Need loop in 1st pass...

Need loop in 1st pass...

work-group size on AMD Stream for CPU-only CL
is smaller than total work size which leads to a race condition.

This means that the FData array is being calculated multiple times, but I'll
fix that eventually.

#pragma OPENCL EXTENSION cl_khr_byte_addressable_store : enable

__constant int bilinear_filters[8][2] = {
    { 128, 0},
    { 112, 16},
    { 96, 32},
    { 80, 48},
    { 64, 64},
    { 48, 80},
    { 32, 96},
    { 16, 112}
};

__constant short sub_pel_filters[8][6] = {
    { 0, 0, 128, 0, 0, 0}, /* note that 1/8 pel positions are just as per alpha -0.5 bicubic */
    { 0, -6, 123, 12, -1, 0},
    { 2, -11, 108, 36, -8, 1}, /* New 1/4 pel 6 tap filter */
    { 0, -9, 93, 50, -6, 0},
    { 3, -16, 77, 77, -16, 3}, /* New 1/2 pel 6 tap filter */
    { 0, -6, 50, 93, -9, 0},
    { 1, -8, 36, 108, -11, 2}, /* New 1/4 pel 6 tap filter */
    { 0, -1, 12, 123, -6, 0},
};

void vp8_filter_block2d_first_pass(
    __global unsigned char *src_ptr,
    __local int *output_ptr,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
){
    uint tid = get_global_id(0);
    uint i = tid;

    int src_offset;
    int Temp;
    int PS2 = 2*(int)pixel_step;
    int PS3 = 3*(int)pixel_step;

    __constant short *vp8_filter = sub_pel_filters[filter_offset];

    if (tid < (output_width*output_height)){
        for (i=0; i < output_width*output_height; i++){
            src_offset = i + (i/output_width * (src_pixels_per_line - output_width)) + PS2;

            Temp = (int)(src_ptr[src_offset - PS2]      * vp8_filter[0]) +
               (int)(src_ptr[src_offset - (int)pixel_step] * vp8_filter[1]) +
               (int)(src_ptr[src_offset]                * vp8_filter[2]) +
               (int)(src_ptr[src_offset + pixel_step]   * vp8_filter[3]) +
               (int)(src_ptr[src_offset + PS2]          * vp8_filter[4]) +
               (int)(src_ptr[src_offset + PS3]          * vp8_filter[5]) +
               (VP8_FILTER_WEIGHT >> 1);      /* Rounding */

            /* Normalize back to 0-255 */
            Temp = Temp >> VP8_FILTER_SHIFT;

            //Temp = (int)src_ptr[2];
            if (Temp < 0)
                Temp = 0;
            else if ( Temp > 255 )
                Temp = 255;

            output_ptr[i] = Temp;
        }
    }

    //Add a fence/barrier so that no 2nd pass stuff starts before 1st pass is done.
    //write_mem_fence(CLK_GLOBAL_MEM_FENCE);
    barrier(CLK_GLOBAL_MEM_FENCE);
}

void vp8_filter_block2d_second_pass
(
    __local int *src_ptr,
    __global unsigned char *output_ptr,
    int output_pitch,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
) {

    int out_offset;
    int src_offset;
    int Temp;
    int PS2 = 2*(int)pixel_step;
    int PS3 = 3*(int)pixel_step;

    unsigned int src_increment = src_pixels_per_line - output_width;

    uint i = get_global_id(0);

    __constant short *vp8_filter = sub_pel_filters[filter_offset];

    if (i < (output_width * output_height)){
        out_offset = i/output_width;
        src_offset = out_offset;

        src_offset = i + (src_offset * src_increment);
        out_offset = i%output_width + (out_offset * output_pitch);

        /* Apply filter */
        Temp = ((int)src_ptr[src_offset - PS2] * vp8_filter[0]) +
           ((int)src_ptr[src_offset -(int)pixel_step] * vp8_filter[1]) +
           ((int)src_ptr[src_offset]                  * vp8_filter[2]) +
           ((int)src_ptr[src_offset + pixel_step]     * vp8_filter[3]) +
           ((int)src_ptr[src_offset + PS2]       * vp8_filter[4]) +
           ((int)src_ptr[src_offset + PS3]       * vp8_filter[5]) +
           (VP8_FILTER_WEIGHT >> 1);   /* Rounding */

        /* Normalize back to 0-255 */
        Temp = Temp >> VP8_FILTER_SHIFT;
        if (Temp < 0)
            Temp = 0;
        else if (Temp > 255)
            Temp = 255;

        output_ptr[out_offset] = (unsigned char)Temp;
        //output_ptr[i] = (unsigned char)out_offset;
    }
}

__kernel void vp8_block_variation_kernel
(
    __global unsigned char  *src_ptr,
    int   src_pixels_per_line,
    __global int *HVar,
    __global int *VVar
)
{
    int i, j;
    __global unsigned char *Ptr = src_ptr;

    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 4; j++)
        {
            *HVar += abs((int)Ptr[j] - (int)Ptr[j+1]);
            *VVar += abs((int)Ptr[j] - (int)Ptr[j+src_pixels_per_line]);
        }

        Ptr += src_pixels_per_line;
    }
}

__kernel void vp8_sixtap_predict_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
        ) {

    __local int FData[9*4]; /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 9, 4, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[8], dst_ptr, dst_pitch, 4, 4, 4, 4, yoffset);
}

__kernel void vp8_sixtap_predict8x8_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
)
{
    __local int FData[13*16];   /* Temp data bufffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 13, 8, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[16], dst_ptr, dst_pitch, 8, 8, 8, 8, yoffset);

}

__kernel void vp8_sixtap_predict8x4_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
)
{
    __local int FData[13*16];   /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 9, 8, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[16], dst_ptr, dst_pitch, 8, 8, 4, 8, yoffset);

}

__kernel void vp8_sixtap_predict16x16_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
)
{
    __local int FData[21*24];   /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 21, 16, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[32], dst_ptr, dst_pitch, 16, 16, 16, 16, yoffset);

    return;
}

__kernel void vp8_filter_block2d_bil_first_pass_kernel(
    __global unsigned char *src_ptr,
    __global int *output_ptr,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
){
    uint i = get_global_id(0);
}

__kernel void vp8_filter_block2d_bil_second_pass_kernel
(
    __global int *src_ptr,
    unsigned int offset,
    __global unsigned char *output_ptr,
    int output_pitch,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
) {
    uint i = get_global_id(0);
}

#pragma OPENCL EXTENSION cl_khr_byte_addressable_store : enable

__constant int bilinear_filters[8][2] = {
    { 128, 0},
    { 112, 16},
    { 96, 32},
    { 80, 48},
    { 64, 64},
    { 48, 80},
    { 32, 96},
    { 16, 112}
};

__constant short sub_pel_filters[8][6] = {
    { 0, 0, 128, 0, 0, 0}, /* note that 1/8 pel positions are just as per alpha -0.5 bicubic */
    { 0, -6, 123, 12, -1, 0},
    { 2, -11, 108, 36, -8, 1}, /* New 1/4 pel 6 tap filter */
    { 0, -9, 93, 50, -6, 0},
    { 3, -16, 77, 77, -16, 3}, /* New 1/2 pel 6 tap filter */
    { 0, -6, 50, 93, -9, 0},
    { 1, -8, 36, 108, -11, 2}, /* New 1/4 pel 6 tap filter */
    { 0, -1, 12, 123, -6, 0},
};

void vp8_filter_block2d_first_pass(
    __global unsigned char *src_ptr,
    __local int *output_ptr,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
){
    uint tid = get_global_id(0);
    uint i = tid;

    int src_offset;
    int Temp;
    int PS2 = 2*(int)pixel_step;
    int PS3 = 3*(int)pixel_step;

    __constant short *vp8_filter = sub_pel_filters[filter_offset];

    if (tid < (output_width*output_height)){
        //for (i=0; i < output_width*output_height; i++){
            src_offset = i + (i/output_width * (src_pixels_per_line - output_width)) + PS2;

            Temp = (int)(src_ptr[src_offset - PS2]      * vp8_filter[0]) +
               (int)(src_ptr[src_offset - (int)pixel_step] * vp8_filter[1]) +
               (int)(src_ptr[src_offset]                * vp8_filter[2]) +
               (int)(src_ptr[src_offset + pixel_step]   * vp8_filter[3]) +
               (int)(src_ptr[src_offset + PS2]          * vp8_filter[4]) +
               (int)(src_ptr[src_offset + PS3]          * vp8_filter[5]) +
               (VP8_FILTER_WEIGHT >> 1);      /* Rounding */

            /* Normalize back to 0-255 */
            Temp = Temp >> VP8_FILTER_SHIFT;

            //Temp = (int)src_ptr[2];
            if (Temp < 0)
                Temp = 0;
            else if ( Temp > 255 )
                Temp = 255;

            output_ptr[i] = Temp;
        //}
    }

    //Add a fence/barrier so that no 2nd pass stuff starts before 1st pass is done.
    //write_mem_fence(CLK_GLOBAL_MEM_FENCE);
    barrier(CLK_GLOBAL_MEM_FENCE);
}

void vp8_filter_block2d_second_pass
(
    __local int *src_ptr,
    __global unsigned char *output_ptr,
    int output_pitch,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
) {

    int out_offset;
    int src_offset;
    int Temp;
    int PS2 = 2*(int)pixel_step;
    int PS3 = 3*(int)pixel_step;

    unsigned int src_increment = src_pixels_per_line - output_width;

    uint i = get_global_id(0);

    __constant short *vp8_filter = sub_pel_filters[filter_offset];

    if (i < (output_width * output_height)){
        out_offset = i/output_width;
        src_offset = out_offset;

        src_offset = i + (src_offset * src_increment);
        out_offset = i%output_width + (out_offset * output_pitch);

        /* Apply filter */
        Temp = ((int)src_ptr[src_offset - PS2] * vp8_filter[0]) +
           ((int)src_ptr[src_offset -(int)pixel_step] * vp8_filter[1]) +
           ((int)src_ptr[src_offset]                  * vp8_filter[2]) +
           ((int)src_ptr[src_offset + pixel_step]     * vp8_filter[3]) +
           ((int)src_ptr[src_offset + PS2]       * vp8_filter[4]) +
           ((int)src_ptr[src_offset + PS3]       * vp8_filter[5]) +
           (VP8_FILTER_WEIGHT >> 1);   /* Rounding */

        /* Normalize back to 0-255 */
        Temp = Temp >> VP8_FILTER_SHIFT;
        if (Temp < 0)
            Temp = 0;
        else if (Temp > 255)
            Temp = 255;

        output_ptr[out_offset] = (unsigned char)Temp;
        //output_ptr[i] = (unsigned char)out_offset;
    }
}

__kernel void vp8_block_variation_kernel
(
    __global unsigned char  *src_ptr,
    int   src_pixels_per_line,
    __global int *HVar,
    __global int *VVar
)
{
    int i, j;
    __global unsigned char *Ptr = src_ptr;

    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 4; j++)
        {
            *HVar += abs((int)Ptr[j] - (int)Ptr[j+1]);
            *VVar += abs((int)Ptr[j] - (int)Ptr[j+src_pixels_per_line]);
        }

