On Fri, Jan 15, 2021 at 9:11 AM Kewen.Lin <li...@linux.ibm.com> wrote:
>
> Hi,
>
> This patch follows Richard's suggestion in the thread discussion[1],
> it's to factor out the nloads computation in vectorizable_load for
> strided access, to ensure we can obtain the consistent information
> when estimating the costs.
>
> btw, the reason why I didn't try to save the information into
> stmt_info during analysis phase and then fetch it in transform phase
> is that the information is just for strided slp loading, and to
> re-compute it looks not very expensive and acceptable.
>
> Bootstrapped/regtested on powerpc64le-linux-gnu P9,
> x86_64-redhat-linux and aarch64-linux-gnu.
>
> Is it ok for trunk? Or it belongs to next stage 1?
First of all I think this is stage1 material now. As we now do
SLP costing from vectorizable_* as well I would prefer to have
vectorizable_* be structured so that costing is done next to
the transform. Thus rather than finish the vectorizable_*
function when !vec_stmt go along further but in places where
code is generated depending on !vec_stmt perform costing.
This makes it easier to keep consting and transform in sync
and match up. It might not be necessary for the simple
vectorizable_ functions but for loads and stores there are
so many paths through code generation that matching it up
with vect_model_{load/store}_cost is almost impossible.
Richard.
> BR,
> Kewen
>
> [1] https://gcc.gnu.org/legacy-ml/gcc-patches/2017-09/msg01433.html
>
> gcc/ChangeLog:
>
> PR tree-optimization/82255
> * tree-vect-stmts.c (vector_vector_composition_type): Adjust function
> location.
> (struct strided_load_info): New structure.
> (vect_get_strided_load_info): New function factored out from...
> (vectorizable_load): ...this. Call function
> vect_get_strided_load_info accordingly.
> (vect_model_load_cost): Call function vect_get_strided_load_info.
>
> gcc/testsuite/ChangeLog:
>
> 2020-01-15 Bill Schmidt <wschm...@linux.ibm.com>
> Kewen Lin <li...@gcc.gnu.org>
>
> PR tree-optimization/82255
> * gcc.dg/vect/costmodel/ppc/costmodel-pr82255.c: New test.
>
