/*
 *
 * Copyright (c) 2021, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 3-Clause Clear License
 * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear
 * License was not distributed with this source code in the LICENSE file, you
 * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/.  If the
 * Alliance for Open Media Patent License 1.0 was not distributed with this
 * source code in the PATENTS file, you can obtain it at
 * aomedia.org/license/patent-license/.
 */

#include <assert.h>
#include <arm_neon.h>

#include "config/av1_rtcd.h"

#include "aom_dsp/aom_dsp_common.h"
#include "aom_ports/mem.h"
#include "av1/common/convolve.h"
#include "av1/common/filter.h"
#include "av1/common/arm/convolve_neon.h"
#include "aom_dsp/arm/mem_neon.h"
#include "aom_dsp/arm/transpose_neon.h"

static INLINE int16x4_t convolve12_4_x(const int16x4_t s0, const int16x4_t s1,
                                       const int16x4_t s2, const int16x4_t s3,
                                       const int16x4_t s4, const int16x4_t s5,
                                       const int16x4_t s6, const int16x4_t s7,
                                       const int16x4_t s8, const int16x4_t s9,
                                       const int16x4_t s10, const int16x4_t s11,
                                       const int16x8_t x_filter_0_7,
                                       const int16x4_t x_filter_8_11,
                                       const int32x4_t horiz_const) {
  const int16x4_t x_filter_0_3 = vget_low_s16(x_filter_0_7);
  const int16x4_t x_filter_4_7 = vget_high_s16(x_filter_0_7);
  int32x4_t sum = horiz_const;
  sum = vmlal_lane_s16(sum, s0, x_filter_0_3, 0);
  sum = vmlal_lane_s16(sum, s1, x_filter_0_3, 1);
  sum = vmlal_lane_s16(sum, s2, x_filter_0_3, 2);
  sum = vmlal_lane_s16(sum, s3, x_filter_0_3, 3);
  sum = vmlal_lane_s16(sum, s4, x_filter_4_7, 0);
  sum = vmlal_lane_s16(sum, s5, x_filter_4_7, 1);
  sum = vmlal_lane_s16(sum, s6, x_filter_4_7, 2);
  sum = vmlal_lane_s16(sum, s7, x_filter_4_7, 3);
  sum = vmlal_lane_s16(sum, s8, x_filter_8_11, 0);
  sum = vmlal_lane_s16(sum, s9, x_filter_8_11, 1);
  sum = vmlal_lane_s16(sum, s10, x_filter_8_11, 2);
  sum = vmlal_lane_s16(sum, s11, x_filter_8_11, 3);
  return vqrshrn_n_s32(sum, FILTER_BITS);
}

static INLINE void convolve_x_sr_12tap_neon(const uint8_t *src_ptr,
                                            int src_stride, uint8_t *dst_ptr,
                                            const int dst_stride, int w, int h,
                                            const int16_t *x_filter_ptr) {
  const int16x8_t x_filter_0_7 = vld1q_s16(x_filter_ptr);
  const int16x4_t x_filter_8_11 = vld1_s16(x_filter_ptr + 8);
  // A shim of 1 << (ROUND0_BITS - 1) enables us to use a single rounding right
  // shift by FILTER_BITS - instead of a first rounding right shift by
  // ROUND0_BITS, followed by second rounding right shift by FILTER_BITS -
  // ROUND0_BITS.
  const int32x4_t horiz_const = vdupq_n_s32(1 << (ROUND0_BITS - 1));
#if AOM_ARCH_AARCH64
  do {
    const uint8_t *s = src_ptr;
    uint8_t *d = dst_ptr;
    int width = w;
    uint8x8_t t0, t1, t2, t3;
    load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
    transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);
    int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s1 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s2 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    int16x4_t s3 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
    int16x4_t s4 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s5 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s6 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    int16x4_t s7 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
    load_u8_8x4(s + 8, src_stride, &t0, &t1, &t2, &t3);
    transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);
    int16x4_t s8 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s9 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s10 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    s += 11;
    do {
      load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
      transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);
      int16x4_t s11 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
      int16x4_t s12 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
      int16x4_t s13 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
      int16x4_t s14 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
      int16x4_t d0 =
          convolve12_4_x(s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11,
                         x_filter_0_7, x_filter_8_11, horiz_const);
      int16x4_t d1 =
          convolve12_4_x(s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12,
                         x_filter_0_7, x_filter_8_11, horiz_const);
      int16x4_t d2 =
          convolve12_4_x(s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13,
                         x_filter_0_7, x_filter_8_11, horiz_const);
      int16x4_t d3 =
          convolve12_4_x(s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14,
                         x_filter_0_7, x_filter_8_11, horiz_const);
      transpose_elems_inplace_s16_4x4(&d0, &d1, &d2, &d3);
      uint8x8_t d01 = vqmovun_s16(vcombine_s16(d0, d1));
      uint8x8_t d23 = vqmovun_s16(vcombine_s16(d2, d3));
      store_u8x4_strided_x2(d, dst_stride, d01);
      store_u8x4_strided_x2(d + 2 * dst_stride, dst_stride, d23);
      s0 = s4;
      s1 = s5;
      s2 = s6;
      s3 = s7;
      s4 = s8;
      s5 = s9;
      s6 = s10;
      s7 = s11;
      s8 = s12;
      s9 = s13;
      s10 = s14;
      s += 4;
      d += 4;
      width -= 4;
    } while (width != 0);
    src_ptr += 4 * src_stride;
    dst_ptr += 4 * dst_stride;
    h -= 4;
  } while (h != 0);
#else   // !AOM_ARCH_AARCH64
  do {
    const uint8_t *s = src_ptr;
    uint8_t *d = dst_ptr;
    int width = w;
    do {
      uint8x16_t t0 = vld1q_u8(s);
      int16x8_t tt0 = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(t0)));
      int16x8_t tt8 = vreinterpretq_s16_u16(vmovl_u8(vget_high_u8(t0)));
      int16x4_t s0 = vget_low_s16(tt0);
      int16x4_t s4 = vget_high_s16(tt0);
      int16x4_t s8 = vget_low_s16(tt8);
      int16x4_t s12 = vget_high_s16(tt8);
      int16x4_t s1 = vext_s16(s0, s4, 1);    //  a1  a2  a3  a4
      int16x4_t s2 = vext_s16(s0, s4, 2);    //  a2  a3  a4  a5
      int16x4_t s3 = vext_s16(s0, s4, 3);    //  a3  a4  a5  a6
      int16x4_t s5 = vext_s16(s4, s8, 1);    //  a5  a6  a7  a8
      int16x4_t s6 = vext_s16(s4, s8, 2);    //  a6  a7  a8  a9
      int16x4_t s7 = vext_s16(s4, s8, 3);    //  a7  a8  a9 a10
      int16x4_t s9 = vext_s16(s8, s12, 1);   //  a9 a10 a11 a12
      int16x4_t s10 = vext_s16(s8, s12, 2);  // a10 a11 a12 a13
      int16x4_t s11 = vext_s16(s8, s12, 3);  // a11 a12 a13 a14
      int16x4_t d0 =
          convolve12_4_x(s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11,
                         x_filter_0_7, x_filter_8_11, horiz_const);
      uint8x8_t dd0 = vqmovun_s16(vcombine_s16(d0, vdup_n_s16(0)));
      store_u8_4x1(d, dd0);
      s += 4;
      d += 4;
      width -= 4;
    } while (width != 0);
    src_ptr += src_stride;
    dst_ptr += dst_stride;
  } while (--h != 0);
#endif  // AOM_ARCH_AARCH64
}

