path: root/third_party/highway/hwy/ops/arm_sve-inl.h

// Copyright 2021 Google LLC
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// ARM SVE[2] vectors (length not known at compile time).
// External include guard in highway.h - see comment there.

#include <arm_sve.h>
#include <stddef.h>
#include <stdint.h>

#include "hwy/base.h"
#include "hwy/ops/shared-inl.h"

// If running on hardware whose vector length is known to be a power of two, we
// can skip fixups for non-power of two sizes.
#undef HWY_SVE_IS_POW2
#if HWY_TARGET == HWY_SVE_256 || HWY_TARGET == HWY_SVE2_128
#define HWY_SVE_IS_POW2 1
#else
#define HWY_SVE_IS_POW2 0
#endif

HWY_BEFORE_NAMESPACE();
namespace hwy {
namespace HWY_NAMESPACE {

template <class V>
struct DFromV_t {};  // specialized in macros
template <class V>
using DFromV = typename DFromV_t<RemoveConst<V>>::type;

template <class V>
using TFromV = TFromD<DFromV<V>>;

// ================================================== MACROS

// Generate specializations and function definitions using X macros. Although
// harder to read and debug, writing everything manually is too bulky.

namespace detail {  // for code folding

// Unsigned:
#define HWY_SVE_FOREACH_U08(X_MACRO, NAME, OP) X_MACRO(uint, u, 8, 8, NAME, OP)
#define HWY_SVE_FOREACH_U16(X_MACRO, NAME, OP) X_MACRO(uint, u, 16, 8, NAME, OP)
#define HWY_SVE_FOREACH_U32(X_MACRO, NAME, OP) \
  X_MACRO(uint, u, 32, 16, NAME, OP)
#define HWY_SVE_FOREACH_U64(X_MACRO, NAME, OP) \
  X_MACRO(uint, u, 64, 32, NAME, OP)

// Signed:
#define HWY_SVE_FOREACH_I08(X_MACRO, NAME, OP) X_MACRO(int, s, 8, 8, NAME, OP)
#define HWY_SVE_FOREACH_I16(X_MACRO, NAME, OP) X_MACRO(int, s, 16, 8, NAME, OP)
#define HWY_SVE_FOREACH_I32(X_MACRO, NAME, OP) X_MACRO(int, s, 32, 16, NAME, OP)
#define HWY_SVE_FOREACH_I64(X_MACRO, NAME, OP) X_MACRO(int, s, 64, 32, NAME, OP)

// Float:
#define HWY_SVE_FOREACH_F16(X_MACRO, NAME, OP) \
  X_MACRO(float, f, 16, 16, NAME, OP)
#define HWY_SVE_FOREACH_F32(X_MACRO, NAME, OP) \
  X_MACRO(float, f, 32, 16, NAME, OP)
#define HWY_SVE_FOREACH_F64(X_MACRO, NAME, OP) \
  X_MACRO(float, f, 64, 32, NAME, OP)

// For all element sizes:
#define HWY_SVE_FOREACH_U(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U08(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_U16(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_U32(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_U64(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_I(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_I08(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_I16(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_I32(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_I64(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_F(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_F16(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_F32(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_F64(X_MACRO, NAME, OP)

// Commonly used type categories for a given element size:
#define HWY_SVE_FOREACH_UI08(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U08(X_MACRO, NAME, OP)        \
  HWY_SVE_FOREACH_I08(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_UI16(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U16(X_MACRO, NAME, OP)        \
  HWY_SVE_FOREACH_I16(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_UI32(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U32(X_MACRO, NAME, OP)        \
  HWY_SVE_FOREACH_I32(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_UI64(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U64(X_MACRO, NAME, OP)        \
  HWY_SVE_FOREACH_I64(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_UIF3264(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_UI32(X_MACRO, NAME, OP)          \
  HWY_SVE_FOREACH_UI64(X_MACRO, NAME, OP)          \
  HWY_SVE_FOREACH_F32(X_MACRO, NAME, OP)           \
  HWY_SVE_FOREACH_F64(X_MACRO, NAME, OP)

// Commonly used type categories:
#define HWY_SVE_FOREACH_UI(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U(X_MACRO, NAME, OP)        \
  HWY_SVE_FOREACH_I(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH_IF(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_I(X_MACRO, NAME, OP)        \
  HWY_SVE_FOREACH_F(X_MACRO, NAME, OP)

#define HWY_SVE_FOREACH(X_MACRO, NAME, OP) \
  HWY_SVE_FOREACH_U(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_I(X_MACRO, NAME, OP)     \
  HWY_SVE_FOREACH_F(X_MACRO, NAME, OP)

// Assemble types for use in x-macros
#define HWY_SVE_T(BASE, BITS) BASE##BITS##_t
#define HWY_SVE_D(BASE, BITS, N, POW2) Simd<HWY_SVE_T(BASE, BITS), N, POW2>
#define HWY_SVE_V(BASE, BITS) sv##BASE##BITS##_t

}  // namespace detail

#define HWY_SPECIALIZE(BASE, CHAR, BITS, HALF, NAME, OP) \
  template <>                                            \
  struct DFromV_t<HWY_SVE_V(BASE, BITS)> {               \
    using type = ScalableTag<HWY_SVE_T(BASE, BITS)>;     \
  };

HWY_SVE_FOREACH(HWY_SPECIALIZE, _, _)
#undef HWY_SPECIALIZE

// Note: _x (don't-care value for inactive lanes) avoids additional MOVPRFX
// instructions, and we anyway only use it when the predicate is ptrue.

// vector = f(vector), e.g. Not
#define HWY_SVE_RETV_ARGPV(BASE, CHAR, BITS, HALF, NAME, OP)    \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v) { \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), v);   \
  }
#define HWY_SVE_RETV_ARGV(BASE, CHAR, BITS, HALF, NAME, OP)     \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v) { \
    return sv##OP##_##CHAR##BITS(v);                            \
  }

// vector = f(vector, scalar), e.g. detail::AddN
#define HWY_SVE_RETV_ARGPVN(BASE, CHAR, BITS, HALF, NAME, OP)    \
  HWY_API HWY_SVE_V(BASE, BITS)                                  \
      NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_T(BASE, BITS) b) {   \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), a, b); \
  }
#define HWY_SVE_RETV_ARGVN(BASE, CHAR, BITS, HALF, NAME, OP)   \
  HWY_API HWY_SVE_V(BASE, BITS)                                \
      NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_T(BASE, BITS) b) { \
    return sv##OP##_##CHAR##BITS(a, b);                        \
  }

// vector = f(vector, vector), e.g. Add
#define HWY_SVE_RETV_ARGPVV(BASE, CHAR, BITS, HALF, NAME, OP)    \
  HWY_API HWY_SVE_V(BASE, BITS)                                  \
      NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_V(BASE, BITS) b) {   \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), a, b); \
  }
#define HWY_SVE_RETV_ARGVV(BASE, CHAR, BITS, HALF, NAME, OP)   \
  HWY_API HWY_SVE_V(BASE, BITS)                                \
      NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_V(BASE, BITS) b) { \
    return sv##OP##_##CHAR##BITS(a, b);                        \
  }

#define HWY_SVE_RETV_ARGVVV(BASE, CHAR, BITS, HALF, NAME, OP) \
  HWY_API HWY_SVE_V(BASE, BITS)                               \
      NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_V(BASE, BITS) b,  \
           HWY_SVE_V(BASE, BITS) c) {                         \
    return sv##OP##_##CHAR##BITS(a, b, c);                    \
  }

// ------------------------------ Lanes

namespace detail {

// Returns actual lanes of a hardware vector without rounding to a power of two.
HWY_INLINE size_t AllHardwareLanes(hwy::SizeTag<1> /* tag */) {
  return svcntb_pat(SV_ALL);
}
HWY_INLINE size_t AllHardwareLanes(hwy::SizeTag<2> /* tag */) {
  return svcnth_pat(SV_ALL);
}
HWY_INLINE size_t AllHardwareLanes(hwy::SizeTag<4> /* tag */) {
  return svcntw_pat(SV_ALL);
}
HWY_INLINE size_t AllHardwareLanes(hwy::SizeTag<8> /* tag */) {
  return svcntd_pat(SV_ALL);
}

// All-true mask from a macro
#define HWY_SVE_ALL_PTRUE(BITS) svptrue_pat_b##BITS(SV_ALL)

#if HWY_SVE_IS_POW2
#define HWY_SVE_PTRUE(BITS) HWY_SVE_ALL_PTRUE(BITS)
#else
#define HWY_SVE_PTRUE(BITS) svptrue_pat_b##BITS(SV_POW2)

// Returns actual lanes of a hardware vector, rounded down to a power of two.
template <typename T, HWY_IF_LANE_SIZE(T, 1)>
HWY_INLINE size_t HardwareLanes() {
  return svcntb_pat(SV_POW2);
}
template <typename T, HWY_IF_LANE_SIZE(T, 2)>
HWY_INLINE size_t HardwareLanes() {
  return svcnth_pat(SV_POW2);
}
template <typename T, HWY_IF_LANE_SIZE(T, 4)>
HWY_INLINE size_t HardwareLanes() {
  return svcntw_pat(SV_POW2);
}
template <typename T, HWY_IF_LANE_SIZE(T, 8)>
HWY_INLINE size_t HardwareLanes() {
  return svcntd_pat(SV_POW2);
}

#endif  // HWY_SVE_IS_POW2

}  // namespace detail

// Returns actual number of lanes after capping by N and shifting. May return 0
// (e.g. for "1/8th" of a u32x4 - would be 1 for 1/8th of u32x8).
#if HWY_TARGET == HWY_SVE_256
template <typename T, size_t N, int kPow2>
HWY_API constexpr size_t Lanes(Simd<T, N, kPow2> /* d */) {
  return HWY_MIN(detail::ScaleByPower(32 / sizeof(T), kPow2), N);
}
#elif HWY_TARGET == HWY_SVE2_128
template <typename T, size_t N, int kPow2>
HWY_API constexpr size_t Lanes(Simd<T, N, kPow2> /* d */) {
  return HWY_MIN(detail::ScaleByPower(16 / sizeof(T), kPow2), N);
}
#else
template <typename T, size_t N, int kPow2>
HWY_API size_t Lanes(Simd<T, N, kPow2> d) {
  const size_t actual = detail::HardwareLanes<T>();
  // Common case of full vectors: avoid any extra instructions.
  if (detail::IsFull(d)) return actual;
  return HWY_MIN(detail::ScaleByPower(actual, kPow2), N);
}
#endif  // HWY_TARGET

// ================================================== MASK INIT

// One mask bit per byte; only the one belonging to the lowest byte is valid.

// ------------------------------ FirstN
#define HWY_SVE_FIRSTN(BASE, CHAR, BITS, HALF, NAME, OP)                       \
  template <size_t N, int kPow2>                                               \
  HWY_API svbool_t NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d, size_t count) {     \
    const size_t limit = detail::IsFull(d) ? count : HWY_MIN(Lanes(d), count); \
    return sv##OP##_b##BITS##_u32(uint32_t{0}, static_cast<uint32_t>(limit));  \
  }
HWY_SVE_FOREACH(HWY_SVE_FIRSTN, FirstN, whilelt)
#undef HWY_SVE_FIRSTN

template <class D>
using MFromD = decltype(FirstN(D(), 0));

namespace detail {

#define HWY_SVE_WRAP_PTRUE(BASE, CHAR, BITS, HALF, NAME, OP)            \
  template <size_t N, int kPow2>                                        \
  HWY_API svbool_t NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */) {      \
    return HWY_SVE_PTRUE(BITS);                                         \
  }                                                                     \
  template <size_t N, int kPow2>                                        \
  HWY_API svbool_t All##NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */) { \
    return HWY_SVE_ALL_PTRUE(BITS);                                     \
  }

HWY_SVE_FOREACH(HWY_SVE_WRAP_PTRUE, PTrue, ptrue)  // return all-true
#undef HWY_SVE_WRAP_PTRUE

HWY_API svbool_t PFalse() { return svpfalse_b(); }

// Returns all-true if d is HWY_FULL or FirstN(N) after capping N.
//
// This is used in functions that load/store memory; other functions (e.g.
// arithmetic) can ignore d and use PTrue instead.
template <class D>
svbool_t MakeMask(D d) {
  return IsFull(d) ? PTrue(d) : FirstN(d, Lanes(d));
}

}  // namespace detail

// ================================================== INIT

// ------------------------------ Set
// vector = f(d, scalar), e.g. Set
#define HWY_SVE_SET(BASE, CHAR, BITS, HALF, NAME, OP)                         \
  template <size_t N, int kPow2>                                              \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, \
                                     HWY_SVE_T(BASE, BITS) arg) {             \
    return sv##OP##_##CHAR##BITS(arg);                                        \
  }

HWY_SVE_FOREACH(HWY_SVE_SET, Set, dup_n)
#undef HWY_SVE_SET

// Required for Zero and VFromD
template <size_t N, int kPow2>
svuint16_t Set(Simd<bfloat16_t, N, kPow2> d, bfloat16_t arg) {
  return Set(RebindToUnsigned<decltype(d)>(), arg.bits);
}

template <class D>
using VFromD = decltype(Set(D(), TFromD<D>()));

// ------------------------------ Zero

template <class D>
VFromD<D> Zero(D d) {
  // Cast to support bfloat16_t.
  const RebindToUnsigned<decltype(d)> du;
  return BitCast(d, Set(du, 0));
}

// ------------------------------ Undefined

#define HWY_SVE_UNDEFINED(BASE, CHAR, BITS, HALF, NAME, OP) \
  template <size_t N, int kPow2>                            \
  HWY_API HWY_SVE_V(BASE, BITS)                             \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */) {       \
    return sv##OP##_##CHAR##BITS();                         \
  }

HWY_SVE_FOREACH(HWY_SVE_UNDEFINED, Undefined, undef)

// ------------------------------ BitCast

namespace detail {

// u8: no change
#define HWY_SVE_CAST_NOP(BASE, CHAR, BITS, HALF, NAME, OP)                \
  HWY_API HWY_SVE_V(BASE, BITS) BitCastToByte(HWY_SVE_V(BASE, BITS) v) {  \
    return v;                                                             \
  }                                                                       \
  template <size_t N, int kPow2>                                          \
  HWY_API HWY_SVE_V(BASE, BITS) BitCastFromByte(                          \
      HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, HWY_SVE_V(BASE, BITS) v) { \
    return v;                                                             \
  }

// All other types
#define HWY_SVE_CAST(BASE, CHAR, BITS, HALF, NAME, OP)                        \
  HWY_INLINE svuint8_t BitCastToByte(HWY_SVE_V(BASE, BITS) v) {               \
    return sv##OP##_u8_##CHAR##BITS(v);                                       \
  }                                                                           \
  template <size_t N, int kPow2>                                              \
  HWY_INLINE HWY_SVE_V(BASE, BITS)                                            \
      BitCastFromByte(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, svuint8_t v) { \
    return sv##OP##_##CHAR##BITS##_u8(v);                                     \
  }

HWY_SVE_FOREACH_U08(HWY_SVE_CAST_NOP, _, _)
HWY_SVE_FOREACH_I08(HWY_SVE_CAST, _, reinterpret)
HWY_SVE_FOREACH_UI16(HWY_SVE_CAST, _, reinterpret)
HWY_SVE_FOREACH_UI32(HWY_SVE_CAST, _, reinterpret)
HWY_SVE_FOREACH_UI64(HWY_SVE_CAST, _, reinterpret)
HWY_SVE_FOREACH_F(HWY_SVE_CAST, _, reinterpret)

#undef HWY_SVE_CAST_NOP
#undef HWY_SVE_CAST

template <size_t N, int kPow2>
HWY_INLINE svuint16_t BitCastFromByte(Simd<bfloat16_t, N, kPow2> /* d */,
                                      svuint8_t v) {
  return BitCastFromByte(Simd<uint16_t, N, kPow2>(), v);
}

}  // namespace detail

template <class D, class FromV>
HWY_API VFromD<D> BitCast(D d, FromV v) {
  return detail::BitCastFromByte(d, detail::BitCastToByte(v));
}

// ================================================== LOGICAL

// detail::*N() functions accept a scalar argument to avoid extra Set().

