Make assignment constexpr

This commit is contained in:
Tyler Veness 2025-02-21 18:16:46 +00:00 committed by Rasmus Munk Larsen
parent 4dda5b927a
commit 0ae7b59018
5 changed files with 81 additions and 44 deletions

View File

@ -191,7 +191,7 @@ struct copy_using_evaluator_DefaultTraversal_CompleteUnrolling {
static constexpr int Outer = Index_ / Kernel::AssignmentTraits::InnerSizeAtCompileTime;
static constexpr int Inner = Index_ % Kernel::AssignmentTraits::InnerSizeAtCompileTime;
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel& kernel) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel& kernel) {
kernel.assignCoeffByOuterInner(Outer, Inner);
copy_using_evaluator_DefaultTraversal_CompleteUnrolling<Kernel, Index_ + 1, Stop>::run(kernel);
}
@ -204,7 +204,7 @@ struct copy_using_evaluator_DefaultTraversal_CompleteUnrolling<Kernel, Stop, Sto
template <typename Kernel, int Index_, int Stop>
struct copy_using_evaluator_DefaultTraversal_InnerUnrolling {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel& kernel, Index outer) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel& kernel, Index outer) {
kernel.assignCoeffByOuterInner(outer, Index_);
copy_using_evaluator_DefaultTraversal_InnerUnrolling<Kernel, Index_ + 1, Stop>::run(kernel, outer);
}
@ -212,7 +212,7 @@ struct copy_using_evaluator_DefaultTraversal_InnerUnrolling {
template <typename Kernel, int Stop>
struct copy_using_evaluator_DefaultTraversal_InnerUnrolling<Kernel, Stop, Stop> {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel&, Index) {}
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel&, Index) {}
};
/***********************
@ -221,7 +221,7 @@ struct copy_using_evaluator_DefaultTraversal_InnerUnrolling<Kernel, Stop, Stop>
template <typename Kernel, int Index_, int Stop>
struct copy_using_evaluator_LinearTraversal_CompleteUnrolling {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel& kernel) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel& kernel) {
kernel.assignCoeff(Index_);
copy_using_evaluator_LinearTraversal_CompleteUnrolling<Kernel, Index_ + 1, Stop>::run(kernel);
}
@ -229,7 +229,7 @@ struct copy_using_evaluator_LinearTraversal_CompleteUnrolling {
template <typename Kernel, int Stop>
struct copy_using_evaluator_LinearTraversal_CompleteUnrolling<Kernel, Stop, Stop> {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel&) {}
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel&) {}
};
/**************************
@ -270,7 +270,7 @@ struct copy_using_evaluator_innervec_InnerUnrolling {
template <typename Kernel, int Stop, int SrcAlignment, int DstAlignment>
struct copy_using_evaluator_innervec_InnerUnrolling<Kernel, Stop, Stop, SrcAlignment, DstAlignment> {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel&, Index) {}
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel&, Index) {}
};
/***************************************************************************
@ -281,7 +281,21 @@ struct copy_using_evaluator_innervec_InnerUnrolling<Kernel, Stop, Stop, SrcAlign
template <typename Kernel, int Traversal = Kernel::AssignmentTraits::Traversal,
int Unrolling = Kernel::AssignmentTraits::Unrolling>
struct dense_assignment_loop;
struct dense_assignment_loop_impl;
template <typename Kernel, int Traversal = Kernel::AssignmentTraits::Traversal,
int Unrolling = Kernel::AssignmentTraits::Unrolling>
struct dense_assignment_loop {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel& kernel) {
#ifdef __cpp_lib_is_constant_evaluated
if (internal::is_constant_evaluated())
dense_assignment_loop_impl<Kernel, Traversal == AllAtOnceTraversal ? AllAtOnceTraversal : DefaultTraversal,
NoUnrolling>::run(kernel);
else
#endif
dense_assignment_loop_impl<Kernel, Traversal, Unrolling>::run(kernel);
}
};
/************************
***** Special Cases *****
@ -289,7 +303,7 @@ struct dense_assignment_loop;
// Zero-sized assignment is a no-op.