        Ptr += src_pixels_per_line;
    }
}

__kernel void vp8_sixtap_predict_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
        ) {

    __local int FData[9*4]; /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 9, 4, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[8], dst_ptr, dst_pitch, 4, 4, 4, 4, yoffset);
}

__kernel void vp8_sixtap_predict8x8_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
)
{
    __local int FData[13*16];   /* Temp data bufffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 13, 8, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[16], dst_ptr, dst_pitch, 8, 8, 8, 8, yoffset);

}

__kernel void vp8_sixtap_predict8x4_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
)
{
    __local int FData[13*16];   /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 9, 8, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[16], dst_ptr, dst_pitch, 8, 8, 4, 8, yoffset);

}

__kernel void vp8_sixtap_predict16x16_kernel
(
    __global unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    __global unsigned char *dst_ptr,
    int  dst_pitch
)
{
    __local int FData[21*24];   /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    vp8_filter_block2d_first_pass(src_ptr, FData, src_pixels_per_line, 1, 21, 16, xoffset);

    /* then filter verticaly... */
    vp8_filter_block2d_second_pass(&FData[32], dst_ptr, dst_pitch, 16, 16, 16, 16, yoffset);

    return;
}

__kernel void vp8_filter_block2d_bil_first_pass_kernel(
    __global unsigned char *src_ptr,
    __global int *output_ptr,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
){
    uint i = get_global_id(0);
}

__kernel void vp8_filter_block2d_bil_second_pass_kernel
(
    __global int *src_ptr,
    unsigned int offset,
    __global unsigned char *output_ptr,
    int output_pitch,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    int filter_offset
) {
    uint i = get_global_id(0);
}


Some ray-tracing. TODO: progress ray & determine hit face.

#define SCREEN_H 512
#define SCREEN_W 512

#define MAX_DRAW_DIST 32

#define WALL_UNDER ((float4)(0.3,0.5,0.5,1.0))
#define WALL_SIDE  ((float4)(0.45,0.75,0.75,1.0))
#define WALL_TOP   ((float4)(0.6,1.0,1.0,1.0))

#define ET_WALL         0
#define ET_PORTAL_TORUS 1
#define ET_SOLID_AIR    2

#define BK_AIR      0
#define BK_WALL     1

#define INSIDE(pos, bounds) ((pos).x >= 0. && (pos).y >= 0. && \
    (pos).z >= 0. && (pos).x < (bounds).x && (pos).y < (bounds).y && \
    (pos).z < (bounds).z)

#define GRID_GET(grid,x,y,z) ((grid)[x + y*x_size + z*x_size*y_size])
#define GRID_GETV(grid,v) GRID_GET((grid), (v).x,(v).y,(v).z)

float ellip_radius_mix(float2 radii, float cos_theta) {
    float a = radii.x > radii.y ? radii.x : radii.y;
    float b = radii.x > radii.y ? radii.y : radii.x;

    float e2 = 1 - (b/a)*(b/a);
    return b / sqrt(1 - e2*cos_theta*cos_theta);
}

__kernel void raytrace(__write_only __global image2d_t bmp,
    uchar x_size, uchar y_size, uchar z_size, uchar edge_type,
    __constant uchar *grid)
{
    /* Screen pixel position: */
    int2 p_pos = (int2)(get_global_id(0), get_global_id(1));
    /* Camera position: */
    float4 c_pos = (float4)(0.5,0.5,0.5,0.0);
    float2 c_size = (float2)(1.,1.);
    uchar4 bounds = (uchar4)(x_size, y_size, z_size, 0);

    float2 ray_rot = (float2)((p_pos.x * M_PI_2) / SCREEN_W - M_PI_4,
                              (p_pos.y * M_PI_2) / SCREEN_H - M_PI_4);
    float2 ray_rot_sin = sin(ray_rot),
           ray_rot_cos = cos(ray_rot);

    float c_size_z = ellip_radius_mix(c_size, ray_rot_cos.y);
    float4 ray_pos = (float4)(
        c_pos.x + c_size.x*ray_rot_sin.x/2,
        c_pos.y + c_size.y*ray_rot_sin.y/2,
        c_pos.z + c_size_z*ray_rot_cos.x*ray_rot_cos.y/2, 0.);
    float4 ray_color = (float4)(0.,0.,0.,1.);
    uint steps = 0;
    while (steps < MAX_DRAW_DIST) {

        bool inside = INSIDE(ray_pos, bounds);
        uchar4 ray_posi = (uchar4)(ray_pos.x, ray_pos.y, ray_pos.z, ray_pos.w);

        uchar block;
        if (!inside) {
            block = edge_type == ET_WALL ? BK_WALL : BK_AIR;
        } else {
            block = GRID_GETV(grid, ray_posi);
        }

        if (block == BK_WALL) {
            /* Determine which face of the wall block we see, and set ray
               color accordingly. */
            // TODO
        }

        if (block != BK_AIR)
            break;

        // TODO: progress ray

        steps++;
    }

    write_imagef(bmp, p_pos, ray_color);
}

#define WALL_UNDER ((float4)(0.3,0.5,0.5,1.0))
#define WALL_SIDE  ((float4)(0.45,0.75,0.75,1.0))
#define WALL_TOP   ((float4)(0.6,1.0,1.0,1.0))

#define ET_WALL         0
#define ET_PORTAL_TORUS 1
#define ET_SOLID_AIR    2

__kernel void raytrace(__write_only __global image2d_t bmp,
    uchar x_size, uchar y_size, uchar z_size, uchar edge_type,
    __constant uchar *grid)
{
    uint x = get_global_id(0),
         y = get_global_id(1);
    int2 coords = (int2)(x,y);

    if (x < x_size && y < y_size) {
        write_imagef(bmp, coords, WALL_TOP);
    } else {
        write_imagef(bmp, coords, WALL_SIDE);
    }
}


wsp + store label_count

wsp + store label_count

#define PREFER_MCL_WORKGROUP_FUNCTIONS
#if __OPENCL_VERSION__ >= 200 && !defined(PREFER_MCL_WORKGROUP_FUNCTIONS)
#define USE_CL2_WORKGROUP_FUNCTIONS
#endif

#include "clcommons/common.h"
#include "clcommons/image.h"
#include "clcommons/work_group.h"

#ifndef PIXELT
#define PIXELT uint
#endif
#ifndef LABELT
#define LABELT uint
#endif
#ifndef CONNECTIVITYPIXELT
#define CONNECTIVITYPIXELT uint
#endif
#ifndef LDSPIXELT
#define LDSPIXELT uint
#endif
#ifndef LDSLABELT
#define LDSLABELT uint
#endif
#ifndef LDSCONNECTIVITYPIXELT
#define LDSCONNECTIVITYPIXELT uint
#endif

typedef PIXELT PixelT;
typedef LDSPIXELT LDSPixelT;
typedef LABELT LabelT;
typedef LDSLABELT LDSLabelT;
typedef CONNECTIVITYPIXELT ConnectivityPixelT;
typedef LDSCONNECTIVITYPIXELT LDSConnectivityPixelT;

#ifndef BG_VALUE
#define BG_VALUE 0
#endif

#ifndef CONNECTIVITY  //4 or 8
#define CONNECTIVITY 8
#endif

#ifndef WORKGROUP_TILE_SIZE_X
#define WORKGROUP_TILE_SIZE_X 32
#endif
#ifndef WORKGROUP_TILE_SIZE_Y
#define WORKGROUP_TILE_SIZE_Y 2
#endif

#ifndef WORKITEM_REPEAT_X
#define WORKITEM_REPEAT_X 1
#endif
#ifndef WORKITEM_REPEAT_Y
#define WORKITEM_REPEAT_Y 16
#endif

#define TILE_COLS (WORKGROUP_TILE_SIZE_X * WORKITEM_REPEAT_X)
#define TILE_ROWS (WORKGROUP_TILE_SIZE_Y * WORKITEM_REPEAT_Y)

__constant const uint UP = (1<<0);
__constant const uint LEFT = (1<<1);
__constant const uint DOWN = (1<<2);
__constant const uint RIGHT = (1<<3);
__constant const uint LEFT_UP = (1<<4);
__constant const uint LEFT_DOWN = (1<<5);
__constant const uint RIGHT_UP = (1<<6);
__constant const uint RIGHT_DOWN = (1<<7);

#define isConnected(p1, p2) ((p1) == (p2))

#define pixel_at(type, basename, r, c) image_pixel_at(type, PASTE2(basename, _p), im_rows, im_cols, PASTE2(basename, _pitch), (r), (c))

//global dimensions: divUp(image.cols, block.x), divUp(image.rows, block.y);
//__attribute__((reqd_work_group_size(WORKGROUP_TILE_SIZE_X, WORKGROUP_TILE_SIZE_Y, 1)))
//__kernel void
//make_connectivity_image(uint im_rows, uint im_cols, __global PixelT *image_p, uint image_pitch, __global ConnectivityPixelT *connectivityim_p, uint connectivityim_pitch){
//    const uint c = get_global_id(1);
//    const uint r = get_global_id(0);
//    const bool valid_pixel_task = (c < im_cols) & (r < im_rows);
//
//    if(valid_pixel_task){
//        PixelT pixel = pixel_at(PixelT, image, r, c);
//        ConnectivityPixelT connectivity = 0;
//
//#if CONNECTIVITY == 8
//        connectivity |= c > 0 && r > 0                     && isConnected(pixel, pixel_at(PixelT, image, r-1, c - 1)) ? LEFT_UP : 0
//        connectivity |= c > 0                              && isConnected(pixel, pixel_at(PixelT, image, r, c - 1)) ? LEFT : 0
//        connectivity |= c > 0 && r < im_rows - 1           && isConnected(pixel, pixel_at(PixelT, image, r+1, c - 1)) ? LEFT_DOWN : 0
//        connectivity |=          r < im_rows - 1           && isConnected(pixel, pixel_at(PixelT, image, r+1, c)) ? DOWN : 0
//        connectivity |= c < im_cols - 1 && r < im_rows - 1 && isConnected(pixel, pixel_at(PixelT, image, r+1, c + 1)) ? RIGHT_DOWN : 0
//        connectivity |= c < im_cols - 1                    && isConnected(pixel, pixel_at(PixelT, image, r, c + 1)) ? RIGHT : 0
//        connectivity |= c < im_cols - 1 && r > 0           && isConnected(pixel, pixel_at(PixelT, image, r-1, c + 1)) ? RIGHT_UP : 0
//        connectivity |=          r > 0                     && isConnected(pixel, pixel_at(PixelT, image, r-1, c)) ? UP : 0
//#else
//        connectivity |= c > 0                              && isConnected(pixel, pixel_at(PixelT, image, r, c - 1)) ? LEFT : 0
//        connectivity |=          r < im_rows - 1           && isConnected(pixel, pixel_at(PixelT, image, r+1, c)) ? DOWN : 0
//        connectivity |= c < im_cols - 1                    && isConnected(pixel, pixel_at(PixelT, image, r, c + 1)) ? RIGHT : 0
//        connectivity |=          r > 0                     && isConnected(pixel, pixel_at(PixelT, image, r-1, c)) ? UP : 0
//#endif
//
//        pixel_at(ConnectivityPixelT, connectivity, r, c) = connectivity;
//    }
//}

