similar to: [LLVMdev] Dataflow equations

Hi David/Renato, By AST I mean Abstract Syntax Tree. We are writing an optimization pass for some FORTRAN95 + MPI code that requires us to analyze the AST. We thought of 2 ways of doing this: 1. Compile the code using Clang/llvm-gfortran, get the textual AST dump (somehow), analyze the AST dump using Ruby, modify it and then feed back the modified AST to LLVM. 2. Do the analysis as an LLVM

2009/11/3 David Greene <dag at cray.com>: > Your best bet is to use llvm-gfortran.  I don't know what you mean by > "AST."  Do you really want an AST or something else (LLVM IR, something > higher-level, etc.)?  LLVM doesn't understand ASTs directly. Probably for high-level optimisations, or just to see if the parser is good, as I do in my compiler. But AST is

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

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 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.

Hi I have just taken a look at the LLVM-compiler and i am trying to write a pass which analyses the dataflow and sideeffects. So far i have written my own pass which works and i can traverse the blocks, functions and instructions. Currently i am using the "runOnFunction" function and iterate over the functions and blocks. But this seems to be not optimal since the instructions

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 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

> > > The algorithm maintains a may-point-to graph. Unfortunately the > algorithm > > doesn't delete an "A-->B" edge when there's a strong update of "A" but > the > > value copied into "A" isn't a pointer. So the interpretation of "A" > having > > only one outbound edge (to "B") is a little

David/Johan, I would love to claim victory, but I don't think that D34901 catches this case. However, I got interested and threw this together quickly: https://reviews.llvm.org/D35140. This does catch the below case. If people are interested I can add test cases and submit for formal review. FWIW, it does hit about 1/3 of all of the SPEC benchmarks. I haven't done any performance

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 >

While attempting to run DataFlowSanitizer for 32 bit target (-m32), I received the following error: unsupported option '-fsanitize=dataflow' for target 'i386-unknown-linux-gnu' Does it mean that DFSan doesn't support 32 bit memory model? -- Thanks & Regards, Dipanjan -------------- next part -------------- An HTML attachment was scrubbed... URL:

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi. I'm sorry if I chose wrong place for my question. I would like to load debugger, attach to working process, and at some breakpoint, instead of numerical values in the CPU registers, I would like to see genesis of each value like "result of f(arg1, arg2,arg3) called at point X" or "result of comparison of values X and Y"

There are passes which mark function parameters as "nocapture", which means that the function does not store the passed-in pointer for use after that function returns. If pointers to a newly created object are only ever passed through "nocapture" parameters, never stored in a global, and not returned from the function, then that object is dead when the function that created

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

Nilesh M. Vaghela Research Scholar c/o Prof. N. V. Sastry, Department of Chemistry, Sardar Patel University Vallabhvidyanagar-388 120 Gujarat, India --- On Thu, 29/7/10, Kurt Hornik <Kurt.Hornik@wu.ac.at> wrote: From: Kurt Hornik <Kurt.Hornik@wu.ac.at> Subject: Re: R statical-script for analysis (India) To: "Nilesh Vaghela" <nilesh_spu25@yahoo.in> Cc:

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

To R-helpers, R offers the polyroot function for solving mentioned equations iteratively. However, Dr Math and Mathworld (and other places) show in detail how to solve mentioned equations non-iteratively. Do implementations for R that are non-iterative and that solve mentioned equations exists? Regards, Mads Jeppe

Hi, I am trying to find a simple way to numerically solve a system of two equations equal to zero with two unknowns (x_loc and y_loc). Here is a mock data set and below it, the equations I need to solve. theta<-c(180,135,90)/(2*pi) x<-c(0,0,15) y<-c(20,0,0) 0 = -sum((y_loc-y)*(sin(theta)*(x_loc-x)-cos(theta)*(y_loc-y))/(((x_loc-x)^2+(y_loc-y)^2)^0.5)^3) 0 =