static INLINE uint8x8_t convolve4_4_x(const int16x4_t s0, const int16x4_t s1,
                                      const int16x4_t s2, const int16x4_t s3,
                                      const int16x4_t filter,
                                      const int16x4_t horiz_const) {
  int16x4_t sum = horiz_const;
  sum = vmla_lane_s16(sum, s0, filter, 0);
  sum = vmla_lane_s16(sum, s1, filter, 1);
  sum = vmla_lane_s16(sum, s2, filter, 2);
  sum = vmla_lane_s16(sum, s3, filter, 3);
  // We halved the convolution filter values so - 1 from the right shift.
  return vqrshrun_n_s16(vcombine_s16(sum, vdup_n_s16(0)), FILTER_BITS - 1);
}

static INLINE uint8x8_t convolve8_8_x(const int16x8_t s0, const int16x8_t s1,
                                      const int16x8_t s2, const int16x8_t s3,
                                      const int16x8_t s4, const int16x8_t s5,
                                      const int16x8_t s6, const int16x8_t s7,
                                      const int16x8_t filter,
                                      const int16x8_t horiz_const) {
  const int16x4_t filter_lo = vget_low_s16(filter);
  const int16x4_t filter_hi = vget_high_s16(filter);
  int16x8_t sum = horiz_const;
  sum = vmlaq_lane_s16(sum, s0, filter_lo, 0);
  sum = vmlaq_lane_s16(sum, s1, filter_lo, 1);
  sum = vmlaq_lane_s16(sum, s2, filter_lo, 2);
  sum = vmlaq_lane_s16(sum, s3, filter_lo, 3);
  sum = vmlaq_lane_s16(sum, s4, filter_hi, 0);
  sum = vmlaq_lane_s16(sum, s5, filter_hi, 1);
  sum = vmlaq_lane_s16(sum, s6, filter_hi, 2);
  sum = vmlaq_lane_s16(sum, s7, filter_hi, 3);
  // We halved the convolution filter values so - 1 from the right shift.
  return vqrshrun_n_s16(sum, FILTER_BITS - 1);
}

static INLINE int16x4_t convolve6_4_y(const int16x4_t s0, const int16x4_t s1,
                                      const int16x4_t s2, const int16x4_t s3,
                                      const int16x4_t s4, const int16x4_t s5,
                                      const int16x8_t y_filter_0_7) {
  const int16x4_t y_filter_0_3 = vget_low_s16(y_filter_0_7);
  const int16x4_t y_filter_4_7 = vget_high_s16(y_filter_0_7);
  // Filter values at indices 0 and 7 are 0.
  int16x4_t sum = vmul_lane_s16(s0, y_filter_0_3, 1);
  sum = vmla_lane_s16(sum, s1, y_filter_0_3, 2);
  sum = vmla_lane_s16(sum, s2, y_filter_0_3, 3);
  sum = vmla_lane_s16(sum, s3, y_filter_4_7, 0);
  sum = vmla_lane_s16(sum, s4, y_filter_4_7, 1);
  sum = vmla_lane_s16(sum, s5, y_filter_4_7, 2);
  return sum;
}

static INLINE uint8x8_t convolve6_8_y(const int16x8_t s0, const int16x8_t s1,
                                      const int16x8_t s2, const int16x8_t s3,
                                      const int16x8_t s4, const int16x8_t s5,
                                      const int16x8_t y_filters) {
  const int16x4_t y_filter_lo = vget_low_s16(y_filters);
  const int16x4_t y_filter_hi = vget_high_s16(y_filters);
  // Filter values at indices 0 and 7 are 0.
  int16x8_t sum = vmulq_lane_s16(s0, y_filter_lo, 1);
  sum = vmlaq_lane_s16(sum, s1, y_filter_lo, 2);
  sum = vmlaq_lane_s16(sum, s2, y_filter_lo, 3);
  sum = vmlaq_lane_s16(sum, s3, y_filter_hi, 0);
  sum = vmlaq_lane_s16(sum, s4, y_filter_hi, 1);
  sum = vmlaq_lane_s16(sum, s5, y_filter_hi, 2);
  // We halved the convolution filter values so -1 from the right shift.
  return vqrshrun_n_s16(sum, FILTER_BITS - 1);
}

static INLINE void convolve_y_sr_6tap_neon(const uint8_t *src_ptr,
                                           int src_stride, uint8_t *dst_ptr,
                                           const int dst_stride, int w, int h,
                                           const int16x8_t y_filter) {
  if (w <= 4) {
    uint8x8_t t0 = load_unaligned_u8_4x1(src_ptr + 0 * src_stride);
    uint8x8_t t1 = load_unaligned_u8_4x1(src_ptr + 1 * src_stride);
    uint8x8_t t2 = load_unaligned_u8_4x1(src_ptr + 2 * src_stride);
    uint8x8_t t3 = load_unaligned_u8_4x1(src_ptr + 3 * src_stride);
    uint8x8_t t4 = load_unaligned_u8_4x1(src_ptr + 4 * src_stride);
    int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s1 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s2 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    int16x4_t s3 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
    int16x4_t s4 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t4)));
    src_ptr += 5 * src_stride;
    do {
#if AOM_ARCH_AARCH64
      uint8x8_t t5 = load_unaligned_u8_4x1(src_ptr + 0 * src_stride);
      uint8x8_t t6 = load_unaligned_u8_4x1(src_ptr + 1 * src_stride);
      uint8x8_t t7 = load_unaligned_u8_4x1(src_ptr + 2 * src_stride);
      uint8x8_t t8 = load_unaligned_u8_4x1(src_ptr + 3 * src_stride);
      int16x4_t s5 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t5)));
      int16x4_t s6 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t6)));
      int16x4_t s7 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t7)));
      int16x4_t s8 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t8)));
      int16x4_t d0 = convolve6_4_y(s0, s1, s2, s3, s4, s5, y_filter);
      int16x4_t d1 = convolve6_4_y(s1, s2, s3, s4, s5, s6, y_filter);
      int16x4_t d2 = convolve6_4_y(s2, s3, s4, s5, s6, s7, y_filter);
      int16x4_t d3 = convolve6_4_y(s3, s4, s5, s6, s7, s8, y_filter);
      // We halved the convolution filter values so -1 from the right shift.
      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);
      store_u8x4_strided_x2(dst_ptr, dst_stride, d01);
      store_u8x4_strided_x2(dst_ptr + 2 * dst_stride, dst_stride, d23);
      s0 = s4;
      s1 = s5;
      s2 = s6;
      s3 = s7;
      s4 = s8;
      src_ptr += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      h -= 4;
#else   // !AOM_ARCH_AARCH64
      uint8x8_t t5 = load_unaligned_u8_4x1(src_ptr);
      int16x4_t s5 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t5)));
      int16x4_t d0 = convolve6_4_y(s0, s1, s2, s3, s4, s5, y_filter);
      // We halved the convolution filter values so -1 from the right shift.
      uint8x8_t d01 =
          vqrshrun_n_s16(vcombine_s16(d0, vdup_n_s16(0)), FILTER_BITS - 1);
      store_u8_4x1(dst_ptr, d01);
      s0 = s1;
      s1 = s2;
      s2 = s3;
      s3 = s4;
      s4 = s5;
      src_ptr += src_stride;
      dst_ptr += dst_stride;
      h--;
#endif  // AOM_ARCH_AARCH64
    } while (h != 0);
  } else {
    do {
      const uint8_t *s = src_ptr;
      uint8_t *d = dst_ptr;
      int height = h;
      uint8x8_t t0, t1, t2, t3, t4;
      load_u8_8x5(s, src_stride, &t0, &t1, &t2, &t3, &t4);
      int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      s += 5 * src_stride;
      do {
#if AOM_ARCH_AARCH64
        uint8x8_t t5, t6, t7, t8;
        load_u8_8x4(s, src_stride, &t5, &t6, &t7, &t8);
        int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
        int16x8_t s6 = vreinterpretq_s16_u16(vmovl_u8(t6));
        int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(t7));
        int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t8));
        uint8x8_t d0 = convolve6_8_y(s0, s1, s2, s3, s4, s5, y_filter);
        uint8x8_t d1 = convolve6_8_y(s1, s2, s3, s4, s5, s6, y_filter);
        uint8x8_t d2 = convolve6_8_y(s2, s3, s4, s5, s6, s7, y_filter);
        uint8x8_t d3 = convolve6_8_y(s3, s4, s5, s6, s7, s8, y_filter);
        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
        s0 = s4;
        s1 = s5;
        s2 = s6;
        s3 = s7;
        s4 = s8;
        s += 4 * src_stride;
        d += 4 * dst_stride;
        height -= 4;
#else   // !AOM_ARCH_AARCH64
        int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s)));
        uint8x8_t d0 = convolve6_8_y(s0, s1, s2, s3, s4, s5, y_filter);
        vst1_u8(d, d0);
        s0 = s1;
        s1 = s2;
        s2 = s3;
        s3 = s4;
        s4 = s5;
        s += src_stride;
        d += dst_stride;
        height--;
#endif  // AOM_ARCH_AARCH64
      } while (height != 0);
      src_ptr += 8;
      dst_ptr += 8;
      w -= 8;
    } while (w != 0);
  }
}

