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/* { dg-do run } */
/* { dg-options "-fdump-tree-crc-details -w" } */
/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-g" "-Os" "-flto" } } */
#include <stdlib.h>
#include <stdint.h>
__attribute__ ((noinline,optimize(0)))
uint16_t crc16_O0 (uint16_t data, uint16_t crc)
{
int carry;
for (int i = 0; i < 16; ++i) {
carry = ((crc & 0x8000) ^ (data & 0x8000));
crc <<= 1;
data <<= 1;
if (carry) crc ^= 0x1021;
}
return crc;
}
uint16_t crc16 (uint16_t data, uint16_t crc)
{
int carry;
for (int i = 0; i < 16; ++i) {
carry = ((crc & 0x8000) ^ (data & 0x8000));
crc <<= 1;
data <<= 1;
if (carry) crc ^= 0x1021;
}
return crc;
}
int main ()
{
uint16_t crc = 0;
for (uint16_t i = 0; i < 655; i++)
{
uint16_t res1 = crc16_O0 (i, crc);
uint16_t res2 = crc16 (i, crc);
crc = res1;
if (res1 != res2)
abort ();
crc = res1;
}
}
/* { dg-final { scan-tree-dump "crc16 function maybe contains CRC calculation." "crc" } } */
/* { dg-final { scan-tree-dump "Loop iteration number is 15" "crc" } } */
/* { dg-final { scan-tree-dump "Bit forward" "crc" } } */
/* { dg-final { scan-tree-dump "calculates CRC!" "crc" } } */
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