template <typename Kernel, int Unrolling>
struct dense_assignment_loop<Kernel, AllAtOnceTraversal, Unrolling> {
struct dense_assignment_loop_impl<Kernel, AllAtOnceTraversal, Unrolling> {
static constexpr int SizeAtCompileTime = Kernel::AssignmentTraits::SizeAtCompileTime;
EIGEN_DEVICE_FUNC static void EIGEN_STRONG_INLINE EIGEN_CONSTEXPR run(Kernel& /*kernel*/) {
@ -302,8 +316,8 @@ struct dense_assignment_loop<Kernel, AllAtOnceTraversal, Unrolling> {
************************/
template <typename Kernel>
struct dense_assignment_loop<Kernel, DefaultTraversal, NoUnrolling> {
EIGEN_DEVICE_FUNC static void EIGEN_STRONG_INLINE run(Kernel& kernel) {
struct dense_assignment_loop_impl<Kernel, DefaultTraversal, NoUnrolling> {
EIGEN_DEVICE_FUNC static void EIGEN_STRONG_INLINE constexpr run(Kernel& kernel) {
for (Index outer = 0; outer < kernel.outerSize(); ++outer) {
for (Index inner = 0; inner < kernel.innerSize(); ++inner) {
kernel.assignCoeffByOuterInner(outer, inner);
@ -313,19 +327,19 @@ struct dense_assignment_loop<Kernel, DefaultTraversal, NoUnrolling> {
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, DefaultTraversal, CompleteUnrolling> {
struct dense_assignment_loop_impl<Kernel, DefaultTraversal, CompleteUnrolling> {
static constexpr int SizeAtCompileTime = Kernel::AssignmentTraits::SizeAtCompileTime;
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel& kernel) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel& kernel) {
copy_using_evaluator_DefaultTraversal_CompleteUnrolling<Kernel, 0, SizeAtCompileTime>::run(kernel);
}
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, DefaultTraversal, InnerUnrolling> {
struct dense_assignment_loop_impl<Kernel, DefaultTraversal, InnerUnrolling> {
static constexpr int InnerSizeAtCompileTime = Kernel::AssignmentTraits::InnerSizeAtCompileTime;
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel& kernel) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(Kernel& kernel) {
const Index outerSize = kernel.outerSize();
for (Index outer = 0; outer < outerSize; ++outer)
copy_using_evaluator_DefaultTraversal_InnerUnrolling<Kernel, 0, InnerSizeAtCompileTime>::run(kernel, outer);
@ -382,7 +396,7 @@ struct copy_using_evaluator_linearvec_CompleteUnrolling<Kernel, Stop, Stop> {
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, LinearVectorizedTraversal, NoUnrolling> {
struct dense_assignment_loop_impl<Kernel, LinearVectorizedTraversal, NoUnrolling> {
using Scalar = typename Kernel::Scalar;
using PacketType = typename Kernel::PacketType;
static constexpr int PacketSize = unpacket_traits<PacketType>::size;
@ -407,7 +421,7 @@ struct dense_assignment_loop<Kernel, LinearVectorizedTraversal, NoUnrolling> {
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, LinearVectorizedTraversal, CompleteUnrolling> {
struct dense_assignment_loop_impl<Kernel, LinearVectorizedTraversal, CompleteUnrolling> {
using PacketType = typename Kernel::PacketType;
static constexpr int PacketSize = unpacket_traits<PacketType>::size;
static constexpr int Size = Kernel::AssignmentTraits::SizeAtCompileTime;
@ -424,7 +438,7 @@ struct dense_assignment_loop<Kernel, LinearVectorizedTraversal, CompleteUnrollin
**************************/
template <typename Kernel>
struct dense_assignment_loop<Kernel, InnerVectorizedTraversal, NoUnrolling> {
struct dense_assignment_loop_impl<Kernel, InnerVectorizedTraversal, NoUnrolling> {
using PacketType = typename Kernel::PacketType;
static constexpr int PacketSize = unpacket_traits<PacketType>::size;
static constexpr int SrcAlignment = Kernel::AssignmentTraits::JointAlignment;
@ -440,7 +454,7 @@ struct dense_assignment_loop<Kernel, InnerVectorizedTraversal, NoUnrolling> {
