[PATCH GCC8][27/33]Extend candidate set if new_cp has cheaper dependence

Richard Biener richard.guenther@gmail.com
Wed Apr 26 13:38:00 GMT 2017


On Tue, Apr 18, 2017 at 12:52 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
> Hi,
> Currently we only allow iv_ca extension if new_cp has cheaper cost and less deps than old_cp.
> This is inaccurate because it's possible the overall deps is reduced even new_cp has more deps
> than old_cp.  This happens in case that new_cp's deps are already in iv_ca.  This patch allows
> more iv_ca extension by checking overall deps in iv_ca.
> Is it OK?

Ok.

Richard.

> Thanks,
> bin
> 2017-04-11  Bin Cheng  <bin.cheng@arm.com>
>
>         * tree-ssa-loop-ivopts.c (compare_cost_pair): New.
>         (iv_ca_more_deps): Renamed to ...
>         (iv_ca_compare_deps): ... this.
>         (iv_ca_extend): Extend iv_ca if NEW_CP is cheaper than OLD_CP.



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