// ------------------------------ Not
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPV, Not, not )  // NOLINT

// ------------------------------ And

namespace detail {
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVN, AndN, and_n)
}  // namespace detail

HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVV, And, and)

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V And(const V a, const V b) {
  const DFromV<V> df;
  const RebindToUnsigned<decltype(df)> du;
  return BitCast(df, And(BitCast(du, a), BitCast(du, b)));
}

// ------------------------------ Or

HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVV, Or, orr)

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V Or(const V a, const V b) {
  const DFromV<V> df;
  const RebindToUnsigned<decltype(df)> du;
  return BitCast(df, Or(BitCast(du, a), BitCast(du, b)));
}

// ------------------------------ Xor

namespace detail {
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVN, XorN, eor_n)
}  // namespace detail

HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVV, Xor, eor)

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V Xor(const V a, const V b) {
  const DFromV<V> df;
  const RebindToUnsigned<decltype(df)> du;
  return BitCast(df, Xor(BitCast(du, a), BitCast(du, b)));
}

// ------------------------------ AndNot

namespace detail {
#define HWY_SVE_RETV_ARGPVN_SWAP(BASE, CHAR, BITS, HALF, NAME, OP) \
  HWY_API HWY_SVE_V(BASE, BITS)                                    \
      NAME(HWY_SVE_T(BASE, BITS) a, HWY_SVE_V(BASE, BITS) b) {     \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), b, a);   \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVN_SWAP, AndNotN, bic_n)
#undef HWY_SVE_RETV_ARGPVN_SWAP
}  // namespace detail

#define HWY_SVE_RETV_ARGPVV_SWAP(BASE, CHAR, BITS, HALF, NAME, OP) \
  HWY_API HWY_SVE_V(BASE, BITS)                                    \
      NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_V(BASE, BITS) b) {     \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), b, a);   \
  }
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVV_SWAP, AndNot, bic)
#undef HWY_SVE_RETV_ARGPVV_SWAP

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V AndNot(const V a, const V b) {
  const DFromV<V> df;
  const RebindToUnsigned<decltype(df)> du;
  return BitCast(df, AndNot(BitCast(du, a), BitCast(du, b)));
}

// ------------------------------ Xor3

#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128

HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGVVV, Xor3, eor3)

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V Xor3(const V x1, const V x2, const V x3) {
  const DFromV<V> df;
  const RebindToUnsigned<decltype(df)> du;
  return BitCast(df, Xor3(BitCast(du, x1), BitCast(du, x2), BitCast(du, x3)));
}

#else
template <class V>
HWY_API V Xor3(V x1, V x2, V x3) {
  return Xor(x1, Xor(x2, x3));
}
#endif

// ------------------------------ Or3
template <class V>
HWY_API V Or3(V o1, V o2, V o3) {
  return Or(o1, Or(o2, o3));
}

// ------------------------------ OrAnd
template <class V>
HWY_API V OrAnd(const V o, const V a1, const V a2) {
  return Or(o, And(a1, a2));
}

// ------------------------------ PopulationCount

#ifdef HWY_NATIVE_POPCNT
#undef HWY_NATIVE_POPCNT
#else
#define HWY_NATIVE_POPCNT
#endif

// Need to return original type instead of unsigned.
#define HWY_SVE_POPCNT(BASE, CHAR, BITS, HALF, NAME, OP)               \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v) {        \
    return BitCast(DFromV<decltype(v)>(),                              \
                   sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), v)); \
  }
HWY_SVE_FOREACH_UI(HWY_SVE_POPCNT, PopulationCount, cnt)
#undef HWY_SVE_POPCNT

// ================================================== SIGN

// ------------------------------ Neg
HWY_SVE_FOREACH_IF(HWY_SVE_RETV_ARGPV, Neg, neg)

// ------------------------------ Abs
HWY_SVE_FOREACH_IF(HWY_SVE_RETV_ARGPV, Abs, abs)

// ------------------------------ CopySign[ToAbs]

template <class V>
HWY_API V CopySign(const V magn, const V sign) {
  const auto msb = SignBit(DFromV<V>());
  return Or(AndNot(msb, magn), And(msb, sign));
}

template <class V>
HWY_API V CopySignToAbs(const V abs, const V sign) {
  const auto msb = SignBit(DFromV<V>());
  return Or(abs, And(msb, sign));
}

// ================================================== ARITHMETIC

// ------------------------------ Add

namespace detail {
HWY_SVE_FOREACH(HWY_SVE_RETV_ARGPVN, AddN, add_n)
}  // namespace detail

HWY_SVE_FOREACH(HWY_SVE_RETV_ARGPVV, Add, add)

// ------------------------------ Sub

namespace detail {
// Can't use HWY_SVE_RETV_ARGPVN because caller wants to specify pg.
#define HWY_SVE_RETV_ARGPVN_MASK(BASE, CHAR, BITS, HALF, NAME, OP)          \
  HWY_API HWY_SVE_V(BASE, BITS)                                             \
      NAME(svbool_t pg, HWY_SVE_V(BASE, BITS) a, HWY_SVE_T(BASE, BITS) b) { \
    return sv##OP##_##CHAR##BITS##_z(pg, a, b);                             \
  }

HWY_SVE_FOREACH(HWY_SVE_RETV_ARGPVN_MASK, SubN, sub_n)
#undef HWY_SVE_RETV_ARGPVN_MASK
}  // namespace detail

HWY_SVE_FOREACH(HWY_SVE_RETV_ARGPVV, Sub, sub)

// ------------------------------ SumsOf8
HWY_API svuint64_t SumsOf8(const svuint8_t v) {
  const ScalableTag<uint32_t> du32;
  const ScalableTag<uint64_t> du64;
  const svbool_t pg = detail::PTrue(du64);

  const svuint32_t sums_of_4 = svdot_n_u32(Zero(du32), v, 1);
  // Compute pairwise sum of u32 and extend to u64.
  // TODO(janwas): on SVE2, we can instead use svaddp.
  const svuint64_t hi = svlsr_n_u64_x(pg, BitCast(du64, sums_of_4), 32);
  // Isolate the lower 32 bits (to be added to the upper 32 and zero-extended)
  const svuint64_t lo = svextw_u64_x(pg, BitCast(du64, sums_of_4));
  return Add(hi, lo);
}

// ------------------------------ SaturatedAdd

HWY_SVE_FOREACH_UI08(HWY_SVE_RETV_ARGVV, SaturatedAdd, qadd)
HWY_SVE_FOREACH_UI16(HWY_SVE_RETV_ARGVV, SaturatedAdd, qadd)

// ------------------------------ SaturatedSub

HWY_SVE_FOREACH_UI08(HWY_SVE_RETV_ARGVV, SaturatedSub, qsub)
HWY_SVE_FOREACH_UI16(HWY_SVE_RETV_ARGVV, SaturatedSub, qsub)

// ------------------------------ AbsDiff
HWY_SVE_FOREACH_IF(HWY_SVE_RETV_ARGPVV, AbsDiff, abd)

// ------------------------------ ShiftLeft[Same]

#define HWY_SVE_SHIFT_N(BASE, CHAR, BITS, HALF, NAME, OP)               \
  template <int kBits>                                                  \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v) {         \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), v, kBits);    \
  }                                                                     \
  HWY_API HWY_SVE_V(BASE, BITS)                                         \
      NAME##Same(HWY_SVE_V(BASE, BITS) v, HWY_SVE_T(uint, BITS) bits) { \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), v, bits);     \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_SHIFT_N, ShiftLeft, lsl_n)

// ------------------------------ ShiftRight[Same]

HWY_SVE_FOREACH_U(HWY_SVE_SHIFT_N, ShiftRight, lsr_n)
HWY_SVE_FOREACH_I(HWY_SVE_SHIFT_N, ShiftRight, asr_n)

#undef HWY_SVE_SHIFT_N

// ------------------------------ RotateRight

// TODO(janwas): svxar on SVE2
template <int kBits, class V>
HWY_API V RotateRight(const V v) {
  constexpr size_t kSizeInBits = sizeof(TFromV<V>) * 8;
  static_assert(0 <= kBits && kBits < kSizeInBits, "Invalid shift count");
  if (kBits == 0) return v;
  return Or(ShiftRight<kBits>(v), ShiftLeft<kSizeInBits - kBits>(v));
}

// ------------------------------ Shl/r

#define HWY_SVE_SHIFT(BASE, CHAR, BITS, HALF, NAME, OP)           \
  HWY_API HWY_SVE_V(BASE, BITS)                                   \
      NAME(HWY_SVE_V(BASE, BITS) v, HWY_SVE_V(BASE, BITS) bits) { \
    const RebindToUnsigned<DFromV<decltype(v)>> du;               \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), v,      \
                                     BitCast(du, bits));          \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_SHIFT, Shl, lsl)

HWY_SVE_FOREACH_U(HWY_SVE_SHIFT, Shr, lsr)
HWY_SVE_FOREACH_I(HWY_SVE_SHIFT, Shr, asr)

#undef HWY_SVE_SHIFT

// ------------------------------ Min/Max

HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVV, Min, min)
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVV, Max, max)
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPVV, Min, minnm)
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPVV, Max, maxnm)

namespace detail {
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVN, MinN, min_n)
HWY_SVE_FOREACH_UI(HWY_SVE_RETV_ARGPVN, MaxN, max_n)
}  // namespace detail

// ------------------------------ Mul
HWY_SVE_FOREACH_UI16(HWY_SVE_RETV_ARGPVV, Mul, mul)
HWY_SVE_FOREACH_UIF3264(HWY_SVE_RETV_ARGPVV, Mul, mul)

// Per-target flag to prevent generic_ops-inl.h from defining i64 operator*.
#ifdef HWY_NATIVE_I64MULLO
#undef HWY_NATIVE_I64MULLO
#else
#define HWY_NATIVE_I64MULLO
#endif

// ------------------------------ MulHigh
HWY_SVE_FOREACH_UI16(HWY_SVE_RETV_ARGPVV, MulHigh, mulh)
// Not part of API, used internally:
HWY_SVE_FOREACH_UI32(HWY_SVE_RETV_ARGPVV, MulHigh, mulh)
HWY_SVE_FOREACH_U64(HWY_SVE_RETV_ARGPVV, MulHigh, mulh)

// ------------------------------ MulFixedPoint15
HWY_API svint16_t MulFixedPoint15(svint16_t a, svint16_t b) {
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  return svqrdmulh_s16(a, b);
#else
  const DFromV<decltype(a)> d;
  const RebindToUnsigned<decltype(d)> du;

  const svuint16_t lo = BitCast(du, Mul(a, b));
  const svint16_t hi = MulHigh(a, b);
  // We want (lo + 0x4000) >> 15, but that can overflow, and if it does we must
  // carry that into the result. Instead isolate the top two bits because only
  // they can influence the result.
  const svuint16_t lo_top2 = ShiftRight<14>(lo);
  // Bits 11: add 2, 10: add 1, 01: add 1, 00: add 0.
  const svuint16_t rounding = ShiftRight<1>(detail::AddN(lo_top2, 1));
  return Add(Add(hi, hi), BitCast(d, rounding));
#endif
}

// ------------------------------ Div
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPVV, Div, div)

// ------------------------------ ApproximateReciprocal
HWY_SVE_FOREACH_F32(HWY_SVE_RETV_ARGV, ApproximateReciprocal, recpe)

// ------------------------------ Sqrt
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPV, Sqrt, sqrt)

// ------------------------------ ApproximateReciprocalSqrt
HWY_SVE_FOREACH_F32(HWY_SVE_RETV_ARGV, ApproximateReciprocalSqrt, rsqrte)

// ------------------------------ MulAdd
#define HWY_SVE_FMA(BASE, CHAR, BITS, HALF, NAME, OP)                   \
  HWY_API HWY_SVE_V(BASE, BITS)                                         \
      NAME(HWY_SVE_V(BASE, BITS) mul, HWY_SVE_V(BASE, BITS) x,          \
           HWY_SVE_V(BASE, BITS) add) {                                 \
    return sv##OP##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), x, mul, add); \
  }

HWY_SVE_FOREACH_F(HWY_SVE_FMA, MulAdd, mad)

// ------------------------------ NegMulAdd
HWY_SVE_FOREACH_F(HWY_SVE_FMA, NegMulAdd, msb)

// ------------------------------ MulSub
HWY_SVE_FOREACH_F(HWY_SVE_FMA, MulSub, nmsb)

// ------------------------------ NegMulSub
HWY_SVE_FOREACH_F(HWY_SVE_FMA, NegMulSub, nmad)

#undef HWY_SVE_FMA

// ------------------------------ Round etc.

HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPV, Round, rintn)
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPV, Floor, rintm)
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPV, Ceil, rintp)
HWY_SVE_FOREACH_F(HWY_SVE_RETV_ARGPV, Trunc, rintz)

// ================================================== MASK

// ------------------------------ RebindMask
template <class D, typename MFrom>
HWY_API svbool_t RebindMask(const D /*d*/, const MFrom mask) {
  return mask;
}

// ------------------------------ Mask logical

HWY_API svbool_t Not(svbool_t m) {
  // We don't know the lane type, so assume 8-bit. For larger types, this will
  // de-canonicalize the predicate, i.e. set bits to 1 even though they do not
  // correspond to the lowest byte in the lane. Per ARM, such bits are ignored.
  return svnot_b_z(HWY_SVE_PTRUE(8), m);
}
HWY_API svbool_t And(svbool_t a, svbool_t b) {
  return svand_b_z(b, b, a);  // same order as AndNot for consistency
}
HWY_API svbool_t AndNot(svbool_t a, svbool_t b) {
  return svbic_b_z(b, b, a);  // reversed order like NEON
}
HWY_API svbool_t Or(svbool_t a, svbool_t b) {
  return svsel_b(a, a, b);  // a ? true : b
}
HWY_API svbool_t Xor(svbool_t a, svbool_t b) {
  return svsel_b(a, svnand_b_z(a, a, b), b);  // a ? !(a & b) : b.
}

HWY_API svbool_t ExclusiveNeither(svbool_t a, svbool_t b) {
  return svnor_b_z(HWY_SVE_PTRUE(8), a, b);  // !a && !b, undefined if a && b.
}

// ------------------------------ CountTrue

#define HWY_SVE_COUNT_TRUE(BASE, CHAR, BITS, HALF, NAME, OP)           \
  template <size_t N, int kPow2>                                       \
  HWY_API size_t NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d, svbool_t m) { \
    return sv##OP##_b##BITS(detail::MakeMask(d), m);                   \
  }

HWY_SVE_FOREACH(HWY_SVE_COUNT_TRUE, CountTrue, cntp)
#undef HWY_SVE_COUNT_TRUE

// For 16-bit Compress: full vector, not limited to SV_POW2.
namespace detail {

#define HWY_SVE_COUNT_TRUE_FULL(BASE, CHAR, BITS, HALF, NAME, OP)            \
  template <size_t N, int kPow2>                                             \
  HWY_API size_t NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, svbool_t m) { \
    return sv##OP##_b##BITS(svptrue_b##BITS(), m);                           \
  }

HWY_SVE_FOREACH(HWY_SVE_COUNT_TRUE_FULL, CountTrueFull, cntp)
#undef HWY_SVE_COUNT_TRUE_FULL

}  // namespace detail

// ------------------------------ AllFalse
template <class D>
HWY_API bool AllFalse(D d, svbool_t m) {
  return !svptest_any(detail::MakeMask(d), m);
}

// ------------------------------ AllTrue
template <class D>
HWY_API bool AllTrue(D d, svbool_t m) {
  return CountTrue(d, m) == Lanes(d);
}

// ------------------------------ FindFirstTrue
template <class D>
HWY_API intptr_t FindFirstTrue(D d, svbool_t m) {
  return AllFalse(d, m) ? intptr_t{-1}
                        : static_cast<intptr_t>(
                              CountTrue(d, svbrkb_b_z(detail::MakeMask(d), m)));
}

// ------------------------------ FindKnownFirstTrue
template <class D>
HWY_API size_t FindKnownFirstTrue(D d, svbool_t m) {
  return CountTrue(d, svbrkb_b_z(detail::MakeMask(d), m));
}

// ------------------------------ IfThenElse
#define HWY_SVE_IF_THEN_ELSE(BASE, CHAR, BITS, HALF, NAME, OP)                \
  HWY_API HWY_SVE_V(BASE, BITS)                                               \
      NAME(svbool_t m, HWY_SVE_V(BASE, BITS) yes, HWY_SVE_V(BASE, BITS) no) { \
    return sv##OP##_##CHAR##BITS(m, yes, no);                                 \
  }

HWY_SVE_FOREACH(HWY_SVE_IF_THEN_ELSE, IfThenElse, sel)
#undef HWY_SVE_IF_THEN_ELSE

// ------------------------------ IfThenElseZero
template <class V>
HWY_API V IfThenElseZero(const svbool_t mask, const V yes) {
  return IfThenElse(mask, yes, Zero(DFromV<V>()));
}

// ------------------------------ IfThenZeroElse
template <class V>
HWY_API V IfThenZeroElse(const svbool_t mask, const V no) {
  return IfThenElse(mask, Zero(DFromV<V>()), no);
}

// ================================================== COMPARE

// mask = f(vector, vector)
#define HWY_SVE_COMPARE(BASE, CHAR, BITS, HALF, NAME, OP)                   \
  HWY_API svbool_t NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_V(BASE, BITS) b) { \
    return sv##OP##_##CHAR##BITS(HWY_SVE_PTRUE(BITS), a, b);                \
  }
#define HWY_SVE_COMPARE_N(BASE, CHAR, BITS, HALF, NAME, OP)                 \
  HWY_API svbool_t NAME(HWY_SVE_V(BASE, BITS) a, HWY_SVE_T(BASE, BITS) b) { \
    return sv##OP##_##CHAR##BITS(HWY_SVE_PTRUE(BITS), a, b);                \
  }

// ------------------------------ Eq
HWY_SVE_FOREACH(HWY_SVE_COMPARE, Eq, cmpeq)
namespace detail {
HWY_SVE_FOREACH(HWY_SVE_COMPARE_N, EqN, cmpeq_n)
}  // namespace detail

// ------------------------------ Ne
HWY_SVE_FOREACH(HWY_SVE_COMPARE, Ne, cmpne)
namespace detail {
HWY_SVE_FOREACH(HWY_SVE_COMPARE_N, NeN, cmpne_n)
}  // namespace detail

