search for: outlin

Hey Everybody, A little while ago I posted an RFC( http://lists.llvm.org/pipermail/llvm-dev/2017-July/115666.html) with the proposition of adding a new outliner at the IR level. There was some confusion and many questions regarding the proposal which I’d like to address here: Note about nomenclature: Candidate: A repeated sequence of instructions within a module. Occurrence: One instance of a candidate sequence. -- Accompanied Graph Data -- Gr...

In general I would love to see an outliner at the IR level also. But rather than a comparison vs. the machine outliner I would like to learn more about how the core data structures between the outliners will be shared. In particular for matching/pruning it seems to be a reasonable approach. A few more remarks/questions are below also. Th...

Hey Gerolf, On Thu, Sep 21, 2017 at 7:10 PM, Gerolf Hoflehner <ghoflehner at apple.com> wrote: > In general I would love to see an outliner at the IR level also. But > rather than a comparison vs. the machine outliner I would like to learn > more about how the core data structures between the outliners will be > shared. > The only structure that needs to be shared is a struct defining what an outlining candidate looks li...

> On Sep 21, 2017, at 8:02 PM, River Riddle <riddleriver at gmail.com> wrote: > > Hey Gerolf, > > On Thu, Sep 21, 2017 at 7:10 PM, Gerolf Hoflehner <ghoflehner at apple.com <mailto:ghoflehner at apple.com>> wrote: > In general I would love to see an outliner at the IR level also. But rather than a comparison vs. the machine outliner I would like to learn more about how the core data structures between the outliners will be shared. > > The only structure that needs to be shared is a struct defining what an outlining candidate looks like. >...

Hi R-help I am trying to mask the ocean from an image plot I have made. Here is some example code: library(mapdata) image(x=110:155, y =-40:-10, z = outer(1:45, 1:30, "+"), xlab = "lon", ylab = "lat") outline <- map("worldHires", plot=FALSE) # returns a list of x/y coords xrange <- range(outline$x, na.rm=TRUE) # get bounding box yrange <- range(outline$y, na.rm=TRUE) xbox <- xrange + c(-2, 2) ybox <- yrange + c(-2, 2) # create the grid path in the current device polypath(...

...liner in opt. Would appreciate any feedback that folks might have. # Partial Inlining in LLVM opt ## Summary ### Background Currently, the partial inliner searches the first few blocks of the callee and looks for a branch to the return block (ie. early return). If found, it attempts to outline the rest of the slow (or heavy) code so the inliner will be able to inline the fast (or light) code. If no early returns are found, the partial inliner will give up. As far as I can tell, BlockFrequency and BranchProbability information is only used when attempting to inline the early return...

Hi Jessica, Thanks for the feedback. I believe the existing partial inliner pass does use some common utilities like the code extractor to do outlining. Is that what you're referring to? I don't recall seeing any other passes that has outlining other than the machine outliner, but I may have missed something. I briefly looked at River's RFC and it seems he's mainly utilizing outlining as a tool to reduce code size while mainta...

I think that, given previous discussion on the topic, we might want a split like this: (1) Search structure Suffix tree or suffix array. (2) Numbering/mapping/congruence scheme Every outliner should implement a function that maps instructions (or whatever structure you want to outline, crazy thoughts…) to integers. That should be passed to the search structure, which will return a list of repeated sequences. The MachineOutliner currently has an “InstructionMapper” struct in it. I thi...

Hi all, The MachineOutliner has come a long way since the original incarnation presented at the 2016 LLVM Developer's Meeting [1]. In particular, we've been pushing a lot on the AArch64 target for the MachineOutliner. It's mature enough at this point that we'd like to take things a step further and turn it o...

Hi Chris, > One particular disagreement that I think very much needs to be revisited in this thread was Jessica's proposal of a pipeline of: > 1. IR outline > 2. Inline > 3. MIR outline IMHO, there is no need to restrict a place of the Outliner in the pipeline at the moment. I hope people representing different architectures will try different configurations and the best will be chosen. I’d like to try the pipeline configuration: 1. Inl...

