[Bug tree-optimization/69042] [6 regression] Missed optimization in ivopts

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69042

--- Comment #7 from amker at gcc dot gnu.org ---
If I add back the candidate, ivopt can fix attached case, but it still can't
handle a slightly tuned case as below:

extern const int indexes[];

int bar (int code);

int
foo (short *data)
{
  register int i, j;

  j = 0;
  for (i = 1; i < 64; i++) {
    if (data[indexes[i]]) {
      j++;
    } else {
      if (bar (j))
        return 0;
      j = 0;
      __asm__("":::"eax","ebx","ecx","edx","esi","edi","ebp");
    }
  }

  return 1;
}

The only difference is change bar from a function definition to a declaration.

The cost computed in ivopt for pic related symbol-ref is different because of
issue described at : https://gcc.gnu.org/ml/gcc/2016-02/msg00040.html