#define apron_pixel(apron, t_r, t_c) apron[(t_r+ 1)][(t_c + 1)]
//global dimensions: divUp(im_cols, tile_cols), divUp(im_rows, tile_rows);
__attribute__((reqd_work_group_size(WORKGROUP_TILE_SIZE_X, WORKGROUP_TILE_SIZE_Y, 1)))
__kernel void make_connectivity_image(
    uint im_rows, uint im_cols, __global const PixelT *image_p, uint image_pitch, __global ConnectivityPixelT *connectivityim_p, uint connectivityim_pitch
){
    const uint tile_col_blocksize = TILE_COLS;
    const uint tile_row_blocksize = TILE_ROWS;
    const uint tile_col_block = get_group_id(0) + get_global_offset(0) / get_local_size(0);
    const uint tile_row_block = get_group_id(1) + get_global_offset(1) / get_local_size(1);
    const uint tile_col = get_local_id(0);
    const uint tile_row = get_local_id(1);

    uint tile_rows = tile_row_blocksize;
    uint tile_cols = tile_col_blocksize;

    const uint tile_row_start = tile_row_block * tile_rows;
    const uint tile_col_start = tile_col_block * tile_cols;
    const uint tile_row_end = min(tile_row_start + tile_rows, (uint) im_rows);
    const uint tile_col_end = min(tile_col_start + tile_cols, (uint) im_cols);
    //adjust to true tile dimensions
    tile_rows = tile_row_end - tile_row_start;
    tile_cols = tile_col_end - tile_col_start;
    const uint apron_tile_cols = tile_cols + 2;;
    const uint n_tile_pixels = tile_rows * tile_cols;
    const uint n_work_items = get_local_size(0) * get_local_size(1);
    const uint n_apron_tile_pixels = (tile_rows + 2) * (apron_tile_cols);
    __local LDSPixelT im_tile[TILE_ROWS + 2][TILE_COLS + 2];
    __local LDSConnectivityPixelT connectivity_tile[TILE_ROWS][TILE_COLS];

    const uint tid = get_local_linear_id();
    for(uint im_tile_fill_task_id = tid; im_tile_fill_task_id < n_apron_tile_pixels; im_tile_fill_task_id += n_work_items){
        const uint im_apron_tile_row = im_tile_fill_task_id / apron_tile_cols;
        const uint im_apron_tile_col = im_tile_fill_task_id % apron_tile_cols;
        const int g_c = ((int)(im_apron_tile_col + tile_col_start)) - 1;
        const int g_r = ((int)(im_apron_tile_row + tile_row_start)) - 1;

        im_tile[im_apron_tile_row][im_apron_tile_col] = image_tex2D(PixelT, image_p, (int) im_rows, (int) im_cols, image_pitch, g_r, g_c, ADDRESS_ZERO);
    }
    lds_barrier();

    #pragma unroll
    for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
        #pragma unroll
        for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
            const uint c = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
            const uint r = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
            PixelT pixel = apron_pixel(im_tile, r, c);
            ConnectivityPixelT connectivity = 0;

#if CONNECTIVITY == 8
            connectivity |= c > 0 && r > 0                         && isConnected(pixel, apron_pixel(im_tile, r-1, c - 1)) ? LEFT_UP : 0;
            connectivity |= c > 0                                  && isConnected(pixel, apron_pixel(im_tile, r  , c - 1)) ? LEFT : 0;
            connectivity |= c > 0 && r < tile_rows - 1             && isConnected(pixel, apron_pixel(im_tile, r+1, c - 1)) ? LEFT_DOWN : 0;
            connectivity |=          r < tile_rows - 1             && isConnected(pixel, apron_pixel(im_tile, r+1, c    )) ? DOWN : 0;
            connectivity |= c < tile_cols - 1 && r < tile_rows - 1 && isConnected(pixel, apron_pixel(im_tile, r+1, c + 1)) ? RIGHT_DOWN : 0;
            connectivity |= c < tile_cols - 1                      && isConnected(pixel, apron_pixel(im_tile, r  , c + 1)) ? RIGHT : 0;
            connectivity |= c < tile_cols - 1 && r > 0             && isConnected(pixel, apron_pixel(im_tile, r-1, c + 1)) ? RIGHT_UP : 0;
            connectivity |=          r > 0                         && isConnected(pixel, apron_pixel(im_tile, r-1, c    )) ? UP : 0;
#else
            connectivity |= c > 0                                  && isConnected(pixel, apron_pixel(im_tile, r  , c - 1)) ? LEFT : 0;
            connectivity |=          r < tile_rows - 1             && isConnected(pixel, apron_pixel(im_tile, r+1, c    )) ? DOWN : 0;
            connectivity |= c < tile_cols - 1                      && isConnected(pixel, apron_pixel(im_tile, r  , c + 1)) ? RIGHT : 0;
            connectivity |=          r > 0                         && isConnected(pixel, apron_pixel(im_tile, r-1, c    )) ? UP : 0;
#endif
            connectivity = (c < tile_cols) & (r < tile_rows) ? connectivity : 0;
            connectivity_tile[r][c] = connectivity;
        }
    }
    lds_barrier();

    for(uint im_tile_fill_task_id = tid; im_tile_fill_task_id < n_tile_pixels; im_tile_fill_task_id += n_work_items){
        const uint im_tile_row = im_tile_fill_task_id / tile_cols;
        const uint im_tile_col = im_tile_fill_task_id % tile_cols;
        const uint g_c = im_tile_col + tile_col_start;
        const uint g_r = im_tile_row + tile_row_start;

        pixel_at(ConnectivityPixelT, connectivityim, g_r, g_c) = connectivity_tile[im_tile_row][im_tile_col];
    }
}

__attribute__((reqd_work_group_size(WORKGROUP_TILE_SIZE_X, WORKGROUP_TILE_SIZE_Y, 1)))
__kernel void label_tiles(
    uint im_rows, uint im_cols, __global LabelT *labelim_p, uint labelim_pitch, __global const ConnectivityPixelT *connectivityim_p, uint connectivityim_pitch
){
    const uint tile_col_blocksize = TILE_COLS;
    const uint tile_row_blocksize = TILE_ROWS;
    const uint tile_col_block = get_group_id(0) + get_global_offset(0) / get_local_size(0);
    const uint tile_row_block = get_group_id(1) + get_global_offset(1) / get_local_size(1);

    uint tile_rows = tile_row_blocksize;
    uint tile_cols = tile_col_blocksize;

    const uint tile_row_start = tile_row_block * tile_rows;
    const uint tile_col_start = tile_col_block * tile_cols;
    const uint tile_row_end = min(tile_row_start + tile_rows, (uint) im_rows);
    const uint tile_col_end = min(tile_col_start + tile_cols, (uint) im_cols);
    //adjust to true tile dimensions
    tile_rows = tile_row_end - tile_row_start;
    tile_cols = tile_col_end - tile_col_start;

    //if (x >= im_rows || y >= im_rows) return;

    __local LDSLabelT label_tile_im[TILE_ROWS][TILE_COLS];
    __local LDSConnectivityPixelT  edge_tile_im[TILE_ROWS][TILE_COLS];

    LDSLabelT new_labels[WORKITEM_REPEAT_Y][WORKITEM_REPEAT_X];
    LDSLabelT old_labels[WORKITEM_REPEAT_Y][WORKITEM_REPEAT_X];

    #pragma unroll
    for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
        #pragma unroll
        for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
            const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
            const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
            const bool valid_pixel_task = (tile_col < tile_cols) & (tile_row < tile_rows);
            ConnectivityPixelT c = valid_pixel_task ? pixel_at(ConnectivityPixelT, connectivityim, tile_row_start + tile_row, tile_col_start + tile_col) : 0;

            c = tile_col == 0 ? c & ~(LEFT|LEFT_DOWN|LEFT_UP) : c;
            c = tile_row == 0 ? c & ~(UP|LEFT_UP|RIGHT_UP) : c;

            c = tile_col >= tile_cols - 1 ? c & ~(RIGHT|RIGHT_DOWN|RIGHT_UP) : c;
            c = tile_row >= tile_rows - 1 ? c & ~(DOWN|LEFT_DOWN|RIGHT_DOWN) : c;

            new_labels[i][j] = valid_pixel_task ? tile_row * tile_cols + tile_col : ((LDSLabelT) -1);
            edge_tile_im[tile_row][tile_col] = c;
        }
    }

    for (uint k = 0; ;++k){
        //make copies
        #pragma unroll
        for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
                old_labels[i][j] = new_labels[i][j];
                label_tile_im[tile_row][tile_col] = new_labels[i][j];
            }
        }
        lds_barrier();

        //take minimum label of local neighboorhood - single writer, multi reader version
        #pragma unroll
        for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;

                const ConnectivityPixelT connectivity = edge_tile_im[tile_row][tile_col];
                LDSLabelT label = new_labels[i][j];

#if CONNECTIVITY == 8
                label = connectivity & UP            ? min(label, label_tile_im[tile_row - 1][tile_col - 0]) : label;
                label = connectivity & LEFT_UP       ? min(label, label_tile_im[tile_row - 1][tile_col - 1]) : label;
                label = connectivity & LEFT          ? min(label, label_tile_im[tile_row - 0][tile_col - 1]) : label;
                label = connectivity & LEFT_DOWN     ? min(label, label_tile_im[tile_row + 1][tile_col - 1]) : label;
                label = connectivity & DOWN          ? min(label, label_tile_im[tile_row + 1][tile_col - 0]) : label;
                label = connectivity & RIGHT_DOWN    ? min(label, label_tile_im[tile_row + 1][tile_col + 1]) : label;
                label = connectivity & RIGHT         ? min(label, label_tile_im[tile_row + 0][tile_col + 1]) : label;
                label = connectivity & RIGHT_UP      ? min(label, label_tile_im[tile_row - 1][tile_col + 1]) : label;
#else
                label = connectivity & UP            ? min(label, label_tile_im[tile_row - 1][tile_col - 0]) : label;
                label = connectivity & LEFT          ? min(label, label_tile_im[tile_row - 0][tile_col - 1]) : label;
                label = connectivity & DOWN          ? min(label, label_tile_im[tile_row + 1][tile_col - 0]) : label;
                label = connectivity & RIGHT         ? min(label, label_tile_im[tile_row + 0][tile_col + 1]) : label;
#endif

                new_labels[i][j] = label;
            }
        }
        lds_barrier();

        __local uint changed;
        if((get_local_id(1) == 0) & (get_local_id(0) == 0)){
            changed = 0;
        }
        lds_barrier();

        uint pchanged = 0;
        #pragma unroll
        for(int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for(int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
                const bool valid_pixel_task = (tile_col < tile_cols) & (tile_row < tile_rows);
                const uint old_label = old_labels[i][j];
                if(valid_pixel_task & (new_labels[i][j] < old_label)){
                    pchanged++;
                    atomic_min(&label_tile_im[old_label / tile_cols][old_label % tile_cols], new_labels[i][j]);
                }
            }
        }
        atomic_add(&changed, pchanged);
        lds_barrier();

        //if there are no updates, we are finished
        if(!changed){
            break;
        }

