On Tue, Jul 21, 2020 at 7:52 AM Kewen.Lin <li...@linux.ibm.com> wrote: > > Hi, > > This patch is to add the cost modeling for vector with length, > it mainly follows what we generate for vector with length in > functions vect_set_loop_controls_directly and vect_gen_len > at the worst case. > > For Power, the length is expected to be in bits 0-7 (high bits), > we have to model the cost of shifting bits. To allow other targets > not suffer this, I used one target hook to describe this extra cost, > I'm not sure if it's a correct way. > > Bootstrapped/regtested on powerpc64le-linux-gnu (P9) with explicit > param vect-partial-vector-usage=1. > > Any comments/suggestions are highly appreciated!
I don't like the introduction of an extra target hook for this. All vectorizer cost modeling should ideally go through init_cost/add_stmt_cost/finish_cost. If the extra costing is not per stmt then either init_cost or finish_cost is appropriate. Currently init_cost only gets a struct loop while we should probably give it a vec_info * parameter so targets can check LOOP_VINFO_USING_PARTIAL_VECTORS_P and friends. Richard. > BR, > Kewen > ----- > gcc/ChangeLog: > > * config/rs6000/rs6000.c (TARGET_VECTORIZE_EXTRA_LENGTH_COST): New > macro. > * doc/tm.texi: Regenerate. > * doc/tm.texi.in (TARGET_VECTORIZE_EXTRA_LENGTH_COST): New target > hook. > * target.def (extra_length_cost): Likewise. > * tree-vect-loop.c (vect_estimate_min_profitable_iters): Add cost > modeling for vector with length.