// ------------------------------ Lt
HWY_SVE_FOREACH(HWY_SVE_COMPARE, Lt, cmplt)
namespace detail {
HWY_SVE_FOREACH(HWY_SVE_COMPARE_N, LtN, cmplt_n)
}  // namespace detail

// ------------------------------ Le
HWY_SVE_FOREACH_F(HWY_SVE_COMPARE, Le, cmple)

#undef HWY_SVE_COMPARE
#undef HWY_SVE_COMPARE_N

// ------------------------------ Gt/Ge (swapped order)
template <class V>
HWY_API svbool_t Gt(const V a, const V b) {
  return Lt(b, a);
}
template <class V>
HWY_API svbool_t Ge(const V a, const V b) {
  return Le(b, a);
}

// ------------------------------ TestBit
template <class V>
HWY_API svbool_t TestBit(const V a, const V bit) {
  return detail::NeN(And(a, bit), 0);
}

// ------------------------------ MaskFromVec (Ne)
template <class V>
HWY_API svbool_t MaskFromVec(const V v) {
  return detail::NeN(v, static_cast<TFromV<V>>(0));
}

// ------------------------------ VecFromMask
template <class D>
HWY_API VFromD<D> VecFromMask(const D d, svbool_t mask) {
  const RebindToSigned<D> di;
  // This generates MOV imm, whereas svdup_n_s8_z generates MOV scalar, which
  // requires an extra instruction plus M0 pipeline.
  return BitCast(d, IfThenElseZero(mask, Set(di, -1)));
}

// ------------------------------ IfVecThenElse (MaskFromVec, IfThenElse)

#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128

#define HWY_SVE_IF_VEC(BASE, CHAR, BITS, HALF, NAME, OP)          \
  HWY_API HWY_SVE_V(BASE, BITS)                                   \
      NAME(HWY_SVE_V(BASE, BITS) mask, HWY_SVE_V(BASE, BITS) yes, \
           HWY_SVE_V(BASE, BITS) no) {                            \
    return sv##OP##_##CHAR##BITS(yes, no, mask);                  \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_IF_VEC, IfVecThenElse, bsl)
#undef HWY_SVE_IF_VEC

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V IfVecThenElse(const V mask, const V yes, const V no) {
  const DFromV<V> d;
  const RebindToUnsigned<decltype(d)> du;
  return BitCast(
      d, IfVecThenElse(BitCast(du, mask), BitCast(du, yes), BitCast(du, no)));
}

#else

template <class V>
HWY_API V IfVecThenElse(const V mask, const V yes, const V no) {
  return Or(And(mask, yes), AndNot(mask, no));
}

#endif  // HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128

// ------------------------------ Floating-point classification (Ne)

template <class V>
HWY_API svbool_t IsNaN(const V v) {
  return Ne(v, v);  // could also use cmpuo
}

template <class V>
HWY_API svbool_t IsInf(const V v) {
  using T = TFromV<V>;
  const DFromV<decltype(v)> d;
  const RebindToSigned<decltype(d)> di;
  const VFromD<decltype(di)> vi = BitCast(di, v);
  // 'Shift left' to clear the sign bit, check for exponent=max and mantissa=0.
  return RebindMask(d, detail::EqN(Add(vi, vi), hwy::MaxExponentTimes2<T>()));
}

// Returns whether normal/subnormal/zero.
template <class V>
HWY_API svbool_t IsFinite(const V v) {
  using T = TFromV<V>;
  const DFromV<decltype(v)> d;
  const RebindToUnsigned<decltype(d)> du;
  const RebindToSigned<decltype(d)> di;  // cheaper than unsigned comparison
  const VFromD<decltype(du)> vu = BitCast(du, v);
  // 'Shift left' to clear the sign bit, then right so we can compare with the
  // max exponent (cannot compare with MaxExponentTimes2 directly because it is
  // negative and non-negative floats would be greater).
  const VFromD<decltype(di)> exp =
      BitCast(di, ShiftRight<hwy::MantissaBits<T>() + 1>(Add(vu, vu)));
  return RebindMask(d, detail::LtN(exp, hwy::MaxExponentField<T>()));
}

// ================================================== MEMORY

// ------------------------------ Load/MaskedLoad/LoadDup128/Store/Stream

#define HWY_SVE_LOAD(BASE, CHAR, BITS, HALF, NAME, OP)     \
  template <size_t N, int kPow2>                           \
  HWY_API HWY_SVE_V(BASE, BITS)                            \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d,              \
           const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT p) { \
    return sv##OP##_##CHAR##BITS(detail::MakeMask(d), p);  \
  }

#define HWY_SVE_MASKED_LOAD(BASE, CHAR, BITS, HALF, NAME, OP)   \
  template <size_t N, int kPow2>                                \
  HWY_API HWY_SVE_V(BASE, BITS)                                 \
      NAME(svbool_t m, HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, \
           const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT p) {      \
    return sv##OP##_##CHAR##BITS(m, p);                         \
  }

#define HWY_SVE_LOAD_DUP128(BASE, CHAR, BITS, HALF, NAME, OP) \
  template <size_t N, int kPow2>                              \
  HWY_API HWY_SVE_V(BASE, BITS)                               \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */,           \
           const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT p) {    \
    /* All-true predicate to load all 128 bits. */            \
    return sv##OP##_##CHAR##BITS(HWY_SVE_PTRUE(8), p);        \
  }

#define HWY_SVE_STORE(BASE, CHAR, BITS, HALF, NAME, OP)       \
  template <size_t N, int kPow2>                              \
  HWY_API void NAME(HWY_SVE_V(BASE, BITS) v,                  \
                    HWY_SVE_D(BASE, BITS, N, kPow2) d,        \
                    HWY_SVE_T(BASE, BITS) * HWY_RESTRICT p) { \
    sv##OP##_##CHAR##BITS(detail::MakeMask(d), p, v);         \
  }

#define HWY_SVE_BLENDED_STORE(BASE, CHAR, BITS, HALF, NAME, OP) \
  template <size_t N, int kPow2>                                \
  HWY_API void NAME(HWY_SVE_V(BASE, BITS) v, svbool_t m,        \
                    HWY_SVE_D(BASE, BITS, N, kPow2) /* d */,    \
                    HWY_SVE_T(BASE, BITS) * HWY_RESTRICT p) {   \
    sv##OP##_##CHAR##BITS(m, p, v);                             \
  }

HWY_SVE_FOREACH(HWY_SVE_LOAD, Load, ld1)
HWY_SVE_FOREACH(HWY_SVE_MASKED_LOAD, MaskedLoad, ld1)
HWY_SVE_FOREACH(HWY_SVE_LOAD_DUP128, LoadDup128, ld1rq)
HWY_SVE_FOREACH(HWY_SVE_STORE, Store, st1)
HWY_SVE_FOREACH(HWY_SVE_STORE, Stream, stnt1)
HWY_SVE_FOREACH(HWY_SVE_BLENDED_STORE, BlendedStore, st1)

#undef HWY_SVE_LOAD
#undef HWY_SVE_MASKED_LOAD
#undef HWY_SVE_LOAD_DUP128
#undef HWY_SVE_STORE
#undef HWY_SVE_BLENDED_STORE

// BF16 is the same as svuint16_t because BF16 is optional before v8.6.
template <size_t N, int kPow2>
HWY_API svuint16_t Load(Simd<bfloat16_t, N, kPow2> d,
                        const bfloat16_t* HWY_RESTRICT p) {
  return Load(RebindToUnsigned<decltype(d)>(),
              reinterpret_cast<const uint16_t * HWY_RESTRICT>(p));
}

template <size_t N, int kPow2>
HWY_API void Store(svuint16_t v, Simd<bfloat16_t, N, kPow2> d,
                   bfloat16_t* HWY_RESTRICT p) {
  Store(v, RebindToUnsigned<decltype(d)>(),
        reinterpret_cast<uint16_t * HWY_RESTRICT>(p));
}

// ------------------------------ Load/StoreU

// SVE only requires lane alignment, not natural alignment of the entire
// vector.
template <class D>
HWY_API VFromD<D> LoadU(D d, const TFromD<D>* HWY_RESTRICT p) {
  return Load(d, p);
}

template <class V, class D>
HWY_API void StoreU(const V v, D d, TFromD<D>* HWY_RESTRICT p) {
  Store(v, d, p);
}

// ------------------------------ ScatterOffset/Index

#define HWY_SVE_SCATTER_OFFSET(BASE, CHAR, BITS, HALF, NAME, OP)             \
  template <size_t N, int kPow2>                                             \
  HWY_API void NAME(HWY_SVE_V(BASE, BITS) v,                                 \
                    HWY_SVE_D(BASE, BITS, N, kPow2) d,                       \
                    HWY_SVE_T(BASE, BITS) * HWY_RESTRICT base,               \
                    HWY_SVE_V(int, BITS) offset) {                           \
    sv##OP##_s##BITS##offset_##CHAR##BITS(detail::MakeMask(d), base, offset, \
                                          v);                                \
  }

#define HWY_SVE_SCATTER_INDEX(BASE, CHAR, BITS, HALF, NAME, OP)                \
  template <size_t N, int kPow2>                                               \
  HWY_API void NAME(                                                           \
      HWY_SVE_V(BASE, BITS) v, HWY_SVE_D(BASE, BITS, N, kPow2) d,              \
      HWY_SVE_T(BASE, BITS) * HWY_RESTRICT base, HWY_SVE_V(int, BITS) index) { \
    sv##OP##_s##BITS##index_##CHAR##BITS(detail::MakeMask(d), base, index, v); \
  }

HWY_SVE_FOREACH_UIF3264(HWY_SVE_SCATTER_OFFSET, ScatterOffset, st1_scatter)
HWY_SVE_FOREACH_UIF3264(HWY_SVE_SCATTER_INDEX, ScatterIndex, st1_scatter)
#undef HWY_SVE_SCATTER_OFFSET
#undef HWY_SVE_SCATTER_INDEX

// ------------------------------ GatherOffset/Index

#define HWY_SVE_GATHER_OFFSET(BASE, CHAR, BITS, HALF, NAME, OP)             \
  template <size_t N, int kPow2>                                            \
  HWY_API HWY_SVE_V(BASE, BITS)                                             \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d,                               \
           const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT base,                 \
           HWY_SVE_V(int, BITS) offset) {                                   \
    return sv##OP##_s##BITS##offset_##CHAR##BITS(detail::MakeMask(d), base, \
                                                 offset);                   \
  }
#define HWY_SVE_GATHER_INDEX(BASE, CHAR, BITS, HALF, NAME, OP)             \
  template <size_t N, int kPow2>                                           \
  HWY_API HWY_SVE_V(BASE, BITS)                                            \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d,                              \
           const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT base,                \
           HWY_SVE_V(int, BITS) index) {                                   \
    return sv##OP##_s##BITS##index_##CHAR##BITS(detail::MakeMask(d), base, \
                                                index);                    \
  }

HWY_SVE_FOREACH_UIF3264(HWY_SVE_GATHER_OFFSET, GatherOffset, ld1_gather)
HWY_SVE_FOREACH_UIF3264(HWY_SVE_GATHER_INDEX, GatherIndex, ld1_gather)
#undef HWY_SVE_GATHER_OFFSET
#undef HWY_SVE_GATHER_INDEX

// ------------------------------ LoadInterleaved2

// Per-target flag to prevent generic_ops-inl.h from defining LoadInterleaved2.
#ifdef HWY_NATIVE_LOAD_STORE_INTERLEAVED
#undef HWY_NATIVE_LOAD_STORE_INTERLEAVED
#else
#define HWY_NATIVE_LOAD_STORE_INTERLEAVED
#endif

#define HWY_SVE_LOAD2(BASE, CHAR, BITS, HALF, NAME, OP)                       \
  template <size_t N, int kPow2>                                              \
  HWY_API void NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d,                        \
                    const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT unaligned,     \
                    HWY_SVE_V(BASE, BITS) & v0, HWY_SVE_V(BASE, BITS) & v1) { \
    const sv##BASE##BITS##x2_t tuple =                                        \
        sv##OP##_##CHAR##BITS(detail::MakeMask(d), unaligned);                \
    v0 = svget2(tuple, 0);                                                    \
    v1 = svget2(tuple, 1);                                                    \
  }
HWY_SVE_FOREACH(HWY_SVE_LOAD2, LoadInterleaved2, ld2)

#undef HWY_SVE_LOAD2

// ------------------------------ LoadInterleaved3

#define HWY_SVE_LOAD3(BASE, CHAR, BITS, HALF, NAME, OP)                     \
  template <size_t N, int kPow2>                                            \
  HWY_API void NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d,                      \
                    const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT unaligned,   \
                    HWY_SVE_V(BASE, BITS) & v0, HWY_SVE_V(BASE, BITS) & v1, \
                    HWY_SVE_V(BASE, BITS) & v2) {                           \
    const sv##BASE##BITS##x3_t tuple =                                      \
        sv##OP##_##CHAR##BITS(detail::MakeMask(d), unaligned);              \
    v0 = svget3(tuple, 0);                                                  \
    v1 = svget3(tuple, 1);                                                  \
    v2 = svget3(tuple, 2);                                                  \
  }
HWY_SVE_FOREACH(HWY_SVE_LOAD3, LoadInterleaved3, ld3)

#undef HWY_SVE_LOAD3

// ------------------------------ LoadInterleaved4

#define HWY_SVE_LOAD4(BASE, CHAR, BITS, HALF, NAME, OP)                       \
  template <size_t N, int kPow2>                                              \
  HWY_API void NAME(HWY_SVE_D(BASE, BITS, N, kPow2) d,                        \
                    const HWY_SVE_T(BASE, BITS) * HWY_RESTRICT unaligned,     \
                    HWY_SVE_V(BASE, BITS) & v0, HWY_SVE_V(BASE, BITS) & v1,   \
                    HWY_SVE_V(BASE, BITS) & v2, HWY_SVE_V(BASE, BITS) & v3) { \
    const sv##BASE##BITS##x4_t tuple =                                        \
        sv##OP##_##CHAR##BITS(detail::MakeMask(d), unaligned);                \
    v0 = svget4(tuple, 0);                                                    \
    v1 = svget4(tuple, 1);                                                    \
    v2 = svget4(tuple, 2);                                                    \
    v3 = svget4(tuple, 3);                                                    \
  }
HWY_SVE_FOREACH(HWY_SVE_LOAD4, LoadInterleaved4, ld4)

#undef HWY_SVE_LOAD4

// ------------------------------ StoreInterleaved2

#define HWY_SVE_STORE2(BASE, CHAR, BITS, HALF, NAME, OP)                 \
  template <size_t N, int kPow2>                                         \
  HWY_API void NAME(HWY_SVE_V(BASE, BITS) v0, HWY_SVE_V(BASE, BITS) v1,  \
                    HWY_SVE_D(BASE, BITS, N, kPow2) d,                   \
                    HWY_SVE_T(BASE, BITS) * HWY_RESTRICT unaligned) {    \
    const sv##BASE##BITS##x2_t tuple = svcreate2##_##CHAR##BITS(v0, v1); \
    sv##OP##_##CHAR##BITS(detail::MakeMask(d), unaligned, tuple);        \
  }
HWY_SVE_FOREACH(HWY_SVE_STORE2, StoreInterleaved2, st2)

#undef HWY_SVE_STORE2

// ------------------------------ StoreInterleaved3

#define HWY_SVE_STORE3(BASE, CHAR, BITS, HALF, NAME, OP)                      \
  template <size_t N, int kPow2>                                              \
  HWY_API void NAME(HWY_SVE_V(BASE, BITS) v0, HWY_SVE_V(BASE, BITS) v1,       \
                    HWY_SVE_V(BASE, BITS) v2,                                 \
                    HWY_SVE_D(BASE, BITS, N, kPow2) d,                        \
                    HWY_SVE_T(BASE, BITS) * HWY_RESTRICT unaligned) {         \
    const sv##BASE##BITS##x3_t triple = svcreate3##_##CHAR##BITS(v0, v1, v2); \
    sv##OP##_##CHAR##BITS(detail::MakeMask(d), unaligned, triple);            \
  }
HWY_SVE_FOREACH(HWY_SVE_STORE3, StoreInterleaved3, st3)

#undef HWY_SVE_STORE3

// ------------------------------ StoreInterleaved4

#define HWY_SVE_STORE4(BASE, CHAR, BITS, HALF, NAME, OP)                \
  template <size_t N, int kPow2>                                        \
  HWY_API void NAME(HWY_SVE_V(BASE, BITS) v0, HWY_SVE_V(BASE, BITS) v1, \
                    HWY_SVE_V(BASE, BITS) v2, HWY_SVE_V(BASE, BITS) v3, \
                    HWY_SVE_D(BASE, BITS, N, kPow2) d,                  \
                    HWY_SVE_T(BASE, BITS) * HWY_RESTRICT unaligned) {   \
    const sv##BASE##BITS##x4_t quad =                                   \
        svcreate4##_##CHAR##BITS(v0, v1, v2, v3);                       \
    sv##OP##_##CHAR##BITS(detail::MakeMask(d), unaligned, quad);        \
  }
HWY_SVE_FOREACH(HWY_SVE_STORE4, StoreInterleaved4, st4)