        //Compact paths
        #pragma unroll
        for(int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for(int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
                const bool valid_pixel_task = (tile_col < tile_cols) & (tile_row < tile_rows);
                if(valid_pixel_task){
                    LDSLabelT label = new_labels[i][j];
                    //find root label
                    while(label_tile_im[label / tile_cols][label % tile_cols] < label){
                        label = label_tile_im[label / tile_cols][label % tile_cols];
                    }

                    new_labels[i][j] = label;
                }
            }
        }
        lds_barrier();
    }

    //save with adjusted global (untiled) labels
    #pragma unroll
    for(int i = 0; i < WORKITEM_REPEAT_Y; ++i){
        #pragma unroll
        for(int j = 0; j < WORKITEM_REPEAT_X; ++j){
            const LabelT tile_label = new_labels[i][j];
            //convert the tile label into it's 2-D equivilent
            const uint l_g_r = (tile_label / tile_cols) + tile_row_start;
            const uint l_g_c = (tile_label % tile_cols) + tile_col_start;

            const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
            const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
            const uint g_r = tile_row_start + tile_row;
            const uint g_c = tile_col_start + tile_col;

            //adjust to global offset and convert to scanline order again - this is globally unique
            const LabelT glabel = l_g_r * im_cols + l_g_c;
            const bool valid_pixel_task = (g_c < im_cols) & (g_r < im_rows);
            if(valid_pixel_task){
                assert_val(tile_label < tile_rows * tile_cols, tile_label);
                pixel_at(LabelT, labelim, g_r, g_c) = glabel;
            }
        }
    }
}

inline
LabelT find_root_global(const __global LabelT *labelim_p, uint labelim_pitch, LabelT label, const uint im_rows, const uint im_cols){
    for(;;){
        const uint y = label / im_cols;
        const uint x = label % im_cols;
        assert_val(y < im_rows, y);
        assert_val(x < im_cols, x);
        const LabelT parent = pixel_at(LabelT, labelim, y, x);
        //printf((__constant char *)"parent of %d (%d, %d) is %d (%d, %d)\n", label, y, x, parent, parent / im_cols, parent % im_cols);

        if(label == parent){
            break;
        }

        label = parent;
        //if(k == kmax-1){
        //    printf("kmax was reached in %d, %d\n", get_global_id(0), get_global_id(1));
        //}
    }
    return label;
}

__kernel void compact_paths_global(uint im_rows, uint im_cols, __global LabelT *labelim_p, uint labelim_pitch){
    const uint x = get_global_id(0);
    const uint y = get_global_id(1);

    if((x < im_cols) & (y < im_rows)){
        const LabelT label = pixel_at(LabelT, labelim, y, x);
        pixel_at(LabelT, labelim, y, x) = find_root_global(labelim_p, labelim_pitch, label, im_rows, im_cols);
    }
}

inline
uint merge_edge_labels(const uint im_rows, const uint im_cols, __global LabelT *labelim_p, const uint labelim_pitch, const LabelT l1, const LabelT l2){
    const LabelT r1 = find_root_global(labelim_p, labelim_pitch, l1, im_rows, im_cols);
    const LabelT r2 = find_root_global(labelim_p, labelim_pitch, l2, im_rows, im_cols);

    if(r1 == r2){
        return 0;
    }

    const LabelT mi = min(r1, r2);
    const LabelT ma = max(r1, r2);

    const uint ma_y = ma / im_cols;
    const uint ma_x = ma % im_cols;

    atomic_min(&pixel_at(LabelT, labelim, ma_y, ma_x), mi);
    return 1;
}

//merge along the adjacent pixels in the grid formed on the image with the following tiles
__kernel void merge_tiles(
    const uint im_rows, const uint im_cols,
    const uint n_vert_tiles, const uint n_horz_tiles,
    uint tile_rows, uint tile_cols,
    const __global ConnectivityPixelT *connectivityim_p, const uint connectivityim_pitch,
    __global LabelT *labelim_p, const uint labelim_pitch,
    const uint yIncomplete, uint xIncomplete
){
    const uint ngroups_x = get_num_groups(0);
    const uint ngroups_y = get_num_groups(1);

    const uint tid = get_local_linear_id();
    const uint nwork_elements = get_local_size(1) * get_local_size(0);

    const uint ybegin = get_group_id(1) * (n_vert_tiles * tile_rows);
    uint yend = ybegin + n_vert_tiles * tile_rows;

    if(get_group_id(1) == ngroups_y - 1){
        yend -= yIncomplete * tile_rows;
        yend -= tile_rows;
        tile_rows = (im_rows % tile_rows);

        yend += tile_rows;
    }

    const uint xbegin = get_group_id(0) * n_horz_tiles * tile_cols;
    uint xend = xbegin + n_horz_tiles * tile_cols;

    if(get_group_id(0) == ngroups_x - 1){
        if (xIncomplete) yend = ybegin;
        xend -= xIncomplete * tile_cols;
        xend -= tile_cols;
        tile_cols = (im_cols % tile_cols);

        xend += tile_cols;
    }

    if(get_group_id(1) == (ngroups_y - 1) && yIncomplete){
        xend = xbegin;
    }

    const uint tasksV = (n_horz_tiles - 1) * (yend - ybegin);
    const uint tasksH = (n_vert_tiles - 1) * (xend - xbegin);

    const uint total = tasksH + tasksV;

    uint pchanged;
    do{
        __local uint changed;
        if(tid == 0){
            changed = 0;
        }
        lds_barrier();

        pchanged = 0;
        for(uint taskIdx = tid; taskIdx < total; taskIdx += nwork_elements){
            if(taskIdx < tasksH){
                const uint indexH = taskIdx;

                const uint row = indexH / (xend - xbegin);
                const uint col = indexH % (xend - xbegin);

                const uint y = ybegin + (row + 1) * tile_rows;
                const uint x = xbegin + col;
                const LabelT lc = pixel_at(LabelT, labelim, y, x);

                const ConnectivityPixelT e = pixel_at(ConnectivityPixelT, connectivityim, y, x);
                if(e & UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#if CONNECTIVITY == 8
                if(e & LEFT_UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
                if(e & RIGHT_UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x + 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#endif
            }else{
                const uint indexV = taskIdx - tasksH;

                const uint col = indexV / (yend - ybegin);
                const uint row = indexV % (yend - ybegin);

                const uint x = xbegin + (col + 1) * tile_cols;
                const uint y = ybegin + row;
                const LabelT lc = pixel_at(LabelT, labelim, y, x);

                const ConnectivityPixelT e = pixel_at(ConnectivityPixelT, connectivityim, y, x);
                if(e & LEFT){
                    const LabelT lu = pixel_at(LabelT, labelim, y, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#if CONNECTIVITY == 8
                if(e & LEFT_UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
                if(e & LEFT_DOWN){
                    const LabelT lu = pixel_at(LabelT, labelim, y + 1, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#endif
            }
        }
        atomic_add(&changed, pchanged);
        lds_barrier();
        pchanged = changed;
    }while(pchanged > 0);
}

#if 0
__kernel void mark_root_classes(
    uint im_rows, uint im_cols,
    __global PixelT *image_p, uint image_pitch,
    __global const LabelT* labelim_p, const uint labelim_pitch,
    __global uint* is_root_class_image_p, const uint is_root_class_image_pitch
){
    const uint c = get_global_id(0);
    const uint r = get_global_id(1);
    const bool valid_pixel_task = (c < im_cols) & (r < im_rows);

    const uint linear_index = c + r * im_cols;
    if(valid_pixel_task){
        const PixelT pixel = pixel_at(PixelT, image, r, c);
        const LabelT label = pixel_at(LabelT, labelim, r, c);
        pixel_at(uint, is_root_class_image, r, c) = (pixel != BG_VALUE) & (label == linear_index);
    }
}
#endif

#ifndef USE_CL2_WORKGROUP_FUNCTIONS
MAKE_WORK_GROUP_FUNCTIONS(uint, uint, 0U, UINT_MAX)
#endif

//root class inclusive prefix sums belonging to each compute unit given to each tile - note if narray_workers == 1, no merge step is necessary
//computes local prefix sums to get intra-wg blocksums, prefix sum that to get intra-wg offsets - this is needed to merge the final blocksums
//global dims: <wgs_per_histogram, n_tiles>, work_dims: <wg_size, 1>
//global blocksums[divUp(nblocks, blocks_per_wg)]
#ifdef PROMISE_WG_IS_WAVEFRONT
__attribute__((reqd_work_group_size(DEVICE_WAVEFRONT_SIZE, 1, 1)))
#endif
__kernel void mark_roots_and_make_intra_wg_block_local_prefix_sums(uint im_rows, uint im_cols,
    __global PixelT *image_p, uint image_pitch,
    __global const LabelT* labelim_p, const uint labelim_pitch,
    __global uint * restrict array_intra_wg_block_sums_p,
    __global uint * restrict array_prefix_sum_p, const uint array_prefix_sum_pitch
){
    const uint array_length = im_rows * im_cols;
    const uint array_wg_id = get_group_id(0);
    const uint narray_workers = get_num_groups(0);
    const uint wg_size = get_local_size(0);
    const uint block_size = wg_size;//efficient block size
    const uint nblocks = divUp(array_length, block_size);//number of efficiently processible blocks
    const uint nblocks_per_wg = nblocks / narray_workers;
    //const uint nblocks_to_merge = nblocks / nblocks_per_wg;
    const uint nblocks_remainder = nblocks - (narray_workers * nblocks_per_wg);
    const uint nblocks_to_left = nblocks_per_wg * array_wg_id + (array_wg_id < nblocks_remainder ? array_wg_id : nblocks_remainder);
    const uint n_wg_blocks = nblocks_per_wg + (array_wg_id < nblocks_remainder ? 1 : 0);

    const uint start_bin = nblocks_to_left * block_size;
    const uint end_bin_ = start_bin + n_wg_blocks * block_size;//block aligned end

    uint inter_block_sum = 0;

    for(uint linear_index = get_local_id(0) + start_bin; linear_index < end_bin_; linear_index += wg_size){
        const uint r = linear_index / im_cols;
        const uint c = linear_index % im_cols;

        uint count = 0;
        if(linear_index < array_length){
            const PixelT pixel = pixel_at(PixelT, image, r, c);
            const LabelT label = pixel_at(LabelT, labelim, r, c);
            count = (pixel != BG_VALUE) & (label == linear_index) ? 1 : 0;
        }

#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        uint block_prefix_sum_inclusive = work_group_scan_inclusive_add(count);
#else
        __local uint lmem[WORK_GROUP_FUNCTION_MAX_MEMORY_SIZE];
        uint block_prefix_sum_inclusive = clc_work_group_scan_inclusive_add_uint(count, lmem);
#endif

        block_prefix_sum_inclusive += inter_block_sum;
        if(linear_index < array_length){
            pixel_at(uint, array_prefix_sum, r, c) = block_prefix_sum_inclusive;
        }
#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        inter_block_sum = work_group_broadcast(block_prefix_sum_inclusive, wg_size - 1);
#else
        __local uint value;
        inter_block_sum = clc_work_group_broadcast1_uint(block_prefix_sum_inclusive, wg_size - 1, &value);
#endif
    }
    if((array_intra_wg_block_sums_p != 0) & (get_local_id(0) == wg_size - 1)){
        array_intra_wg_block_sums_p[array_wg_id] = inter_block_sum;
    }
}