static INLINE int16x4_t convolve8_4_y(const int16x4_t s0, const int16x4_t s1,
                                      const int16x4_t s2, const int16x4_t s3,
                                      const int16x4_t s4, const int16x4_t s5,
                                      const int16x4_t s6, const int16x4_t s7,
                                      const int16x8_t filter) {
  const int16x4_t filter_lo = vget_low_s16(filter);
  const int16x4_t filter_hi = vget_high_s16(filter);
  int16x4_t sum = vmul_lane_s16(s0, filter_lo, 0);
  sum = vmla_lane_s16(sum, s1, filter_lo, 1);
  sum = vmla_lane_s16(sum, s2, filter_lo, 2);
  sum = vmla_lane_s16(sum, s3, filter_lo, 3);
  sum = vmla_lane_s16(sum, s4, filter_hi, 0);
  sum = vmla_lane_s16(sum, s5, filter_hi, 1);
  sum = vmla_lane_s16(sum, s6, filter_hi, 2);
  sum = vmla_lane_s16(sum, s7, filter_hi, 3);
  return sum;
}

static INLINE uint8x8_t convolve8_8_y(const int16x8_t s0, const int16x8_t s1,
                                      const int16x8_t s2, const int16x8_t s3,
                                      const int16x8_t s4, const int16x8_t s5,
                                      const int16x8_t s6, const int16x8_t s7,
                                      const int16x8_t filter) {
  const int16x4_t filter_lo = vget_low_s16(filter);
  const int16x4_t filter_hi = vget_high_s16(filter);
  int16x8_t sum = vmulq_lane_s16(s0, filter_lo, 0);
  sum = vmlaq_lane_s16(sum, s1, filter_lo, 1);
  sum = vmlaq_lane_s16(sum, s2, filter_lo, 2);
  sum = vmlaq_lane_s16(sum, s3, filter_lo, 3);
  sum = vmlaq_lane_s16(sum, s4, filter_hi, 0);
  sum = vmlaq_lane_s16(sum, s5, filter_hi, 1);
  sum = vmlaq_lane_s16(sum, s6, filter_hi, 2);
  sum = vmlaq_lane_s16(sum, s7, filter_hi, 3);
  // We halved the convolution filter values so -1 from the right shift.
  return vqrshrun_n_s16(sum, FILTER_BITS - 1);
}

