similar to: [LLVMdev] Register Allocation by Graph Coloring

Hi, Well, yes i did try your suggestion but i keep on running into a compilation problem. The error is: llvm[0]: Compiling Hello.cpp for Release build (PIC) /home/saraswat/llvm/llvm-2.1/include/llvm/ADT/GraphTraits.h: In instantiation of `llvm::GraphTraits<llvm::ilist_iterator<llvm::BasicBlock> >': Hello.cpp:59: instantiated from here

On 12/14/2017 10:18 PM, Leslie Zhai wrote: > Hi GCC and LLVM developers, > > I am learning Register Allocation algorithms and I am clear that: > > * Unlimited VirtReg (pseudo) -> limited or fixed or alias[1] PhysReg > (hard) > > * Memory (20 - 100 cycles) is expensive than Register (1 cycle), but > it has to spill code when PhysReg is unavailable > It might be

Hi GCC and LLVM developers, I am learning Register Allocation algorithms and I am clear that: * Unlimited VirtReg (pseudo) -> limited or fixed or alias[1] PhysReg (hard) * Memory (20 - 100 cycles) is expensive than Register (1 cycle), but it has to spill code when PhysReg is unavailable * Folding spill code into instructions, handling register coallescing, splitting live ranges, doing

Hi Pabhat, Have you checked out DepthFirstIterator? (include/llvm/ADT/ DepthFirstIterator.h). It provides an iterator abstraction to perform a forward/reverse DFS traversal of a graph. Many of the LLVM datatypes that represent graphs have a template specialization of the GraphTraits<> class which allows separate algorithms to treat them as graphs, walk them, etc. (Both BasicBlock

Hi all, Is there a way to walk through ALL the predecessors of a basic block in a CFG. I tried to iterate over the preds using this method for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++I) { BasicBlock *PredBB = *PI; } but this only gives the immediate predecessors for a basic block. For example, in this sample control flow graph. entry -> bb1 -> bb2 -> bb4

Hi aditya, There are two ways to cound the number of predecessors for each basic block. You can generate the control flow graph using the CallGraphScc pass with the granularity of basic block and can simply traverse the graph bottom up till the root. The number of nodes encountered would be the number of predecessors. The second way would be to use the special ;preds marker in the llvm IR. Each

Hi Leslie, I suggest adding these 3 papers to your reading list. Register allocation for programs in SSA-form Sebastian Hack, Daniel Grund, and Gerhard Goos http://www.rw.cdl.uni-saarland.de/~grund/papers/cc06-ra_ssa.pdf Simple and Efficient Construction of Static Single Assignment Form Matthias Braun , Sebastian Buchwald , Sebastian Hack , Roland Leißa , Christoph Mallon , and Andreas

Hi all, I was wondering if its possible to identify loop control variables from the induction variables in a Loop using LLVM. Also, How does one can use the LoopInfo class to identify the natural loops from the IR. In other words how to use the class in the pass? Thanks, Regards Prabhat

Hi all... I am developing a program slicing framework using LLVM. The idea is to remove the computation parts from the program and only keep the parts relevant for the control flow. For example, in the following C loop. for (i=0;i<=VAL;) { printf("In the loop"); a=b+c; b=h+k; i++; printf("%d",i); } after slicing... for (i=0;i<=VAL;) { i++;

Hi! I want to know How to count the number of predecessors for each basic block? Thank You ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs

Hi all, I was working on writing a slicing pass which would remove the parts of the code which are not relevant from the control flow point of view (mainly, the repetitive computations in the body of the loops etc). I have been able to implement it successfully. From the POV of implementation, the pass locates the conditional branches, and then the conditions are identified, all the

Hello, I am working on developing register allocator for irregular architectures (with register pair, and banks) and plan to base my work on graph coloring register allocator. I wonder if LLVM already has basic graph coloring register allocator, or somebody is working on it? Also, I'm not sure what is the best way to even describe the register constraints in tablegen: - How can I

Hi Matthias, Thanks for your hint! It is just for learning and practicing for me, just like migrate DragonEgg http://lists.llvm.org/pipermail/llvm-dev/2017-September/117201.html the motivating is for learning from GCC and LLVM developers. 在 2017年12月19日 10:07, Matthias Braun 写道: > > >> On Dec 18, 2017, at 9:52 AM, Leslie Zhai via llvm-dev >> <llvm-dev at lists.llvm.org

Hi all, I was looking at the register allocator code and had a question about that: CodeGen/RegAlloc/PhysRegAlloc.cpp implements a graph coloring register allocator for the Sparc back end. It requests target machine register information via a call to getRegInfo() which returns a class TargetRegInfo containing the required information. For the x86 target machine, this interface has not been

On Sun, 28 Dec 2003, Anshu Dasgupta wrote: > CodeGen/RegAlloc/PhysRegAlloc.cpp implements a graph coloring register > allocator for the Sparc back end. It requests target machine register > information via a call to getRegInfo() which returns a class > TargetRegInfo containing the required information. For the x86 target > machine, this interface has not been implemented. Is an

Hi all, Just wanted to announce that I've implemented a preliminary version of a Chaitin-Briggs graph coloring register allocator for the LLVM x86 back-end. Right now, as it stands, the allocator works correctly for the benchmarks that I tested it on (from the LLVM test suite and some of the SPEC benchmarks). It performs better than the local register allocator in terms of spills and

On Dec 25, 2007, at 5:56 AM, Török Edwin wrote: > I was looking at how to use debug info to find out original > source:line > for a certain function/variable in the llvm bytecode. > > I read http://llvm.org/docs/SourceLevelDebugging.html, and then I have > looked in lib/Debugger/ProgramInfo.cpp. > getFunction() looks useful, however I am not sure how to call it. I >

Hi, I was looking at how to use debug info to find out original source:line for a certain function/variable in the llvm bytecode. I read http://llvm.org/docs/SourceLevelDebugging.html, and then I have looked in lib/Debugger/ProgramInfo.cpp. getFunction() looks useful, however I am not sure how to call it. I have a reference to a Function, however getFunction() takes a GlobalVariable. I tried

Hello, I want learn more about register allocation and do some analysis for a current research project. After reading some papers (eg. Chaitin, Briggs) I think its time to get my hands dirty :). First I plan to (re)implement some of the classic approaches to get familiar with the framework. At the beginning the following questions came up: - Is there some documentation about register allocation

On Saturday 01 May 2010 08:34:50 Josef Eisl wrote: > Hello, > > I want learn more about register allocation and do some analysis for a > current research project. After reading some papers (eg. Chaitin, > Briggs) I think its time to get my hands dirty :). Welcome! > First I plan to (re)implement some of the classic approaches to get > familiar with the framework. Before