[patch] Vectorizer cost model implementation

[Jagasia, Harsha]

>you mean to do the following, right?:
>
>      if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
>          || LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor
!= 0
>)
>        vec_outside_cost += 2*TARG_COND_BRANCH_COST;

Yes.

Thanks,
Harsha