/* { dg-do run } */
/* { dg-options "-fdump-tree-crc-details" } */
/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Os" "-flto" } } */
/* { dg-require-effective-target int32plus } */

#include <stdint.h>
#include <stdlib.h>

__attribute__ ((noinline,optimize(0)))
uint16_t crc16_update_O0 (uint16_t crc, uint8_t a) {
    int i;
    crc ^= a;
    for (i = 0; i < 8; ++i) {
        if (crc & 1)
            crc = (crc >> 1) ^ 0xA001;
        else
            crc = (crc >> 1);
    }
    return crc;
}

uint16_t crc16_update (uint16_t crc, uint8_t a) {
    int i;
    crc ^= a;
    for (i = 0; i < 8; ++i) {
        if (crc & 1)
            crc = (crc >> 1) ^ 0xA001;
        else
            crc = (crc >> 1);
    }
    return crc;
}

int main ()
{
  uint16_t crc = 0x0D80;
  for (uint8_t i = 0; i < 255; i++)
    {
      uint16_t res1 = crc16_update (crc, i);
      uint16_t res2 = crc16_update_O0 (crc, i);
      if (res1 != res2)
	__builtin_abort ();
      crc = res1;
    }
  __builtin_exit (0);
}

/* { dg-final { scan-tree-dump "function maybe contains CRC calculation." "crc" } } */
/* { dg-final { scan-tree-dump "Loop iteration number is 7" "crc" } } */
/* { dg-final { scan-tree-dump "Bit reversed" "crc" } } */
/* { dg-final { scan-tree-dump "calculates CRC!" "crc" } } */
/* { dg-final { scan-tree-dump "Polynomial's value is \\\{1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1\\\}" "crc" } } */
/* { dg-final { scan-tree-dump-times "Couldn't generate faster CRC code." 0 "crc" } } */