#undef HWY_SVE_STORE4

// ================================================== CONVERT

// ------------------------------ PromoteTo

// Same sign
#define HWY_SVE_PROMOTE_TO(BASE, CHAR, BITS, HALF, NAME, OP)                \
  template <size_t N, int kPow2>                                            \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(                                       \
      HWY_SVE_D(BASE, BITS, N, kPow2) /* tag */, HWY_SVE_V(BASE, HALF) v) { \
    return sv##OP##_##CHAR##BITS(v);                                        \
  }

HWY_SVE_FOREACH_UI16(HWY_SVE_PROMOTE_TO, PromoteTo, unpklo)
HWY_SVE_FOREACH_UI32(HWY_SVE_PROMOTE_TO, PromoteTo, unpklo)
HWY_SVE_FOREACH_UI64(HWY_SVE_PROMOTE_TO, PromoteTo, unpklo)

// 2x
template <size_t N, int kPow2>
HWY_API svuint32_t PromoteTo(Simd<uint32_t, N, kPow2> dto, svuint8_t vfrom) {
  const RepartitionToWide<DFromV<decltype(vfrom)>> d2;
  return PromoteTo(dto, PromoteTo(d2, vfrom));
}
template <size_t N, int kPow2>
HWY_API svint32_t PromoteTo(Simd<int32_t, N, kPow2> dto, svint8_t vfrom) {
  const RepartitionToWide<DFromV<decltype(vfrom)>> d2;
  return PromoteTo(dto, PromoteTo(d2, vfrom));
}

// Sign change
template <size_t N, int kPow2>
HWY_API svint16_t PromoteTo(Simd<int16_t, N, kPow2> dto, svuint8_t vfrom) {
  const RebindToUnsigned<decltype(dto)> du;
  return BitCast(dto, PromoteTo(du, vfrom));
}
template <size_t N, int kPow2>
HWY_API svint32_t PromoteTo(Simd<int32_t, N, kPow2> dto, svuint16_t vfrom) {
  const RebindToUnsigned<decltype(dto)> du;
  return BitCast(dto, PromoteTo(du, vfrom));
}
template <size_t N, int kPow2>
HWY_API svint32_t PromoteTo(Simd<int32_t, N, kPow2> dto, svuint8_t vfrom) {
  const Repartition<uint16_t, DFromV<decltype(vfrom)>> du16;
  const Repartition<int16_t, decltype(du16)> di16;
  return PromoteTo(dto, BitCast(di16, PromoteTo(du16, vfrom)));
}

// ------------------------------ PromoteTo F

// Unlike Highway's ZipLower, this returns the same type.
namespace detail {
HWY_SVE_FOREACH(HWY_SVE_RETV_ARGVV, ZipLowerSame, zip1)
}  // namespace detail

template <size_t N, int kPow2>
HWY_API svfloat32_t PromoteTo(Simd<float32_t, N, kPow2> /* d */,
                              const svfloat16_t v) {
  // svcvt* expects inputs in even lanes, whereas Highway wants lower lanes, so
  // first replicate each lane once.
  const svfloat16_t vv = detail::ZipLowerSame(v, v);
  return svcvt_f32_f16_x(detail::PTrue(Simd<float16_t, N, kPow2>()), vv);
}

template <size_t N, int kPow2>
HWY_API svfloat64_t PromoteTo(Simd<float64_t, N, kPow2> /* d */,
                              const svfloat32_t v) {
  const svfloat32_t vv = detail::ZipLowerSame(v, v);
  return svcvt_f64_f32_x(detail::PTrue(Simd<float32_t, N, kPow2>()), vv);
}

template <size_t N, int kPow2>
HWY_API svfloat64_t PromoteTo(Simd<float64_t, N, kPow2> /* d */,
                              const svint32_t v) {
  const svint32_t vv = detail::ZipLowerSame(v, v);
  return svcvt_f64_s32_x(detail::PTrue(Simd<int32_t, N, kPow2>()), vv);
}

// For 16-bit Compress
namespace detail {
HWY_SVE_FOREACH_UI32(HWY_SVE_PROMOTE_TO, PromoteUpperTo, unpkhi)
#undef HWY_SVE_PROMOTE_TO

template <size_t N, int kPow2>
HWY_API svfloat32_t PromoteUpperTo(Simd<float, N, kPow2> df, svfloat16_t v) {
  const RebindToUnsigned<decltype(df)> du;
  const RepartitionToNarrow<decltype(du)> dn;
  return BitCast(df, PromoteUpperTo(du, BitCast(dn, v)));
}

}  // namespace detail

// ------------------------------ DemoteTo U

namespace detail {

// Saturates unsigned vectors to half/quarter-width TN.
template <typename TN, class VU>
VU SaturateU(VU v) {
  return detail::MinN(v, static_cast<TFromV<VU>>(LimitsMax<TN>()));
}

// Saturates unsigned vectors to half/quarter-width TN.
template <typename TN, class VI>
VI SaturateI(VI v) {
  return detail::MinN(detail::MaxN(v, LimitsMin<TN>()), LimitsMax<TN>());
}

}  // namespace detail

template <size_t N, int kPow2>
HWY_API svuint8_t DemoteTo(Simd<uint8_t, N, kPow2> dn, const svint16_t v) {
  const DFromV<decltype(v)> di;
  const RebindToUnsigned<decltype(di)> du;
  using TN = TFromD<decltype(dn)>;
  // First clamp negative numbers to zero and cast to unsigned.
  const svuint16_t clamped = BitCast(du, detail::MaxN(v, 0));
  // Saturate to unsigned-max and halve the width.
  const svuint8_t vn = BitCast(dn, detail::SaturateU<TN>(clamped));
  return svuzp1_u8(vn, vn);
}

template <size_t N, int kPow2>
HWY_API svuint16_t DemoteTo(Simd<uint16_t, N, kPow2> dn, const svint32_t v) {
  const DFromV<decltype(v)> di;
  const RebindToUnsigned<decltype(di)> du;
  using TN = TFromD<decltype(dn)>;
  // First clamp negative numbers to zero and cast to unsigned.
  const svuint32_t clamped = BitCast(du, detail::MaxN(v, 0));
  // Saturate to unsigned-max and halve the width.
  const svuint16_t vn = BitCast(dn, detail::SaturateU<TN>(clamped));
  return svuzp1_u16(vn, vn);
}

template <size_t N, int kPow2>
HWY_API svuint8_t DemoteTo(Simd<uint8_t, N, kPow2> dn, const svint32_t v) {
  const DFromV<decltype(v)> di;
  const RebindToUnsigned<decltype(di)> du;
  const RepartitionToNarrow<decltype(du)> d2;
  using TN = TFromD<decltype(dn)>;
  // First clamp negative numbers to zero and cast to unsigned.
  const svuint32_t clamped = BitCast(du, detail::MaxN(v, 0));
  // Saturate to unsigned-max and quarter the width.
  const svuint16_t cast16 = BitCast(d2, detail::SaturateU<TN>(clamped));
  const svuint8_t x2 = BitCast(dn, svuzp1_u16(cast16, cast16));
  return svuzp1_u8(x2, x2);
}

HWY_API svuint8_t U8FromU32(const svuint32_t v) {
  const DFromV<svuint32_t> du32;
  const RepartitionToNarrow<decltype(du32)> du16;
  const RepartitionToNarrow<decltype(du16)> du8;

  const svuint16_t cast16 = BitCast(du16, v);
  const svuint16_t x2 = svuzp1_u16(cast16, cast16);
  const svuint8_t cast8 = BitCast(du8, x2);
  return svuzp1_u8(cast8, cast8);
}

// ------------------------------ Truncations

template <size_t N, int kPow2>
HWY_API svuint8_t TruncateTo(Simd<uint8_t, N, kPow2> /* tag */,
                             const svuint64_t v) {
  const DFromV<svuint8_t> d;
  const svuint8_t v1 = BitCast(d, v);
  const svuint8_t v2 = svuzp1_u8(v1, v1);
  const svuint8_t v3 = svuzp1_u8(v2, v2);
  return svuzp1_u8(v3, v3);
}

template <size_t N, int kPow2>
HWY_API svuint16_t TruncateTo(Simd<uint16_t, N, kPow2> /* tag */,
                              const svuint64_t v) {
  const DFromV<svuint16_t> d;
  const svuint16_t v1 = BitCast(d, v);
  const svuint16_t v2 = svuzp1_u16(v1, v1);
  return svuzp1_u16(v2, v2);
}

template <size_t N, int kPow2>
HWY_API svuint32_t TruncateTo(Simd<uint32_t, N, kPow2> /* tag */,
                              const svuint64_t v) {
  const DFromV<svuint32_t> d;
  const svuint32_t v1 = BitCast(d, v);
  return svuzp1_u32(v1, v1);
}

template <size_t N, int kPow2>
HWY_API svuint8_t TruncateTo(Simd<uint8_t, N, kPow2> /* tag */,
                             const svuint32_t v) {
  const DFromV<svuint8_t> d;
  const svuint8_t v1 = BitCast(d, v);
  const svuint8_t v2 = svuzp1_u8(v1, v1);
  return svuzp1_u8(v2, v2);
}

template <size_t N, int kPow2>
HWY_API svuint16_t TruncateTo(Simd<uint16_t, N, kPow2> /* tag */,
                              const svuint32_t v) {
  const DFromV<svuint16_t> d;
  const svuint16_t v1 = BitCast(d, v);
  return svuzp1_u16(v1, v1);
}

template <size_t N, int kPow2>
HWY_API svuint8_t TruncateTo(Simd<uint8_t, N, kPow2> /* tag */,
                             const svuint16_t v) {
  const DFromV<svuint8_t> d;
  const svuint8_t v1 = BitCast(d, v);
  return svuzp1_u8(v1, v1);
}

// ------------------------------ DemoteTo I

template <size_t N, int kPow2>
HWY_API svint8_t DemoteTo(Simd<int8_t, N, kPow2> dn, const svint16_t v) {
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  const svint8_t vn = BitCast(dn, svqxtnb_s16(v));
#else
  using TN = TFromD<decltype(dn)>;
  const svint8_t vn = BitCast(dn, detail::SaturateI<TN>(v));
#endif
  return svuzp1_s8(vn, vn);
}

template <size_t N, int kPow2>
HWY_API svint16_t DemoteTo(Simd<int16_t, N, kPow2> dn, const svint32_t v) {
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  const svint16_t vn = BitCast(dn, svqxtnb_s32(v));
#else
  using TN = TFromD<decltype(dn)>;
  const svint16_t vn = BitCast(dn, detail::SaturateI<TN>(v));
#endif
  return svuzp1_s16(vn, vn);
}

template <size_t N, int kPow2>
HWY_API svint8_t DemoteTo(Simd<int8_t, N, kPow2> dn, const svint32_t v) {
  const RepartitionToWide<decltype(dn)> d2;
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  const svint16_t cast16 = BitCast(d2, svqxtnb_s16(svqxtnb_s32(v)));
#else
  using TN = TFromD<decltype(dn)>;
  const svint16_t cast16 = BitCast(d2, detail::SaturateI<TN>(v));
#endif
  const svint8_t v2 = BitCast(dn, svuzp1_s16(cast16, cast16));
  return BitCast(dn, svuzp1_s8(v2, v2));
}

// ------------------------------ ConcatEven/ConcatOdd

// WARNING: the upper half of these needs fixing up (uzp1/uzp2 use the
// full vector length, not rounded down to a power of two as we require).
namespace detail {

#define HWY_SVE_CONCAT_EVERY_SECOND(BASE, CHAR, BITS, HALF, NAME, OP) \
  HWY_INLINE HWY_SVE_V(BASE, BITS)                                    \
      NAME(HWY_SVE_V(BASE, BITS) hi, HWY_SVE_V(BASE, BITS) lo) {      \
    return sv##OP##_##CHAR##BITS(lo, hi);                             \
  }
HWY_SVE_FOREACH(HWY_SVE_CONCAT_EVERY_SECOND, ConcatEvenFull, uzp1)
HWY_SVE_FOREACH(HWY_SVE_CONCAT_EVERY_SECOND, ConcatOddFull, uzp2)
#if defined(__ARM_FEATURE_SVE_MATMUL_FP64)
HWY_SVE_FOREACH(HWY_SVE_CONCAT_EVERY_SECOND, ConcatEvenBlocks, uzp1q)
HWY_SVE_FOREACH(HWY_SVE_CONCAT_EVERY_SECOND, ConcatOddBlocks, uzp2q)
#endif
#undef HWY_SVE_CONCAT_EVERY_SECOND

// Used to slide up / shift whole register left; mask indicates which range
// to take from lo, and the rest is filled from hi starting at its lowest.
#define HWY_SVE_SPLICE(BASE, CHAR, BITS, HALF, NAME, OP)                   \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(                                      \
      HWY_SVE_V(BASE, BITS) hi, HWY_SVE_V(BASE, BITS) lo, svbool_t mask) { \
    return sv##OP##_##CHAR##BITS(mask, lo, hi);                            \
  }
HWY_SVE_FOREACH(HWY_SVE_SPLICE, Splice, splice)
#undef HWY_SVE_SPLICE

}  // namespace detail

template <class D>
HWY_API VFromD<D> ConcatOdd(D d, VFromD<D> hi, VFromD<D> lo) {
#if HWY_SVE_IS_POW2
  (void)d;
  return detail::ConcatOddFull(hi, lo);
#else
  const VFromD<D> hi_odd = detail::ConcatOddFull(hi, hi);
  const VFromD<D> lo_odd = detail::ConcatOddFull(lo, lo);
  return detail::Splice(hi_odd, lo_odd, FirstN(d, Lanes(d) / 2));
#endif
}

template <class D>
HWY_API VFromD<D> ConcatEven(D d, VFromD<D> hi, VFromD<D> lo) {
#if HWY_SVE_IS_POW2
  (void)d;
  return detail::ConcatEvenFull(hi, lo);
#else
  const VFromD<D> hi_odd = detail::ConcatEvenFull(hi, hi);
  const VFromD<D> lo_odd = detail::ConcatEvenFull(lo, lo);
  return detail::Splice(hi_odd, lo_odd, FirstN(d, Lanes(d) / 2));
#endif
}

// ------------------------------ DemoteTo F

template <size_t N, int kPow2>
HWY_API svfloat16_t DemoteTo(Simd<float16_t, N, kPow2> d, const svfloat32_t v) {
  const svfloat16_t in_even = svcvt_f16_f32_x(detail::PTrue(d), v);
  return detail::ConcatEvenFull(in_even,
                                in_even);  // lower half
}

template <size_t N, int kPow2>
HWY_API svuint16_t DemoteTo(Simd<bfloat16_t, N, kPow2> /* d */, svfloat32_t v) {
  const svuint16_t in_even = BitCast(ScalableTag<uint16_t>(), v);
  return detail::ConcatOddFull(in_even, in_even);  // lower half
}

template <size_t N, int kPow2>
HWY_API svfloat32_t DemoteTo(Simd<float32_t, N, kPow2> d, const svfloat64_t v) {
  const svfloat32_t in_even = svcvt_f32_f64_x(detail::PTrue(d), v);
  return detail::ConcatEvenFull(in_even,
                                in_even);  // lower half
}

template <size_t N, int kPow2>
HWY_API svint32_t DemoteTo(Simd<int32_t, N, kPow2> d, const svfloat64_t v) {
  const svint32_t in_even = svcvt_s32_f64_x(detail::PTrue(d), v);
  return detail::ConcatEvenFull(in_even,
                                in_even);  // lower half
}

// ------------------------------ ConvertTo F

#define HWY_SVE_CONVERT(BASE, CHAR, BITS, HALF, NAME, OP)                     \
  /* signed integers */                                                       \
  template <size_t N, int kPow2>                                              \
  HWY_API HWY_SVE_V(BASE, BITS)                                               \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, HWY_SVE_V(int, BITS) v) { \
    return sv##OP##_##CHAR##BITS##_s##BITS##_x(HWY_SVE_PTRUE(BITS), v);       \
  }                                                                           \
  /* unsigned integers */                                                     \
  template <size_t N, int kPow2>                                              \
  HWY_API HWY_SVE_V(BASE, BITS)                                               \
      NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, HWY_SVE_V(uint, BITS) v) { \
    return sv##OP##_##CHAR##BITS##_u##BITS##_x(HWY_SVE_PTRUE(BITS), v);       \
  }                                                                           \
  /* Truncates (rounds toward zero). */                                       \
  template <size_t N, int kPow2>                                              \
  HWY_API HWY_SVE_V(int, BITS)                                                \
      NAME(HWY_SVE_D(int, BITS, N, kPow2) /* d */, HWY_SVE_V(BASE, BITS) v) { \
    return sv##OP##_s##BITS##_##CHAR##BITS##_x(HWY_SVE_PTRUE(BITS), v);       \
  }

// API only requires f32 but we provide f64 for use by Iota.
HWY_SVE_FOREACH_F(HWY_SVE_CONVERT, ConvertTo, cvt)
#undef HWY_SVE_CONVERT

// ------------------------------ NearestInt (Round, ConvertTo)
template <class VF, class DI = RebindToSigned<DFromV<VF>>>
HWY_API VFromD<DI> NearestInt(VF v) {
  // No single instruction, round then truncate.
  return ConvertTo(DI(), Round(v));
}

// ------------------------------ Iota (Add, ConvertTo)

