[Bug tree-optimization/113261] missing vectorization for dot_prod chain.

[liuhongt at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113261

--- Comment #1 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
For foo1, 

  _99 = .REDUC_PLUS (vect_patt_79.51_97);
  _90 = .REDUC_PLUS (vect_patt_28.43_88);
  _19 = _90 + _99;

can be optimized to 

   _tmp = vect_patt_79.51_97 + vect_patt_28.43_88;
   _19 = .REDUC_PLUS (_tmp);