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On 21.02.2011 20:27, Douglas do Couto Teixeira wrote:
> My work is not part of the LLVM mainline yet. But I would be happy to
> contribute with the code of my range analysis implementation if it can help
> you in something else.
We were thinking of adding VRP to LLVM too, though we were mostly
interested in Patterson's approach (i.e. not connected with SSI form). It
would be great if you can share the code nevertheless.
Andrey
> On 21.02.2011 20:27, Douglas do Couto Teixeira wrote:
>> My work is not part of the LLVM mainline yet. But I would be happy to
>> contribute with the code of my range analysis implementation if it can help
>> you in something else.
> We were thinking of adding VRP to LLVM too, though we were mostly
> interested in Patterson's approach (i.e. not connected with SSI form). It
> would be great if you can share the code nevertheless.
the big problem with Patterson's VRP is that it is expensive in terms of
compile time. LLVM used to have some passes (ABCD, predsimplify) that did
this kind of thing, but they were removed essentially because their compile
time was too great for the goodness they brought.
Ciao, Duncan.
Any reason not to just leave them on at O3? Based on the discussion
around your simple condition propagation pass, it seemed predsimplify
did delete dead code, but it didn't really improve generated code
performance. O3 seems the appropriate place to put expensive
optimizations with diminishing returns.
Reid
I was under the impression that ABCD was removed because no one was
maintaining and improving it. Is my impression incorrect?
The SAFECode compiler adds additional run-time checks for array bounds
checking. If the ABCD code was working but just wasn't useful for
regular C code, I'd like to know. It may still have value for projects
like SAFECode.
-- John T.
> On Tue, Feb 22, 2011 at 6:19 AM, Duncan Sands <bald...@free.fr> wrote:
>> the big problem with Patterson's VRP is that it is expensive in terms of
>> compile time. LLVM used to have some passes (ABCD, predsimplify) that did
>> this kind of thing, but they were removed essentially because their compile
>> time was too great for the goodness they brought.
>
> Any reason not to just leave them on at O3? Based on the discussion
> around your simple condition propagation pass, it seemed predsimplify
> did delete dead code, but it didn't really improve generated code
> performance. O3 seems the appropriate place to put expensive
> optimizations with diminishing returns.
Hi Reid,
-O3 compile time matters. We don't turn things on in -O3 or -O4 that just burn compiler cycles but don't add value.
-Chris
Hi, Andrey,
О©╫О©╫О©╫ sorry for the delay: I made a page with the code available for download: http://homepages.dcc.ufmg.br/~douglas/projects/RangeAnalysis/RangeAnalysis.html
О©╫О©╫О©╫ Feel free to get it, and if you need some help, I will be happy to tell you how to set the analysis up, in case the explanation in the page is not good.
О©╫О©╫О©╫ I also have a report describing the implementation here: (http://homepages.dcc.ufmg.br/~douglas/projects/RangeAnalysis/RangeAnalysis.paper.pdf)
О©╫О©╫О©╫ Indeed, if any of you guys have some free time, and want to give me a review, that would be very kind of you :)
Warm regards,
Douglas
2011/2/22 Andrey Belevantsev <ab...@ispras.ru>
Hi Douglas,
On 21.02.2011 20:27, Douglas do Couto Teixeira wrote:
My work is not part of the LLVM mainline yet. But I would be happy to
contribute with the code of my range analysis implementation if it can help
you in something else.
We were thinking of adding VRP to LLVM too, though we were mostly interested in Patterson's approach (i.e. not connected with SSI form). О©╫It would be great if you can share the code nevertheless.
Andrey
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Can't read your paper because the permission is not set.
Chuck
On 2/25/2011 12:16 PM, Douglas do Couto Teixeira wrote:
Hi, Andrey,
sorry for the delay: I made a page with the code available for download: http://homepages.dcc.ufmg.br/~douglas/projects/RangeAnalysis/RangeAnalysis.html
Feel free to get it, and if you need some help, I will be happy to tell you how to set the analysis up, in case the explanation in the page is not good.
I also have a report describing the implementation here: (http://homepages.dcc.ufmg.br/~douglas/projects/RangeAnalysis/RangeAnalysis.paper.pdf)
Indeed, if any of you guys have some free time, and want to give me a review, that would be very kind of you :)
Warm regards,
Douglas
2011/2/22 Andrey Belevantsev <ab...@ispras.ru>
Hi Douglas,
On 21.02.2011 20:27, Douglas do Couto Teixeira wrote:
My work is not part of the LLVM mainline yet. But I would be happy to
contribute with the code of my range analysis implementation if it can help
you in something else.
We were thinking of adding VRP to LLVM too, though we were mostly interested in Patterson's approach (i.e. not connected with SSI form). It would be great if you can share the code nevertheless.
Andrey
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