search for: chordal

Hello, we are currently working on my project that aims at improving the register allocation scheme by identifying if the interference graphs are chordal or not. we are working on the llvm compiler .we are forcing the compiler to use PBQP register allocation scheme by an option of ' ' regalloc=pbqp ' during the execution of prgm. we have been succesfull in accessing the interference graph information and creating our version of interfer...

...ets are supported, especially the x86. Many optimizations are very similar to those of LLVM. But there are also some differences. This is what I could find out by quickly looking at the source code: - It seems to have a different register allocator that works directly on the SSA form and performs chordal graph register allocation. This is implemented by Sebastian Hack who is one of the pioneers working on the register allocation by means of chordal graph coloring. - libFirm seems to have more advanced spilling and coalescing heuristics - libFirm contains the implementation of the very fast liv...

Fernando Magno Quintao Pereira wrote: > Yes, I have a tech report on this page: > > http://compilers/fernando/projects/soc/ Cool. I'm also interested in the Chordal Graph allocator. Are you planning to integrate it into the main llvm repository? It would make an interesting research project to compare allocation algorithms on real-world machines. -Dave

...e Dominators Construction ET Forest Construction -- Immediate Dominators Construction Natural Loop Construction -- ET Forest Construction Virtual to def/use mapping - Fernando. -- Natural Loop Construction Edge liveness analyses - Fernando. Register allocation via coloring of chordal graphs. -- Register allocation via coloring of chordal graphs. -- Virtual to def/use mapping - Fernando. -- Edge liveness analyses - Fernando. ***************************************************************** Live Variable Analysis X86 FP Stackifier -- X86 FP Stackifier -- Live Variabl...

...answer to the linear scan question? Cheers, Lang. On Tue, May 11, 2010 at 8:56 PM, prasad dp <prasu.kothinti at gmail.com> wrote: > Hello, > we are currently working on my project that aims at improving the register > allocation scheme by identifying if the interference graphs are chordal or > not. > we are working on the llvm compiler .we are forcing the compiler to use > PBQP register allocation scheme by an option of ' ' regalloc=pbqp ' during > the execution of prgm. we have been succesfull in accessing the interference > graph information and creatin...

...ng to the documentation, currently the LLVM IR is in the SSA form, but I don't see additional information about *strict* SSA form. The strict SSA form provide opportunities of optimization in register allocation, because is proved that all interference graphs of the IR in *strict* SSA form are chordal and for those, there are polynomial algorithms for the graph coloring (http://web.cs.ucla.edu/~palsberg/paper/aplas05.pdf). -- Natanael Ramos Membro do corpo discente de Ciência da Computação pelo Instituto Federal de Minas Gerais - Campus Formiga -------------- next part -------------- An HTML a...

...T Forest Construction > -- Immediate Dominators Construction > Natural Loop Construction > -- ET Forest Construction > Virtual to def/use mapping - Fernando. > -- Natural Loop Construction > Edge liveness analyses - Fernando. > Register allocation via coloring of chordal graphs. > -- Register allocation via coloring of chordal graphs. > -- Virtual to def/use mapping - Fernando. > -- Edge liveness analyses - Fernando. > ***************************************************************** > Live Variable Analysis > X86 FP Stackifier > -- X...

...ioned it on this list directly though. Currently, my implementation is in the testing state. Probably I'll try commit it before the 2.0 release. However, my progress on this work is very unstable and the main goal of implementing the algorithm is my diploma. Register allocation via coloring of chordal graphs was also developed within LLVM by someone (Fernando Magno Quintao Pereira if I remember well), AFAIK, but I don't know whether he wants to commit his implementation. Probably, he'll answer you, too :) I've just downloaded llvm from cvs. And didn't find any RegAllocGraphColor...

...Immediate Dominators Construction > > Natural Loop Construction > > -- ET Forest Construction > > Virtual to def/use mapping - Fernando. > > -- Natural Loop Construction > > Edge liveness analyses - Fernando. > > Register allocation via coloring of chordal graphs. > > -- Register allocation via coloring of chordal graphs. > > -- Virtual to def/use mapping - Fernando. > > -- Edge liveness analyses - Fernando. > > ***************************************************************** > > Live Variable Analysis > >...