static INLINE void convolve_y_sr_8tap_neon(const uint8_t *src_ptr,
                                           int src_stride, uint8_t *dst_ptr,
                                           const int dst_stride, int w, int h,
                                           const int16x8_t y_filter) {
  if (w <= 4) {
    uint8x8_t t0 = load_unaligned_u8_4x1(src_ptr + 0 * src_stride);
    uint8x8_t t1 = load_unaligned_u8_4x1(src_ptr + 1 * src_stride);
    uint8x8_t t2 = load_unaligned_u8_4x1(src_ptr + 2 * src_stride);
    uint8x8_t t3 = load_unaligned_u8_4x1(src_ptr + 3 * src_stride);
    uint8x8_t t4 = load_unaligned_u8_4x1(src_ptr + 4 * src_stride);
    uint8x8_t t5 = load_unaligned_u8_4x1(src_ptr + 5 * src_stride);
    uint8x8_t t6 = load_unaligned_u8_4x1(src_ptr + 6 * src_stride);
    int16x4_t s0 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t0)));
    int16x4_t s1 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t1)));
    int16x4_t s2 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t2)));
    int16x4_t s3 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t3)));
    int16x4_t s4 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t4)));
    int16x4_t s5 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t5)));
    int16x4_t s6 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t6)));
    src_ptr += 7 * src_stride;
    do {
#if AOM_ARCH_AARCH64
      uint8x8_t t7 = load_unaligned_u8_4x1(src_ptr + 0 * src_stride);
      uint8x8_t t8 = load_unaligned_u8_4x1(src_ptr + 1 * src_stride);
      uint8x8_t t9 = load_unaligned_u8_4x1(src_ptr + 2 * src_stride);
      uint8x8_t t10 = load_unaligned_u8_4x1(src_ptr + 3 * src_stride);
      int16x4_t s7 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t7)));
      int16x4_t s8 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t8)));
      int16x4_t s9 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t9)));
      int16x4_t s10 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t10)));
      int16x4_t d0 = convolve8_4_y(s0, s1, s2, s3, s4, s5, s6, s7, y_filter);
      int16x4_t d1 = convolve8_4_y(s1, s2, s3, s4, s5, s6, s7, s8, y_filter);
      int16x4_t d2 = convolve8_4_y(s2, s3, s4, s5, s6, s7, s8, s9, y_filter);
      int16x4_t d3 = convolve8_4_y(s3, s4, s5, s6, s7, s8, s9, s10, y_filter);
      // We halved the convolution filter values so -1 from the right shift.
      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);
      store_u8x4_strided_x2(dst_ptr, dst_stride, d01);
      store_u8x4_strided_x2(dst_ptr + 2 * dst_stride, dst_stride, d23);
      s0 = s4;
      s1 = s5;
      s2 = s6;
      s3 = s7;
      s4 = s8;
      s5 = s9;
      s6 = s10;
      src_ptr += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      h -= 4;
#else   // !AOM_ARCH_AARCH64
      uint8x8_t t7 = load_unaligned_u8_4x1(src_ptr);
      int16x4_t s7 = vreinterpret_s16_u16(vget_low_u16(vmovl_u8(t7)));
      int16x4_t d0 = convolve8_4_y(s0, s1, s2, s3, s4, s5, s6, s7, y_filter);
      // We halved the convolution filter values so -1 from the right shift.
      uint8x8_t d01 =
          vqrshrun_n_s16(vcombine_s16(d0, vdup_n_s16(0)), FILTER_BITS - 1);
      store_u8_4x1(dst_ptr, d01);
      s0 = s1;
      s1 = s2;
      s2 = s3;
      s3 = s4;
      s4 = s5;
      s5 = s6;
      s6 = s7;
      src_ptr += src_stride;
      dst_ptr += dst_stride;
      h--;
#endif  // AOM_ARCH_AARCH64
    } while (h != 0);
  } else {
    do {
      const uint8_t *s = src_ptr;
      uint8_t *d = dst_ptr;
      int height = h;
      uint8x8_t t0, t1, t2, t3, t4, t5, t6;
      load_u8_8x7(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6);
      int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
      int16x8_t s6 = vreinterpretq_s16_u16(vmovl_u8(t6));
      s += 7 * src_stride;
      do {
#if AOM_ARCH_AARCH64
        uint8x8_t t7, t8, t9, t10;
        load_u8_8x4(s, src_stride, &t7, &t8, &t9, &t10);
        int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(t7));
        int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t8));
        int16x8_t s9 = vreinterpretq_s16_u16(vmovl_u8(t9));
        int16x8_t s10 = vreinterpretq_s16_u16(vmovl_u8(t10));
        uint8x8_t d0 = convolve8_8_y(s0, s1, s2, s3, s4, s5, s6, s7, y_filter);
        uint8x8_t d1 = convolve8_8_y(s1, s2, s3, s4, s5, s6, s7, s8, y_filter);
        uint8x8_t d2 = convolve8_8_y(s2, s3, s4, s5, s6, s7, s8, s9, y_filter);
        uint8x8_t d3 = convolve8_8_y(s3, s4, s5, s6, s7, s8, s9, s10, y_filter);
        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
        s0 = s4;
        s1 = s5;
        s2 = s6;
        s3 = s7;
        s4 = s8;
        s5 = s9;
        s6 = s10;
        s += 4 * src_stride;
        d += 4 * dst_stride;
        height -= 4;
#else   // !AOM_ARCH_AARCH64
        int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s)));
        uint8x8_t d0 = convolve8_8_y(s0, s1, s2, s3, s4, s5, s6, s7, y_filter);
        vst1_u8(d, d0);
        s0 = s1;
        s1 = s2;
        s2 = s3;
        s3 = s4;
        s4 = s5;
        s5 = s6;
        s6 = s7;
        s += src_stride;
        d += dst_stride;
        height--;
#endif  // AOM_ARCH_AARCH64
      } while (height != 0);
      src_ptr += 8;
      dst_ptr += 8;
      w -= 8;
    } while (w != 0);
  }
}

static INLINE int16x4_t convolve12_4_y(const int16x4_t s0, const int16x4_t s1,
                                       const int16x4_t s2, const int16x4_t s3,
                                       const int16x4_t s4, const int16x4_t s5,
                                       const int16x4_t s6, const int16x4_t s7,
                                       const int16x4_t s8, const int16x4_t s9,
                                       const int16x4_t s10, const int16x4_t s11,
                                       const int16x8_t y_filter_0_7,
                                       const int16x4_t y_filter_8_11) {
  const int16x4_t y_filter_0_3 = vget_low_s16(y_filter_0_7);
  const int16x4_t y_filter_4_7 = vget_high_s16(y_filter_0_7);
  int16x4_t sum;
  sum = vmul_lane_s16(s0, y_filter_0_3, 0);
  sum = vmla_lane_s16(sum, s1, y_filter_0_3, 1);
  sum = vmla_lane_s16(sum, s2, y_filter_0_3, 2);
  sum = vmla_lane_s16(sum, s3, y_filter_0_3, 3);
  sum = vmla_lane_s16(sum, s4, y_filter_4_7, 0);
  sum = vmla_lane_s16(sum, s7, y_filter_4_7, 3);
  sum = vmla_lane_s16(sum, s8, y_filter_8_11, 0);
  sum = vmla_lane_s16(sum, s9, y_filter_8_11, 1);
  sum = vmla_lane_s16(sum, s10, y_filter_8_11, 2);
  sum = vmla_lane_s16(sum, s11, y_filter_8_11, 3);
  // Saturating addition is required for the largest filter taps to avoid
  // overflow (while staying in 16-bit elements.)
  sum = vqadd_s16(sum, vmul_lane_s16(s5, y_filter_4_7, 1));
  sum = vqadd_s16(sum, vmul_lane_s16(s6, y_filter_4_7, 2));
  return sum;
}

static INLINE uint8x8_t convolve12_8_y(const int16x8_t s0, const int16x8_t s1,
                                       const int16x8_t s2, const int16x8_t s3,
                                       const int16x8_t s4, const int16x8_t s5,
                                       const int16x8_t s6, const int16x8_t s7,
                                       const int16x8_t s8, const int16x8_t s9,
                                       const int16x8_t s10, const int16x8_t s11,
                                       const int16x8_t y_filter_0_7,
                                       const int16x4_t y_filter_8_11) {
  const int16x4_t y_filter_0_3 = vget_low_s16(y_filter_0_7);
  const int16x4_t y_filter_4_7 = vget_high_s16(y_filter_0_7);
  int16x8_t sum;
  sum = vmulq_lane_s16(s0, y_filter_0_3, 0);
  sum = vmlaq_lane_s16(sum, s1, y_filter_0_3, 1);
  sum = vmlaq_lane_s16(sum, s2, y_filter_0_3, 2);
  sum = vmlaq_lane_s16(sum, s3, y_filter_0_3, 3);
  sum = vmlaq_lane_s16(sum, s4, y_filter_4_7, 0);
  sum = vmlaq_lane_s16(sum, s7, y_filter_4_7, 3);
  sum = vmlaq_lane_s16(sum, s8, y_filter_8_11, 0);
  sum = vmlaq_lane_s16(sum, s9, y_filter_8_11, 1);
  sum = vmlaq_lane_s16(sum, s10, y_filter_8_11, 2);
  sum = vmlaq_lane_s16(sum, s11, y_filter_8_11, 3);
  // Saturating addition is required for the largest filter taps to avoid
  // overflow (while staying in 16-bit elements.)
  sum = vqaddq_s16(sum, vmulq_lane_s16(s5, y_filter_4_7, 1));
  sum = vqaddq_s16(sum, vmulq_lane_s16(s6, y_filter_4_7, 2));
  return vqrshrun_n_s16(sum, FILTER_BITS);
}

