[Bug tree-optimization/90270] [8/9/10 Regression] Do not select best induction variable optimization

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90270

--- Comment #11 from bin cheng <amker at gcc dot gnu.org> ---
For the record, this test reveals another issue that original iv cand is not
considered:

Group 0:
  Type: REFERENCE ADDRESS
  Use 0.0:
    At stmt:    _1 = final_counts[i_21];
    At pos:     final_counts[i_21]
    IV struct:
      Type:     unsigned int *
      Base:     (unsigned int *) &final_counts
      Step:     4
      Object:   (void *) &final_counts
      Biv:      N
      Overflowness wrto loop niter:     Overflow

Candidate 7:
  Incr POS: orig biv
  IV struct:
    Type:       unsigned int
    Base:       0
    Step:       1
    Biv:        N
    Overflowness wrto loop niter:       No-overflow

<Group-candidate Costs>:
Group 0:
  cand  cost    compl.  inv.expr.       inv.vars
  1     9       2       NIL;    NIL;
  6     2       2       1;      NIL;
  8     0       0       NIL;    NIL;
  10    9       1       NIL;    NIL;

Group 1:
  cand  cost    compl.  inv.expr.       inv.vars
  1     9       2       NIL;    NIL;
  6     2       2       2;      NIL;
  9     0       0       NIL;    NIL;
  10    9       1       NIL;    NIL;