#define HWY_SVE_IOTA(BASE, CHAR, BITS, HALF, NAME, OP)                        \
  template <size_t N, int kPow2>                                              \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /* d */, \
                                     HWY_SVE_T(BASE, BITS) first) {           \
    return sv##OP##_##CHAR##BITS(first, 1);                                   \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_IOTA, Iota, index)
#undef HWY_SVE_IOTA

template <class D, HWY_IF_FLOAT_D(D)>
HWY_API VFromD<D> Iota(const D d, TFromD<D> first) {
  const RebindToSigned<D> di;
  return detail::AddN(ConvertTo(d, Iota(di, 0)), first);
}

// ------------------------------ InterleaveLower

template <class D, class V>
HWY_API V InterleaveLower(D d, const V a, const V b) {
  static_assert(IsSame<TFromD<D>, TFromV<V>>(), "D/V mismatch");
#if HWY_TARGET == HWY_SVE2_128
  (void)d;
  return detail::ZipLowerSame(a, b);
#else
  // Move lower halves of blocks to lower half of vector.
  const Repartition<uint64_t, decltype(d)> d64;
  const auto a64 = BitCast(d64, a);
  const auto b64 = BitCast(d64, b);
  const auto a_blocks = detail::ConcatEvenFull(a64, a64);  // lower half
  const auto b_blocks = detail::ConcatEvenFull(b64, b64);
  return detail::ZipLowerSame(BitCast(d, a_blocks), BitCast(d, b_blocks));
#endif
}

template <class V>
HWY_API V InterleaveLower(const V a, const V b) {
  return InterleaveLower(DFromV<V>(), a, b);
}

// ------------------------------ InterleaveUpper

// Only use zip2 if vector are a powers of two, otherwise getting the actual
// "upper half" requires MaskUpperHalf.
#if HWY_TARGET == HWY_SVE2_128
namespace detail {
// Unlike Highway's ZipUpper, this returns the same type.
HWY_SVE_FOREACH(HWY_SVE_RETV_ARGVV, ZipUpperSame, zip2)
}  // namespace detail
#endif

// Full vector: guaranteed to have at least one block
template <class D, class V = VFromD<D>,
          hwy::EnableIf<detail::IsFull(D())>* = nullptr>
HWY_API V InterleaveUpper(D d, const V a, const V b) {
#if HWY_TARGET == HWY_SVE2_128
  (void)d;
  return detail::ZipUpperSame(a, b);
#else
  // Move upper halves of blocks to lower half of vector.
  const Repartition<uint64_t, decltype(d)> d64;
  const auto a64 = BitCast(d64, a);
  const auto b64 = BitCast(d64, b);
  const auto a_blocks = detail::ConcatOddFull(a64, a64);  // lower half
  const auto b_blocks = detail::ConcatOddFull(b64, b64);
  return detail::ZipLowerSame(BitCast(d, a_blocks), BitCast(d, b_blocks));
#endif
}

// Capped/fraction: need runtime check
template <class D, class V = VFromD<D>,
          hwy::EnableIf<!detail::IsFull(D())>* = nullptr>
HWY_API V InterleaveUpper(D d, const V a, const V b) {
  // Less than one block: treat as capped
  if (Lanes(d) * sizeof(TFromD<D>) < 16) {
    const Half<decltype(d)> d2;
    return InterleaveLower(d, UpperHalf(d2, a), UpperHalf(d2, b));
  }
  return InterleaveUpper(DFromV<V>(), a, b);
}

// ================================================== COMBINE

namespace detail {

#if HWY_TARGET == HWY_SVE_256 || HWY_IDE
template <class D, HWY_IF_LANE_SIZE_D(D, 1)>
svbool_t MaskLowerHalf(D d) {
  switch (Lanes(d)) {
    case 32:
      return svptrue_pat_b8(SV_VL16);
    case 16:
      return svptrue_pat_b8(SV_VL8);
    case 8:
      return svptrue_pat_b8(SV_VL4);
    case 4:
      return svptrue_pat_b8(SV_VL2);
    default:
      return svptrue_pat_b8(SV_VL1);
  }
}
template <class D, HWY_IF_LANE_SIZE_D(D, 2)>
svbool_t MaskLowerHalf(D d) {
  switch (Lanes(d)) {
    case 16:
      return svptrue_pat_b16(SV_VL8);
    case 8:
      return svptrue_pat_b16(SV_VL4);
    case 4:
      return svptrue_pat_b16(SV_VL2);
    default:
      return svptrue_pat_b16(SV_VL1);
  }
}
template <class D, HWY_IF_LANE_SIZE_D(D, 4)>
svbool_t MaskLowerHalf(D d) {
  switch (Lanes(d)) {
    case 8:
      return svptrue_pat_b32(SV_VL4);
    case 4:
      return svptrue_pat_b32(SV_VL2);
    default:
      return svptrue_pat_b32(SV_VL1);
  }
}
template <class D, HWY_IF_LANE_SIZE_D(D, 8)>
svbool_t MaskLowerHalf(D d) {
  switch (Lanes(d)) {
    case 4:
      return svptrue_pat_b64(SV_VL2);
    default:
      return svptrue_pat_b64(SV_VL1);
  }
}
#endif
#if HWY_TARGET == HWY_SVE2_128 || HWY_IDE
template <class D, HWY_IF_LANE_SIZE_D(D, 1)>
svbool_t MaskLowerHalf(D d) {
  switch (Lanes(d)) {
    case 16:
      return svptrue_pat_b8(SV_VL8);
    case 8:
      return svptrue_pat_b8(SV_VL4);
    case 4:
      return svptrue_pat_b8(SV_VL2);
    case 2:
    case 1:
    default:
      return svptrue_pat_b8(SV_VL1);
  }
}
template <class D, HWY_IF_LANE_SIZE_D(D, 2)>
svbool_t MaskLowerHalf(D d) {
  switch (Lanes(d)) {
    case 8:
      return svptrue_pat_b16(SV_VL4);
    case 4:
      return svptrue_pat_b16(SV_VL2);
    case 2:
    case 1:
    default:
      return svptrue_pat_b16(SV_VL1);
  }
}
template <class D, HWY_IF_LANE_SIZE_D(D, 4)>
svbool_t MaskLowerHalf(D d) {
  return svptrue_pat_b32(Lanes(d) == 4 ? SV_VL2 : SV_VL1);
}
template <class D, HWY_IF_LANE_SIZE_D(D, 8)>
svbool_t MaskLowerHalf(D /*d*/) {
  return svptrue_pat_b64(SV_VL1);
}
#endif  // HWY_TARGET == HWY_SVE2_128
#if HWY_TARGET != HWY_SVE_256 && HWY_TARGET != HWY_SVE2_128
template <class D>
svbool_t MaskLowerHalf(D d) {
  return FirstN(d, Lanes(d) / 2);
}
#endif

template <class D>
svbool_t MaskUpperHalf(D d) {
  // TODO(janwas): WHILEGE on pow2 SVE2
  if (HWY_SVE_IS_POW2 && IsFull(d)) {
    return Not(MaskLowerHalf(d));
  }

  // For Splice to work as intended, make sure bits above Lanes(d) are zero.
  return AndNot(MaskLowerHalf(d), detail::MakeMask(d));
}

// Right-shift vector pair by constexpr; can be used to slide down (=N) or up
// (=Lanes()-N).
#define HWY_SVE_EXT(BASE, CHAR, BITS, HALF, NAME, OP)            \
  template <size_t kIndex>                                       \
  HWY_API HWY_SVE_V(BASE, BITS)                                  \
      NAME(HWY_SVE_V(BASE, BITS) hi, HWY_SVE_V(BASE, BITS) lo) { \
    return sv##OP##_##CHAR##BITS(lo, hi, kIndex);                \
  }
HWY_SVE_FOREACH(HWY_SVE_EXT, Ext, ext)
#undef HWY_SVE_EXT

}  // namespace detail

// ------------------------------ ConcatUpperLower
template <class D, class V>
HWY_API V ConcatUpperLower(const D d, const V hi, const V lo) {
  return IfThenElse(detail::MaskLowerHalf(d), lo, hi);
}

// ------------------------------ ConcatLowerLower
template <class D, class V>
HWY_API V ConcatLowerLower(const D d, const V hi, const V lo) {
  if (detail::IsFull(d)) {
#if defined(__ARM_FEATURE_SVE_MATMUL_FP64) && HWY_TARGET == HWY_SVE_256
    return detail::ConcatEvenBlocks(hi, lo);
#endif
#if HWY_TARGET == HWY_SVE2_128
    const Repartition<uint64_t, D> du64;
    const auto lo64 = BitCast(du64, lo);
    return BitCast(d, InterleaveLower(du64, lo64, BitCast(du64, hi)));
#endif
  }
  return detail::Splice(hi, lo, detail::MaskLowerHalf(d));
}

// ------------------------------ ConcatLowerUpper
template <class D, class V>
HWY_API V ConcatLowerUpper(const D d, const V hi, const V lo) {
#if HWY_TARGET == HWY_SVE_256 || HWY_TARGET == HWY_SVE2_128  // constexpr Lanes
  if (detail::IsFull(d)) {
    return detail::Ext<Lanes(d) / 2>(hi, lo);
  }
#endif
  return detail::Splice(hi, lo, detail::MaskUpperHalf(d));
}

// ------------------------------ ConcatUpperUpper
template <class D, class V>
HWY_API V ConcatUpperUpper(const D d, const V hi, const V lo) {
  if (detail::IsFull(d)) {
#if defined(__ARM_FEATURE_SVE_MATMUL_FP64) && HWY_TARGET == HWY_SVE_256
    return detail::ConcatOddBlocks(hi, lo);
#endif
#if HWY_TARGET == HWY_SVE2_128
    const Repartition<uint64_t, D> du64;
    const auto lo64 = BitCast(du64, lo);
    return BitCast(d, InterleaveUpper(du64, lo64, BitCast(du64, hi)));
#endif
  }
  const svbool_t mask_upper = detail::MaskUpperHalf(d);
  const V lo_upper = detail::Splice(lo, lo, mask_upper);
  return IfThenElse(mask_upper, hi, lo_upper);
}

// ------------------------------ Combine
template <class D, class V2>
HWY_API VFromD<D> Combine(const D d, const V2 hi, const V2 lo) {
  return ConcatLowerLower(d, hi, lo);
}

// ------------------------------ ZeroExtendVector
template <class D, class V>
HWY_API V ZeroExtendVector(const D d, const V lo) {
  return Combine(d, Zero(Half<D>()), lo);
}

// ------------------------------ Lower/UpperHalf

template <class D2, class V>
HWY_API V LowerHalf(D2 /* tag */, const V v) {
  return v;
}

template <class V>
HWY_API V LowerHalf(const V v) {
  return v;
}

template <class DH, class V>
HWY_API V UpperHalf(const DH dh, const V v) {
  const Twice<decltype(dh)> d;
  // Cast so that we support bfloat16_t.
  const RebindToUnsigned<decltype(d)> du;
  const VFromD<decltype(du)> vu = BitCast(du, v);
#if HWY_TARGET == HWY_SVE_256 || HWY_TARGET == HWY_SVE2_128  // constexpr Lanes
  return BitCast(d, detail::Ext<Lanes(dh)>(vu, vu));
#else
  const MFromD<decltype(du)> mask = detail::MaskUpperHalf(du);
  return BitCast(d, detail::Splice(vu, vu, mask));
#endif
}

// ================================================== REDUCE

// These return T, whereas the Highway op returns a broadcasted vector.
namespace detail {
#define HWY_SVE_REDUCE_ADD(BASE, CHAR, BITS, HALF, NAME, OP)                   \
  HWY_API HWY_SVE_T(BASE, BITS) NAME(svbool_t pg, HWY_SVE_V(BASE, BITS) v) {   \
    /* The intrinsic returns [u]int64_t; truncate to T so we can broadcast. */ \
    using T = HWY_SVE_T(BASE, BITS);                                           \
    using TU = MakeUnsigned<T>;                                                \
    constexpr uint64_t kMask = LimitsMax<TU>();                                \
    return static_cast<T>(static_cast<TU>(                                     \
        static_cast<uint64_t>(sv##OP##_##CHAR##BITS(pg, v)) & kMask));         \
  }

#define HWY_SVE_REDUCE(BASE, CHAR, BITS, HALF, NAME, OP)                     \
  HWY_API HWY_SVE_T(BASE, BITS) NAME(svbool_t pg, HWY_SVE_V(BASE, BITS) v) { \
    return sv##OP##_##CHAR##BITS(pg, v);                                     \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_REDUCE_ADD, SumOfLanesM, addv)
HWY_SVE_FOREACH_F(HWY_SVE_REDUCE, SumOfLanesM, addv)

HWY_SVE_FOREACH_UI(HWY_SVE_REDUCE, MinOfLanesM, minv)
HWY_SVE_FOREACH_UI(HWY_SVE_REDUCE, MaxOfLanesM, maxv)
// NaN if all are
HWY_SVE_FOREACH_F(HWY_SVE_REDUCE, MinOfLanesM, minnmv)
HWY_SVE_FOREACH_F(HWY_SVE_REDUCE, MaxOfLanesM, maxnmv)

#undef HWY_SVE_REDUCE
#undef HWY_SVE_REDUCE_ADD
}  // namespace detail

template <class D, class V>
V SumOfLanes(D d, V v) {
  return Set(d, detail::SumOfLanesM(detail::MakeMask(d), v));
}

template <class D, class V>
V MinOfLanes(D d, V v) {
  return Set(d, detail::MinOfLanesM(detail::MakeMask(d), v));
}

template <class D, class V>
V MaxOfLanes(D d, V v) {
  return Set(d, detail::MaxOfLanesM(detail::MakeMask(d), v));
}


// ================================================== SWIZZLE

// ------------------------------ GetLane

namespace detail {
#define HWY_SVE_GET_LANE(BASE, CHAR, BITS, HALF, NAME, OP) \
  HWY_INLINE HWY_SVE_T(BASE, BITS)                         \
      NAME(HWY_SVE_V(BASE, BITS) v, svbool_t mask) {       \
    return sv##OP##_##CHAR##BITS(mask, v);                 \
  }

HWY_SVE_FOREACH(HWY_SVE_GET_LANE, GetLaneM, lasta)
#undef HWY_SVE_GET_LANE
}  // namespace detail

template <class V>
HWY_API TFromV<V> GetLane(V v) {
  return detail::GetLaneM(v, detail::PFalse());
}

// ------------------------------ ExtractLane
template <class V>
HWY_API TFromV<V> ExtractLane(V v, size_t i) {
  return detail::GetLaneM(v, FirstN(DFromV<V>(), i));
}

// ------------------------------ InsertLane (IfThenElse)
template <class V>
HWY_API V InsertLane(const V v, size_t i, TFromV<V> t) {
  const DFromV<V> d;
  const auto is_i = detail::EqN(Iota(d, 0), static_cast<TFromV<V>>(i));
  return IfThenElse(RebindMask(d, is_i), Set(d, t), v);
}

// ------------------------------ DupEven

namespace detail {
HWY_SVE_FOREACH(HWY_SVE_RETV_ARGVV, InterleaveEven, trn1)
}  // namespace detail

template <class V>
HWY_API V DupEven(const V v) {
  return detail::InterleaveEven(v, v);
}

// ------------------------------ DupOdd

namespace detail {
HWY_SVE_FOREACH(HWY_SVE_RETV_ARGVV, InterleaveOdd, trn2)
}  // namespace detail

template <class V>
HWY_API V DupOdd(const V v) {
  return detail::InterleaveOdd(v, v);
}

// ------------------------------ OddEven

#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128

#define HWY_SVE_ODD_EVEN(BASE, CHAR, BITS, HALF, NAME, OP)          \
  HWY_API HWY_SVE_V(BASE, BITS)                                     \
      NAME(HWY_SVE_V(BASE, BITS) odd, HWY_SVE_V(BASE, BITS) even) { \
    return sv##OP##_##CHAR##BITS(even, odd, /*xor=*/0);             \
  }

HWY_SVE_FOREACH_UI(HWY_SVE_ODD_EVEN, OddEven, eortb_n)
#undef HWY_SVE_ODD_EVEN

template <class V, HWY_IF_FLOAT_V(V)>
HWY_API V OddEven(const V odd, const V even) {
  const DFromV<V> d;
  const RebindToUnsigned<decltype(d)> du;
  return BitCast(d, OddEven(BitCast(du, odd), BitCast(du, even)));
}

#else

template <class V>
HWY_API V OddEven(const V odd, const V even) {
  const auto odd_in_even = detail::Ext<1>(odd, odd);
  return detail::InterleaveEven(even, odd_in_even);
}

#endif  // HWY_TARGET

// ------------------------------ OddEvenBlocks
template <class V>
HWY_API V OddEvenBlocks(const V odd, const V even) {
  const DFromV<V> d;
#if HWY_TARGET == HWY_SVE_256
  return ConcatUpperLower(d, odd, even);
#elif HWY_TARGET == HWY_SVE2_128
  (void)odd;
  (void)d;
  return even;
#else
  const RebindToUnsigned<decltype(d)> du;
  using TU = TFromD<decltype(du)>;
  constexpr size_t kShift = CeilLog2(16 / sizeof(TU));
  const auto idx_block = ShiftRight<kShift>(Iota(du, 0));
  const auto lsb = detail::AndN(idx_block, static_cast<TU>(1));
  const svbool_t is_even = detail::EqN(lsb, static_cast<TU>(0));
  return IfThenElse(is_even, even, odd);
#endif
}