Hi David, So I've began doing some implementation on the outlining portion of the code. Currently, I got the partial inliner to outline cold regions (single entry, single exit) of the code, based solely on the existence of ProfileSummaryInfo (ie. profiling data). However, I have some concerns on how this will co-exist with the existing code that peels early r...

Hi David, The only reason I can see to use the 'pattern matching' part as a fall-back is in case we cannot inline the (what I'm assuming would be) a much bigger hot-path-only cloned function for whatever reason. What I'm assuming here is that after cold-region outlining, we may still have a large portion of the original function body to attempt to inline, whereas the pattern matching method will only contain a few basic blocks, giving a better chance to inline something. For your (2) point, I think we'll have to be careful here. Without a sense of how ...

I second the fact that a way to outline specific function regions independently of the partial inliner sound very useful. I am not sure however if we would want a mode within the partialInliner or something completely independent. As a general question, does anybody has a clear idea of what are the constraints on the region CodeExtra...

...l road blocks that prevented it from really going anywhere( like > the inliner not preserving pgo data) but those problems should be gone by > now. > Some thoughts: > > : In terms of cost modeling, you will want to consider the interaction > with loops: > - Whats the impact of outlining from inside of a loop. > - What if the hot region does not include the entry/exit, i.e hot loop. > > : Something that would also benefit, but would require more tuning, is the > relationship between size and "hotness". If for example you have a function > that looks lik...

..."? Given that there are a number of disagreements and opinions floating around I think it benefits us all to speak clearly about who is taking what stances. One particular disagreement that I think very much needs to be revisited in this thread was Jessica's proposal of a pipeline of: IR outline Inline MIR outline In your response to that proposal you dismissed it out of hand with "feelings" but not data. Given that the proposal came from Jessica (a community member with significant relevant experience in outlining), and it was also recognized as interesting by Eric Christopher...

Hi, On Wed, Jul 26, 2017 at 12:54 PM, Sean Silva <chisophugis at gmail.com> wrote: > The way I interpret Quentin's statement is something like: > > - Inlining turns an interprocedural problem into an intraprocedural problem > - Outlining turns an intraprocedural problem into an interprocedural problem > > Insofar as our intraprocedural analyses and transformations are strictly > more powerful than interprocedural, then there is a precise sense in which > inlining exposes optimization opportunities while outlining doe...

Hi Evgeny, I know of the current machine outliner in LLVM. If you look in the "More detailed performance data" in the end section it includes performance comparisons to the machine outliner. As for the algorithmic approach they are kind of similar. Machine Outliner: - Builds a suffix tree based on identical equivalence between mach...

Hi, On Wed, Jul 26, 2017 at 10:10 AM, Quentin Colombet via llvm-dev <llvm-dev at lists.llvm.org> wrote: > No, I mean in terms of enabling other optimizations in the pipeline like > vectorizer. Outliner does not expose any of that. I have not made a lot of effort to understand the full discussion here (so what I say below may be off-base), but I think there are some cases where outlining (especially working with function-attrs) can make optimization easier. It can help transforms that duplicat...

...and adding $0.02 to the "IR outline + inline + MIR outline" idea, my gut feeling (yes, only a "feeling" -- and one coming from my gut, not head!) is that inlining correcting wrong IR outlining decisions with MIR outlining correcting wrong inlining decisions is absolutely unrealistic and a heuristics nightmare at best....

I’m River and I’m a compiler engineer at PlayStation. Recently, I’ve been working on an interprocedural outlining (code folding) pass for code size improvement at the IR level. We hit a couple of use cases that the current code size solutions didn’t handle well enough. Outlining is one of the avenues that seemed potentially beneficial. -- Algorithmic Approach -- The general implementation can be explained...