similar to: [LLVMdev] Data dependence analysis

On Aug 20, 2008, at 8:56 AM, David Greene wrote: > What I really need is a dependence analysis interface. I need to know > about loop-carried dependencies and that sort of things, whether two > memory > operations reference the same data, distance information, etc.. As > far as I > can tell, there's no infrastructure for this in LLVM. Right, this is something we've

On Monday 18 August 2008 17:48, David Greene wrote: > > Normally, the conversion to SSA form is sufficient. Can you talk > > about cases where this matters to you? > > Mostly it involves tying into our memory dependence analysis which > annotates things on program points. I need a way to translate back > to our optimizer data structures. > > So it's not

Hi Wojtek, This is a great start. I'll focus and try to understand your interface design and choices. Here are my initial thoughts based on a quick read. The only interface provided by LoopMemDepAnalysis is "bool carriesDependence()" which may not be sufficient. But we can extend this. The ArrayDepTest provides testDependenc() as well as testPositions(). I'm not very

Hi Sanjoy, Here's a version of Banerjee and Wolfe's Exact SIV test: https://sites.google.com/site/parallelizationforllvm/weak-siv-test It assumes you've already filtered out the easy cases handled by ZIV, strong SIV, etc. I'm not confident about my uses of APInt. If you have any comments, I'd love to hear them. Thanks, Preston On Thu, Apr 12, 2012 at 5:14 AM, Sanjoy Das

Hi, Here is a preliminary (monolithic) version you can comment on. This is still buggy, however, and I'll be testing for and fixing bugs over the next few days. I've used your version of the strong siv test. Thanks! -- Sanjoy Das. http://playingwithpointers.com -------------- next part -------------- A non-text attachment was scrubbed... Name: patch.diff Type: application/octet-stream

On Wed, 18 Apr 2012 18:16:47 -0700 Preston Briggs <preston.briggs at gmail.com> wrote: > Hi Sanjoy, > > Here's a version of Banerjee and Wolfe's Exact SIV test: > https://sites.google.com/site/parallelizationforllvm/weak-siv-test > It assumes you've already filtered out the easy cases handled by ZIV, > strong SIV, etc. > > I'm not confident about my

Hi, > Cool! I think the most critical part of this is to get a good > interface for dependence analysis. There are lots of interesting > implementations that have various time/space tradeoffs. > > For example, it would be great if Omega was available as an option, > even if the compiler didn't use it by default. This argues for making > dependence analysis

>> As part of the advanced compilers course semester project (at >> UIUC), we >> are starting to implement array dependence analysis for LLVM. Great! This is something we've needed for a long time. > I'm currently working on a similar project and hoping to finish it in > about two weeks. Cool! I think the most critical part of this is to get a good

Wojtek Matyjewicz has written a simple DependenceAnalysis interface and sent email about it to llvmdev in June -- the message is attached. He said he wrote several tests behind that interface -- ZIV, strong SIV, Banerjee, and some form of the Delta test -- and two students in my Spring class added the Omega test. I have not reviewed his interface yet because I've been traveling

On Mar 18, 2008, at 9:21 AM, Wojciech Matyjewicz wrote: > Hi, > >> Cool! I think the most critical part of this is to get a good >> interface for dependence analysis. There are lots of interesting >> implementations that have various time/space tradeoffs. >> >> For example, it would be great if Omega was available as an option, >> even if the compiler

> Wojtek, > > Please see David's message below. Have you or can you check in your > code, perhaps as a project for now? That will allow us to start > looking at it and perhaps collaborating on it. Sure. For now, I am posting it as an attachment, because it does not build against the current SVN version. It is really basic (for example, it cannot produce distance vectors,

On Thu, 29 Nov 2007, Wojciech Matyjewicz wrote: > As for the dependence analysis, I need this piece for my project, and I > am preparing myself to write it. Great! > I am currently studying some papers, but haven't yet decided on the > method. Maybe some of you have experience in the area and would like to > advise me something? In the next few days I am going to take a look

Wojtek, Please see David's message below. Have you or can you check in your code, perhaps as a project for now? That will allow us to start looking at it and perhaps collaborating on it. --Vikram Associate Professor, Computer Science University of Illinois at Urbana-Champaign http://llvm.org/~vadve On Aug 20, 2008, at 3:05 PM, David Greene wrote: > On Wednesday 20 August 2008

> I asked myself the same question. Without mod, how do you ensure that for instance the expression 2*i+255 was not actually 2*i-1 ? I think it is not possible in general, but I believe it is possible in case of affine expressions used as GEP indices. I assume, GEP indices (except indexing into struct) are interpreted as signed integers. It isn't explicitly stated in the LangRef, but

Hi, Devang Patel wrote: > LLVM loop transformer operates at loop level, which is not what many > optimizers do in general. So, a loop level interface (i.e. based on > LoopPass in llvm) to find loop-carried dependence is preferable to > loop optimizer. Do you mean making Array Dependence Analysis a loop-level analysis? Would its results be available for some function-level pass

On Nov 29, 2007, at 11:11 AM, Wojciech Matyjewicz wrote: > As you have noticed, loops aren't represented directly in the LLVM IR. > However, there are analysis passes which may be helpful to > "reconstruct" > them. For example: LoopInfo pass detects natural loops (as sets of > basic > blocks) and ScalarEvolution pass finds loop induction variables (and >

Devang Patel wrote: > Right now, one big missing piece in this puzzle is - dependence > analysis. Right. I was only trying to say that it shouldn't be very difficult to find these for/do loops which are interesting from the parallelization perspective (in general, not all for/do loops can be reconstructed). As for the dependence analysis, I need this piece for my project, and I am

Hi! Haifeng He wrote: > okay. I guess I figured it out. It seems "poolalloc" needs to be put > in llvm/projects/ directory. Yes, it will compile then. However, it seems the resulting shared library LLVMDataStructure.so (I haven't checked the others) has some undefined symbols. Trying to load it into the opt tool produces an error: undefined symbol:

On Sun, Aug 24, 2008 at 2:46 PM, Wojciech Matyjewicz <wmatyjewicz at fastmail.fm> wrote: >> I asked myself the same question. Without mod, how do you ensure that for instance the expression 2*i+255 was not actually 2*i-1 ? > > I think it is not possible in general, but I believe it is possible in > case of affine expressions used as GEP indices. > > I assume, GEP indices

On Mar 18, 2008, at 8:03 AM, Wojciech Matyjewicz wrote: > Hi, > > Devang Patel wrote: >> LLVM loop transformer operates at loop level, which is not what many >> optimizers do in general. So, a loop level interface (i.e. based on >> LoopPass in llvm) to find loop-carried dependence is preferable to >> loop optimizer. > > Do you mean making Array Dependence