// ------------------------------ TableLookupLanes

template <class D, class VI>
HWY_API VFromD<RebindToUnsigned<D>> IndicesFromVec(D d, VI vec) {
  using TI = TFromV<VI>;
  static_assert(sizeof(TFromD<D>) == sizeof(TI), "Index/lane size mismatch");
  const RebindToUnsigned<D> du;
  const auto indices = BitCast(du, vec);
#if HWY_IS_DEBUG_BUILD
  HWY_DASSERT(AllTrue(du, detail::LtN(indices, static_cast<TI>(Lanes(d)))));
#else
  (void)d;
#endif
  return indices;
}

template <class D, typename TI>
HWY_API VFromD<RebindToUnsigned<D>> SetTableIndices(D d, const TI* idx) {
  static_assert(sizeof(TFromD<D>) == sizeof(TI), "Index size must match lane");
  return IndicesFromVec(d, LoadU(Rebind<TI, D>(), idx));
}

// <32bit are not part of Highway API, but used in Broadcast.
#define HWY_SVE_TABLE(BASE, CHAR, BITS, HALF, NAME, OP)          \
  HWY_API HWY_SVE_V(BASE, BITS)                                  \
      NAME(HWY_SVE_V(BASE, BITS) v, HWY_SVE_V(uint, BITS) idx) { \
    return sv##OP##_##CHAR##BITS(v, idx);                        \
  }

HWY_SVE_FOREACH(HWY_SVE_TABLE, TableLookupLanes, tbl)
#undef HWY_SVE_TABLE

// ------------------------------ SwapAdjacentBlocks (TableLookupLanes)

namespace detail {

template <typename T, size_t N, int kPow2>
constexpr size_t LanesPerBlock(Simd<T, N, kPow2> /* tag */) {
  // We might have a capped vector smaller than a block, so honor that.
  return HWY_MIN(16 / sizeof(T), detail::ScaleByPower(N, kPow2));
}

}  // namespace detail

template <class V>
HWY_API V SwapAdjacentBlocks(const V v) {
  const DFromV<V> d;
#if HWY_TARGET == HWY_SVE_256
  return ConcatLowerUpper(d, v, v);
#elif HWY_TARGET == HWY_SVE2_128
  (void)d;
  return v;
#else
  const RebindToUnsigned<decltype(d)> du;
  constexpr auto kLanesPerBlock =
      static_cast<TFromD<decltype(du)>>(detail::LanesPerBlock(d));
  const VFromD<decltype(du)> idx = detail::XorN(Iota(du, 0), kLanesPerBlock);
  return TableLookupLanes(v, idx);
#endif
}

// ------------------------------ Reverse

namespace detail {

#define HWY_SVE_REVERSE(BASE, CHAR, BITS, HALF, NAME, OP)       \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v) { \
    return sv##OP##_##CHAR##BITS(v);                            \
  }

HWY_SVE_FOREACH(HWY_SVE_REVERSE, ReverseFull, rev)
#undef HWY_SVE_REVERSE

}  // namespace detail

template <class D, class V>
HWY_API V Reverse(D d, V v) {
  using T = TFromD<D>;
  const auto reversed = detail::ReverseFull(v);
  if (HWY_SVE_IS_POW2 && detail::IsFull(d)) return reversed;
  // Shift right to remove extra (non-pow2 and remainder) lanes.
  // TODO(janwas): on SVE2, use WHILEGE.
  // Avoids FirstN truncating to the return vector size. Must also avoid Not
  // because that is limited to SV_POW2.
  const ScalableTag<T> dfull;
  const svbool_t all_true = detail::AllPTrue(dfull);
  const size_t all_lanes = detail::AllHardwareLanes(hwy::SizeTag<sizeof(T)>());
  const svbool_t mask =
      svnot_b_z(all_true, FirstN(dfull, all_lanes - Lanes(d)));
  return detail::Splice(reversed, reversed, mask);
}

// ------------------------------ Reverse2

template <class D, HWY_IF_LANE_SIZE_D(D, 2)>
HWY_API VFromD<D> Reverse2(D d, const VFromD<D> v) {
  const RebindToUnsigned<decltype(d)> du;
  const RepartitionToWide<decltype(du)> dw;
  return BitCast(d, svrevh_u32_x(detail::PTrue(d), BitCast(dw, v)));
}

template <class D, HWY_IF_LANE_SIZE_D(D, 4)>
HWY_API VFromD<D> Reverse2(D d, const VFromD<D> v) {
  const RebindToUnsigned<decltype(d)> du;
  const RepartitionToWide<decltype(du)> dw;
  return BitCast(d, svrevw_u64_x(detail::PTrue(d), BitCast(dw, v)));
}

template <class D, HWY_IF_LANE_SIZE_D(D, 8)>
HWY_API VFromD<D> Reverse2(D d, const VFromD<D> v) {  // 3210
#if HWY_TARGET == HWY_SVE2_128
  if (detail::IsFull(d)) {
    return detail::Ext<1>(v, v);
  }
#endif
  (void)d;
  const auto odd_in_even = detail::Ext<1>(v, v);  // x321
  return detail::InterleaveEven(odd_in_even, v);  // 2301
}
// ------------------------------ Reverse4 (TableLookupLanes)
template <class D>
HWY_API VFromD<D> Reverse4(D d, const VFromD<D> v) {
  if (HWY_TARGET == HWY_SVE_256 && sizeof(TFromD<D>) == 8 &&
      detail::IsFull(d)) {
    return detail::ReverseFull(v);
  }
  // TODO(janwas): is this approach faster than Shuffle0123?
  const RebindToUnsigned<decltype(d)> du;
  const auto idx = detail::XorN(Iota(du, 0), 3);
  return TableLookupLanes(v, idx);
}

// ------------------------------ Reverse8 (TableLookupLanes)
template <class D>
HWY_API VFromD<D> Reverse8(D d, const VFromD<D> v) {
  const RebindToUnsigned<decltype(d)> du;
  const auto idx = detail::XorN(Iota(du, 0), 7);
  return TableLookupLanes(v, idx);
}

// ------------------------------ Compress (PromoteTo)

template <typename T>
struct CompressIsPartition {
#if HWY_TARGET == HWY_SVE_256 || HWY_TARGET == HWY_SVE2_128
  // Optimization for 64-bit lanes (could also be applied to 32-bit, but that
  // requires a larger table).
  enum { value = (sizeof(T) == 8) };
#else
  enum { value = 0 };
#endif  // HWY_TARGET == HWY_SVE_256
};

#define HWY_SVE_COMPRESS(BASE, CHAR, BITS, HALF, NAME, OP)                     \
  HWY_API HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v, svbool_t mask) { \
    return sv##OP##_##CHAR##BITS(mask, v);                                     \
  }

#if HWY_TARGET == HWY_SVE_256 || HWY_TARGET == HWY_SVE2_128
HWY_SVE_FOREACH_UI32(HWY_SVE_COMPRESS, Compress, compact)
HWY_SVE_FOREACH_F32(HWY_SVE_COMPRESS, Compress, compact)
#else
HWY_SVE_FOREACH_UIF3264(HWY_SVE_COMPRESS, Compress, compact)
#endif
#undef HWY_SVE_COMPRESS

#if HWY_TARGET == HWY_SVE_256 || HWY_IDE
template <class V, HWY_IF_LANE_SIZE_V(V, 8)>
HWY_API V Compress(V v, svbool_t mask) {
  const DFromV<V> d;
  const RebindToUnsigned<decltype(d)> du64;

  // Convert mask into bitfield via horizontal sum (faster than ORV) of masked
  // bits 1, 2, 4, 8. Pre-multiply by N so we can use it as an offset for
  // SetTableIndices.
  const svuint64_t bits = Shl(Set(du64, 1), Iota(du64, 2));
  const size_t offset = detail::SumOfLanesM(mask, bits);

  // See CompressIsPartition.
  alignas(16) static constexpr uint64_t table[4 * 16] = {
      // PrintCompress64x4Tables
      0, 1, 2, 3, 0, 1, 2, 3, 1, 0, 2, 3, 0, 1, 2, 3, 2, 0, 1, 3, 0, 2,
      1, 3, 1, 2, 0, 3, 0, 1, 2, 3, 3, 0, 1, 2, 0, 3, 1, 2, 1, 3, 0, 2,
      0, 1, 3, 2, 2, 3, 0, 1, 0, 2, 3, 1, 1, 2, 3, 0, 0, 1, 2, 3};
  return TableLookupLanes(v, SetTableIndices(d, table + offset));
}

#endif  // HWY_TARGET == HWY_SVE_256
#if HWY_TARGET == HWY_SVE2_128 || HWY_IDE
template <class V, HWY_IF_LANE_SIZE_V(V, 8)>
HWY_API V Compress(V v, svbool_t mask) {
  // If mask == 10: swap via splice. A mask of 00 or 11 leaves v unchanged, 10
  // swaps upper/lower (the lower half is set to the upper half, and the
  // remaining upper half is filled from the lower half of the second v), and
  // 01 is invalid because it would ConcatLowerLower. zip1 and AndNot keep 10
  // unchanged and map everything else to 00.
  const svbool_t maskLL = svzip1_b64(mask, mask);  // broadcast lower lane
  return detail::Splice(v, v, AndNot(maskLL, mask));
}

#endif  // HWY_TARGET == HWY_SVE2_128

template <class V, HWY_IF_LANE_SIZE_V(V, 2)>
HWY_API V Compress(V v, svbool_t mask16) {
  static_assert(!IsSame<V, svfloat16_t>(), "Must use overload");
  const DFromV<V> d16;

  // Promote vector and mask to 32-bit
  const RepartitionToWide<decltype(d16)> dw;
  const auto v32L = PromoteTo(dw, v);
  const auto v32H = detail::PromoteUpperTo(dw, v);
  const svbool_t mask32L = svunpklo_b(mask16);
  const svbool_t mask32H = svunpkhi_b(mask16);

  const auto compressedL = Compress(v32L, mask32L);
  const auto compressedH = Compress(v32H, mask32H);

  // Demote to 16-bit (already in range) - separately so we can splice
  const V evenL = BitCast(d16, compressedL);
  const V evenH = BitCast(d16, compressedH);
  const V v16L = detail::ConcatEvenFull(evenL, evenL);  // lower half
  const V v16H = detail::ConcatEvenFull(evenH, evenH);

  // We need to combine two vectors of non-constexpr length, so the only option
  // is Splice, which requires us to synthesize a mask. NOTE: this function uses
  // full vectors (SV_ALL instead of SV_POW2), hence we need unmasked svcnt.
  const size_t countL = detail::CountTrueFull(dw, mask32L);
  const auto compressed_maskL = FirstN(d16, countL);
  return detail::Splice(v16H, v16L, compressed_maskL);
}

// Must treat float16_t as integers so we can ConcatEven.
HWY_API svfloat16_t Compress(svfloat16_t v, svbool_t mask16) {
  const DFromV<decltype(v)> df;
  const RebindToSigned<decltype(df)> di;
  return BitCast(df, Compress(BitCast(di, v), mask16));
}

// ------------------------------ CompressNot

// 2 or 4 bytes
template <class V, typename T = TFromV<V>, HWY_IF_LANE_SIZE_ONE_OF(T, 0x14)>
HWY_API V CompressNot(V v, const svbool_t mask) {
  return Compress(v, Not(mask));
}

template <class V, HWY_IF_LANE_SIZE_V(V, 8)>
HWY_API V CompressNot(V v, svbool_t mask) {
#if HWY_TARGET == HWY_SVE2_128 || HWY_IDE
  // If mask == 01: swap via splice. A mask of 00 or 11 leaves v unchanged, 10
  // swaps upper/lower (the lower half is set to the upper half, and the
  // remaining upper half is filled from the lower half of the second v), and
  // 01 is invalid because it would ConcatLowerLower. zip1 and AndNot map
  // 01 to 10, and everything else to 00.
  const svbool_t maskLL = svzip1_b64(mask, mask);  // broadcast lower lane
  return detail::Splice(v, v, AndNot(mask, maskLL));
#endif
#if HWY_TARGET == HWY_SVE_256 || HWY_IDE
  const DFromV<V> d;
  const RebindToUnsigned<decltype(d)> du64;

  // Convert mask into bitfield via horizontal sum (faster than ORV) of masked
  // bits 1, 2, 4, 8. Pre-multiply by N so we can use it as an offset for
  // SetTableIndices.
  const svuint64_t bits = Shl(Set(du64, 1), Iota(du64, 2));
  const size_t offset = detail::SumOfLanesM(mask, bits);

  // See CompressIsPartition.
  alignas(16) static constexpr uint64_t table[4 * 16] = {
      // PrintCompressNot64x4Tables
      0, 1, 2, 3, 1, 2, 3, 0, 0, 2, 3, 1, 2, 3, 0, 1, 0, 1, 3, 2, 1, 3,
      0, 2, 0, 3, 1, 2, 3, 0, 1, 2, 0, 1, 2, 3, 1, 2, 0, 3, 0, 2, 1, 3,
      2, 0, 1, 3, 0, 1, 2, 3, 1, 0, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3};
  return TableLookupLanes(v, SetTableIndices(d, table + offset));
#endif  // HWY_TARGET == HWY_SVE_256

  return Compress(v, Not(mask));
}

// ------------------------------ CompressBlocksNot
HWY_API svuint64_t CompressBlocksNot(svuint64_t v, svbool_t mask) {
#if HWY_TARGET == HWY_SVE2_128
  (void)mask;
  return v;
#endif
#if HWY_TARGET == HWY_SVE_256 || HWY_IDE
  uint64_t bits = 0;  // predicate reg is 32-bit
  CopyBytes<4>(&mask, &bits);  // not same size - 64-bit more efficient
  // Concatenate LSB for upper and lower blocks, pre-scale by 4 for table idx.
  const size_t offset = ((bits & 1) ? 4u : 0u) + ((bits & 0x10000) ? 8u : 0u);
  // See CompressIsPartition. Manually generated; flip halves if mask = [0, 1].
  alignas(16) static constexpr uint64_t table[4 * 4] = {0, 1, 2, 3, 2, 3, 0, 1,
                                                        0, 1, 2, 3, 0, 1, 2, 3};
  const ScalableTag<uint64_t> d;
  return TableLookupLanes(v, SetTableIndices(d, table + offset));
#endif

  return CompressNot(v, mask);
}

// ------------------------------ CompressStore
template <class V, class D, HWY_IF_NOT_LANE_SIZE_D(D, 1)>
HWY_API size_t CompressStore(const V v, const svbool_t mask, const D d,
                             TFromD<D>* HWY_RESTRICT unaligned) {
  StoreU(Compress(v, mask), d, unaligned);
  return CountTrue(d, mask);
}

// ------------------------------ CompressBlendedStore
template <class V, class D, HWY_IF_NOT_LANE_SIZE_D(D, 1)>
HWY_API size_t CompressBlendedStore(const V v, const svbool_t mask, const D d,
                                    TFromD<D>* HWY_RESTRICT unaligned) {
  const size_t count = CountTrue(d, mask);
  const svbool_t store_mask = FirstN(d, count);
  BlendedStore(Compress(v, mask), store_mask, d, unaligned);
  return count;
}

// ================================================== BLOCKWISE

// ------------------------------ CombineShiftRightBytes

// Prevent accidentally using these for 128-bit vectors - should not be
// necessary.
#if HWY_TARGET != HWY_SVE2_128
namespace detail {

// For x86-compatible behaviour mandated by Highway API: TableLookupBytes
// offsets are implicitly relative to the start of their 128-bit block.
template <class D, class V>
HWY_INLINE V OffsetsOf128BitBlocks(const D d, const V iota0) {
  using T = MakeUnsigned<TFromD<D>>;
  return detail::AndNotN(static_cast<T>(LanesPerBlock(d) - 1), iota0);
}

template <size_t kLanes, class D, HWY_IF_LANE_SIZE_D(D, 1)>
svbool_t FirstNPerBlock(D d) {
  const RebindToUnsigned<decltype(d)> du;
  constexpr size_t kLanesPerBlock = detail::LanesPerBlock(du);
  const svuint8_t idx_mod =
      svdupq_n_u8(0 % kLanesPerBlock, 1 % kLanesPerBlock, 2 % kLanesPerBlock,
                  3 % kLanesPerBlock, 4 % kLanesPerBlock, 5 % kLanesPerBlock,
                  6 % kLanesPerBlock, 7 % kLanesPerBlock, 8 % kLanesPerBlock,
                  9 % kLanesPerBlock, 10 % kLanesPerBlock, 11 % kLanesPerBlock,
                  12 % kLanesPerBlock, 13 % kLanesPerBlock, 14 % kLanesPerBlock,
                  15 % kLanesPerBlock);
  return detail::LtN(BitCast(du, idx_mod), kLanes);
}
template <size_t kLanes, class D, HWY_IF_LANE_SIZE_D(D, 2)>
svbool_t FirstNPerBlock(D d) {
  const RebindToUnsigned<decltype(d)> du;
  constexpr size_t kLanesPerBlock = detail::LanesPerBlock(du);
  const svuint16_t idx_mod =
      svdupq_n_u16(0 % kLanesPerBlock, 1 % kLanesPerBlock, 2 % kLanesPerBlock,
                   3 % kLanesPerBlock, 4 % kLanesPerBlock, 5 % kLanesPerBlock,
                   6 % kLanesPerBlock, 7 % kLanesPerBlock);
  return detail::LtN(BitCast(du, idx_mod), kLanes);
}
template <size_t kLanes, class D, HWY_IF_LANE_SIZE_D(D, 4)>
svbool_t FirstNPerBlock(D d) {
  const RebindToUnsigned<decltype(d)> du;
  constexpr size_t kLanesPerBlock = detail::LanesPerBlock(du);
  const svuint32_t idx_mod =
      svdupq_n_u32(0 % kLanesPerBlock, 1 % kLanesPerBlock, 2 % kLanesPerBlock,
                   3 % kLanesPerBlock);
  return detail::LtN(BitCast(du, idx_mod), kLanes);
}
template <size_t kLanes, class D, HWY_IF_LANE_SIZE_D(D, 8)>
svbool_t FirstNPerBlock(D d) {
  const RebindToUnsigned<decltype(d)> du;
  constexpr size_t kLanesPerBlock = detail::LanesPerBlock(du);
  const svuint64_t idx_mod =
      svdupq_n_u64(0 % kLanesPerBlock, 1 % kLanesPerBlock);
  return detail::LtN(BitCast(du, idx_mod), kLanes);
}

