[Bug tree-optimization/70729] Loop marked with omp simd pragma is not vectorized

[ysrumyan at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70729

--- Comment #6 from Yuri Rumyantsev <ysrumyan at gmail dot com> ---
Richard,

I did change proposed by you but it still does not help since we have
loop-carried dependency through this_4(D)->S_n:

  <bb 2>:
  _5 = this_4(D)->S_n;
...
  <bb 4>:
  pretmp_54 = this_4(D)->C2;
  pretmp_57 = this_4(D)->C1;
  pretmp_60 = MEM[(int * *)this_4(D) + 56B];
  _20 = this_4(D)->S_n;
  <bb 5>:   Loop header
  # i_33 = PHI <0(4), i_28(6)>
  # prephitmp_56 = PHI <_5(4), _20(6)> Recurrent phi.
...
test.cpp:66:25: note: vect_is_simple_use: operand prephitmp_56
test.cpp:66:25: note: def_stmt: prephitmp_56 = PHI <_5(4), _20(6)>
test.cpp:66:25: note: type of def: unknown
test.cpp:66:25: note: Unsupported pattern.
test.cpp:66:25: note: not vectorized: unsupported use in stmt.