similar to: [LLVMdev] Writing a dataflow analysis

Is there a traditional dataflow algorithm buried in LLVM somewhere? I need to be able to do some very late transformations (after regalloc) and we aren't in SSA anymore. I will need a dataflow analysis to ensure correctness. At one point I thought I remembered seeing a generic fixed-point dataflow analysis engine but now I can't find it. Does it still exist or did it ever exist? If

On 4/16/13 11:30 AM, dag at cray.com wrote: > Is there a traditional dataflow algorithm buried in LLVM somewhere? I > need to be able to do some very late transformations (after regalloc) > and we aren't in SSA anymore. I will need a dataflow analysis to ensure > correctness. > > At one point I thought I remembered seeing a generic fixed-point > dataflow analysis engine

Hi all, I just found an optimization regression regarding simple dataflow/constprop analysis: https://godbolt.org/g/Uz8P7t This code ``` int dataflow(int b) { int a; if (b==4) a = 3*b; // fully optimized when changed to a = 3; else a = 5; if (a == 4) return 0; else return 1; } ``` is no longer optimized to just a "return 1". The regression happened in LLVM

I am learning to do some basic dataflow analysis on C code projects, such as Apache httpd. Now I am a newbie of LLVM IR, and there are some problems in doing that. In the official User Manual of how to write a LLVM PASS, they only show the way to generate IR of a single ".c" source file. But in fact there are so many examples that the usage and definition of a function are not in the

On Thu, Jul 6, 2017 at 7:00 AM, Davide Italiano <davide at freebsd.org> wrote: > On Wed, Jul 5, 2017 at 3:59 PM, Johan Engelen via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > Hi all, > > I just found an optimization regression regarding simple > > dataflow/constprop analysis: > > https://godbolt.org/g/Uz8P7t > > > > This code >

As mentioned in the title, I want to do some control-flow and dataflow analysis. I can only find the assignment statement in a function, but the assigned variable is just a parameter of this function. For example, **************************************** int foo(struct A* a, int b, ...){ ... a->Int_field = b; ... return 0; } ***************************************** in the code

I'm working on an LLVM-based compiler for a very closure-centric language. It's becoming apparent that it's going to suffer heavily from garbage collector churn, as all the useful programming idioms the language makes possible are going to involve memory allocations, either to create objects or to allocate storage for upvalues. However, it's possible to optimise away a lot of heap

Hi Chris and list Thanks for your quick answer :-). Am Freitag, 12. Mai 2006 19:09 schrieb Chris Lattner: > On Fri, 12 May 2006, Silken Tiger wrote: > > To find the first instructions which are not depending on others results. > > So far it seems to be working but i am missing instructions like: > > %tmp.1 = seteq int %argc, 2 ; <bool> [#uses=1] > >

Edwin, thank you for your effort, but I'm not sure I understand. Are you describing a graph traversal problem? Is the data model stored in a predecessor/successor fashion, which requires you to 'walk' the graph in order to visit all nodes? (and what happens when you have disjointed DFGs?). inline comments follow... Török Edwin wrote: > On 2009-09-06 17:30, Ioannis Nousias

On 2009-09-06 19:57, Ioannis Nousias wrote: > Edwin, > > thank you for your effort, but I'm not sure I understand. > Are you describing a graph traversal problem? Is the data model stored > in a predecessor/successor fashion, which requires you to 'walk' the > graph in order to visit all nodes? (and what happens when you have > disjointed DFGs?). Sorry for the

On 2009-09-06 17:30, Ioannis Nousias wrote: > I've tried to write a DFGPrinter based on the CFGPrinter, as you > suggested, but encountered problems. > > The GraphWriter expects > GraphTraits<GraphType>::nodes_begin()/nodes_end(). The way this is > implemented in CFG.h, a function is a graph of basic blocks. A > GraphTraits<Function*> inherits from

Edwin, thanks, it starts making sense inline comments... Török Edwin wrote: > On 2009-09-06 19:57, Ioannis Nousias wrote: > >> Edwin, >> >> thank you for your effort, but I'm not sure I understand. >> Are you describing a graph traversal problem? Is the data model stored >> in a predecessor/successor fashion, which requires you to 'walk' the

On Apr 16, 2013, at 10:27 AM, John Criswell <criswell at illinois.edu> wrote: > On 4/16/13 11:30 AM, dag at cray.com wrote: >> Is there a traditional dataflow algorithm buried in LLVM somewhere? I >> need to be able to do some very late transformations (after regalloc) >> and we aren't in SSA anymore. I will need a dataflow analysis to ensure >> correctness.

I am in the process of submitting a package to CRAN. R CMD check ran successfully on the package on my local computer, using R version 2.1.1. However, on the computers for CRAN (with version 2.10.0), the following errors occurred: Warning in parse_Rd("./man/predict.Rd", encoding = "unknown") : ./man/predict.Rd:28: unknown macro '\dquote' *** error on file

Do you know whether it has been fixed on the 8.0.1 release? Scott On Fri, Nov 8, 2019 at 9:45 AM Krzysztof Parzyszek <kparzysz at quicinc.com<mailto:kparzysz at quicinc.com>> wrote: The one blocking issue that existed in the past has been fixed. I haven’t had time to do any work on it lately, but I’m not aware of any fundamental problems that would make it not work on x86. --

Dear Shulin, Sounds like you'll need an inter-procedural analysis across different source files. One option I can think of is to manually update the Makefiles, make compiler emit bitcode files, merge them with llvm-link and run it through your optimization pass as a big bitcode file. This somehow could involve huge amount of tedious work for a huge project like Apache, and may be error-prone.

Hi I am currently trying to schedule instructions with my own algorithm. For that i need to get the data dependency between the instructions. So currently i am dooing s.t. like: for(BasicBlock::iterator j=B.begin(),bbe=B.end();j!=bbe;++j) { InstructionList.push_back(j); if (const AllocaInst *AI = dyn_cast<AllocaInst>(j)) {

I came across this thread from a couple years ago: http://lists.llvm.org/pipermail/llvm-dev/2017-November/119346.html Has there been any progress on RDF for X86? Or is there some other preferred alternative for performing reachability analysis after register allocation? Thanks, Scott Constable -------------- next part -------------- An HTML attachment was scrubbed... URL:

wine: Unhandled page fault on read access to 0x409ffd80 at address 0x4000ba7c (thread 0009), starting debugger... err:seh:start_debugger Couldn't start debugger ("winedbg --auto 8 32") (2) Read the Wine Developers Guide on how to set up winedbg or another debugger This happens on everything I try run. Note: Still a problem with latest upgrade. It may have more sideeffects than

On Fri, 12 May 2006, Silken Tiger wrote: > To find the first instructions which are not depending on others results. So > far it seems to be working but i am missing instructions like: > %tmp.1 = seteq int %argc, 2 ; <bool> [#uses=1] > There seems only an function like llvm::Instruction::mayWriteToMemory > but nothing like llvm::Instruction::mayReadFromMemory or