[Bug tree-optimization/109892] SLP reduction failure with explicit fma

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109892

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
For a larger VF we have to (with associative math) enhance how we handle

      else if (!commutative_binary_op_p (orig_code, op.type)
               || !associative_binary_op_p (orig_code, op.type))
        {
          if (dump_enabled_p ())
            dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
                            "reduction: not commutative/associative\n");
          return false;

and we have to verify the reduc_idx is the add.