}  // namespace detail
#endif  // HWY_TARGET != HWY_SVE2_128

template <size_t kBytes, class D, class V = VFromD<D>>
HWY_API V CombineShiftRightBytes(const D d, const V hi, const V lo) {
  const Repartition<uint8_t, decltype(d)> d8;
  const auto hi8 = BitCast(d8, hi);
  const auto lo8 = BitCast(d8, lo);
#if HWY_TARGET == HWY_SVE2_128
  return BitCast(d, detail::Ext<kBytes>(hi8, lo8));
#else
  const auto hi_up = detail::Splice(hi8, hi8, FirstN(d8, 16 - kBytes));
  const auto lo_down = detail::Ext<kBytes>(lo8, lo8);
  const svbool_t is_lo = detail::FirstNPerBlock<16 - kBytes>(d8);
  return BitCast(d, IfThenElse(is_lo, lo_down, hi_up));
#endif
}

// ------------------------------ Shuffle2301
template <class V>
HWY_API V Shuffle2301(const V v) {
  const DFromV<V> d;
  static_assert(sizeof(TFromD<decltype(d)>) == 4, "Defined for 32-bit types");
  return Reverse2(d, v);
}

// ------------------------------ Shuffle2103
template <class V>
HWY_API V Shuffle2103(const V v) {
  const DFromV<V> d;
  const Repartition<uint8_t, decltype(d)> d8;
  static_assert(sizeof(TFromD<decltype(d)>) == 4, "Defined for 32-bit types");
  const svuint8_t v8 = BitCast(d8, v);
  return BitCast(d, CombineShiftRightBytes<12>(d8, v8, v8));
}

// ------------------------------ Shuffle0321
template <class V>
HWY_API V Shuffle0321(const V v) {
  const DFromV<V> d;
  const Repartition<uint8_t, decltype(d)> d8;
  static_assert(sizeof(TFromD<decltype(d)>) == 4, "Defined for 32-bit types");
  const svuint8_t v8 = BitCast(d8, v);
  return BitCast(d, CombineShiftRightBytes<4>(d8, v8, v8));
}

// ------------------------------ Shuffle1032
template <class V>
HWY_API V Shuffle1032(const V v) {
  const DFromV<V> d;
  const Repartition<uint8_t, decltype(d)> d8;
  static_assert(sizeof(TFromD<decltype(d)>) == 4, "Defined for 32-bit types");
  const svuint8_t v8 = BitCast(d8, v);
  return BitCast(d, CombineShiftRightBytes<8>(d8, v8, v8));
}

// ------------------------------ Shuffle01
template <class V>
HWY_API V Shuffle01(const V v) {
  const DFromV<V> d;
  const Repartition<uint8_t, decltype(d)> d8;
  static_assert(sizeof(TFromD<decltype(d)>) == 8, "Defined for 64-bit types");
  const svuint8_t v8 = BitCast(d8, v);
  return BitCast(d, CombineShiftRightBytes<8>(d8, v8, v8));
}

// ------------------------------ Shuffle0123
template <class V>
HWY_API V Shuffle0123(const V v) {
  return Shuffle2301(Shuffle1032(v));
}

// ------------------------------ ReverseBlocks (Reverse, Shuffle01)
template <class D, class V = VFromD<D>>
HWY_API V ReverseBlocks(D d, V v) {
#if HWY_TARGET == HWY_SVE_256
  if (detail::IsFull(d)) {
    return SwapAdjacentBlocks(v);
  } else if (detail::IsFull(Twice<D>())) {
    return v;
  }
#elif HWY_TARGET == HWY_SVE2_128
  (void)d;
  return v;
#endif
  const Repartition<uint64_t, D> du64;
  return BitCast(d, Shuffle01(Reverse(du64, BitCast(du64, v))));
}

// ------------------------------ TableLookupBytes

template <class V, class VI>
HWY_API VI TableLookupBytes(const V v, const VI idx) {
  const DFromV<VI> d;
  const Repartition<uint8_t, decltype(d)> du8;
#if HWY_TARGET == HWY_SVE2_128
  return BitCast(d, TableLookupLanes(BitCast(du8, v), BitCast(du8, idx)));
#else
  const auto offsets128 = detail::OffsetsOf128BitBlocks(du8, Iota(du8, 0));
  const auto idx8 = Add(BitCast(du8, idx), offsets128);
  return BitCast(d, TableLookupLanes(BitCast(du8, v), idx8));
#endif
}

template <class V, class VI>
HWY_API VI TableLookupBytesOr0(const V v, const VI idx) {
  const DFromV<VI> d;
  // Mask size must match vector type, so cast everything to this type.
  const Repartition<int8_t, decltype(d)> di8;

  auto idx8 = BitCast(di8, idx);
  const auto msb = detail::LtN(idx8, 0);

  const auto lookup = TableLookupBytes(BitCast(di8, v), idx8);
  return BitCast(d, IfThenZeroElse(msb, lookup));
}

// ------------------------------ Broadcast

#if HWY_TARGET == HWY_SVE2_128
namespace detail {
#define HWY_SVE_BROADCAST(BASE, CHAR, BITS, HALF, NAME, OP)        \
  template <int kLane>                                             \
  HWY_INLINE HWY_SVE_V(BASE, BITS) NAME(HWY_SVE_V(BASE, BITS) v) { \
    return sv##OP##_##CHAR##BITS(v, kLane);                        \
  }

HWY_SVE_FOREACH(HWY_SVE_BROADCAST, BroadcastLane, dup_lane)
#undef HWY_SVE_BROADCAST
}  // namespace detail
#endif

template <int kLane, class V>
HWY_API V Broadcast(const V v) {
  const DFromV<V> d;
  const RebindToUnsigned<decltype(d)> du;
  constexpr size_t kLanesPerBlock = detail::LanesPerBlock(du);
  static_assert(0 <= kLane && kLane < kLanesPerBlock, "Invalid lane");
#if HWY_TARGET == HWY_SVE2_128
  return detail::BroadcastLane<kLane>(v);
#else
  auto idx = detail::OffsetsOf128BitBlocks(du, Iota(du, 0));
  if (kLane != 0) {
    idx = detail::AddN(idx, kLane);
  }
  return TableLookupLanes(v, idx);
#endif
}

// ------------------------------ ShiftLeftLanes

template <size_t kLanes, class D, class V = VFromD<D>>
HWY_API V ShiftLeftLanes(D d, const V v) {
  const auto zero = Zero(d);
  const auto shifted = detail::Splice(v, zero, FirstN(d, kLanes));
#if HWY_TARGET == HWY_SVE2_128
  return shifted;
#else
  // Match x86 semantics by zeroing lower lanes in 128-bit blocks
  return IfThenElse(detail::FirstNPerBlock<kLanes>(d), zero, shifted);
#endif
}

template <size_t kLanes, class V>
HWY_API V ShiftLeftLanes(const V v) {
  return ShiftLeftLanes<kLanes>(DFromV<V>(), v);
}

// ------------------------------ ShiftRightLanes
template <size_t kLanes, class D, class V = VFromD<D>>
HWY_API V ShiftRightLanes(D d, V v) {
  // For capped/fractional vectors, clear upper lanes so we shift in zeros.
  if (!detail::IsFull(d)) {
    v = IfThenElseZero(detail::MakeMask(d), v);
  }

#if HWY_TARGET == HWY_SVE2_128
  return detail::Ext<kLanes>(Zero(d), v);
#else
  const auto shifted = detail::Ext<kLanes>(v, v);
  // Match x86 semantics by zeroing upper lanes in 128-bit blocks
  constexpr size_t kLanesPerBlock = detail::LanesPerBlock(d);
  const svbool_t mask = detail::FirstNPerBlock<kLanesPerBlock - kLanes>(d);
  return IfThenElseZero(mask, shifted);
#endif
}

// ------------------------------ ShiftLeftBytes

template <int kBytes, class D, class V = VFromD<D>>
HWY_API V ShiftLeftBytes(const D d, const V v) {
  const Repartition<uint8_t, decltype(d)> d8;
  return BitCast(d, ShiftLeftLanes<kBytes>(BitCast(d8, v)));
}

template <int kBytes, class V>
HWY_API V ShiftLeftBytes(const V v) {
  return ShiftLeftBytes<kBytes>(DFromV<V>(), v);
}

// ------------------------------ ShiftRightBytes
template <int kBytes, class D, class V = VFromD<D>>
HWY_API V ShiftRightBytes(const D d, const V v) {
  const Repartition<uint8_t, decltype(d)> d8;
  return BitCast(d, ShiftRightLanes<kBytes>(d8, BitCast(d8, v)));
}

// ------------------------------ ZipLower

template <class V, class DW = RepartitionToWide<DFromV<V>>>
HWY_API VFromD<DW> ZipLower(DW dw, V a, V b) {
  const RepartitionToNarrow<DW> dn;
  static_assert(IsSame<TFromD<decltype(dn)>, TFromV<V>>(), "D/V mismatch");
  return BitCast(dw, InterleaveLower(dn, a, b));
}
template <class V, class D = DFromV<V>, class DW = RepartitionToWide<D>>
HWY_API VFromD<DW> ZipLower(const V a, const V b) {
  return BitCast(DW(), InterleaveLower(D(), a, b));
}

// ------------------------------ ZipUpper
template <class V, class DW = RepartitionToWide<DFromV<V>>>
HWY_API VFromD<DW> ZipUpper(DW dw, V a, V b) {
  const RepartitionToNarrow<DW> dn;
  static_assert(IsSame<TFromD<decltype(dn)>, TFromV<V>>(), "D/V mismatch");
  return BitCast(dw, InterleaveUpper(dn, a, b));
}

// ================================================== Ops with dependencies

// ------------------------------ PromoteTo bfloat16 (ZipLower)
template <size_t N, int kPow2>
HWY_API svfloat32_t PromoteTo(Simd<float32_t, N, kPow2> df32,
                              const svuint16_t v) {
  return BitCast(df32, detail::ZipLowerSame(svdup_n_u16(0), v));
}

// ------------------------------ ReorderDemote2To (OddEven)

template <size_t N, int kPow2>
HWY_API svuint16_t ReorderDemote2To(Simd<bfloat16_t, N, kPow2> dbf16,
                                    svfloat32_t a, svfloat32_t b) {
  const RebindToUnsigned<decltype(dbf16)> du16;
  const Repartition<uint32_t, decltype(dbf16)> du32;
  const svuint32_t b_in_even = ShiftRight<16>(BitCast(du32, b));
  return BitCast(dbf16, OddEven(BitCast(du16, a), BitCast(du16, b_in_even)));
}

template <size_t N, int kPow2>
HWY_API svint16_t ReorderDemote2To(Simd<int16_t, N, kPow2> d16, svint32_t a,
                                   svint32_t b) {
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  (void)d16;
  const svint16_t a_in_even = svqxtnb_s32(a);
  return svqxtnt_s32(a_in_even, b);
#else
  const Half<decltype(d16)> dh;
  const svint16_t a16 = BitCast(dh, detail::SaturateI<int16_t>(a));
  const svint16_t b16 = BitCast(dh, detail::SaturateI<int16_t>(b));
  return detail::InterleaveEven(a16, b16);
#endif
}

// ------------------------------ ZeroIfNegative (Lt, IfThenElse)
template <class V>
HWY_API V ZeroIfNegative(const V v) {
  return IfThenZeroElse(detail::LtN(v, 0), v);
}

// ------------------------------ BroadcastSignBit (ShiftRight)
template <class V>
HWY_API V BroadcastSignBit(const V v) {
  return ShiftRight<sizeof(TFromV<V>) * 8 - 1>(v);
}

// ------------------------------ IfNegativeThenElse (BroadcastSignBit)
template <class V>
HWY_API V IfNegativeThenElse(V v, V yes, V no) {
  static_assert(IsSigned<TFromV<V>>(), "Only works for signed/float");
  const DFromV<V> d;
  const RebindToSigned<decltype(d)> di;

  const svbool_t m = MaskFromVec(BitCast(d, BroadcastSignBit(BitCast(di, v))));
  return IfThenElse(m, yes, no);
}

// ------------------------------ AverageRound (ShiftRight)

#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
HWY_SVE_FOREACH_U08(HWY_SVE_RETV_ARGPVV, AverageRound, rhadd)
HWY_SVE_FOREACH_U16(HWY_SVE_RETV_ARGPVV, AverageRound, rhadd)
#else
template <class V>
V AverageRound(const V a, const V b) {
  return ShiftRight<1>(detail::AddN(Add(a, b), 1));
}
#endif  // HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128

// ------------------------------ LoadMaskBits (TestBit)

// `p` points to at least 8 readable bytes, not all of which need be valid.
template <class D, HWY_IF_LANE_SIZE_D(D, 1)>
HWY_INLINE svbool_t LoadMaskBits(D d, const uint8_t* HWY_RESTRICT bits) {
  const RebindToUnsigned<D> du;
  const svuint8_t iota = Iota(du, 0);

  // Load correct number of bytes (bits/8) with 7 zeros after each.
  const svuint8_t bytes = BitCast(du, svld1ub_u64(detail::PTrue(d), bits));
  // Replicate bytes 8x such that each byte contains the bit that governs it.
  const svuint8_t rep8 = svtbl_u8(bytes, detail::AndNotN(7, iota));

  const svuint8_t bit =
      svdupq_n_u8(1, 2, 4, 8, 16, 32, 64, 128, 1, 2, 4, 8, 16, 32, 64, 128);
  return TestBit(rep8, bit);
}

template <class D, HWY_IF_LANE_SIZE_D(D, 2)>
HWY_INLINE svbool_t LoadMaskBits(D /* tag */,
                                 const uint8_t* HWY_RESTRICT bits) {
  const RebindToUnsigned<D> du;
  const Repartition<uint8_t, D> du8;

  // There may be up to 128 bits; avoid reading past the end.
  const svuint8_t bytes = svld1(FirstN(du8, (Lanes(du) + 7) / 8), bits);

  // Replicate bytes 16x such that each lane contains the bit that governs it.
  const svuint8_t rep16 = svtbl_u8(bytes, ShiftRight<4>(Iota(du8, 0)));

  const svuint16_t bit = svdupq_n_u16(1, 2, 4, 8, 16, 32, 64, 128);
  return TestBit(BitCast(du, rep16), bit);
}

template <class D, HWY_IF_LANE_SIZE_D(D, 4)>
HWY_INLINE svbool_t LoadMaskBits(D /* tag */,
                                 const uint8_t* HWY_RESTRICT bits) {
  const RebindToUnsigned<D> du;
  const Repartition<uint8_t, D> du8;

  // Upper bound = 2048 bits / 32 bit = 64 bits; at least 8 bytes are readable,
  // so we can skip computing the actual length (Lanes(du)+7)/8.
  const svuint8_t bytes = svld1(FirstN(du8, 8), bits);

  // Replicate bytes 32x such that each lane contains the bit that governs it.
  const svuint8_t rep32 = svtbl_u8(bytes, ShiftRight<5>(Iota(du8, 0)));

  // 1, 2, 4, 8, 16, 32, 64, 128,  1, 2 ..
  const svuint32_t bit = Shl(Set(du, 1), detail::AndN(Iota(du, 0), 7));

  return TestBit(BitCast(du, rep32), bit);
}

template <class D, HWY_IF_LANE_SIZE_D(D, 8)>
HWY_INLINE svbool_t LoadMaskBits(D /* tag */,
                                 const uint8_t* HWY_RESTRICT bits) {
  const RebindToUnsigned<D> du;

  // Max 2048 bits = 32 lanes = 32 input bits; replicate those into each lane.
  // The "at least 8 byte" guarantee in quick_reference ensures this is safe.
  uint32_t mask_bits;
  CopyBytes<4>(bits, &mask_bits);  // copy from bytes
  const auto vbits = Set(du, mask_bits);

