[Bug middle-end/24627] [4.1 Regression] xntp miscompiled

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2005-11-01 23:22 -------
Here is a little cleaned up testcase without any do {} while(0);:
extern void abort (void) __attribute__ ((noreturn));

typedef unsigned int u_int32;
typedef struct {
  union {u_int32 Xl_ui;} Ul_i;
  union {u_int32 Xl_uf;} Ul_f;
} l_fp;
void dolfptoa(short ndec)
{
  l_fp work, ftmp;
  work.Ul_i.Xl_ui = 0;
  work.Ul_f.Xl_uf = 0x535f3d8;
  while (ndec > 0) {

    ndec--;
    work.Ul_i.Xl_ui = 0;
    work.Ul_i.Xl_ui <<= 1;
    if ((work.Ul_f.Xl_uf) & 0x80000000)
      (work.Ul_i.Xl_ui) |= 0x1; (work.Ul_f.Xl_uf) <<= 1;
  //  printf("%d\t", work.Ul_i.Xl_ui);

    ftmp = work;
    (work.Ul_i.Xl_ui) <<= 1;
    if ((work.Ul_f.Xl_uf) & 0x80000000)
      (work.Ul_i.Xl_ui) |= 0x1; (work.Ul_f.Xl_uf) <<= 1;

    (work.Ul_i.Xl_ui) <<= 1;
    if ((work.Ul_f.Xl_uf) & 0x80000000)
      (work.Ul_i.Xl_ui) |= 0x1; (work.Ul_f.Xl_uf) <<= 1;
  //  printf("%d\t", work.Ul_i.Xl_ui);
    u_int32 lo_tmp;
    u_int32 hi_tmp;
    lo_tmp = ((work.Ul_f.Xl_uf) & 0xffff) + ((ftmp.Ul_f.Xl_uf) & 0xffff);
    hi_tmp = (((work.Ul_f.Xl_uf) >> 16) & 0xffff) + (((ftmp.Ul_f.Xl_uf) >> 16)
& 0xffff);

    if (lo_tmp & 0x10000)
      hi_tmp++;

    (work.Ul_f.Xl_uf) = ((hi_tmp & 0xffff) << 16) | (lo_tmp & 0xffff);
    (work.Ul_i.Xl_ui) += (ftmp.Ul_i.Xl_ui);

    if (hi_tmp & 0x10000)
     (work.Ul_i.Xl_ui)++;
   // printf("%d\n", work.Ul_i.Xl_ui);
    if (!(work.Ul_i.Xl_ui < 10))
      abort ();
  }
}
int main()
{
  dolfptoa(6);
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24627