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, InnerVectorizedTraversal, CompleteUnrolling> {
struct dense_assignment_loop_impl<Kernel, InnerVectorizedTraversal, CompleteUnrolling> {
static constexpr int SizeAtCompileTime = Kernel::AssignmentTraits::SizeAtCompileTime;
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(Kernel& kernel) {
@ -449,7 +463,7 @@ struct dense_assignment_loop<Kernel, InnerVectorizedTraversal, CompleteUnrolling
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, InnerVectorizedTraversal, InnerUnrolling> {
struct dense_assignment_loop_impl<Kernel, InnerVectorizedTraversal, InnerUnrolling> {
static constexpr int InnerSize = Kernel::AssignmentTraits::InnerSizeAtCompileTime;
static constexpr int SrcAlignment = Kernel::AssignmentTraits::SrcAlignment;
static constexpr int DstAlignment = Kernel::AssignmentTraits::DstAlignment;
@ -467,7 +481,7 @@ struct dense_assignment_loop<Kernel, InnerVectorizedTraversal, InnerUnrolling> {
***********************/
template <typename Kernel>
struct dense_assignment_loop<Kernel, LinearTraversal, NoUnrolling> {
struct dense_assignment_loop_impl<Kernel, LinearTraversal, NoUnrolling> {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE EIGEN_CONSTEXPR void run(Kernel& kernel) {
const Index size = kernel.size();
for (Index i = 0; i < size; ++i) kernel.assignCoeff(i);
@ -475,7 +489,7 @@ struct dense_assignment_loop<Kernel, LinearTraversal, NoUnrolling> {
};
template <typename Kernel>
struct dense_assignment_loop<Kernel, LinearTraversal, CompleteUnrolling> {
struct dense_assignment_loop_impl<Kernel, LinearTraversal, CompleteUnrolling> {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE EIGEN_CONSTEXPR void run(Kernel& kernel) {
copy_using_evaluator_LinearTraversal_CompleteUnrolling<Kernel, 0, Kernel::AssignmentTraits::SizeAtCompileTime>::run(
kernel);
@ -487,7 +501,7 @@ struct dense_assignment_loop<Kernel, LinearTraversal, CompleteUnrolling> {
***************************/
template <typename Kernel>
struct dense_assignment_loop<Kernel, SliceVectorizedTraversal, NoUnrolling> {
struct dense_assignment_loop_impl<Kernel, SliceVectorizedTraversal, NoUnrolling> {
using Scalar = typename Kernel::Scalar;
using PacketType = typename Kernel::PacketType;
static constexpr int PacketSize = unpacket_traits<PacketType>::size;
@ -528,7 +542,7 @@ struct dense_assignment_loop<Kernel, SliceVectorizedTraversal, NoUnrolling> {
#if EIGEN_UNALIGNED_VECTORIZE
template <typename Kernel>
struct dense_assignment_loop<Kernel, SliceVectorizedTraversal, InnerUnrolling> {
struct dense_assignment_loop_impl<Kernel, SliceVectorizedTraversal, InnerUnrolling> {
using PacketType = typename Kernel::PacketType;
static constexpr int PacketSize = unpacket_traits<PacketType>::size;
static constexpr int InnerSize = Kernel::AssignmentTraits::InnerSizeAtCompileTime;
@ -566,9 +580,10 @@ class generic_dense_assignment_kernel {
typedef copy_using_evaluator_traits<DstEvaluatorTypeT, SrcEvaluatorTypeT, Functor> AssignmentTraits;
typedef typename AssignmentTraits::PacketType PacketType;
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE generic_dense_assignment_kernel(DstEvaluatorType& dst,
const SrcEvaluatorType& src,
const Functor& func, DstXprType& dstExpr)
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr generic_dense_assignment_kernel(DstEvaluatorType& dst,
const SrcEvaluatorType& src,
const Functor& func,
DstXprType& dstExpr)
: m_dst(dst), m_src(src), m_functor(func), m_dstExpr(dstExpr) {
#ifdef EIGEN_DEBUG_ASSIGN
AssignmentTraits::debug();
@ -586,7 +601,7 @@ class generic_dense_assignment_kernel {
EIGEN_DEVICE_FUNC const SrcEvaluatorType& srcEvaluator() const EIGEN_NOEXCEPT { return m_src; }
/// Assign src(row,col) to dst(row,col) through the assignment functor.
