On Wed, Nov 29, 2017 at 10:02 AM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Tue, Nov 28, 2017 at 3:48 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
>> Hi,
>> This patch renames remove_dead_inserted_code to simple_dce_from_worklist, moves it to tree-ssa-dce.c
>> and makes it a simple public DCE interface.  Bootstrap and test along with loop interchange.  It's required
>> for interchange pass.  Is it OK?
>
> +  /* ???  Re-use seeds as worklist not only as initial set.  This may end up
> +     removing more code as well.  If we keep seeds unchanged we could restrict
> +     new worklist elements to members of seed.  */
>
> Please remove this comment, while it applies to PRE when one takes
> remove_dead_inserted_code
> literally it doesn't apply to a seeded DCE.
>
> Please also rename 'seeds' to 'worklist' directly and document that
> worklist is consumed by the function.
> The function has linear complexity in the number of dead stmts, the
> constant factor is the number of
> SSA use operands in those stmts (so 2 on average I'd say).
>
> Ok with that change.
Updated, will commit new patch as attached.

Thanks,
bin

>
> Thanks,
> Richard.
>
>> BTW, I will push this along with interchange to branch: gcc.gnu.org/svn/gcc/branches/gimple-linterchange.
>>
>> Thanks,
>> bin
>> 2017-11-27  Bin Cheng  <bin.cheng@arm.com>
>>
>>         * tree-ssa-dce.c (simple_dce_from_worklist): Move and rename from
>>         tree-ssa-pre.c::remove_dead_inserted_code.
>>         * tree-ssa-dce.h: New file.
>>         * tree-ssa-pre.c (tree-ssa-dce.h): Include new header file.
>>         (remove_dead_inserted_code): Move and rename to function
>>         tree-ssa-dce.c::simple_dce_from_worklist.
>>         (pass_pre::execute): Update use.