//exclusive prefix sums intra-wg blocksums to get intra-wg offsets - needed to merge together all the wg-local prefix sums
//global dims: <1, n_tiles>, work_dims: <wg_size, 1>
//global tile_intra_wg_block_sums[n_tiles][nblocks_to_merge]
#ifdef PROMISE_WG_IS_WAVEFRONT
__attribute__((reqd_work_group_size(DEVICE_WAVEFRONT_SIZE, 1, 1)))
#endif
__kernel void make_intra_wg_block_global_sums(
    __global uint * restrict intra_wg_block_sums_p, uint nblocks_to_merge
){
    const uint wg_size = get_local_size(0);

    __local uint intra_wg_block_sums[WG_SIZE_MAX + 1];
    if(get_local_id(0) == 0){
        intra_wg_block_sums[0] = 0;
    }
    lds_barrier();
    uint intra_wg_block_offset = 0;

    for(uint intra_wg_block_id = get_local_id(0); intra_wg_block_id < divUp(nblocks_to_merge, wg_size) * wg_size; intra_wg_block_id += wg_size){
        //get the unsumed blocksums
        const uint intra_wg_block_sum = intra_wg_block_id < nblocks_to_merge ? intra_wg_block_sums_p[intra_wg_block_id] : 0;
        intra_wg_block_sums[get_local_id(0) + 1] = intra_wg_block_sum;
        lds_barrier();

        const uint intra_wg_block_sum_delayed = intra_wg_block_sums[get_local_id(0)];
#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        intra_wg_block_offset += work_group_scan_inclusive_add(intra_wg_block_sum_delayed);
#else
        __local uint lmem[WORK_GROUP_FUNCTION_MAX_MEMORY_SIZE];
        intra_wg_block_offset += clc_work_group_scan_inclusive_add_uint(intra_wg_block_sum_delayed, lmem);
#endif
        if(intra_wg_block_id < nblocks_to_merge){
            intra_wg_block_sums_p[intra_wg_block_id] = intra_wg_block_offset;
        }
#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        intra_wg_block_offset = work_group_broadcast(intra_wg_block_offset, wg_size - 1);
#else
        __local uint value;
        intra_wg_block_offset = clc_work_group_broadcast1_uint(intra_wg_block_offset, wg_size - 1, &value);
#endif

        if(get_local_id(0) == 0){
            intra_wg_block_sums[0] = intra_wg_block_sums[wg_size];
        }
        lds_barrier();
    }
}

//merges global offsets of intra-wg-block offsets of prefix sums
//global dims: <wgs_per_sum>, work_dims: <wg_size> : wg_size >= nblocks_to_merge
//global array_of_prefix_sums[im_rows*im_cols] : as input partial sums, as output full prefix sum
#ifdef PROMISE_WG_IS_WAVEFRONT
__attribute__((reqd_work_group_size(DEVICE_WAVEFRONT_SIZE, 1, 1)))
#endif
__kernel void make_prefix_sums_with_intra_wg_block_global_sums(
    const uint im_rows, const uint im_cols,
    __global const uint * restrict intra_wg_block_sums_p,
    __global uint * restrict array_of_prefix_sums_p, uint array_of_prefix_sums_pitch,
    __global LabelT* label_count_p
){
    const uint array_length = im_rows * im_cols;
    const uint n_arrays = get_num_groups(1);
    const uint array_id = get_group_id(1);
    const uint array_wg_id = get_group_id(0);
    const uint narray_workers = get_num_groups(0);
    const uint wg_size = get_local_size(0);
    const uint block_size = wg_size;//efficient block size
    const uint nblocks = divUp(array_length, block_size);//number of efficiently processible blocks
    const uint nblocks_per_wg = nblocks / narray_workers;
    const uint nblocks_to_merge = nblocks / nblocks_per_wg;
    const uint nblocks_remainder = nblocks - (narray_workers * nblocks_per_wg);
    const uint nblocks_to_left = nblocks_per_wg * array_wg_id + (array_wg_id < nblocks_remainder ? array_wg_id : nblocks_remainder);
    const uint n_wg_blocks = nblocks_per_wg + (array_wg_id < nblocks_remainder ? 1 : 0);

    const uint start_index = nblocks_to_left * block_size;
    const uint end_index_ = start_index + n_wg_blocks * block_size;//block aligned end

    const uint inter_block_sum = intra_wg_block_sums_p[array_wg_id];
            //note we could save a honest chunk of time by putting the relabeling here
    for(uint linear_index = get_local_id(0) + start_index; linear_index < end_index_; linear_index += wg_size){
        if(linear_index < array_length){
            const uint r = linear_index / im_cols;
            const uint c = linear_index % im_cols;
            const uint count = image_pixel_at(uint, array_of_prefix_sums_p, im_rows, im_cols, array_of_prefix_sums_pitch, r, c) + inter_block_sum;
            if(linear_index == array_length - 1){
                *label_count_p = count + 2;//include BG and count shift
            }
            image_pixel_at(uint, array_of_prefix_sums_p, im_rows, im_cols, array_of_prefix_sums_pitch, r, c) = count;
        }
    }
}

__kernel void relabel_with_scanline_order(
    uint im_rows, uint im_cols,
    __global LabelT* labelim_out_p, const uint labelim_out_pitch,
    __global const PixelT* image_p, const uint image_pitch,
    __global const LabelT* labelim_p, const uint labelim_pitch,
    __global uint* scanline_prefix_sum_of_root_classes_p, const uint scanline_prefix_sum_of_root_classes_pitch
){
    const uint c = get_global_id(0);
    const uint r = get_global_id(1);
    const bool valid_pixel_task = (c < im_cols) & (r < im_rows);

    if(valid_pixel_task){
        const PixelT pixel = pixel_at(PixelT, image, r, c);
        LabelT final_label = 0;
        if(pixel != BG_VALUE){
            const LabelT label = pixel_at(LabelT, labelim, r, c);
            const uint label_r = label / im_cols;
            const uint label_c = label % im_cols;
            const uint scan_id = pixel_at(uint, scanline_prefix_sum_of_root_classes, label_r, label_c);
            final_label = scan_id + 1;
        }
        pixel_at(LabelT, labelim_out, r, c) = final_label;
    }
}

#define PREFER_MCL_WORKGROUP_FUNCTIONS
#if __OPENCL_VERSION__ >= 200 && !defined(PREFER_MCL_WORKGROUP_FUNCTIONS)
#define USE_CL2_WORKGROUP_FUNCTIONS
#endif

#include "clcommons/common.h"
#include "clcommons/image.h"
#include "clcommons/work_group.h"

#ifndef PIXELT
#define PIXELT uint
#endif
#ifndef LABELT
#define LABELT uint
#endif
#ifndef CONNECTIVITYPIXELT
#define CONNECTIVITYPIXELT uint
#endif
#ifndef LDSPIXELT
#define LDSPIXELT uint
#endif
#ifndef LDSLABELT
#define LDSLABELT uint
#endif
#ifndef LDSCONNECTIVITYPIXELT
#define LDSCONNECTIVITYPIXELT uint
#endif

typedef PIXELT PixelT;
typedef LDSPIXELT LDSPixelT;
typedef LABELT LabelT;
typedef LDSLABELT LDSLabelT;
typedef CONNECTIVITYPIXELT ConnectivityPixelT;
typedef LDSCONNECTIVITYPIXELT LDSConnectivityPixelT;

#ifndef BG_VALUE
#define BG_VALUE 0
#endif

#ifndef CONNECTIVITY  //4 or 8
#define CONNECTIVITY 8
#endif

#ifndef WORKGROUP_TILE_SIZE_X
#define WORKGROUP_TILE_SIZE_X 32
#endif
#ifndef WORKGROUP_TILE_SIZE_Y
#define WORKGROUP_TILE_SIZE_Y 2
#endif

#ifndef WORKITEM_REPEAT_X
#define WORKITEM_REPEAT_X 1
#endif
#ifndef WORKITEM_REPEAT_Y
#define WORKITEM_REPEAT_Y 16
#endif

#define TILE_COLS (WORKGROUP_TILE_SIZE_X * WORKITEM_REPEAT_X)
#define TILE_ROWS (WORKGROUP_TILE_SIZE_Y * WORKITEM_REPEAT_Y)

__constant const uint UP = (1<<0);
__constant const uint LEFT = (1<<1);
__constant const uint DOWN = (1<<2);
__constant const uint RIGHT = (1<<3);
__constant const uint LEFT_UP = (1<<4);
__constant const uint LEFT_DOWN = (1<<5);
__constant const uint RIGHT_UP = (1<<6);
__constant const uint RIGHT_DOWN = (1<<7);

#define isConnected(p1, p2) ((p1) == (p2))

#define pixel_at(type, basename, r, c) image_pixel_at(type, PASTE2(basename, _p), im_rows, im_cols, PASTE2(basename, _pitch), (r), (c))

//global dimensions: divUp(image.cols, block.x), divUp(image.rows, block.y);
//__attribute__((reqd_work_group_size(WORKGROUP_TILE_SIZE_X, WORKGROUP_TILE_SIZE_Y, 1)))
//__kernel void
//make_connectivity_image(uint im_rows, uint im_cols, __global PixelT *image_p, uint image_pitch, __global ConnectivityPixelT *connectivityim_p, uint connectivityim_pitch){
//    const uint c = get_global_id(1);
//    const uint r = get_global_id(0);
//    const bool valid_pixel_task = (c < im_cols) & (r < im_rows);
//
//    if(valid_pixel_task){
//        PixelT pixel = pixel_at(PixelT, image, r, c);
//        ConnectivityPixelT connectivity = 0;
//
//#if CONNECTIVITY == 8
//        connectivity |= c > 0 && r > 0                     && isConnected(pixel, pixel_at(PixelT, image, r-1, c - 1)) ? LEFT_UP : 0
//        connectivity |= c > 0                              && isConnected(pixel, pixel_at(PixelT, image, r, c - 1)) ? LEFT : 0
//        connectivity |= c > 0 && r < im_rows - 1           && isConnected(pixel, pixel_at(PixelT, image, r+1, c - 1)) ? LEFT_DOWN : 0
//        connectivity |=          r < im_rows - 1           && isConnected(pixel, pixel_at(PixelT, image, r+1, c)) ? DOWN : 0
//        connectivity |= c < im_cols - 1 && r < im_rows - 1 && isConnected(pixel, pixel_at(PixelT, image, r+1, c + 1)) ? RIGHT_DOWN : 0
//        connectivity |= c < im_cols - 1                    && isConnected(pixel, pixel_at(PixelT, image, r, c + 1)) ? RIGHT : 0
//        connectivity |= c < im_cols - 1 && r > 0           && isConnected(pixel, pixel_at(PixelT, image, r-1, c + 1)) ? RIGHT_UP : 0
//        connectivity |=          r > 0                     && isConnected(pixel, pixel_at(PixelT, image, r-1, c)) ? UP : 0
//#else
//        connectivity |= c > 0                              && isConnected(pixel, pixel_at(PixelT, image, r, c - 1)) ? LEFT : 0
//        connectivity |=          r < im_rows - 1           && isConnected(pixel, pixel_at(PixelT, image, r+1, c)) ? DOWN : 0
//        connectivity |= c < im_cols - 1                    && isConnected(pixel, pixel_at(PixelT, image, r, c + 1)) ? RIGHT : 0
//        connectivity |=          r > 0                     && isConnected(pixel, pixel_at(PixelT, image, r-1, c)) ? UP : 0
//#endif
//
//        pixel_at(ConnectivityPixelT, connectivity, r, c) = connectivity;
//    }
//}

