +949,11 @@ public:
}

_NODISCARD constexpr size_type size() const noexcept {
return static_cast<size_type>(_Map.extents()._Fwd_prod_of_extents(rank()));
return static_cast<size_type>(_Map.extents()._Fwd_prod_of_extents(extents_type::_Rank));
}

_NODISCARD constexpr bool empty() const noexcept {
for (rank_type _Idx = 0; _Idx < rank(); ++_Idx) {
for (rank_type _Idx = 0; _Idx < extents_type::_Rank; ++_Idx) {
if (_Map.extents().extent(_Idx) == 0) {
return true;
}
Expand Down
6 changes: 3 additions & 3 deletions tests/std/tests/P0009R18_mdspan_layout_stride/test.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ using namespace std;

template <class IndexType, size_t... Extents, size_t... Indices>
constexpr void do_check_members(const extents<IndexType, Extents...>& ext,
const array<IndexType, sizeof...(Extents)> strs, index_sequence<Indices...>) {
const array<IndexType, sizeof...(Extents)>& strs, index_sequence<Indices...>) {
using Ext = extents<IndexType, Extents...>;
using Strides = array<IndexType, sizeof...(Extents)>;
using Mapping = layout_stride::mapping<Ext>;
Expand Down Expand Up @@ -116,7 +116,7 @@ constexpr void do_check_members(const extents<IndexType, Extents...>& ext,
// Tests of 'is_exhaustive' are defined in 'check_is_exhaustive' function [FIXME]
}

{ // Check 'stride' function (intentionally not if constexpr)
{ // Check 'stride' function
for (size_t i = 0; i < strs.size(); ++i) {
same_as<IndexType> decltype(auto) s = m.stride(i);
assert(strs[i] == s);
Expand All @@ -132,7 +132,7 @@ constexpr void do_check_members(const extents<IndexType, Extents...>& ext,
}

template <class IndexType, size_t... Extents>
constexpr void check_members(extents<IndexType, Extents...> ext, const array<IndexType, sizeof...(Extents)> strides) {
constexpr void check_members(extents<IndexType, Extents...> ext, const array<IndexType, sizeof...(Extents)>& strides) {
do_check_members<IndexType, Extents...>(ext, strides, make_index_sequence<sizeof...(Extents)>{});
}

Expand Down