static INLINE void convolve_y_sr_12tap_neon(const uint8_t *src_ptr,
                                            int src_stride, uint8_t *dst_ptr,
                                            int dst_stride, int w, int h,
                                            const int16_t *y_filter_ptr) {
  const int16x8_t y_filter_0_7 = vld1q_s16(y_filter_ptr);
  const int16x4_t y_filter_8_11 = vld1_s16(y_filter_ptr + 8);
  if (w <= 4) {
    uint8x8_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9, t10;
    load_u8_8x11(src_ptr, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7,
                 &t8, &t9, &t10);
    int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s1 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s2 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    int16x4_t s3 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
    int16x4_t s4 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t4)));
    int16x4_t s5 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t5)));
    int16x4_t s6 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t6)));
    int16x4_t s7 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t7)));
    int16x4_t s8 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t8)));
    int16x4_t s9 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t9)));
    int16x4_t s10 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t10)));
    src_ptr += 11 * src_stride;
    do {
      uint8x8_t t11, t12, t13, t14;
      load_u8_8x4(src_ptr, src_stride, &t11, &t12, &t13, &t14);
      int16x4_t s11 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t11)));
      int16x4_t s12 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t12)));
      int16x4_t s13 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t13)));
      int16x4_t s14 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t14)));
      int16x4_t d0 = convolve12_4_y(s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10,
                                    s11, y_filter_0_7, y_filter_8_11);
      int16x4_t d1 = convolve12_4_y(s1, s2, s3, s4, s5, s6, s7, s8, s9, s10,
                                    s11, s12, y_filter_0_7, y_filter_8_11);
      int16x4_t d2 = convolve12_4_y(s2, s3, s4, s5, s6, s7, s8, s9, s10, s11,
                                    s12, s13, y_filter_0_7, y_filter_8_11);
      int16x4_t d3 = convolve12_4_y(s3, s4, s5, s6, s7, s8, s9, s10, s11, s12,
                                    s13, s14, y_filter_0_7, y_filter_8_11);
      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS);
      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS);
      store_u8x4_strided_x2(dst_ptr, dst_stride, d01);
      store_u8x4_strided_x2(dst_ptr + 2 * dst_stride, dst_stride, d23);
      s0 = s4;
      s1 = s5;
      s2 = s6;
      s3 = s7;
      s4 = s8;
      s5 = s9;
      s6 = s10;
      s7 = s11;
      s8 = s12;
      s9 = s13;
      s10 = s14;
      src_ptr += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  } else {
    do {
      const uint8_t *s = src_ptr;
      uint8_t *d = dst_ptr;
      int height = h;
      uint8x8_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9, t10;
      load_u8_8x11(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7, &t8,
                   &t9, &t10);
      int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
      int16x8_t s6 = vreinterpretq_s16_u16(vmovl_u8(t6));
      int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(t7));
      int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t8));
      int16x8_t s9 = vreinterpretq_s16_u16(vmovl_u8(t9));
      int16x8_t s10 = vreinterpretq_s16_u16(vmovl_u8(t10));
      s += 11 * src_stride;
      do {
        uint8x8_t t11, t12, t13, t14;
        load_u8_8x4(s, src_stride, &t11, &t12, &t13, &t14);
        int16x8_t s11 = vreinterpretq_s16_u16(vmovl_u8(t11));
        int16x8_t s12 = vreinterpretq_s16_u16(vmovl_u8(t12));
        int16x8_t s13 = vreinterpretq_s16_u16(vmovl_u8(t13));
        int16x8_t s14 = vreinterpretq_s16_u16(vmovl_u8(t14));
        uint8x8_t d0 = convolve12_8_y(s0, s1, s2, s3, s4, s5, s6, s7, s8, s9,
                                      s10, s11, y_filter_0_7, y_filter_8_11);
        uint8x8_t d1 = convolve12_8_y(s1, s2, s3, s4, s5, s6, s7, s8, s9, s10,
                                      s11, s12, y_filter_0_7, y_filter_8_11);
        uint8x8_t d2 = convolve12_8_y(s2, s3, s4, s5, s6, s7, s8, s9, s10, s11,
                                      s12, s13, y_filter_0_7, y_filter_8_11);
        uint8x8_t d3 = convolve12_8_y(s3, s4, s5, s6, s7, s8, s9, s10, s11, s12,
                                      s13, s14, y_filter_0_7, y_filter_8_11);
        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
        s0 = s4;
        s1 = s5;
        s2 = s6;
        s3 = s7;
        s4 = s8;
        s5 = s9;
        s6 = s10;
        s7 = s11;
        s8 = s12;
        s9 = s13;
        s10 = s14;
        s += 4 * src_stride;
        d += 4 * dst_stride;
        height -= 4;
      } while (height != 0);
      src_ptr += 8;
      dst_ptr += 8;
      w -= 8;
    } while (w != 0);
  }
}

static INLINE int16x4_t
convolve12_4_2d_h(const int16x4_t s0, const int16x4_t s1, const int16x4_t s2,
                  const int16x4_t s3, const int16x4_t s4, const int16x4_t s5,
                  const int16x4_t s6, const int16x4_t s7, const int16x4_t s8,
                  const int16x4_t s9, const int16x4_t s10, const int16x4_t s11,
                  const int16x8_t x_filter_0_7, const int16x4_t x_filter_8_11,
                  const int32x4_t horiz_const) {
  const int16x4_t x_filter_0_3 = vget_low_s16(x_filter_0_7);
  const int16x4_t x_filter_4_7 = vget_high_s16(x_filter_0_7);
  int32x4_t sum = horiz_const;
  sum = vmlal_lane_s16(sum, s0, x_filter_0_3, 0);
  sum = vmlal_lane_s16(sum, s1, x_filter_0_3, 1);
  sum = vmlal_lane_s16(sum, s2, x_filter_0_3, 2);
  sum = vmlal_lane_s16(sum, s3, x_filter_0_3, 3);
  sum = vmlal_lane_s16(sum, s4, x_filter_4_7, 0);
  sum = vmlal_lane_s16(sum, s5, x_filter_4_7, 1);
  sum = vmlal_lane_s16(sum, s6, x_filter_4_7, 2);
  sum = vmlal_lane_s16(sum, s7, x_filter_4_7, 3);
  sum = vmlal_lane_s16(sum, s8, x_filter_8_11, 0);
  sum = vmlal_lane_s16(sum, s9, x_filter_8_11, 1);
  sum = vmlal_lane_s16(sum, s10, x_filter_8_11, 2);
  sum = vmlal_lane_s16(sum, s11, x_filter_8_11, 3);
  return vshrn_n_s32(sum, ROUND0_BITS);
}

