search for: ssa

Hi, Silly question from an LLVM newbie: the LLVM LRM say that the bytecode is "is an SSA based representation". Indeed, my experience with llvm-gcc is that the generated code is not necessarily SSA, while the one given by "llvm-gcc -O1" is. Is this assumption correct? Is there a non-SSA to SSA translator available? Thanks, -- Matthieu

All register uses are SSA. Memory is not in SSA. The mem2reg pass which promotes stack variables to registers effectively converts non- SSA to SSA. There was a reg2mem pass, written by Andrew Lenharth, I'm not sure if it's still being maintained. On Jul 7, 2008, at 8:47 AM, Matthieu Moy wrote: > Hi, &gt...

[ sorry for the late reply ] Patrick Meredith <pmeredit at uiuc.edu> wrote: > All register uses are SSA. Memory is not in SSA. The mem2reg pass > which promotes stack variables to registers effectively converts non- > SSA to SSA. There was a reg2mem pass, written by Andrew Lenharth, I'm > not sure if it's still being maintained. What is the difference between register and me...

Thanks John, The reason I want to do this is that register allocator works only on SSA form, and if you instrument regallocated code with non-regallocated machine instructions, then you cannot regallocate the result. A workaround is to assign physical registers while doing the instrumentation, which I don't think is as easy as the above. On Tue, Sep 23, 2014 at 11:01 AM, John C...

Hello to all LLVM Developers. The LLVM IR is in strict SSA form (i.e. every variable is defined before it is used along every path from the entry to exit point)? According 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 optimiza...

Hi, I'm wondering how I can convert "register allocated" code back to SSA form. I realized from MachineRegisterInfo.h that a function leaves SSA form only once and cannot be taken back to it. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140923/0124addd/attachment.html>

Memory is what the i32* points too. The i32* itself is in a register. You can store to it as many times as you want, but you can't change the address, because that would violate SSA. On Jul 17, 2008, at 4:26 AM, Matthieu Moy wrote: > [ sorry for the late reply ] > > Patrick Meredith <pmeredit at uiuc.edu> wrote: >> All register uses are SSA. Memory is not in SSA. The mem2reg pass >> which promotes stack variables to registers effectively converts...

Hi LLVM community, Currently LLVM backend do pre-RA machine instruction scheduling in non-SSA form, I doubt why not do machine scheduling in SSA machine instruction form? Now LLVM’s machine scheduling uses a list-scheduling algorithm, but if we wang to support more complex scheduling algorithms, for example, modulo scheduling for loops, it seems more easy to accomplish this in SSA form as S...

Hi, We are planning to implement an analysis and optimization specifically meant for non-SSA code. We would like to know whether LLVM supports non-SSA IR? The other choice we have is to work with the GIMPLE code of GCC. We need your help in choosing the appropriate framework. thanks Saleena N National Institute of Technology Calicut India -------------- next part -------------- An HTML att...

Hi, Diego, Thanks for your quick reply. Inserting a copy instruction may not work here because I have a limitation of virtual register number. I need to assign registers with ssa form to registers without ssa form. I will look the source code you point out. Thanks Xiangyang On Fri, Apr 24, 2015 at 4:19 PM, Diego Novillo <dnovillo at google.com> wrote: > > > On Fri, Apr 24, 2015 at 3:17 PM, Xiangyang Guo <xguo6 at ncsu.edu> wrote: > >> Hi, &...

Hello everyone, We are working on a particular points-to analysis. The final output of that analysis should not have the LLVM SSA temporaries (like, %0, %1). My doubt is that whether we can extract the normal C variables from LLVM IR or is there any way to differentiate between SSA temporary and local C variable? For e.g. in GCC I can check whether a particular variable is an SSA temporary like, if(TREE_CODE(t) == SSA_...

...as much as it does to me. :) > This includes researchers at Rice, Argonne, and LLNL. Great! > John Mellor-Crummey has discussed the possibility of us incorporating > parts of LLVM into OpenAnalysis. For now, we have some specific > questions about LLVM. >>> - LLVM is in SSA. It is in SSA before alias analysis has been >>> performed. With OA, it has been mentioned that the SSA generation is >>> incorrect because it doesn't take alias analysis information into >>> account. This seems logical, because the definition of SSA requires >...

Hi, I am wondering if there are options that can be given to LLVM can be used to generate code that is not in SSA, but in plain 3-address form ? (for example, if there is an existing pass that does the register allocation and dead variable elimination) For example, if I have: int x = 0; void main() { x++; x++; } I guess, if that is not the case, then, one needs to write their own pass. I have writt...

Hi All, Another nls related problem (for background, I'm migrating a complicated modelling package from S-plus to R). Below I've reduced this to the minimum necessary to demonstrate my problem (I think); the real situation is more complicated. Two similar selfStart functions, ssA and ssB. The 'initial' function for ssB modifies its arguments a little and then calls getInital for ssA. In addition to the "x" and the fitted coefficients (&quo...

hi all I read LLVM manual, and have a question in the LLVM IR. The IR is low-level SSA based instruction set. I want to know what the difference between the LLVM IR and SSA form? They are same, similar to tree-ssa of GCC convertion GIMPLE tree to SSA and convert back when optimizations finish? or just attach the SSA info in the LLVM IR? Thanks for your feedback. -Joey ---------...

I am familiar with the LLVM IR a little bit and I am parsing much more complex examples. I just gave this example, to show that I would like to have only 1 variable, not 2, the way SSA would generate it. I am actually using LLVM purely as a front end to translate to .bc files and then I have my own parser from there. At any rate, is there an option to the llvm-gcc --emit-llvm to tell it to produce .bc files that are at least space optimized (or even better, not in SSA form) ? t...

Hi, does LLVM have a mechanism to automatically update SSA form, e.g. after insertion of additional definitions of a variable? This would recursively traverse the dominance tree of all uses of the definition backwards and insert phi-functions where ever they are needed. http://portal.acm.org/citation.cfm?id=277656&dl=GUIDE, (Paragraph 4.5) provides an...

ivtm <martinaide1 at yahoo.com> writes: > I am wondering if there are options that can be given to LLVM can be used to > generate code that is not in SSA, but in plain 3-address form ? (for > example, if there is an existing pass that does the register allocation and > dead variable elimination) > > For example, if I have: > > int x = 0; > > void main() > { > x++; > x++; > } > > I guess, if that is no...

I am experimenting with LLVM optimizer and found that the bit code file clang emits is already in SSA form, but I want to generate it in non-SSA form. Would you let me know if there is any way of doing it? Cheera,Amruth -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120613/9439e9cb/attachment.ht...

> llvm-gcc HelloWorld.c > /home/LLVM/install/lib/gcc/arm-elf/4.2.1/../../../../arm-elf/bin/ld: this linker was not configured to use sysroots > collect2: ld returned 1 exit status > > I would appreciate some help from you. You have to pass --with-sysroot when building binutils too. > Corina Cheers, -- Rafael Ávila de Espíndola