[Bug tree-optimization/66873] fortran variant of outer-1.c not parallelized by autopar

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66873

--- Comment #2 from vries at gcc dot gnu.org ---
Another obvious difference is that the fortran 2-dimensional array access is
rewritten into a single dimension array access:
...
  <bb 3>:
  # ii_7 = PHI <0(2), ii_16(7)>
  pretmp_52 = (integer(kind=8)) ii_7;
  pretmp_53 = pretmp_52 * 500;

  <bb 4>:
  # jj_10 = PHI <0(3), jj_15(5)>
  _11 = (integer(kind=8)) jj_10;
  _12 = _11 + pretmp_53;
  _13 = ii_7 + jj_10;
  _14 = _13 + 3;
  x[_12] = _14;
  jj_15 = jj_10 + 1;
  if (jj_10 == 499)
    goto <bb 6>;
  else
    goto <bb 5>;
...

While the outer-1.c 2-dimensional array access is still 2-dimensional:
...
  <bb 9>:
  # i_34 = PHI <0(3), i_15(8)>
  goto <bb 5>;

  <bb 5>:
  # j_36 = PHI <0(9), j_14(4)>
  _11 = i_34 + j_36;
  _12 = _11 + 3;
  x[i_34][j_36] = _12;
  j_14 = j_36 + 1;
  if (N_9(D) > j_14)
    goto <bb 4>;
  else
    goto <bb 6>;
...

Which results in different access functions, and the dependence analysis
succeeds:
...
(Data Dep:
#(Data Ref:
#  bb: 5
#  stmt: x[i_34][j_36] = _12;
#  ref: x[i_34][j_36];
#  base_object: x;
#  Access function 0: {0, +, 1}_4
#  Access function 1: {0, +, 1}_1
#)
#(Data Ref:
#  bb: 5
#  stmt: x[i_34][j_36] = _12;
#  ref: x[i_34][j_36];
#  base_object: x;
#  Access function 0: {0, +, 1}_4
#  Access function 1: {0, +, 1}_1
#)
  access_fn_A: {0, +, 1}_4
  access_fn_B: {0, +, 1}_4

 (subscript
  iterations_that_access_an_element_twice_in_A: [0]
  last_conflict: scev_not_known
  iterations_that_access_an_element_twice_in_B: [0]
  last_conflict: scev_not_known
  (Subscript distance: 0 ))
  access_fn_A: {0, +, 1}_1
  access_fn_B: {0, +, 1}_1

 (subscript
  iterations_that_access_an_element_twice_in_A: [0]
  last_conflict: scev_not_known
  iterations_that_access_an_element_twice_in_B: [0]
  last_conflict: scev_not_known
  (Subscript distance: 0 ))
  inner loop index: 0
  loop nest: (1 4 )
  distance_vector:   0   0
  direction_vector:     =    =
)
  SUCCESS: may be parallelized
...