#define apron_pixel(apron, t_r, t_c) apron[(t_r+ 1)][(t_c + 1)]
//global dimensions: divUp(im_cols, tile_cols), divUp(im_rows, tile_rows);
__attribute__((reqd_work_group_size(WORKGROUP_TILE_SIZE_X, WORKGROUP_TILE_SIZE_Y, 1)))
__kernel void make_connectivity_image(
    uint im_rows, uint im_cols, __global const PixelT *image_p, uint image_pitch, __global ConnectivityPixelT *connectivityim_p, uint connectivityim_pitch
){
    const uint tile_col_blocksize = TILE_COLS;
    const uint tile_row_blocksize = TILE_ROWS;
    const uint tile_col_block = get_group_id(0) + get_global_offset(0) / get_local_size(0);
    const uint tile_row_block = get_group_id(1) + get_global_offset(1) / get_local_size(1);
    const uint tile_col = get_local_id(0);
    const uint tile_row = get_local_id(1);

    uint tile_rows = tile_row_blocksize;
    uint tile_cols = tile_col_blocksize;

    const uint tile_row_start = tile_row_block * tile_rows;
    const uint tile_col_start = tile_col_block * tile_cols;
    const uint tile_row_end = min(tile_row_start + tile_rows, (uint) im_rows);
    const uint tile_col_end = min(tile_col_start + tile_cols, (uint) im_cols);
    //adjust to true tile dimensions
    tile_rows = tile_row_end - tile_row_start;
    tile_cols = tile_col_end - tile_col_start;
    const uint apron_tile_cols = tile_cols + 2;;
    const uint n_tile_pixels = tile_rows * tile_cols;
    const uint n_work_items = get_local_size(0) * get_local_size(1);
    const uint n_apron_tile_pixels = (tile_rows + 2) * (apron_tile_cols);
    __local LDSPixelT im_tile[TILE_ROWS + 2][TILE_COLS + 2];
    __local LDSConnectivityPixelT connectivity_tile[TILE_ROWS][TILE_COLS];

    const uint tid = get_local_linear_id();
    for(uint im_tile_fill_task_id = tid; im_tile_fill_task_id < n_apron_tile_pixels; im_tile_fill_task_id += n_work_items){
        const uint im_apron_tile_row = im_tile_fill_task_id / apron_tile_cols;
        const uint im_apron_tile_col = im_tile_fill_task_id % apron_tile_cols;
        const int g_c = ((int)(im_apron_tile_col + tile_col_start)) - 1;
        const int g_r = ((int)(im_apron_tile_row + tile_row_start)) - 1;

        im_tile[im_apron_tile_row][im_apron_tile_col] = image_tex2D(PixelT, image_p, (int) im_rows, (int) im_cols, image_pitch, g_r, g_c, ADDRESS_ZERO);
    }
    lds_barrier();

    #pragma unroll
    for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
        #pragma unroll
        for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
            const uint c = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
            const uint r = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
            PixelT pixel = apron_pixel(im_tile, r, c);
            ConnectivityPixelT connectivity = 0;

#if CONNECTIVITY == 8
            connectivity |= c > 0 && r > 0                         && isConnected(pixel, apron_pixel(im_tile, r-1, c - 1)) ? LEFT_UP : 0;
            connectivity |= c > 0                                  && isConnected(pixel, apron_pixel(im_tile, r  , c - 1)) ? LEFT : 0;
            connectivity |= c > 0 && r < tile_rows - 1             && isConnected(pixel, apron_pixel(im_tile, r+1, c - 1)) ? LEFT_DOWN : 0;
            connectivity |=          r < tile_rows - 1             && isConnected(pixel, apron_pixel(im_tile, r+1, c    )) ? DOWN : 0;
            connectivity |= c < tile_cols - 1 && r < tile_rows - 1 && isConnected(pixel, apron_pixel(im_tile, r+1, c + 1)) ? RIGHT_DOWN : 0;
            connectivity |= c < tile_cols - 1                      && isConnected(pixel, apron_pixel(im_tile, r  , c + 1)) ? RIGHT : 0;
            connectivity |= c < tile_cols - 1 && r > 0             && isConnected(pixel, apron_pixel(im_tile, r-1, c + 1)) ? RIGHT_UP : 0;
            connectivity |=          r > 0                         && isConnected(pixel, apron_pixel(im_tile, r-1, c    )) ? UP : 0;
#else
            connectivity |= c > 0                                  && isConnected(pixel, apron_pixel(im_tile, r  , c - 1)) ? LEFT : 0;
            connectivity |=          r < tile_rows - 1             && isConnected(pixel, apron_pixel(im_tile, r+1, c    )) ? DOWN : 0;
            connectivity |= c < tile_cols - 1                      && isConnected(pixel, apron_pixel(im_tile, r  , c + 1)) ? RIGHT : 0;
            connectivity |=          r > 0                         && isConnected(pixel, apron_pixel(im_tile, r-1, c    )) ? UP : 0;
#endif
            connectivity = (c < tile_cols) & (r < tile_rows) ? connectivity : 0;
            connectivity_tile[r][c] = connectivity;
        }
    }
    lds_barrier();

    for(uint im_tile_fill_task_id = tid; im_tile_fill_task_id < n_tile_pixels; im_tile_fill_task_id += n_work_items){
        const uint im_tile_row = im_tile_fill_task_id / tile_cols;
        const uint im_tile_col = im_tile_fill_task_id % tile_cols;
        const uint g_c = im_tile_col + tile_col_start;
        const uint g_r = im_tile_row + tile_row_start;

        pixel_at(ConnectivityPixelT, connectivityim, g_r, g_c) = connectivity_tile[im_tile_row][im_tile_col];
    }
}

__attribute__((reqd_work_group_size(WORKGROUP_TILE_SIZE_X, WORKGROUP_TILE_SIZE_Y, 1)))
__kernel void label_tiles(
    uint im_rows, uint im_cols, __global LabelT *labelim_p, uint labelim_pitch, __global const ConnectivityPixelT *connectivityim_p, uint connectivityim_pitch
){
    const uint tile_col_blocksize = TILE_COLS;
    const uint tile_row_blocksize = TILE_ROWS;
    const uint tile_col_block = get_group_id(0) + get_global_offset(0) / get_local_size(0);
    const uint tile_row_block = get_group_id(1) + get_global_offset(1) / get_local_size(1);

    uint tile_rows = tile_row_blocksize;
    uint tile_cols = tile_col_blocksize;

    const uint tile_row_start = tile_row_block * tile_rows;
    const uint tile_col_start = tile_col_block * tile_cols;
    const uint tile_row_end = min(tile_row_start + tile_rows, (uint) im_rows);
    const uint tile_col_end = min(tile_col_start + tile_cols, (uint) im_cols);
    //adjust to true tile dimensions
    tile_rows = tile_row_end - tile_row_start;
    tile_cols = tile_col_end - tile_col_start;

    //if (x >= im_rows || y >= im_rows) return;

    __local LDSLabelT label_tile_im[TILE_ROWS][TILE_COLS];
    __local LDSConnectivityPixelT  edge_tile_im[TILE_ROWS][TILE_COLS];

    LDSLabelT new_labels[WORKITEM_REPEAT_Y][WORKITEM_REPEAT_X];
    LDSLabelT old_labels[WORKITEM_REPEAT_Y][WORKITEM_REPEAT_X];

    #pragma unroll
    for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
        #pragma unroll
        for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
            const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
            const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
            const bool valid_pixel_task = (tile_col < tile_cols) & (tile_row < tile_rows);
            ConnectivityPixelT c = valid_pixel_task ? pixel_at(ConnectivityPixelT, connectivityim, tile_row_start + tile_row, tile_col_start + tile_col) : 0;

            c = tile_col == 0 ? c & ~(LEFT|LEFT_DOWN|LEFT_UP) : c;
            c = tile_row == 0 ? c & ~(UP|LEFT_UP|RIGHT_UP) : c;

            c = tile_col >= tile_cols - 1 ? c & ~(RIGHT|RIGHT_DOWN|RIGHT_UP) : c;
            c = tile_row >= tile_rows - 1 ? c & ~(DOWN|LEFT_DOWN|RIGHT_DOWN) : c;

            new_labels[i][j] = valid_pixel_task ? tile_row * tile_cols + tile_col : ((LDSLabelT) -1);
            edge_tile_im[tile_row][tile_col] = c;
        }
    }

    for (uint k = 0; ;++k){
        //make copies
        #pragma unroll
        for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
                old_labels[i][j] = new_labels[i][j];
                label_tile_im[tile_row][tile_col] = new_labels[i][j];
            }
        }
        lds_barrier();

        //take minimum label of local neighboorhood - single writer, multi reader version
        #pragma unroll
        for (int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for (int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;

                const ConnectivityPixelT connectivity = edge_tile_im[tile_row][tile_col];
                LDSLabelT label = new_labels[i][j];

#if CONNECTIVITY == 8
                label = connectivity & UP            ? min(label, label_tile_im[tile_row - 1][tile_col - 0]) : label;
                label = connectivity & LEFT_UP       ? min(label, label_tile_im[tile_row - 1][tile_col - 1]) : label;
                label = connectivity & LEFT          ? min(label, label_tile_im[tile_row - 0][tile_col - 1]) : label;
                label = connectivity & LEFT_DOWN     ? min(label, label_tile_im[tile_row + 1][tile_col - 1]) : label;
                label = connectivity & DOWN          ? min(label, label_tile_im[tile_row + 1][tile_col - 0]) : label;
                label = connectivity & RIGHT_DOWN    ? min(label, label_tile_im[tile_row + 1][tile_col + 1]) : label;
                label = connectivity & RIGHT         ? min(label, label_tile_im[tile_row + 0][tile_col + 1]) : label;
                label = connectivity & RIGHT_UP      ? min(label, label_tile_im[tile_row - 1][tile_col + 1]) : label;
#else
                label = connectivity & UP            ? min(label, label_tile_im[tile_row - 1][tile_col - 0]) : label;
                label = connectivity & LEFT          ? min(label, label_tile_im[tile_row - 0][tile_col - 1]) : label;
                label = connectivity & DOWN          ? min(label, label_tile_im[tile_row + 1][tile_col - 0]) : label;
                label = connectivity & RIGHT         ? min(label, label_tile_im[tile_row + 0][tile_col + 1]) : label;
#endif

                new_labels[i][j] = label;
            }
        }
        lds_barrier();

