Ticket #444 (Fixed)Wed Dec 13 18:05:55 UTC 2017

cc 5.72 abort on data transfer with __packed structs

Details by Colin (478):

The following code causes an abort on data transfer error. If I remove the __packed keyword it works ok, if I uncomment ‘buf.size = buf.size’ it works ok or if I reverse the nested loop order so that s is outer and i is inner it works ok.

#include <stdint.h>

uint32_t array[] = {100, 200, 300, 400, 500, 600, 700, 800, 900};

#define ARRAYSIZE (sizeof(array) / sizeof(array[0]))

int main(void)
{
    __packed struct 
    {
            uint16_t size;
            struct
            {
                    uint32_t min, max, res;
            } range[ARRAYSIZE];
    } buf;
    
    buf.size = 2;
    
    for (unsigned i = 0; i < buf.size; i++)
    {
        for (int s = 0; s < ARRAYSIZE; s++)
        {
        //    buf.size = buf.size;
            if (array[s] >= buf.range[i].min && array[s] <= buf.range[i].max)
            {
                break;
            }
        }
    }
    return 0;
}