similar to: [LLVMdev] Inter-procedural program flow analysis

Isn't this effectively the halting problem? Consider the case where block Y is the exit block of main() and block X is the entry block of main(). Jim On Oct 2, 2012, at 4:29 PM, Stephen Schiffli <sschiffli at gmail.com> wrote: > Is there any inter-procedural analysis that could tell me if some BasicBlock Y is guaranteed to execute based on my knowledge that BasicBlock X will

I think you're looking for an inter-procedural post dominator analysis. I don't think there is one in LLVM already, but it should be relatively straightforward. This gives a sound approximation (i.e. no false positives) of something sort-of equivalent to the halting problem: if the program terminates, then block Y was executed. Cheers, Scott On Tue, Oct 2, 2012 at 7:43 PM, Jim Grosbach

Okay thanks for the info. The term program termination was probably a poor choice of words. I'm really just trying to build an inter-procedural BasicBlock graph, and then look for postdominance as Scott suggested. I'll go about making my own since it doesn't sound like there is one out there already. Thanks, -Stephen On Tue, Oct 2, 2012 at 5:06 PM, Scott Moore <sdmoore at

Hello, I have a simple program using aliases to functions, and it seems that the CallGraph doesn't follow these aliases. Here is the example: @alias = alias void ()* @realfunc define void @realfunc() { entry: ret void } define i32 @main() { entry: call void @alias() ret i32 0 } ******* Output of the CallGraph ******* Call graph node <<null

On Thu, Oct 11, 2012 at 3:56 PM, Stephen Schiffli <sschiffli at gmail.com> wrote: > Hello, I have a simple program using aliases to functions, and it seems that > the CallGraph doesn't follow these aliases. Here is the example: > > @alias = alias void ()* @realfunc > > define void @realfunc() { > entry: > ret void > } > > define i32 @main() { >

Hello, I am trying to compile some code to LLVM IR with a simple "__thread int x" but hitting this error: test.cpp:1:1: error: thread-local storage is unsupported for the current target I'm using both the -S and -emit-llvm options on clang, and was expecting to see "@x = thread_local global i32 0" come out of clang. I am curious why clang even cares about this since

Hello all, I was playing with the demo and found that I couldn't use any c++11: warning: 'noexcept' is a keyword in C++11 [-Wc++11-compat] I was wondering if the demo will be updated to LLVM/Clang 3.2 once that finishes, and if it would be possible to enable c++11 support. Thanks, -Stephen -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hello Community, I would like to know status of the project and also importance of it. If the project is still open I would like to work on GSoC 2016 proposal for Inter-procedural Register Allocation, in that case please also suggest possible mentor or let me know if anyone is willing to be mentor for this. Sincerely, *Vivek Pandya* -------------- next part -------------- An HTML attachment was

Hi, I used the following commands on the program attached below: llvm-gcc --emit-llvm main.c -c -o main.bc opt -ipconstprop main.bc -o main1.bc diff main.bc main1.bc no difference was o/p :( The Program Segment is as shown below: #include <stdio.h> void f1(int a) { a=a+1; printf("%d",a); } void f2() { int b; b=1; f1(b); } int main() { int

Hi, I want to see the output of a InterProcedural Constant Propagation Pass IPCP in llvm. I have llvm 2.8 installed.And i used opt -print-after-all command to see the .bc output generated after each pass. However,this does not include dump produced by IPCP :( why? Kindly tell me how to view dump produced by IPCP. P.S: i have tried opt -ipcp src.bc -o src1.bc However the src.bc and src1.bc both

> On Mar 24, 2016, at 1:55 PM, Mehdi Amini <mehdi.amini at apple.com> wrote: > >> One more, just for fun: Inter-procedural stack allocation. That is of calls bar, bar needs 4 bytes of stack space. Instead of bar allocating 4 bytes, it adds an attribute to itself, then foo allocates 4 bytes of space at the bottom of the stack for bar to use. > > This is something that

Hi Vivek, [+CC Matthias, Quentin] Inter-procedural register allocation can be a big win, but my estimate is that it will be challenging to complete within one summer unless you're already familiar with LLVM's register allocator. I've CC'ed some people who can give you some more detailed information. -- Sanjoy On Tue, Feb 9, 2016 at 9:17 PM, vivek pandya via llvm-dev

The BlockFrequency analysis has been useful for machine block placement, register allocation and other function-level optimizations. How could we extend it for use in an inter-procedural (whole-program) context? For example, if we would like to compare the hotness of two call sites in different functions, or calculate the hotness of two global variables referenced in multiple functions. If the

>From the research and code I've seen - Doesn't this break regalloc down into a global and location allocation strategy? (maybe I'm remembering incorrectly) On Wed, Mar 23, 2016 at 12:04 PM, Mehdi Amini via llvm-dev <llvm-dev at lists.llvm.org> wrote: > >> On Mar 22, 2016, at 6:04 PM, Matthias Braun via llvm-dev <llvm-dev at lists.llvm.org> wrote: >>

*Vivek Pandya* On Wed, Mar 23, 2016 at 9:43 AM, C Bergström <cbergstrom at pathscale.com> wrote: > From the research and code I've seen - Doesn't this break regalloc > down into a global and location allocation strategy? (maybe I'm > remembering incorrectly) > > Yes I think you are correct. If I recall IP Reg allocation allocates some registers to varibale that

On 03/16, Fahad Nayyar wrote: > I can see that Johanned have put up some issues for GSOC aspirants. I think > that [2] <https://github.com/llvm/llvm-project/issues/179> ([Attributor] > Cleanup and upstream `Attribute::MaxObjectSize`) will be a very good issue > for me, It seems doable and I can get familiar with the whole process of > writing a patch for an issue. How should I

*Vivek Pandya* On Wed, Mar 23, 2016 at 10:18 PM, Quentin Colombet <qcolombet at apple.com> wrote: > The pass manager already has support for calligraph connected region IIRC. > If I am not wrong Quentin and Mehdi Amini refers to CallGraphSCCPass.cpp > As for the regmask part, we probably could hack something up in a week or > so, but I believe this is not what Vivek had in

David Is this true for static heuristics as well ? If the bb freqs are scaled wrt to the entry block freq and a) use such scaled freqs for the bb's that have calls b) propagate this info topologically over the call graph, how representative will be the info if one just wants to use in a comparative sense ? -Dibyendu Sent from my Windows Phone ________________________________ From: Xinliang

No need to apologize this thread surely deserved some answers :) From my perspective this project sounds doable. I would expect the register allocation parts to be not too hard: I imagine this being just distilling a new clobber regmask after allocating a function. I would expect the challenging (or annoying) part to get a machine module pass (or a similar mechanism to influence the order in

The pass manager already has support for calligraph connected region IIRC. As for the regmask part, we probably could hack something up in a week or so, but I believe this is not what Vivek had in mind. I think the main challenge of a real inter-procedural register allocator is to change all of the calling convention dynamically and more importantly convey the right information to other tools