similar to: [LLVMdev] Live range of variables

Hello. Thank you very much for the research paper. I will try to make use of the algorithms it presents. I just want to add that I found a 3rd party project doing dataflow analysis for LLVM IR at https://github.com/rohitjha/cse231-proj2. As written at http://cseweb.ucsd.edu/~r1jha/#five , the project's description is: "Dataflow Analysis Framework for LLVM This is an

On Aug 8, 2013, at 9:01 AM, David Tweed <David.Tweed at arm.com> wrote: > Just as general comments not related to the specific implementation in LLVM: > > I believe that 2-state Ising models can be reduced to max-flow/min-cut (eg, Finding ground states in random-field Ising ferromagnets by F Barahona) , so were a guaranteed polynomial time solution wanted that could be used

Maybe someone on the list who knows about GHC internals (I don't) can chime in here, but GHC has (had?) a concept of "optimization fuel": http://blog.ezyang.com/2011/06/debugging-compilers-with-optimization-fuel/ that is very similar to what Mehdi is suggesting. -- Sanjoy On Fri, Mar 25, 2016 at 12:37 PM, Mehdi Amini via llvm-dev <llvm-dev at lists.llvm.org> wrote: > >

Hi, guys, thank you for all the feedback. I will try to answer your questions below. But, if you think that might not be a good GSoC project, do not hesitate to tell me. I can try to write a different proposal. Nevertheless, I would like to hear from you what you think is important to have in the range analysis. By reading your e-mails, I see that there are still a lot of things that we do

Hello llvmer: I am develop new registerb allocation for my study . my register allocation do not depend on live variable . I add an option which will be cheked whether the pass should be add or not in "addOptimizeRegalloc ,". But live variable analysis still appeare After debug,I'm sure that live variable is not add during addPass stage . FYI ,I disable the phiEliminate,live

Andy, I'd love to see this feature. I wouldn't care too much wether the interface is a single number or two numbers, but if possible print the name of the function and the name of the pass that was just skipped so the developers knows where to start looking. - Matthias > On Mar 25, 2016, at 12:13 PM, Kaylor, Andrew via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi

> On Mar 25, 2016, at 12:10 PM, Adrian Prantl via llvm-dev <llvm-dev at lists.llvm.org> wrote: > >> >> On Mar 25, 2016, at 11:56 AM, Mehdi Amini via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >> >> Hi Andy, >> >>> On Mar 25, 2016, at 11:41 AM, Kaylor, Andrew via llvm-dev <llvm-dev at

With the D-Wave computer in the news recently, you may find it interesting that LLVM’s register allocator is using Ising models to compute regions for live range splitting. The problem of finding a region for splitting a live range is mapped to an Ising model with the help of the edge bundle graph, see EdgeBundles.h. A node in the edge bundle graph represents a set of CFG edges that enter or

On 7 August 2013 17:06, Jakob Stoklund Olesen <stoklund at 2pi.dk> wrote: > With the D-Wave computer in the news recently, you may find it interesting that LLVM’s register allocator is using Ising models to compute regions for live range splitting. > > The problem of finding a region for splitting a live range is mapped to an Ising model with the help of the edge bundle graph, see

Hi, Anton and Fernando have answered most of your questions. I don't have anything to add there. I do want to comment on the "conservative" nature of LiveIntervalAnalysis. I think the comment is misleading and is probably just a relic of early implementation. The biggest problem with the current implementation is the overly aggressive copy coalescer. Right now the

> On Mar 25, 2016, at 4:30 PM, Matthias Braun via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Andy, > > I'd love to see this feature. I wouldn't care too much wether the interface is a single number or two numbers, but if possible print the name of the function and the name of the pass that was just skipped so the developers knows where to start looking. We do

Hi I am seeing an issue (compiled application seg faults) when llc is used at -O1. I first need to triage out which optimization/pass is responsible for the seg fault. As such I am following this strategy: disable gradually those passes at -O1 which do not exist at -O0. For this I used -pass-debug=Structure. [ diff pasted at the end for reference] The problem is I have used almost all -disable-*

I will describe the complete process for completeness thus hopefully forestalling all questions [tell me if I did not ; )]. There is not much to it TBH. ./utils/bisect is a dumb python script that allows for arbitrary bisecting via the exit status of a script it runs . The way you use it is you write a script (lets call it test.sh). Then you invoke: ./utils/bisect --start=N --end=M ./test.sh

Hi Andy, > On Mar 25, 2016, at 11:41 AM, Kaylor, Andrew via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > The Intel C++ compiler has long had an internal facility to help our development teams track down the source of optimization related bugs by allowing a sort of binary search in which optimization passes and even individual optimizations are selectively disabled in response

LiveVariables gives you something like liveness analysis: where each variable is alive, that is, across each basic blocks, where it is defined, and where it is killed. LiveIntervals gives you a linear representation of the variables as a set of intervals. Yes, it handle holes in the live ranges. There is a very nice description of these analysis and related data structures here:

> On Mar 25, 2016, at 4:37 PM, Matthias Braun <matze at braunis.de> wrote: > > And as we are on the topic of bisecting/diagnosing scripts I attached my personal script I used before. > > You give it two directories with assembly files (typically from a known good compiler and a "bad" compiler). The script will then go on and create permutations by picking all files

On 4/3/07, David Greene <greened at obbligato.org> wrote: > > Toward a better register allocator, I'm attempting to understand > the dataflow information available to the allocator. > > What's the difference between LiveInterval information and LiveVariable > information? If a LiveInterval is based on a linear ordering of > the machine instructions, isn't it

Chris, one way to look at array bounds check optimization, and the value range propagation that it can be based on, is that it's usefulness is language dependent. Ada and Java benefit from it greatly, C/C++ not at all, but then a "codesafe" version of C/C++ would, as John T was pointing out below. It seems like the software engineering modularity of llvm's

> On Mar 25, 2016, at 12:13 PM, Kaylor, Andrew <andrew.kaylor at intel.com> wrote: > > Hi Mehdi, > > I started by trying to implement a single number approach, but it doesn’t allow quite the approach I wanted in terms of isolating individual functions. Do you have an example where it matters? I wonder if there are enough real-world use case that justify the complexity?

On 3/29/12 3:59 PM, Victor Campos wrote: > Dear LLVMers, > > I have been working on Douglas's range analysis, and today, after > toiling with it for two years, we have a very mature and robust > implementation, which is publicly available at > http://code.google.com/p/range-analysis/. We can, at this point, > perform range analysis on very large benchmarks in a few