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Core: Name the Array shift operators for the shift they perform

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libeigen/eigen!2816

Co-authored-by: Rasmus Munk Larsen <rmlarsen@gmail.com>
This commit is contained in:
Rasmus Munk Larsen
2026-08-15 18:19:50 -07:00
co-authored by Rasmus Munk Larsen
parent 9b1c027e6d
commit a0edc3964b
5 changed files with 117 additions and 49 deletions
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test/array_cwise.cpp
+9 -26
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@@ -8,6 +8,9 @@
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// SPDX-License-Identifier: MPL-2.0
// Silence warnings about the deprecated shiftLeft()/shiftRight(), which are still being tested.
#define EIGEN_NO_DEPRECATED_WARNING
#include <vector>
#include "main.h"
#include "random_without_cast_overflow.h"
@@ -1170,29 +1173,6 @@ void min_max(const ArrayType& m) {
}
}
template <typename Scalar>
struct shift_imm_traits {
enum { Cost = 1, PacketAccess = internal::packet_traits<Scalar>::HasShift };
};
// ArrayBase exposes an arithmetic right shift and a logical left shift, but no logical right shift,
// so that packet op is still reached through a functor of its own.
template <int N, typename Scalar>
struct logical_right_shift_op {
Scalar operator()(const Scalar& v) const { return numext::logical_shift_right(v, N); }
template <typename Packet>
Packet packetOp(const Packet& v) const {
return internal::plogical_shift_right<N>(v);
}
};
namespace Eigen {
namespace internal {
template <int N, typename Scalar>
struct functor_traits<logical_right_shift_op<N, Scalar>> : shift_imm_traits<Scalar> {};
} // namespace internal
} // namespace Eigen
// A lambda takes the default functor_traits, so each reference arm stays scalar while the arm under
// test vectorizes. Comparing the reference against the shift expression as well as against the
// assigned result evaluates the expression coefficient-wise, which is the only path that reaches the
@@ -1217,20 +1197,23 @@ struct shift_test_impl {
m1(rows - 1, cols - 1) = NumTraits<Scalar>::highest();
m2 = m1.unaryExpr([](const Scalar& v) { return numext::logical_shift_left(v, N); });
m3 = m1.template shiftLeft<N>();
m3 = m1.template logicalShiftLeft<N>();
VERIFY_IS_CWISE_EQUAL(m2, m3);
VERIFY_IS_CWISE_EQUAL(m2, m1.template logicalShiftLeft<N>());
VERIFY_IS_CWISE_EQUAL(m2, m1.template shiftLeft<N>());
m2 = m1.unaryExpr([](const Scalar& v) { return numext::logical_shift_right(v, N); });
m3 = m1.unaryExpr(logical_right_shift_op<N, Scalar>());
m3 = m1.template logicalShiftRight<N>();
VERIFY_IS_CWISE_EQUAL(m2, m3);
VERIFY_IS_CWISE_EQUAL(m2, m1.template logicalShiftRight<N>());
// Referencing Scalar's own operator>> rather than the numext helper the functor calls keeps this
// arm independent of the implementation under test, and states the semantics: fill with the sign
// bit when Scalar is signed and with zero when it is not.
m2 = m1.unaryExpr([](const Scalar& v) { return static_cast<Scalar>(v >> N); });
m3 = m1.template shiftRight<N>();
m3 = m1.template arithmeticShiftRight<N>();
VERIFY_IS_CWISE_EQUAL(m2, m3);
VERIFY_IS_CWISE_EQUAL(m2, m1.template arithmeticShiftRight<N>());
VERIFY_IS_CWISE_EQUAL(m2, m1.template shiftRight<N>());
run<N + 1>(m);