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...ast few months (wrote a front-end for the Classroom Object Oriented Language and have been studying pieces of code.) I would like to work with LLVM and contribute to the community. For starters, I have a couple of questions. What is the GVN algorithm used in LLVM? Is it the one by Alpern, Wegman, Zadeck or Briggs, Cooper or some other? How much of PRE is done in LLVM? Are any of the well known algorithms for PRE used in LLVM? Thanks and regards, Rakshit Singla Third Year Undergrad Indian Institute of Technology Hyderabad -------------- next part -------------- An HTML attachment was scrubbed......

...y to determine if the dummy entry node is a member of the post-dominance frontier of a basic block. Is there a way to get that information? Regards, Ryan * "Efficiently Computing Static Single Assignment Form and the Control Dependence Graph" by Cytron, Ferrante, Rosen, Wegman, and Zadeck -- Ryan M. Lefever [http://www.ews.uiuc.edu/~lefever]

...iented Language and >> have been studying pieces of code.) I would like to work with LLVM and >> contribute to the community. >> >> For starters, I have a couple of questions. >> >> What is the GVN algorithm used in LLVM? Is it the one by Alpern, Wegman, >> Zadeck or Briggs, Cooper or some other? >> >> How much of PRE is done in LLVM? Are any of the well known algorithms for >> PRE used in LLVM? >> >> Thanks and regards, >> Rakshit Singla >> Third Year Undergrad >> Indian Institute of Technology Hyderabad >&...

...s LLVM MI is already in SSA form before reg allocation so for LLVM I think it does not require to build SSA graph and converting it back after optimization completed as mentioned in [1] 2 ) We would like to add a pass similar to SCCP.cpp (Sparse Conditional Constant Propagation based on Wegman and Zadeck's work http://dl.acm.org/citation.cfm?id=103136) as desribed in [1]. This pass will be scheduled to run before register allocation. 3 ) Output of the pass added in Step 2 will be a Map of def to instructions pointers (instructions which can be used to remat the given live range). The map will...

...always have a single entry node (the first BB in the function) and multiple exits are handled specially. -Chris > Regards, > Ryan > > > * "Efficiently Computing Static Single Assignment Form and the Control > Dependence Graph" by Cytron, Ferrante, Rosen, Wegman, and Zadeck > > -Chris -- http://nondot.org/sabre/ http://llvm.org/

...form before reg allocation so for LLVM I think it does not require to build SSA graph and converting it back after optimization completed as mentioned in [1] >> >> 2 ) We would like to add a pass similar to SCCP.cpp (Sparse Conditional Constant >> Propagation based on Wegman and Zadeck's work http://dl.acm.org/citation.cfm?id=103136 <http://dl.acm.org/citation.cfm?id=103136>) as desribed in [1]. This pass will be scheduled to run before register allocation. >> >> 3 ) Output of the pass added in Step 2 will be a Map of def to instructions pointers (instructi...

...n so for LLVM I >> think it does not require to build SSA graph and converting it back after >> optimization completed as mentioned in [1] >> >> 2 ) We would like to add a pass similar to SCCP.cpp (Sparse Conditional >> Constant >> Propagation based on Wegman and Zadeck's work http://dl.acm.org/citation. >> cfm?id=103136) as desribed in [1]. This pass will be scheduled to run >> before register allocation. >> >> 3 ) Output of the pass added in Step 2 will be a Map of def to >> instructions pointers (instructions which can be used...

Hi, Can someone tell which algorithm is used for GVN in LLVM? -- Rekha -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130928/ca06c78a/attachment.html>

...Pereira > (http://homepages.dcc.ufmg.br/~douglas/projects/RangeAnalysis/RangeAnalysis.paper.pdf > <http://homepages.dcc.ufmg.br/%7Edouglas/projects/RangeAnalysis/RangeAnalysis.paper.pdf>) > > 5. Constant propagation with conditional branches. Mark N. Wegman and > F. Kenneth Zadeck, In ACM Transactions on Programming Languages and > Systems (TOPLAS), 181-210, 1991. > > 6. Efficient SSI Conversion.André Luiz C. Tavares, Fernando Magno > Quintão Pereira, Mariza A. S. Bigonha and Roberto S. Bigonha. Simpósio > Brasileiro de Linguagens de Programação. 2010. >...