        __local uint changed;
        if((get_local_id(1) == 0) & (get_local_id(0) == 0)){
            changed = 0;
        }
        lds_barrier();

        uint pchanged = 0;
        #pragma unroll
        for(int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for(int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
                const bool valid_pixel_task = (tile_col < tile_cols) & (tile_row < tile_rows);
                const uint old_label = old_labels[i][j];
                if(valid_pixel_task & (new_labels[i][j] < old_label)){
                    pchanged++;
                    atomic_min(&label_tile_im[old_label / tile_cols][old_label % tile_cols], new_labels[i][j]);
                }
            }
        }
        atomic_add(&changed, pchanged);
        lds_barrier();

        //if there are no updates, we are finished
        if(!changed){
            break;
        }

        //Compact paths
        #pragma unroll
        for(int i = 0; i < WORKITEM_REPEAT_Y; ++i){
            #pragma unroll
            for(int j = 0; j < WORKITEM_REPEAT_X; ++j){
                const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
                const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
                const bool valid_pixel_task = (tile_col < tile_cols) & (tile_row < tile_rows);
                if(valid_pixel_task){
                    LDSLabelT label = new_labels[i][j];
                    //find root label
                    while(label_tile_im[label / tile_cols][label % tile_cols] < label){
                        label = label_tile_im[label / tile_cols][label % tile_cols];
                    }

                    new_labels[i][j] = label;
                }
            }
        }
        lds_barrier();
    }

    //save with adjusted global (untiled) labels
    #pragma unroll
    for(int i = 0; i < WORKITEM_REPEAT_Y; ++i){
        #pragma unroll
        for(int j = 0; j < WORKITEM_REPEAT_X; ++j){
            const LabelT tile_label = new_labels[i][j];
            //convert the tile label into it's 2-D equivilent
            const uint l_g_r = (tile_label / tile_cols) + tile_row_start;
            const uint l_g_c = (tile_label % tile_cols) + tile_col_start;

            const uint tile_row = get_local_id(1) + WORKGROUP_TILE_SIZE_Y * i;
            const uint tile_col = get_local_id(0) + WORKGROUP_TILE_SIZE_X * j;
            const uint g_r = tile_row_start + tile_row;
            const uint g_c = tile_col_start + tile_col;

            //adjust to global offset and convert to scanline order again - this is globally unique
            const LabelT glabel = l_g_r * im_cols + l_g_c;
            const bool valid_pixel_task = (g_c < im_cols) & (g_r < im_rows);
            if(valid_pixel_task){
                assert_val(tile_label < tile_rows * tile_cols, tile_label);
                pixel_at(LabelT, labelim, g_r, g_c) = glabel;
            }
        }
    }
}

inline
LabelT find_root_global(const __global LabelT *labelim_p, uint labelim_pitch, LabelT label, const uint im_rows, const uint im_cols){
    for(;;){
        const uint y = label / im_cols;
        const uint x = label % im_cols;
        assert_val(y < im_rows, y);
        assert_val(x < im_cols, x);
        const LabelT parent = pixel_at(LabelT, labelim, y, x);
        //printf((__constant char *)"parent of %d (%d, %d) is %d (%d, %d)\n", label, y, x, parent, parent / im_cols, parent % im_cols);

        if(label == parent){
            break;
        }

        label = parent;
        //if(k == kmax-1){
        //    printf("kmax was reached in %d, %d\n", get_global_id(0), get_global_id(1));
        //}
    }
    return label;
}

__kernel void compact_paths_global(uint im_rows, uint im_cols, __global LabelT *labelim_p, uint labelim_pitch){
    const uint x = get_global_id(0);
    const uint y = get_global_id(1);

    if((x < im_cols) & (y < im_rows)){
        const LabelT label = pixel_at(LabelT, labelim, y, x);
        pixel_at(LabelT, labelim, y, x) = find_root_global(labelim_p, labelim_pitch, label, im_rows, im_cols);
    }
}

inline
uint merge_edge_labels(const uint im_rows, const uint im_cols, __global LabelT *labelim_p, const uint labelim_pitch, const LabelT l1, const LabelT l2){
    const LabelT r1 = find_root_global(labelim_p, labelim_pitch, l1, im_rows, im_cols);
    const LabelT r2 = find_root_global(labelim_p, labelim_pitch, l2, im_rows, im_cols);

    if(r1 == r2){
        return 0;
    }

    const LabelT mi = min(r1, r2);
    const LabelT ma = max(r1, r2);

    const uint ma_y = ma / im_cols;
    const uint ma_x = ma % im_cols;

    atomic_min(&pixel_at(LabelT, labelim, ma_y, ma_x), mi);
    return 1;
}

//merge along the adjacent pixels in the grid formed on the image with the following tiles
__kernel void merge_tiles(
    const uint im_rows, const uint im_cols,
    const uint n_vert_tiles, const uint n_horz_tiles,
    uint tile_rows, uint tile_cols,
    const __global ConnectivityPixelT *connectivityim_p, const uint connectivityim_pitch,
    __global LabelT *labelim_p, const uint labelim_pitch,
    const uint yIncomplete, uint xIncomplete
){
    const uint ngroups_x = get_num_groups(0);
    const uint ngroups_y = get_num_groups(1);

    const uint tid = get_local_linear_id();
    const uint nwork_elements = get_local_size(1) * get_local_size(0);

    const uint ybegin = get_group_id(1) * (n_vert_tiles * tile_rows);
    uint yend = ybegin + n_vert_tiles * tile_rows;

    if(get_group_id(1) == ngroups_y - 1){
        yend -= yIncomplete * tile_rows;
        yend -= tile_rows;
        tile_rows = (im_rows % tile_rows);

        yend += tile_rows;
    }

    const uint xbegin = get_group_id(0) * n_horz_tiles * tile_cols;
    uint xend = xbegin + n_horz_tiles * tile_cols;

    if(get_group_id(0) == ngroups_x - 1){
        if (xIncomplete) yend = ybegin;
        xend -= xIncomplete * tile_cols;
        xend -= tile_cols;
        tile_cols = (im_cols % tile_cols);

        xend += tile_cols;
    }

    if(get_group_id(1) == (ngroups_y - 1) && yIncomplete){
        xend = xbegin;
    }

    const uint tasksV = (n_horz_tiles - 1) * (yend - ybegin);
    const uint tasksH = (n_vert_tiles - 1) * (xend - xbegin);

    const uint total = tasksH + tasksV;

    uint pchanged;
    do{
        __local uint changed;
        if(tid == 0){
            changed = 0;
        }
        lds_barrier();

        pchanged = 0;
        for(uint taskIdx = tid; taskIdx < total; taskIdx += nwork_elements){
            if(taskIdx < tasksH){
                const uint indexH = taskIdx;

                const uint row = indexH / (xend - xbegin);
                const uint col = indexH % (xend - xbegin);

                const uint y = ybegin + (row + 1) * tile_rows;
                const uint x = xbegin + col;
                const LabelT lc = pixel_at(LabelT, labelim, y, x);

                const ConnectivityPixelT e = pixel_at(ConnectivityPixelT, connectivityim, y, x);
                if(e & UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#if CONNECTIVITY == 8
                if(e & LEFT_UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
                if(e & RIGHT_UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x + 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#endif
            }else{
                const uint indexV = taskIdx - tasksH;

                const uint col = indexV / (yend - ybegin);
                const uint row = indexV % (yend - ybegin);

                const uint x = xbegin + (col + 1) * tile_cols;
                const uint y = ybegin + row;
                const LabelT lc = pixel_at(LabelT, labelim, y, x);

                const ConnectivityPixelT e = pixel_at(ConnectivityPixelT, connectivityim, y, x);
                if(e & LEFT){
                    const LabelT lu = pixel_at(LabelT, labelim, y, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#if CONNECTIVITY == 8
                if(e & LEFT_UP){
                    const LabelT lu = pixel_at(LabelT, labelim, y - 1, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
                if(e & LEFT_DOWN){
                    const LabelT lu = pixel_at(LabelT, labelim, y + 1, x - 1);
                    pchanged += merge_edge_labels(im_rows, im_cols, labelim_p, labelim_pitch, lc, lu);
                }
#endif
            }
        }
        atomic_add(&changed, pchanged);
        lds_barrier();
        pchanged = changed;
    }while(pchanged > 0);
}

#if 0
__kernel void mark_root_classes(
    uint im_rows, uint im_cols,
    __global PixelT *image_p, uint image_pitch,
    __global const LabelT* labelim_p, const uint labelim_pitch,
    __global uint* is_root_class_image_p, const uint is_root_class_image_pitch
){
    const uint c = get_global_id(0);
    const uint r = get_global_id(1);
    const bool valid_pixel_task = (c < im_cols) & (r < im_rows);

    const uint linear_index = c + r * im_cols;
    if(valid_pixel_task){
        const PixelT pixel = pixel_at(PixelT, image, r, c);
        const LabelT label = pixel_at(LabelT, labelim, r, c);
        pixel_at(uint, is_root_class_image, r, c) = (pixel != BG_VALUE) & (label == linear_index);
    }
}
#endif

#ifndef USE_CL2_WORKGROUP_FUNCTIONS
MAKE_WORK_GROUP_FUNCTIONS(uint, uint, 0U, UINT_MAX)
#endif

//root class inclusive prefix sums belonging to each compute unit given to each tile - note if narray_workers == 1, no merge step is necessary
//computes local prefix sums to get intra-wg blocksums, prefix sum that to get intra-wg offsets - this is needed to merge the final blocksums
//global dims: <wgs_per_histogram, n_tiles>, work_dims: <wg_size, 1>
//global blocksums[divUp(nblocks, blocks_per_wg)]
#ifdef PROMISE_WG_IS_WAVEFRONT
__attribute__((reqd_work_group_size(DEVICE_WAVEFRONT_SIZE, 1, 1)))
#endif
__kernel void mark_roots_and_make_intra_wg_block_local_prefix_sums(uint im_rows, uint im_cols,
    __global PixelT *image_p, uint image_pitch,
    __global const LabelT* labelim_p, const uint labelim_pitch,
    __global uint * restrict array_intra_wg_block_sums_p,
    __global uint * restrict array_prefix_sum_p, const uint array_prefix_sum_pitch
){
    const uint array_length = im_rows * im_cols;
    const uint array_wg_id = get_group_id(0);
    const uint narray_workers = get_num_groups(0);
    const uint wg_size = get_local_size(0);
    const uint block_size = wg_size;//efficient block size
    const uint nblocks = divUp(array_length, block_size);//number of efficiently processible blocks
    const uint nblocks_per_wg = nblocks / narray_workers;
    //const uint nblocks_to_merge = nblocks / nblocks_per_wg;
    const uint nblocks_remainder = nblocks - (narray_workers * nblocks_per_wg);
    const uint nblocks_to_left = nblocks_per_wg * array_wg_id + (array_wg_id < nblocks_remainder ? array_wg_id : nblocks_remainder);
    const uint n_wg_blocks = nblocks_per_wg + (array_wg_id < nblocks_remainder ? 1 : 0);

    const uint start_bin = nblocks_to_left * block_size;
    const uint end_bin_ = start_bin + n_wg_blocks * block_size;//block aligned end

    uint inter_block_sum = 0;

    for(uint linear_index = get_local_id(0) + start_bin; linear_index < end_bin_; linear_index += wg_size){
        const uint r = linear_index / im_cols;
        const uint c = linear_index % im_cols;

        uint count = 0;
        if(linear_index < array_length){
            const PixelT pixel = pixel_at(PixelT, image, r, c);
            const LabelT label = pixel_at(LabelT, labelim, r, c);
            count = (pixel != BG_VALUE) & (label == linear_index) ? 1 : 0;
        }