static INLINE void convolve_2d_sr_horiz_12tap_neon(
    const uint8_t *src_ptr, int src_stride, int16_t *dst_ptr,
    const int dst_stride, int w, int h, const int16x8_t x_filter_0_7,
    const int16x4_t x_filter_8_11) {
  const int bd = 8;
  // A shim of 1 << (ROUND0_BITS - 1) enables us to use non-rounding shifts -
  // which are generally faster than rounding shifts on modern CPUs.
  const int32x4_t horiz_const =
      vdupq_n_s32((1 << (bd + FILTER_BITS - 1)) + (1 << (ROUND0_BITS - 1)));
#if AOM_ARCH_AARCH64
  do {
    const uint8_t *s = src_ptr;
    int16_t *d = dst_ptr;
    int width = w;
    uint8x8_t t0, t1, t2, t3;
    load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
    transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);
    int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s1 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s2 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    int16x4_t s3 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
    int16x4_t s4 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s5 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s6 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    int16x4_t s7 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
    load_u8_8x4(s + 8, src_stride, &t0, &t1, &t2, &t3);
    transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);
    int16x4_t s8 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
    int16x4_t s9 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
    int16x4_t s10 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
    s += 11;
    do {
      load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
      transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);
      int16x4_t s11 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
      int16x4_t s12 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
      int16x4_t s13 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
      int16x4_t s14 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
      int16x4_t d0 =
          convolve12_4_2d_h(s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11,
                            x_filter_0_7, x_filter_8_11, horiz_const);
      int16x4_t d1 =
          convolve12_4_2d_h(s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12,
                            x_filter_0_7, x_filter_8_11, horiz_const);
      int16x4_t d2 =
          convolve12_4_2d_h(s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13,
                            x_filter_0_7, x_filter_8_11, horiz_const);
      int16x4_t d3 =
          convolve12_4_2d_h(s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14,
                            x_filter_0_7, x_filter_8_11, horiz_const);
      transpose_elems_inplace_s16_4x4(&d0, &d1, &d2, &d3);
      store_s16_4x4(d, dst_stride, d0, d1, d2, d3);
      s0 = s4;
      s1 = s5;
      s2 = s6;
      s3 = s7;
      s4 = s8;
      s5 = s9;
      s6 = s10;
      s7 = s11;
      s8 = s12;
      s9 = s13;
      s10 = s14;
      s += 4;
      d += 4;
      width -= 4;
    } while (width != 0);
    src_ptr += 4 * src_stride;
    dst_ptr += 4 * dst_stride;
    h -= 4;
  } while (h > 4);
#endif  // AOM_ARCH_AARCH64
  do {
    const uint8_t *s = src_ptr;
    int16_t *d = dst_ptr;
    int width = w;
    do {
      uint8x16_t t0 = vld1q_u8(s);
      int16x8_t tt0 = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(t0)));
      int16x8_t tt1 = vreinterpretq_s16_u16(vmovl_u8(vget_high_u8(t0)));
      int16x4_t s0 = vget_low_s16(tt0);
      int16x4_t s4 = vget_high_s16(tt0);
      int16x4_t s8 = vget_low_s16(tt1);
      int16x4_t s12 = vget_high_s16(tt1);
      int16x4_t s1 = vext_s16(s0, s4, 1);    //  a1  a2  a3  a4
      int16x4_t s2 = vext_s16(s0, s4, 2);    //  a2  a3  a4  a5
      int16x4_t s3 = vext_s16(s0, s4, 3);    //  a3  a4  a5  a6
      int16x4_t s5 = vext_s16(s4, s8, 1);    //  a5  a6  a7  a8
      int16x4_t s6 = vext_s16(s4, s8, 2);    //  a6  a7  a8  a9
      int16x4_t s7 = vext_s16(s4, s8, 3);    //  a7  a8  a9 a10
      int16x4_t s9 = vext_s16(s8, s12, 1);   //  a9 a10 a11 a12
      int16x4_t s10 = vext_s16(s8, s12, 2);  // a10 a11 a12 a13
      int16x4_t s11 = vext_s16(s8, s12, 3);  // a11 a12 a13 a14
      int16x4_t d0 =
          convolve12_4_2d_h(s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11,
                            x_filter_0_7, x_filter_8_11, horiz_const);
      vst1_s16(d, d0);
      s += 4;
      d += 4;
      width -= 4;
    } while (width != 0);
    src_ptr += src_stride;
    dst_ptr += dst_stride;
  } while (--h != 0);
}

static INLINE int16x4_t convolve4_4_2d_h(const int16x4_t s0, const int16x4_t s1,
                                         const int16x4_t s2, const int16x4_t s3,
                                         const int16x4_t filter,
                                         const int16x4_t horiz_const) {
  int16x4_t sum = horiz_const;
  sum = vmla_lane_s16(sum, s0, filter, 0);
  sum = vmla_lane_s16(sum, s1, filter, 1);
  sum = vmla_lane_s16(sum, s2, filter, 2);
  sum = vmla_lane_s16(sum, s3, filter, 3);
  // We halved the convolution filter values so -1 from the right shift.
  return vshr_n_s16(sum, ROUND0_BITS - 1);
}

static INLINE int16x8_t convolve8_8_2d_h(const int16x8_t s0, const int16x8_t s1,
                                         const int16x8_t s2, const int16x8_t s3,
                                         const int16x8_t s4, const int16x8_t s5,
                                         const int16x8_t s6, const int16x8_t s7,
                                         const int16x8_t filter,
                                         const int16x8_t horiz_const) {
  const int16x4_t filter_lo = vget_low_s16(filter);
  const int16x4_t filter_hi = vget_high_s16(filter);
  int16x8_t sum = horiz_const;
  sum = vmlaq_lane_s16(sum, s0, filter_lo, 0);
  sum = vmlaq_lane_s16(sum, s1, filter_lo, 1);
  sum = vmlaq_lane_s16(sum, s2, filter_lo, 2);
  sum = vmlaq_lane_s16(sum, s3, filter_lo, 3);
  sum = vmlaq_lane_s16(sum, s4, filter_hi, 0);
  sum = vmlaq_lane_s16(sum, s5, filter_hi, 1);
  sum = vmlaq_lane_s16(sum, s6, filter_hi, 2);
  sum = vmlaq_lane_s16(sum, s7, filter_hi, 3);
  // We halved the convolution filter values so -1 from the right shift.
  return vshrq_n_s16(sum, ROUND0_BITS - 1);
}