On Wed, Mar 23, 2011 at 6:24 PM, John Criswell <criswell at illinois.edu> wrote: > > > On 3/23/11 8:06 AM, Douglas do Couto Teixeira wrote: > > > > the execution of a program. Thus, for each integer variable, a range > > analysis determines its lower and upper limits. A very simple range analysis > > > would, for instance, map each variable to the limits

...09: 422-437 4. Linear Time Range Analysis with Affine Constraints. Douglas do Couto Teixeira and Fernando Magno Quintao Pereira ( http://homepages.dcc.ufmg.br/~douglas/projects/RangeAnalysis/RangeAnalysis.paper.pdf ) 5. Constant propagation with conditional branches. Mark N. Wegman and F. Kenneth Zadeck, In ACM Transactions on Programming Languages and Systems (TOPLAS), 181-210, 1991. 6. Efficient SSI Conversion. André Luiz C. Tavares, Fernando Magno Quintão Pereira, Mariza A. S. Bigonha and Roberto S. Bigonha. Simpósio Brasileiro de Linguagens de Programação. 2010. 7. ABCD: eliminating array bo...

...rt at the top of the dominator tree and process each node breadth first). Convert all of the instructions in each basic block (except phis). c) Revisit all the phis and plug in their new operands. 3) Delete all the old instructions. This is a variation of the SSA construction algorithm in Zadeck et. al.'s paper (Effeciently Computing Single Static Assignment Form and the Control Dependence Graph). The only tricky part is handling non-instruction operands (e.g., function arguments, global variables, etc.). Some might be trivial to convert. Others may be difficult. You should loo...

...gt; > > > > > > > > 2 ) We would like to add a pass similar to SCCP.cpp (Sparse > > > > > > Conditional Constant > > > > > > > > > > > > > > > > > > > > > Propagation based on Wegman and Zadeck's work > > > > > > http://dl.acm.org/citation.cfm?id=103136 ) as desribed in > > > > > > [1]. > > > > > > This > > > > > > pass will be scheduled to run before register allocation. > > > > > > > > &...

...tree and > process each node breadth first). Convert all of the instructions in each > basic block (except phis). > c) Revisit all the phis and plug in their new operands. > > 3) Delete all the old instructions. > > This is a variation of the SSA construction algorithm in Zadeck et. al.'s > paper (Effeciently Computing Single Static Assignment Form and the Control > Dependence Graph). > > The only tricky part is handling non-instruction operands (e.g., function > arguments, global variables, etc.). Some might be trivial to convert. > Others may be di...

On Mon, Jan 24, 2011 at 3:01 PM, Nick Lewycky <nicholas at mxc.ca> wrote: > On 01/24/2011 04:41 AM, Douglas do Couto Teixeira wrote: > >> Hi, >> >> Nick, thanks for the reply. >> I still have a problem: I only need to "clone" an Instruction, changing >> its type. That is, I would like to keep all characteristics of the old >> Instruction

On Fri, Dec 30, 2016 at 11:55 PM, Sanjoy Das <sanjoy at playingwithpointers.com > wrote: > Hi Daniel, > > On Fri, Dec 30, 2016 at 10:55 PM, Daniel Berlin <dberlin at dberlin.org> > wrote: > >> Right, but we are talking about "when, in the intermediate state, can i > >> transform an undef to a different value". > >> > >>

...otherwise > (you should just end up in overdefined more). > > I'm not sure i believe the last part though. I have to think about it. > Thanks for the comments Sanjoy, I'll have to think about it further. My problem with this is when you put undef into the equation the original Zadeck's algorithm becomes not entirely obvious. I mean, I originally thought it was only my problem, but we're here discussing (and have discussed this already in the past, so it seems it's not). > > FWIW: My initial proposal to all of this was "stop caring about trying to > op...

> > > > Also as a side note, I think in the original MachineOutliner RFC thread > there was some confusion as to whether it was possible to solve the code > folding outlining problem exactly as a graph problem on SSA using standard > value numbering algorithms in polynomial time. > > I can elaborate further, but > 1. it is easy to see that you can map an arbitrary