#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        uint block_prefix_sum_inclusive = work_group_scan_inclusive_add(count);
#else
        __local uint lmem[WORK_GROUP_FUNCTION_MAX_MEMORY_SIZE];
        uint block_prefix_sum_inclusive = clc_work_group_scan_inclusive_add_uint(count, lmem);
#endif

        block_prefix_sum_inclusive += inter_block_sum;
        if(linear_index < array_length){
            pixel_at(uint, array_prefix_sum, r, c) = block_prefix_sum_inclusive;
        }
#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        inter_block_sum = work_group_broadcast(block_prefix_sum_inclusive, wg_size - 1);
#else
        __local uint value;
        inter_block_sum = clc_work_group_broadcast1_uint(block_prefix_sum_inclusive, wg_size - 1, &value);
#endif
    }
    if((array_intra_wg_block_sums_p != 0) & (get_local_id(0) == wg_size - 1)){
        array_intra_wg_block_sums_p[array_wg_id] = inter_block_sum;
    }
}

//exclusive prefix sums intra-wg blocksums to get intra-wg offsets - needed to merge together all the wg-local prefix sums
//global dims: <1, n_tiles>, work_dims: <wg_size, 1>
//global tile_intra_wg_block_sums[n_tiles][nblocks_to_merge]
#ifdef PROMISE_WG_IS_WAVEFRONT
__attribute__((reqd_work_group_size(DEVICE_WAVEFRONT_SIZE, 1, 1)))
#endif
__kernel void make_intra_wg_block_global_sums(
    __global uint * restrict intra_wg_block_sums_p, uint nblocks_to_merge
){
    const uint wg_size = get_local_size(0);

    __local uint intra_wg_block_sums[WG_SIZE_MAX + 1];
    if(get_local_id(0) == 0){
        intra_wg_block_sums[0] = 0;
    }
    lds_barrier();
    uint intra_wg_block_offset = 0;

    for(uint intra_wg_block_id = get_local_id(0); intra_wg_block_id < divUp(nblocks_to_merge, wg_size) * wg_size; intra_wg_block_id += wg_size){
        //get the unsumed blocksums
        const uint intra_wg_block_sum = intra_wg_block_id < nblocks_to_merge ? intra_wg_block_sums_p[intra_wg_block_id] : 0;
        intra_wg_block_sums[get_local_id(0) + 1] = intra_wg_block_sum;
        lds_barrier();

        const uint intra_wg_block_sum_delayed = intra_wg_block_sums[get_local_id(0)];
#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        intra_wg_block_offset += work_group_scan_inclusive_add(intra_wg_block_sum_delayed);
#else
        __local uint lmem[WORK_GROUP_FUNCTION_MAX_MEMORY_SIZE];
        intra_wg_block_offset += clc_work_group_scan_inclusive_add_uint(intra_wg_block_sum_delayed, lmem);
#endif
        if(intra_wg_block_id < nblocks_to_merge){
            intra_wg_block_sums_p[intra_wg_block_id] = intra_wg_block_offset;
        }
#ifdef USE_CL2_WORKGROUP_FUNCTIONS
        intra_wg_block_offset = work_group_broadcast(intra_wg_block_offset, wg_size - 1);
#else
        __local uint value;
        intra_wg_block_offset = clc_work_group_broadcast1_uint(intra_wg_block_offset, wg_size - 1, &value);
#endif

        if(get_local_id(0) == 0){
            intra_wg_block_sums[0] = intra_wg_block_sums[wg_size];
        }
        lds_barrier();
    }
}

//merges global offsets of intra-wg-block offsets of prefix sums
//global dims: <wgs_per_sum>, work_dims: <wg_size> : wg_size >= nblocks_to_merge
//global array_of_prefix_sums[im_rows*im_cols] : as input partial sums, as output full prefix sum
#ifdef PROMISE_WG_IS_WAVEFRONT
__attribute__((reqd_work_group_size(DEVICE_WAVEFRONT_SIZE, 1, 1)))
#endif
__kernel void make_prefix_sums_with_intra_wg_block_global_sums(
        const uint im_rows, const uint im_cols,
        __global const uint * restrict intra_wg_block_sums_p,
        __global uint * restrict array_of_prefix_sums_p, uint array_of_prefix_sums_pitch //input -> partial/local prefix sums, output: global prefix sums
){
    const uint array_length = im_rows * im_cols;
    const uint n_arrays = get_num_groups(1);
    const uint array_id = get_group_id(1);
    const uint array_wg_id = get_group_id(0);
    const uint narray_workers = get_num_groups(0);
    const uint wg_size = get_local_size(0);
    const uint block_size = wg_size;//efficient block size
    const uint nblocks = divUp(array_length, block_size);//number of efficiently processible blocks
    const uint nblocks_per_wg = nblocks / narray_workers;
    const uint nblocks_to_merge = nblocks / nblocks_per_wg;
    const uint nblocks_remainder = nblocks - (narray_workers * nblocks_per_wg);
    const uint nblocks_to_left = nblocks_per_wg * array_wg_id + (array_wg_id < nblocks_remainder ? array_wg_id : nblocks_remainder);
    const uint n_wg_blocks = nblocks_per_wg + (array_wg_id < nblocks_remainder ? 1 : 0);

    const uint start_index = nblocks_to_left * block_size;
    const uint end_index_ = start_index + n_wg_blocks * block_size;//block aligned end

    const uint inter_block_sum = intra_wg_block_sums_p[array_wg_id];
            //note we could save a honest chunk of time by putting the relabeling here
    for(uint linear_index = get_local_id(0) + start_index; linear_index < end_index_; linear_index += wg_size){
        if(linear_index < array_length){
            const uint r = linear_index / im_cols;
            const uint c = linear_index % im_cols;
            image_pixel_at(uint, array_of_prefix_sums_p, im_rows, im_cols, array_of_prefix_sums_pitch, r, c) += inter_block_sum;
        }
    }
}

__kernel void relabel_with_scanline_order(
    uint im_rows, uint im_cols,
    __global LabelT* labelim_out_p, const uint labelim_out_pitch,
    __global const PixelT* image_p, const uint image_pitch,
    __global const LabelT* labelim_p, const uint labelim_pitch,
    __global uint* scanline_prefix_sum_of_root_classes_p, const uint scanline_prefix_sum_of_root_classes_pitch
){
    const uint c = get_global_id(0);
    const uint r = get_global_id(1);
    const bool valid_pixel_task = (c < im_cols) & (r < im_rows);

    if(valid_pixel_task){
        const PixelT pixel = pixel_at(PixelT, image, r, c);
        LabelT final_label = 0;
        if(pixel != BG_VALUE){
            const LabelT label = pixel_at(LabelT, labelim, r, c);
            const uint label_r = label / im_cols;
            const uint label_c = label % im_cols;
            const uint scan_id = pixel_at(uint, scanline_prefix_sum_of_root_classes, label_r, label_c);
            final_label = scan_id + 1;
        }
        pixel_at(LabelT, labelim_out, r, c) = final_label;
    }
}


Add -fsyntax-only to Driver/opencl.cl test.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@273150 91177308-0d34-0410-b5e6-96231b3b80d8

// RUN: %clang -fsyntax-only %s
// RUN: %clang -fsyntax-only -std=cl %s
// RUN: %clang -fsyntax-only -std=cl1.1 %s
// RUN: %clang -fsyntax-only -std=cl1.2 %s
// RUN: %clang -fsyntax-only -std=cl2.0 %s
// RUN: %clang -fsyntax-only -std=CL %s
// RUN: %clang -fsyntax-only -std=CL1.1 %s
// RUN: %clang -fsyntax-only -std=CL1.2 %s
// RUN: %clang -fsyntax-only -std=CL2.0 %s
// RUN: not %clang_cc1 -std=c99 -DOPENCL %s 2>&1 | FileCheck --check-prefix=CHECK-C99 %s
// RUN: not %clang_cc1 -std=invalid -DOPENCL %s 2>&1 | FileCheck --check-prefix=CHECK-INVALID %s
// CHECK-C99: error: invalid argument '-std=c99' not allowed with 'OpenCL'
// CHECK-INVALID: error: invalid value 'invalid' in '-std=invalid'

kernel void func(void);

// RUN: %clang %s
// RUN: %clang -std=cl %s
// RUN: %clang -std=cl1.1 %s
// RUN: %clang -std=cl1.2 %s
// RUN: %clang -std=cl2.0 %s
// RUN: %clang -std=CL %s
// RUN: %clang -std=CL1.1 %s
// RUN: %clang -std=CL1.2 %s
// RUN: %clang -std=CL2.0 %s
// RUN: not %clang_cc1 -std=c99 -DOPENCL %s 2>&1 | FileCheck --check-prefix=CHECK-C99 %s
// RUN: not %clang_cc1 -std=invalid -DOPENCL %s 2>&1 | FileCheck --check-prefix=CHECK-INVALID %s
// CHECK-C99: error: invalid argument '-std=c99' not allowed with 'OpenCL'
// CHECK-INVALID: error: invalid value 'invalid' in '-std=invalid'

kernel void func(void);


[OpenCL] Added regression test on invalid vector initialization.

Summary: This patch increases code coverage.

Reviewers: Anastasia

Reviewed By: Anastasia

Subscribers: cfe-commits, bader, yaxunl

Differential Revision: https://reviews.llvm.org/D33489

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@303844 91177308-0d34-0410-b5e6-96231b3b80d8

// RUN: %clang_cc1 -verify %s

typedef __attribute__(( ext_vector_type(4) ))  float float4;
typedef __attribute__(( ext_vector_type(4) ))  int int4;
typedef __attribute__(( ext_vector_type(8) ))  int int8;

void vector_literals_invalid()
{
  int4 a = (int4)(1,2,3); // expected-error{{too few elements}}
  int4 b = (int4)(1,2,3,4,5); // expected-error{{excess elements in vector}}
  ((float4)(1.0f))++; // expected-error{{cannot increment value of type 'float4'}}
  int8 d = (int8)(a,(float4)(1)); // expected-error{{initializing 'int' with an expression of incompatible type 'float4'}}
  ((int4)(0)).x = 8; // expected-error{{expression is not assignable}}
}

// RUN: %clang_cc1 -verify %s

typedef __attribute__(( ext_vector_type(4) ))  float float4;
typedef __attribute__(( ext_vector_type(4) ))  int int4;
typedef __attribute__(( ext_vector_type(8) ))  int int8;

void vector_literals_invalid()
{
  int4 a = (int4)(1,2,3); // expected-error{{too few elements}}
  int4 b = (int4)(1,2,3,4,5); // expected-error{{excess elements in vector}}
  ((float4)(1.0f))++; // expected-error{{cannot increment value of type 'float4'}}
  int8 d = (int8)(a,(float4)(1)); // expected-error{{initializing 'int' with an expression of incompatible type 'float4'}}
}