I'm just starting to dive into llvm, hoping to implement a good graph coloring register allocator. I gather that this has been discussed before. What is the RegAllocGraphColoring.cpp currently in the sources? It seems to be the Fred Chow algorithm but it's not mentioned in the documentation anywhere. Does it work? -Dave

...loc command line options. /// //===---------------------------------------------------------------------===// namespace { cl::opt<RegisterRegAlloc::FunctionPassCtor, false, RegisterPassParser<RegisterRegAlloc> > RegAlloc("regalloc", cl::init(&createChordalRegisterAllocator), cl::desc("Register allocator to use: (default = chordal)")); } All the best, Fernando > Hi! > > I've did what Jim Laskey wrote but llc didn't reckognize my regalloc option. > > So I moved my allocator implementation into seperate fol...

Hi all. I’ve heard a couple of times that some of the problems solved by various passes in the optimizer are indeed NP-hard, even though the instances are small enough to be tractable (and very quickly). Is this true? If so, which are these problems? Register allocation? Instruction scheduling? Are they solved exactly or by approximations? Or not solved at all (the need of solving them is

> > What do you think about this approach? Whould it be interesting to > implement something like that for LLVM? May be you already have > considered something like that? Are there any plans to it? We have talked about whole function instruction selection but does not have immediate plan to implement it. If we were to implement it today, it would probably be done on DAGs with

...e can improve on clang -Oz by almost 10% in MiBench, for instance. * We can perform many types of explorations on real-world code. For instance, we have found that 95.4% of all the interference graphs of these programs, even in machine code (no phi-functions and lots of pre-colored registers), are chordal. * We can check how well different tools are doing on real-world code. For instance, we can use these benchmarks to check how many programs can be analyzed by Ultimate Buchi Automizer (https://ultimate.informatik.uni-freiburg.de/downloads/BuchiAutomizer/). This is a tool that tries to prove termin...

Hello, all, I want to implement the register allocation algorithm described in the paper "Register Allocation via Coloring of Chordal Graphs, APLAS'05" in LLVM. This is a graph coloring algorithm that can find an optimal coloring of the interference graph in most of the cases. I've downloaded LLVM last week, and started studying the code. Basically, I have to implement: 1) A new register allocation pass, similar to...

...us research in Register Allocation has been in the context of programs that were not in SSA form. i.e. the Chaitin-Briggs paper states that register allocation is NP-complete and proposes an iterative algorithm. If one reads Hack Goos, there is the discovery that programs that are in SSA form have chordal graphs, and the colouring algorithm for chordal graphs can be completed in polynomial time. After the cost of building the interference graph, it is possible to perform register allocation in a single pass. The key is in not modifying the graph. If one has frequency for each basic block, then one...

...h Laplacian calculation (graph.laplacian()) supports edge weights now. - Biconnected component calculation, biconnected.components() now returns the components themselves. - bipartite.projection() calculates multiplicity of edges. - Maximum cardinality search: maximum.cardinality.search() and chordality test: is.chordal() - Convex hull computation, convex.hull(). - Contract vertices, contract.vertices(). _______________________________________________ R-packages mailing list R-packages at r-project.org https://stat.ethz.ch/mailman/listinfo/r-packages

...h Laplacian calculation (graph.laplacian()) supports edge weights now. - Biconnected component calculation, biconnected.components() now returns the components themselves. - bipartite.projection() calculates multiplicity of edges. - Maximum cardinality search: maximum.cardinality.search() and chordality test: is.chordal() - Convex hull computation, convex.hull(). - Contract vertices, contract.vertices(). _______________________________________________ R-packages mailing list R-packages at r-project.org https://stat.ethz.ch/mailman/listinfo/r-packages

...ch, for instance. > > > > * We can perform many types of explorations on real-world code. For > > instance, we have found that 95.4% of all the interference graphs of > > these programs, even in machine code (no phi-functions and lots of > > pre-colored registers), are chordal. > > > > * We can check how well different tools are doing on real-world code. > > For instance, we can use these benchmarks to check how many programs > > can be analyzed by Ultimate Buchi Automizer > > (https://ultimate.informatik.uni-freiburg.de/downloads/BuchiAutom...

Hi, LLVM already uses dynamic-programming based optimal pattern matching selectors for some of the target architectures. But as far as I know, the code is first converted out of the SSA form, before the selection process takes place. The same approach is used by many other compilers. But there is an article from Erik Eckstein, where a different method is proposed. In the described approach, the