static INLINE void convolve_2d_sr_horiz_neon(const uint8_t *src, int src_stride,
                                             int16_t *im_block, int im_stride,
                                             int w, int im_h,
                                             const int16_t *x_filter_ptr) {
  const int bd = 8;
  const uint8_t *src_ptr = src;
  int16_t *dst_ptr = im_block;
  int dst_stride = im_stride;
  int height = im_h;
  if (w <= 4) {
    // A shim of 1 << ((ROUND0_BITS - 1) - 1) enables us to use non-rounding
    // shifts - which are generally faster than rounding shifts on modern CPUs.
    // (The extra -1 is needed because we halved the filter values.)
    const int16x4_t horiz_const = vdup_n_s16((1 << (bd + FILTER_BITS - 2)) +
                                             (1 << ((ROUND0_BITS - 1) - 1)));
    // 4-tap filters are used for blocks having width <= 4.
    // Filter values are even, so halve to reduce intermediate precision reqs.
    const int16x4_t x_filter = vshr_n_s16(vld1_s16(x_filter_ptr + 2), 1);
    src_ptr += 2;
    do {
      uint8x8_t t0 = vld1_u8(src_ptr);  // a0 a1 a2 a3 a4 a5 a6 a7
      int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
      int16x4_t s4 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
      int16x4_t s1 = vext_s16(s0, s4, 1);  // a1 a2 a3 a4
      int16x4_t s2 = vext_s16(s0, s4, 2);  // a2 a3 a4 a5
      int16x4_t s3 = vext_s16(s0, s4, 3);  // a3 a4 a5 a6
      int16x4_t d0 = convolve4_4_2d_h(s0, s1, s2, s3, x_filter, horiz_const);
      vst1_s16(dst_ptr, d0);
      src_ptr += src_stride;
      dst_ptr += dst_stride;
    } while (--height != 0);
  } else {
    // A shim of 1 << ((ROUND0_BITS - 1) - 1) enables us to use non-rounding
    // shifts - which are generally faster than rounding shifts on modern CPUs.
    // (The extra -1 is needed because we halved the filter values.)
    const int16x8_t horiz_const = vdupq_n_s16((1 << (bd + FILTER_BITS - 2)) +
                                              (1 << ((ROUND0_BITS - 1) - 1)));
    // Filter values are even, so halve to reduce intermediate precision reqs.
    const int16x8_t x_filter = vshrq_n_s16(vld1q_s16(x_filter_ptr), 1);
#if AOM_ARCH_AARCH64
    while (height > 8) {
      const uint8_t *s = src_ptr;
      int16_t *d = dst_ptr;
      int width = w;
      uint8x8_t t0, t1, t2, t3, t4, t5, t6, t7;
      load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
      transpose_elems_inplace_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
      int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
      int16x8_t s6 = vreinterpretq_s16_u16(vmovl_u8(t6));
      s += 7;
      do {
        load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
        transpose_elems_inplace_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
        int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(t0));
        int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t1));
        int16x8_t s9 = vreinterpretq_s16_u16(vmovl_u8(t2));
        int16x8_t s10 = vreinterpretq_s16_u16(vmovl_u8(t3));
        int16x8_t s11 = vreinterpretq_s16_u16(vmovl_u8(t4));
        int16x8_t s12 = vreinterpretq_s16_u16(vmovl_u8(t5));
        int16x8_t s13 = vreinterpretq_s16_u16(vmovl_u8(t6));
        int16x8_t s14 = vreinterpretq_s16_u16(vmovl_u8(t7));
        int16x8_t d0 = convolve8_8_2d_h(s0, s1, s2, s3, s4, s5, s6, s7,
                                        x_filter, horiz_const);
        int16x8_t d1 = convolve8_8_2d_h(s1, s2, s3, s4, s5, s6, s7, s8,
                                        x_filter, horiz_const);
        int16x8_t d2 = convolve8_8_2d_h(s2, s3, s4, s5, s6, s7, s8, s9,
                                        x_filter, horiz_const);
        int16x8_t d3 = convolve8_8_2d_h(s3, s4, s5, s6, s7, s8, s9, s10,
                                        x_filter, horiz_const);
        int16x8_t d4 = convolve8_8_2d_h(s4, s5, s6, s7, s8, s9, s10, s11,
                                        x_filter, horiz_const);
        int16x8_t d5 = convolve8_8_2d_h(s5, s6, s7, s8, s9, s10, s11, s12,
                                        x_filter, horiz_const);
        int16x8_t d6 = convolve8_8_2d_h(s6, s7, s8, s9, s10, s11, s12, s13,
                                        x_filter, horiz_const);
        int16x8_t d7 = convolve8_8_2d_h(s7, s8, s9, s10, s11, s12, s13, s14,
                                        x_filter, horiz_const);
        transpose_elems_inplace_s16_8x8(&d0, &d1, &d2, &d3, &d4, &d5, &d6, &d7);
        store_s16_8x8(d, dst_stride, d0, d1, d2, d3, d4, d5, d6, d7);
        s0 = s8;
        s1 = s9;
        s2 = s10;
        s3 = s11;
        s4 = s12;
        s5 = s13;
        s6 = s14;
        s += 8;
        d += 8;
        width -= 8;
      } while (width != 0);
      src_ptr += 8 * src_stride;
      dst_ptr += 8 * dst_stride;
      height -= 8;
    }
#endif  // AOM_ARCH_AARCH64
    do {
      const uint8_t *s = src_ptr;
      int16_t *d = dst_ptr;
      int width = w;
      uint8x8_t t0 = vld1_u8(s);  // a0 a1 a2 a3 a4 a5 a6 a7
      int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      do {
        uint8x8_t t1 = vld1_u8(s + 8);  // a8 a9 a10 a11 a12 a13 a14 a15
        int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t1));
        int16x8_t s1 = vextq_s16(s0, s8, 1);  // a1 a2 a3 a4 a5 a6 a7 a8
        int16x8_t s2 = vextq_s16(s0, s8, 2);  // a2 a3 a4 a5 a6 a7 a8 a9
        int16x8_t s3 = vextq_s16(s0, s8, 3);  // a3 a4 a5 a6 a7 a8 a9 a10
        int16x8_t s4 = vextq_s16(s0, s8, 4);  // a4 a5 a6 a7 a8 a9 a10 a11
        int16x8_t s5 = vextq_s16(s0, s8, 5);  // a5 a6 a7 a8 a9 a10 a11 a12
        int16x8_t s6 = vextq_s16(s0, s8, 6);  // a6 a7 a8 a9 a10 a11 a12 a13
        int16x8_t s7 = vextq_s16(s0, s8, 7);  // a7 a8 a9 a10 a11 a12 a13 a14
        int16x8_t d0 = convolve8_8_2d_h(s0, s1, s2, s3, s4, s5, s6, s7,
                                        x_filter, horiz_const);
        vst1q_s16(d, d0);
        s0 = s8;
        s += 8;
        d += 8;
        width -= 8;
      } while (width != 0);
      src_ptr += src_stride;
      dst_ptr += dst_stride;
    } while (--height != 0);
  }
}

void av1_convolve_x_sr_intrabc_neon(const uint8_t *src, int src_stride,
                                    uint8_t *dst, int dst_stride, int w, int h,
                                    const InterpFilterParams *filter_params_x,
                                    const int subpel_x_qn,
                                    ConvolveParams *conv_params) {
  assert(subpel_x_qn == 8);
  assert(filter_params_x->taps == 2);
  assert((conv_params->round_0 + conv_params->round_1) == 2 * FILTER_BITS);
  (void)filter_params_x;
  (void)subpel_x_qn;
  (void)conv_params;
  if (w <= 4) {
    do {
      uint8x8_t s0_0 = vld1_u8(src);
      uint8x8_t s0_1 = vld1_u8(src + 1);
      uint8x8_t s1_0 = vld1_u8(src + src_stride);
      uint8x8_t s1_1 = vld1_u8(src + src_stride + 1);
      uint8x8_t d0 = vrhadd_u8(s0_0, s0_1);
      uint8x8_t d1 = vrhadd_u8(s1_0, s1_1);
      if (w == 2) {
        store_u8_2x1(dst + 0 * dst_stride, d0);
        store_u8_2x1(dst + 1 * dst_stride, d1);
      } else {
        store_u8_4x1(dst + 0 * dst_stride, d0);
        store_u8_4x1(dst + 1 * dst_stride, d1);
      }
      src += 2 * src_stride;
      dst += 2 * dst_stride;
      h -= 2;
    } while (h != 0);
  } else if (w == 8) {
    do {
      uint8x8_t s0_0 = vld1_u8(src);
      uint8x8_t s0_1 = vld1_u8(src + 1);
      uint8x8_t s1_0 = vld1_u8(src + src_stride);
      uint8x8_t s1_1 = vld1_u8(src + src_stride + 1);
      uint8x8_t d0 = vrhadd_u8(s0_0, s0_1);
      uint8x8_t d1 = vrhadd_u8(s1_0, s1_1);
      vst1_u8(dst, d0);
      vst1_u8(dst + dst_stride, d1);
      src += 2 * src_stride;
      dst += 2 * dst_stride;
      h -= 2;
    } while (h != 0);
  } else {
    do {
      const uint8_t *src_ptr = src;
      uint8_t *dst_ptr = dst;
      int width = w;
      do {
        uint8x16_t s0 = vld1q_u8(src_ptr);
        uint8x16_t s1 = vld1q_u8(src_ptr + 1);
        uint8x16_t d0 = vrhaddq_u8(s0, s1);
        vst1q_u8(dst_ptr, d0);
        src_ptr += 16;
        dst_ptr += 16;
        width -= 16;
      } while (width != 0);
      src += src_stride;
      dst += dst_stride;
    } while (--h != 0);
  }
}