  // 2 ^ {0,1, .., 31}, will not have more lanes than that.
  const svuint64_t bit = Shl(Set(du, 1), Iota(du, 0));

  return TestBit(vbits, bit);
}

// ------------------------------ StoreMaskBits

namespace detail {

// For each mask lane (governing lane type T), store 1 or 0 in BYTE lanes.
template <class T, HWY_IF_LANE_SIZE(T, 1)>
HWY_INLINE svuint8_t BoolFromMask(svbool_t m) {
  return svdup_n_u8_z(m, 1);
}
template <class T, HWY_IF_LANE_SIZE(T, 2)>
HWY_INLINE svuint8_t BoolFromMask(svbool_t m) {
  const ScalableTag<uint8_t> d8;
  const svuint8_t b16 = BitCast(d8, svdup_n_u16_z(m, 1));
  return detail::ConcatEvenFull(b16, b16);  // lower half
}
template <class T, HWY_IF_LANE_SIZE(T, 4)>
HWY_INLINE svuint8_t BoolFromMask(svbool_t m) {
  return U8FromU32(svdup_n_u32_z(m, 1));
}
template <class T, HWY_IF_LANE_SIZE(T, 8)>
HWY_INLINE svuint8_t BoolFromMask(svbool_t m) {
  const ScalableTag<uint32_t> d32;
  const svuint32_t b64 = BitCast(d32, svdup_n_u64_z(m, 1));
  return U8FromU32(detail::ConcatEvenFull(b64, b64));  // lower half
}

// Compacts groups of 8 u8 into 8 contiguous bits in a 64-bit lane.
HWY_INLINE svuint64_t BitsFromBool(svuint8_t x) {
  const ScalableTag<uint8_t> d8;
  const ScalableTag<uint16_t> d16;
  const ScalableTag<uint32_t> d32;
  const ScalableTag<uint64_t> d64;
  // TODO(janwas): could use SVE2 BDEP, but it's optional.
  x = Or(x, BitCast(d8, ShiftRight<7>(BitCast(d16, x))));
  x = Or(x, BitCast(d8, ShiftRight<14>(BitCast(d32, x))));
  x = Or(x, BitCast(d8, ShiftRight<28>(BitCast(d64, x))));
  return BitCast(d64, x);
}

}  // namespace detail

// `p` points to at least 8 writable bytes.
// TODO(janwas): specialize for HWY_SVE_256
template <class D>
HWY_API size_t StoreMaskBits(D d, svbool_t m, uint8_t* bits) {
  svuint64_t bits_in_u64 =
      detail::BitsFromBool(detail::BoolFromMask<TFromD<D>>(m));

  const size_t num_bits = Lanes(d);
  const size_t num_bytes = (num_bits + 8 - 1) / 8;  // Round up, see below

  // Truncate each u64 to 8 bits and store to u8.
  svst1b_u64(FirstN(ScalableTag<uint64_t>(), num_bytes), bits, bits_in_u64);

  // Non-full byte, need to clear the undefined upper bits. Can happen for
  // capped/fractional vectors or large T and small hardware vectors.
  if (num_bits < 8) {
    const int mask = static_cast<int>((1ull << num_bits) - 1);
    bits[0] = static_cast<uint8_t>(bits[0] & mask);
  }
  // Else: we wrote full bytes because num_bits is a power of two >= 8.

  return num_bytes;
}

// ------------------------------ CompressBits (LoadMaskBits)
template <class V, class D = DFromV<V>, HWY_IF_NOT_LANE_SIZE_D(D, 1)>
HWY_INLINE V CompressBits(V v, const uint8_t* HWY_RESTRICT bits) {
  return Compress(v, LoadMaskBits(D(), bits));
}

// ------------------------------ CompressBitsStore (LoadMaskBits)
template <class D, HWY_IF_NOT_LANE_SIZE_D(D, 1)>
HWY_API size_t CompressBitsStore(VFromD<D> v, const uint8_t* HWY_RESTRICT bits,
                                 D d, TFromD<D>* HWY_RESTRICT unaligned) {
  return CompressStore(v, LoadMaskBits(d, bits), d, unaligned);
}

// ------------------------------ MulEven (InterleaveEven)

#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
namespace detail {
#define HWY_SVE_MUL_EVEN(BASE, CHAR, BITS, HALF, NAME, OP)     \
  HWY_API HWY_SVE_V(BASE, BITS)                                \
      NAME(HWY_SVE_V(BASE, HALF) a, HWY_SVE_V(BASE, HALF) b) { \
    return sv##OP##_##CHAR##BITS(a, b);                        \
  }

HWY_SVE_FOREACH_UI64(HWY_SVE_MUL_EVEN, MulEvenNative, mullb)
#undef HWY_SVE_MUL_EVEN
}  // namespace detail
#endif

template <class V, class DW = RepartitionToWide<DFromV<V>>>
HWY_API VFromD<DW> MulEven(const V a, const V b) {
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  return BitCast(DW(), detail::MulEvenNative(a, b));
#else
  const auto lo = Mul(a, b);
  const auto hi = MulHigh(a, b);
  return BitCast(DW(), detail::InterleaveEven(lo, hi));
#endif
}

HWY_API svuint64_t MulEven(const svuint64_t a, const svuint64_t b) {
  const auto lo = Mul(a, b);
  const auto hi = MulHigh(a, b);
  return detail::InterleaveEven(lo, hi);
}

HWY_API svuint64_t MulOdd(const svuint64_t a, const svuint64_t b) {
  const auto lo = Mul(a, b);
  const auto hi = MulHigh(a, b);
  return detail::InterleaveOdd(lo, hi);
}

// ------------------------------ ReorderWidenMulAccumulate (MulAdd, ZipLower)

template <size_t N, int kPow2>
HWY_API svfloat32_t ReorderWidenMulAccumulate(Simd<float, N, kPow2> df32,
                                              svuint16_t a, svuint16_t b,
                                              const svfloat32_t sum0,
                                              svfloat32_t& sum1) {
  // TODO(janwas): svbfmlalb_f32 if __ARM_FEATURE_SVE_BF16.
  const RebindToUnsigned<decltype(df32)> du32;
  // Using shift/and instead of Zip leads to the odd/even order that
  // RearrangeToOddPlusEven prefers.
  using VU32 = VFromD<decltype(du32)>;
  const VU32 odd = Set(du32, 0xFFFF0000u);
  const VU32 ae = ShiftLeft<16>(BitCast(du32, a));
  const VU32 ao = And(BitCast(du32, a), odd);
  const VU32 be = ShiftLeft<16>(BitCast(du32, b));
  const VU32 bo = And(BitCast(du32, b), odd);
  sum1 = MulAdd(BitCast(df32, ao), BitCast(df32, bo), sum1);
  return MulAdd(BitCast(df32, ae), BitCast(df32, be), sum0);
}

template <size_t N, int kPow2>
HWY_API svint32_t ReorderWidenMulAccumulate(Simd<int32_t, N, kPow2> d32,
                                            svint16_t a, svint16_t b,
                                            const svint32_t sum0,
                                            svint32_t& sum1) {
#if HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128
  (void)d32;
  sum1 = svmlalt_s32(sum1, a, b);
  return svmlalb_s32(sum0, a, b);
#else
  const svbool_t pg = detail::PTrue(d32);
  // Shifting extracts the odd lanes as RearrangeToOddPlusEven prefers.
  // Fortunately SVE has sign-extension for the even lanes.
  const svint32_t ae = svexth_s32_x(pg, BitCast(d32, a));
  const svint32_t be = svexth_s32_x(pg, BitCast(d32, b));
  const svint32_t ao = ShiftRight<16>(BitCast(d32, a));
  const svint32_t bo = ShiftRight<16>(BitCast(d32, b));
  sum1 = svmla_s32_x(pg, sum1, ao, bo);
  return svmla_s32_x(pg, sum0, ae, be);
#endif
}

// ------------------------------ RearrangeToOddPlusEven
template <class VW>
HWY_API VW RearrangeToOddPlusEven(const VW sum0, const VW sum1) {
  // sum0 is the sum of bottom/even lanes and sum1 of top/odd lanes.
  return Add(sum0, sum1);
}

// ------------------------------ AESRound / CLMul

#if defined(__ARM_FEATURE_SVE2_AES) ||                         \
    ((HWY_TARGET == HWY_SVE2 || HWY_TARGET == HWY_SVE2_128) && \
     HWY_HAVE_RUNTIME_DISPATCH)

// Per-target flag to prevent generic_ops-inl.h from defining AESRound.
#ifdef HWY_NATIVE_AES
#undef HWY_NATIVE_AES
#else
#define HWY_NATIVE_AES
#endif

HWY_API svuint8_t AESRound(svuint8_t state, svuint8_t round_key) {
  // It is not clear whether E and MC fuse like they did on NEON.
  const svuint8_t zero = svdup_n_u8(0);
  return Xor(svaesmc_u8(svaese_u8(state, zero)), round_key);
}

HWY_API svuint8_t AESLastRound(svuint8_t state, svuint8_t round_key) {
  return Xor(svaese_u8(state, svdup_n_u8(0)), round_key);
}

HWY_API svuint64_t CLMulLower(const svuint64_t a, const svuint64_t b) {
  return svpmullb_pair(a, b);
}

HWY_API svuint64_t CLMulUpper(const svuint64_t a, const svuint64_t b) {
  return svpmullt_pair(a, b);
}

#endif  // __ARM_FEATURE_SVE2_AES

// ------------------------------ Lt128

namespace detail {
#define HWY_SVE_DUP(BASE, CHAR, BITS, HALF, NAME, OP)                        \
  template <size_t N, int kPow2>                                             \
  HWY_API svbool_t NAME(HWY_SVE_D(BASE, BITS, N, kPow2) /*d*/, svbool_t m) { \
    return sv##OP##_b##BITS(m, m);                                           \
  }

HWY_SVE_FOREACH_U(HWY_SVE_DUP, DupEvenB, trn1)  // actually for bool
HWY_SVE_FOREACH_U(HWY_SVE_DUP, DupOddB, trn2)   // actually for bool
#undef HWY_SVE_DUP

#if HWY_TARGET == HWY_SVE_256 || HWY_IDE
template <class D>
HWY_INLINE svuint64_t Lt128Vec(D d, const svuint64_t a, const svuint64_t b) {
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t eqHx = Eq(a, b);  // only odd lanes used
  // Convert to vector: more pipelines can execute vector TRN* instructions
  // than the predicate version.
  const svuint64_t ltHL = VecFromMask(d, Lt(a, b));
  // Move into upper lane: ltL if the upper half is equal, otherwise ltH.
  // Requires an extra IfThenElse because INSR, EXT, TRN2 are unpredicated.
  const svuint64_t ltHx = IfThenElse(eqHx, DupEven(ltHL), ltHL);
  // Duplicate upper lane into lower.
  return DupOdd(ltHx);
}
#endif
}  // namespace detail

template <class D>
HWY_INLINE svbool_t Lt128(D d, const svuint64_t a, const svuint64_t b) {
#if HWY_TARGET == HWY_SVE_256
  return MaskFromVec(detail::Lt128Vec(d, a, b));
#else
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t eqHx = Eq(a, b);  // only odd lanes used
  const svbool_t ltHL = Lt(a, b);
  // Move into upper lane: ltL if the upper half is equal, otherwise ltH.
  const svbool_t ltHx = svsel_b(eqHx, detail::DupEvenB(d, ltHL), ltHL);
  // Duplicate upper lane into lower.
  return detail::DupOddB(d, ltHx);
#endif  // HWY_TARGET != HWY_SVE_256
}

// ------------------------------ Lt128Upper

template <class D>
HWY_INLINE svbool_t Lt128Upper(D d, svuint64_t a, svuint64_t b) {
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t ltHL = Lt(a, b);
  return detail::DupOddB(d, ltHL);
}

// ------------------------------ Eq128, Ne128

#if HWY_TARGET == HWY_SVE_256 || HWY_IDE
namespace detail {

template <class D>
HWY_INLINE svuint64_t Eq128Vec(D d, const svuint64_t a, const svuint64_t b) {
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  // Convert to vector: more pipelines can execute vector TRN* instructions
  // than the predicate version.
  const svuint64_t eqHL = VecFromMask(d, Eq(a, b));
  // Duplicate upper and lower.
  const svuint64_t eqHH = DupOdd(eqHL);
  const svuint64_t eqLL = DupEven(eqHL);
  return And(eqLL, eqHH);
}

template <class D>
HWY_INLINE svuint64_t Ne128Vec(D d, const svuint64_t a, const svuint64_t b) {
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  // Convert to vector: more pipelines can execute vector TRN* instructions
  // than the predicate version.
  const svuint64_t neHL = VecFromMask(d, Ne(a, b));
  // Duplicate upper and lower.
  const svuint64_t neHH = DupOdd(neHL);
  const svuint64_t neLL = DupEven(neHL);
  return Or(neLL, neHH);
}

}  // namespace detail
#endif

template <class D>
HWY_INLINE svbool_t Eq128(D d, const svuint64_t a, const svuint64_t b) {
#if HWY_TARGET == HWY_SVE_256
  return MaskFromVec(detail::Eq128Vec(d, a, b));
#else
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t eqHL = Eq(a, b);
  const svbool_t eqHH = detail::DupOddB(d, eqHL);
  const svbool_t eqLL = detail::DupEvenB(d, eqHL);
  return And(eqLL, eqHH);
#endif  // HWY_TARGET != HWY_SVE_256
}

template <class D>
HWY_INLINE svbool_t Ne128(D d, const svuint64_t a, const svuint64_t b) {
#if HWY_TARGET == HWY_SVE_256
  return MaskFromVec(detail::Ne128Vec(d, a, b));
#else
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t neHL = Ne(a, b);
  const svbool_t neHH = detail::DupOddB(d, neHL);
  const svbool_t neLL = detail::DupEvenB(d, neHL);
  return Or(neLL, neHH);
#endif  // HWY_TARGET != HWY_SVE_256
}

// ------------------------------ Eq128Upper, Ne128Upper

template <class D>
HWY_INLINE svbool_t Eq128Upper(D d, svuint64_t a, svuint64_t b) {
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t eqHL = Eq(a, b);
  return detail::DupOddB(d, eqHL);
}

template <class D>
HWY_INLINE svbool_t Ne128Upper(D d, svuint64_t a, svuint64_t b) {
  static_assert(!IsSigned<TFromD<D>>() && sizeof(TFromD<D>) == 8,
                "D must be u64");
  const svbool_t neHL = Ne(a, b);
  return detail::DupOddB(d, neHL);
}

// ------------------------------ Min128, Max128 (Lt128)

template <class D>
HWY_INLINE svuint64_t Min128(D d, const svuint64_t a, const svuint64_t b) {
#if HWY_TARGET == HWY_SVE_256
  return IfVecThenElse(detail::Lt128Vec(d, a, b), a, b);
#else
  return IfThenElse(Lt128(d, a, b), a, b);
#endif
}

template <class D>
HWY_INLINE svuint64_t Max128(D d, const svuint64_t a, const svuint64_t b) {
#if HWY_TARGET == HWY_SVE_256
  return IfVecThenElse(detail::Lt128Vec(d, b, a), a, b);
#else
  return IfThenElse(Lt128(d, b, a), a, b);
#endif
}

template <class D>
HWY_INLINE svuint64_t Min128Upper(D d, const svuint64_t a, const svuint64_t b) {
  return IfThenElse(Lt128Upper(d, a, b), a, b);
}

template <class D>
HWY_INLINE svuint64_t Max128Upper(D d, const svuint64_t a, const svuint64_t b) {
  return IfThenElse(Lt128Upper(d, b, a), a, b);
}

// ================================================== END MACROS
namespace detail {  // for code folding
#undef HWY_IF_FLOAT_V
#undef HWY_IF_LANE_SIZE_V
#undef HWY_SVE_ALL_PTRUE
#undef HWY_SVE_D
#undef HWY_SVE_FOREACH
#undef HWY_SVE_FOREACH_F
#undef HWY_SVE_FOREACH_F16
#undef HWY_SVE_FOREACH_F32
#undef HWY_SVE_FOREACH_F64
#undef HWY_SVE_FOREACH_I
#undef HWY_SVE_FOREACH_I08
#undef HWY_SVE_FOREACH_I16
#undef HWY_SVE_FOREACH_I32
#undef HWY_SVE_FOREACH_I64
#undef HWY_SVE_FOREACH_IF
#undef HWY_SVE_FOREACH_U
#undef HWY_SVE_FOREACH_U08
#undef HWY_SVE_FOREACH_U16
#undef HWY_SVE_FOREACH_U32
#undef HWY_SVE_FOREACH_U64
#undef HWY_SVE_FOREACH_UI
#undef HWY_SVE_FOREACH_UI08
#undef HWY_SVE_FOREACH_UI16
#undef HWY_SVE_FOREACH_UI32
#undef HWY_SVE_FOREACH_UI64
#undef HWY_SVE_FOREACH_UIF3264
#undef HWY_SVE_PTRUE
#undef HWY_SVE_RETV_ARGPV
#undef HWY_SVE_RETV_ARGPVN
#undef HWY_SVE_RETV_ARGPVV
#undef HWY_SVE_RETV_ARGV
#undef HWY_SVE_RETV_ARGVN
#undef HWY_SVE_RETV_ARGVV
#undef HWY_SVE_RETV_ARGVVV
#undef HWY_SVE_T
#undef HWY_SVE_UNDEFINED
#undef HWY_SVE_V

}  // namespace detail
// NOLINTNEXTLINE(google-readability-namespace-comments)
}  // namespace HWY_NAMESPACE
}  // namespace hwy
HWY_AFTER_NAMESPACE();