llvm dev - Jul 2016 - [IPRA] Do we required more aggressive shrink-wrapping optimization?

Hello Quentin,

I see your work on shrink-wrapping optimization at
http://reviews.llvm.org/rL236507
IPRA has benefited shrink-wrapping optimization ( I have noticed that on
sqlite3 test-case) so I did read Fred Chow's paper and compare that
approach with yours I did not understand much of your work :-( in
comparison to  original paper but I feel that current approach is not
generating same results as data flow analysis based approach. Also I do not
understand one of your comment on review :
>
>    1. Right now, we only support one save point and one restore point. At
>    some point we can expand this to several save point and restore point,
>
> Do you here meant to get more effective results as original paper? With
IPRA should we go for more aggressive version or the current version is as
capable as original paper ?

Sincerely,
Vivek
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On Wed, Jun 29, 2016 at 1:43 AM, vivek pandya via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hello Quentin,
>
> I see your work on shrink-wrapping optimization at
> http://reviews.llvm.org/rL236507
> IPRA has benefited shrink-wrapping optimization ( I have noticed that on
> sqlite3 test-case) so I did read Fred Chow's paper and compare that
> approach with yours I did not understand much of your work :-( in
> comparison to  original paper but I feel that current approach is not
> generating same results as data flow analysis based approach. Also I do not
> understand one of your comment on review :
>
>>
>>    1. Right now, we only support one save point and one restore point.
>>    At some point we can expand this to several save point and restore
point,
>>
>> Do you here meant to get more effective results as original paper? With
> IPRA should we go for more aggressive version or the current version is as
> capable as original paper ?
>
I can't make any promises, but Fred is a friend of mine - Please email me
offlist if you need an extra hand with this and think his input may be of
value.
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> On Jun 28, 2016, at 1:48 PM, C Bergström via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> 
> 
> On Wed, Jun 29, 2016 at 1:43 AM, vivek pandya via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
> Hello Quentin,
> 
> I see your work on shrink-wrapping optimization at
http://reviews.llvm.org/rL236507 <http://reviews.llvm.org/rL236507>
> IPRA has benefited shrink-wrapping optimization ( I have noticed that on
sqlite3 test-case) so I did read Fred Chow's paper and compare that approach
with yours I did not understand much of your work :-( in comparison to  original
paper but I feel that current approach is not generating same results as data
flow analysis based approach. Also I do not understand one of your comment on
review :
> Right now, we only support one save point and one restore point. At some
point we can expand this to several save point and restore point,
> Do you here meant to get more effective results as original paper? With
IPRA should we go for more aggressive version or the current version is as
capable as original paper ?
> 
> I can't make any promises, but Fred is a friend of mine - Please email
me offlist if you need an extra hand with this and think his input may be of
value.
Could he send his input on the list instead of having to side-channel?
I’m sure it can be interesting for everyone :)

Thanks,

— 
Mehdi

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Hi Vivek,
> On Jun 28, 2016, at 10:43 AM, vivek pandya <vivekvpandya at
gmail.com> wrote:
> 
> Hello Quentin,
> 
> I see your work on shrink-wrapping optimization at
http://reviews.llvm.org/rL236507 <http://reviews.llvm.org/rL236507>
> IPRA has benefited shrink-wrapping optimization ( I have noticed that on
sqlite3 test-case) so I did read Fred Chow's paper and compare that approach
with yours I did not understand much of your work :-( in comparison to  original
paper but I feel that current approach is not generating same results as data
flow analysis based approach.
That’s not surprising that you do not get the implementation in comparison of
the original paper, the goal is the same but the approaches are completely
different.
Fred’s approach is data flow based, that one is dominance based.
> Also I do not understand one of your comment on review :
> Right now, we only support one save point and one restore point. At some
point we can expand this to several save point and restore point,
> Do you here meant to get more effective results as original paper?
No, I mean to improve the current approach, we would need to support several
save and restore insertion points. The original paper already supports that, but
so far, we did not find compelling reason to add this (complex) support.
> With IPRA should we go for more aggressive version or the current version
is as capable as original paper ?
The current version is not as capable as the original paper in terms of the
granularity we have for the placement of save and restore points, but it is much
faster.
Anyhow, shrink-wrapping and the scope of the current IPRA are orthogonal. Put
differently, improving our shrink-wrapping implementation is a different topic.

Cheers,
-Quentin
> 
> Sincerely,
> Vivek
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