void av1_convolve_y_sr_intrabc_neon(const uint8_t *src, int src_stride,
                                    uint8_t *dst, int dst_stride, int w, int h,
                                    const InterpFilterParams *filter_params_y,
                                    const int subpel_y_qn) {
  assert(subpel_y_qn == 8);
  assert(filter_params_y->taps == 2);
  (void)filter_params_y;
  (void)subpel_y_qn;
  if (w <= 4) {
    do {
      uint8x8_t s0 = load_unaligned_u8_4x1(src);
      uint8x8_t s1 = load_unaligned_u8_4x1(src + src_stride);
      uint8x8_t s2 = load_unaligned_u8_4x1(src + 2 * src_stride);
      uint8x8_t d0 = vrhadd_u8(s0, s1);
      uint8x8_t d1 = vrhadd_u8(s1, s2);
      if (w == 2) {
        store_u8_2x1(dst + 0 * dst_stride, d0);
        store_u8_2x1(dst + 1 * dst_stride, d1);
      } else {
        store_u8_4x1(dst + 0 * dst_stride, d0);
        store_u8_4x1(dst + 1 * dst_stride, d1);
      }
      src += 2 * src_stride;
      dst += 2 * dst_stride;
      h -= 2;
    } while (h != 0);
  } else if (w == 8) {
    do {
      uint8x8_t s0 = vld1_u8(src);
      uint8x8_t s1 = vld1_u8(src + src_stride);
      uint8x8_t s2 = vld1_u8(src + 2 * src_stride);
      uint8x8_t d0 = vrhadd_u8(s0, s1);
      uint8x8_t d1 = vrhadd_u8(s1, s2);
      vst1_u8(dst, d0);
      vst1_u8(dst + dst_stride, d1);
      src += 2 * src_stride;
      dst += 2 * dst_stride;
      h -= 2;
    } while (h != 0);
  } else {
    do {
      const uint8_t *src_ptr = src;
      uint8_t *dst_ptr = dst;
      int height = h;
      do {
        uint8x16_t s0 = vld1q_u8(src_ptr);
        uint8x16_t s1 = vld1q_u8(src_ptr + src_stride);
        uint8x16_t d0 = vrhaddq_u8(s0, s1);
        vst1q_u8(dst_ptr, d0);
        src_ptr += src_stride;
        dst_ptr += dst_stride;
      } while (--height != 0);
      src += 16;
      dst += 16;
      w -= 16;
    } while (w != 0);
  }
}

void av1_convolve_2d_sr_intrabc_neon(const uint8_t *src, int src_stride,
                                     uint8_t *dst, int dst_stride, int w, int h,
                                     const InterpFilterParams *filter_params_x,
                                     const InterpFilterParams *filter_params_y,
                                     const int subpel_x_qn,
                                     const int subpel_y_qn,
                                     ConvolveParams *conv_params) {
  assert(subpel_x_qn == 8);
  assert(subpel_y_qn == 8);
  assert(filter_params_x->taps == 2 && filter_params_y->taps == 2);
  assert((conv_params->round_0 + conv_params->round_1) == 2 * FILTER_BITS);
  (void)filter_params_x;
  (void)subpel_x_qn;
  (void)filter_params_y;
  (void)subpel_y_qn;
  (void)conv_params;
  uint16_t im_block[(MAX_SB_SIZE + MAX_FILTER_TAP - 1) * MAX_SB_SIZE];
  int im_h = h + 1;
  int im_stride = w;
  assert(w <= MAX_SB_SIZE && h <= MAX_SB_SIZE);
  uint16_t *im = im_block;
  // Horizontal filter.
  if (w <= 4) {
    do {
      uint8x8_t s0 = vld1_u8(src);
      uint8x8_t s1 = vld1_u8(src + 1);
      uint16x4_t sum = vget_low_u16(vaddl_u8(s0, s1));
      // Safe to store the whole vector, the im buffer is big enough.
      vst1_u16(im, sum);
      src += src_stride;
      im += im_stride;
    } while (--im_h != 0);
  } else {
    do {
      const uint8_t *src_ptr = src;
      uint16_t *im_ptr = im;
      int width = w;
      do {
        uint8x8_t s0 = vld1_u8(src_ptr);
        uint8x8_t s1 = vld1_u8(src_ptr + 1);
        uint16x8_t sum = vaddl_u8(s0, s1);
        vst1q_u16(im_ptr, sum);
        src_ptr += 8;
        im_ptr += 8;
        width -= 8;
      } while (width != 0);
      src += src_stride;
      im += im_stride;
    } while (--im_h != 0);
  }
  im = im_block;
  // Vertical filter.
  if (w <= 4) {
    do {
      uint16x4_t s0 = vld1_u16(im);
      uint16x4_t s1 = vld1_u16(im + im_stride);
      uint16x4_t s2 = vld1_u16(im + 2 * im_stride);
      uint16x4_t sum0 = vadd_u16(s0, s1);
      uint16x4_t sum1 = vadd_u16(s1, s2);
      uint8x8_t d0 = vqrshrn_n_u16(vcombine_u16(sum0, vdup_n_u16(0)), 2);
      uint8x8_t d1 = vqrshrn_n_u16(vcombine_u16(sum1, vdup_n_u16(0)), 2);
      if (w == 2) {
        store_u8_2x1(dst + 0 * dst_stride, d0);
        store_u8_2x1(dst + 1 * dst_stride, d1);
      } else {
        store_u8_4x1(dst + 0 * dst_stride, d0);
        store_u8_4x1(dst + 1 * dst_stride, d1);
      }
      im += 2 * im_stride;
      dst += 2 * dst_stride;
      h -= 2;
    } while (h != 0);
  } else {
    do {
      uint16_t *im_ptr = im;
      uint8_t *dst_ptr = dst;
      int height = h;
      do {
        uint16x8_t s0 = vld1q_u16(im_ptr);
        uint16x8_t s1 = vld1q_u16(im_ptr + im_stride);
        uint16x8_t sum = vaddq_u16(s0, s1);
        uint8x8_t d0 = vqrshrn_n_u16(sum, 2);
        vst1_u8(dst_ptr, d0);
        im_ptr += im_stride;
        dst_ptr += dst_stride;
      } while (--height != 0);
      im += 8;
      dst += 8;
      w -= 8;
    } while (w != 0);
  }
}