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(Index row, Index col) {
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void assignCoeff(Index row, Index col) {
m_functor.assignCoeff(m_dst.coeffRef(row, col), m_src.coeff(row, col));
}
@ -596,7 +611,7 @@ class generic_dense_assignment_kernel {
}
/// \sa assignCoeff(Index,Index)
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeffByOuterInner(Index outer, Index inner) {
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void assignCoeffByOuterInner(Index outer, Index inner) {
Index row = rowIndexByOuterInner(outer, inner);
Index col = colIndexByOuterInner(outer, inner);
assignCoeff(row, col);
@ -620,7 +635,7 @@ class generic_dense_assignment_kernel {
assignPacket<StoreMode, LoadMode, Packet>(row, col);
}
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE Index rowIndexByOuterInner(Index outer, Index inner) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr Index rowIndexByOuterInner(Index outer, Index inner) {
typedef typename DstEvaluatorType::ExpressionTraits Traits;
return int(Traits::RowsAtCompileTime) == 1 ? 0
: int(Traits::ColsAtCompileTime) == 1 ? inner
@ -628,7 +643,7 @@ class generic_dense_assignment_kernel {
: inner;
}
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE Index colIndexByOuterInner(Index outer, Index inner) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr Index colIndexByOuterInner(Index outer, Index inner) {
typedef typename DstEvaluatorType::ExpressionTraits Traits;
return int(Traits::ColsAtCompileTime) == 1 ? 0
: int(Traits::RowsAtCompileTime) == 1 ? inner
@ -672,16 +687,16 @@ class restricted_packet_dense_assignment_kernel
***************************************************************************/
template <typename DstXprType, typename SrcXprType, typename Functor>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void resize_if_allowed(DstXprType& dst, const SrcXprType& src,
const Functor& /*func*/) {
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void resize_if_allowed(DstXprType& dst, const SrcXprType& src,
const Functor& /*func*/) {
EIGEN_ONLY_USED_FOR_DEBUG(dst);
EIGEN_ONLY_USED_FOR_DEBUG(src);
eigen_assert(dst.rows() == src.rows() && dst.cols() == src.cols());
}
template <typename DstXprType, typename SrcXprType, typename T1, typename T2>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void resize_if_allowed(DstXprType& dst, const SrcXprType& src,
const internal::assign_op<T1, T2>& /*func*/) {
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void resize_if_allowed(DstXprType& dst, const SrcXprType& src,
const internal::assign_op<T1, T2>& /*func*/) {
Index dstRows = src.rows();
Index dstCols = src.cols();
if (((dst.rows() != dstRows) || (dst.cols() != dstCols))) dst.resize(dstRows, dstCols);
@ -750,7 +765,7 @@ struct Assignment;
// not has to bother about these annoying details.
