[Bug rtl-optimization/21485] [4.0/4.1/4.2 Regression] codegen regression due to PRE increasing register pressure

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #17 from pinskia at gcc dot gnu dot org  2006-03-10 13:56 -------
What happens to the time if you replace that function with:
void
NumSift (long *array, unsigned long i, unsigned long j)
{
  unsigned long k;
  while ((i + i) <= j)
    {
      k = i + i;
      long t, t1;
      t = array[k];
      if (k < j)
        {
          t1 = array[k+1];
          if (t < t1)
            ++k, t = t1;
        }
      t1 = array[i];
      if (t1 < t)
        {
          array[k] = t1;
          array[i] = t;
          i = k;
        }
      else
        i = j + 1;
    }
  return;
}
-----------
The semantics should be the same, I just pulled out the PREs as much as I
could.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21485