template <typename Dst, typename Src>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void call_assignment(Dst& dst, const Src& src) {
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void call_assignment(Dst& dst, const Src& src) {
call_assignment(dst, src, internal::assign_op<typename Dst::Scalar, typename Src::Scalar>());
}
template <typename Dst, typename Src>
@ -767,7 +782,7 @@ EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR void call_assignment(
}
template <typename Dst, typename Src, typename Func>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void call_assignment(
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void call_assignment(
Dst& dst, const Src& src, const Func& func, std::enable_if_t<!evaluator_assume_aliasing<Src>::value, void*> = 0) {
call_assignment_no_alias(dst, src, func);
}
@ -851,9 +866,12 @@ EIGEN_DEVICE_FUNC void check_for_aliasing(const Dst& dst, const Src& src);
// both partial specialization+SFINAE without ambiguous specialization
template <typename DstXprType, typename SrcXprType, typename Functor, typename Weak>
struct Assignment<DstXprType, SrcXprType, Functor, Dense2Dense, Weak> {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE void run(DstXprType& dst, const SrcXprType& src, const Functor& func) {
EIGEN_DEVICE_FUNC static EIGEN_STRONG_INLINE constexpr void run(DstXprType& dst, const SrcXprType& src,
const Functor& func) {
#ifndef EIGEN_NO_DEBUG
internal::check_for_aliasing(dst, src);
if (!internal::is_constant_evaluated()) {
internal::check_for_aliasing(dst, src);
}
#endif
call_dense_assignment_loop(dst, src, func);

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@ -50,7 +50,7 @@ struct EigenBase {
/** \returns a const reference to the derived object */
EIGEN_DEVICE_FUNC constexpr const Derived& derived() const { return *static_cast<const Derived*>(this); }
EIGEN_DEVICE_FUNC inline Derived& const_cast_derived() const {
EIGEN_DEVICE_FUNC inline constexpr Derived& const_cast_derived() const {
return *static_cast<Derived*>(const_cast<EigenBase*>(this));
}
EIGEN_DEVICE_FUNC inline const Derived& const_derived() const { return *static_cast<const Derived*>(this); }

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@ -60,12 +60,12 @@ struct eigen_fill_impl<Xpr, /*use_fill*/ false> {
using Func = scalar_constant_op<Scalar>;
using PlainObject = typename Xpr::PlainObject;
using Constant = typename PlainObject::ConstantReturnType;
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Xpr& dst, const Scalar& val) {
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void run(Xpr& dst, const Scalar& val) {
const Constant src(dst.rows(), dst.cols(), val);
run(dst, src);
}
template <typename SrcXpr>
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Xpr& dst, const SrcXpr& src) {
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void run(Xpr& dst, const SrcXpr& src) {
call_dense_assignment_loop(dst, src, assign_op<Scalar, Scalar>());
}
};
@ -100,12 +100,12 @@ struct eigen_zero_impl<Xpr, /*use_memset*/ false> {
using Scalar = typename Xpr::Scalar;
using PlainObject = typename Xpr::PlainObject;
using Zero = typename PlainObject::ZeroReturnType;
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Xpr& dst) {
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void run(Xpr& dst) {
const Zero src(dst.rows(), dst.cols());
run(dst, src);
}
template <typename SrcXpr>
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Xpr& dst, const SrcXpr& src) {
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void run(Xpr& dst, const SrcXpr& src) {
call_dense_assignment_loop(dst, src, assign_op<Scalar, Scalar>());
}
};

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@ -23,7 +23,7 @@ namespace internal {
*/
template <typename DstScalar, typename SrcScalar>
struct assign_op {
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a = b; }
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr void assignCoeff(DstScalar& a, const SrcScalar& b) const { a = b; }
template <int Alignment, typename Packet>
EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const {

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@ -10,6 +10,13 @@
#define EIGEN_TESTING_CONSTEXPR
#include "main.h"
template <typename Scalar, int Rows>
struct ConstexprTest {
constexpr ConstexprTest(const Matrix<Scalar, Rows, Rows>& B) { A = B; }
Matrix<Scalar, Rows, Rows> A;
};
EIGEN_DECLARE_TEST(constexpr) {
// Clang accepts (some of) this code when using C++14/C++17, but GCC does not like
// the fact that `T array[Size]` inside Eigen::internal::plain_array is not initialized
@ -33,6 +40,18 @@ EIGEN_DECLARE_TEST(constexpr) {
VERIFY_IS_EQUAL(vec.size(), 3);
static_assert(vec.coeff(0, 1) == 2);
// Check assignment. A wrapper struct is used to avoid copy ellision.
constexpr ConstexprTest obj1(Matrix2d({{1, 2}, {3, 4}}));
VERIFY_IS_EQUAL(obj1.A.size(), 4);
static_assert(obj1.A(0, 0) == 1);
static_assert(obj1.A(0) == 1);
static_assert(obj1.A.coeff(0, 1) == 2);
constexpr ConstexprTest obj2(Matrix3d({{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}));
VERIFY_IS_EQUAL(obj2.A.size(), 9);
static_assert(obj2.A(0, 0) == 1);
static_assert(obj2.A(0) == 1);
static_assert(obj2.A.coeff(0, 1) == 2);
// Also check dynamic size arrays/matrices with fixed-size storage (currently
// only works if all elements are initialized, since otherwise the compiler
// complains about uninitialized trailing elements.