similar to: [LLVMdev] Optimization pass questions

Larry, On Wed, Aug 11, 2010 at 4:55 PM, Larry Gritz <lg at larrygritz.com> wrote: > I have a whole slew of questions about optimization passes. Answers to any > or all would be extremely helpful: > > How important are doInitialization/doFinalization? Most of the passes do not use them. > I can't detect any difference if I use them or not. Say, if you are writing

On Aug 11, 2010, at 4:55 PM, Larry Gritz wrote: > I have a whole slew of questions about optimization passes. Answers to any or all would be extremely helpful: > > How important are doInitialization/doFinalization? I can't detect any difference if I use them or not. Why does the function pass manager have doInitialization/doFinalization, but the global pass manager doesn't?

On Aug 11, 2010, at 5:57 PM, Tanya Lattner wrote: > Have you read this document? > http://llvm.org/docs/WritingAnLLVMPass.html#passtype Yes, but I didn't find it as instructive as I'd hoped. The only two examples of pass sets I can find are the Kaleidoscope tutorial and StandardPasses.h (corresponding, I assume, to what llvm-gcc does). Just looking at the two of these, some

This may seem odd, but I want to really encourage the list to help Larry Gritz with this issue. I've been following the development of his project (OpenShadingLanguage) for months now and he has a *very* good use case for LLVM. It may be tempting to just "send him to the docs", but if anyone here can help take their use of LLVM to the next level, I can tell you that many, many people

OK, fine -- an example of MCJIT that sets up for PTX JIT would also be helpful. On Dec 6, 2013, at 12:32 PM, Eli Bendersky <eliben at google.com> wrote: > > You'll have to switch to MCJIT for this purpose. Legacy JIT doesn't emit PTX. > > Eli -- Larry Gritz lg at larrygritz.com -------------- next part -------------- An HTML attachment was scrubbed... URL:

Thanks for the pointer, it's always helpful to be able to see how another project solved similar problems. > On Mar 8, 2016, at 11:24 AM, Andy Ayers <andya at microsoft.com> wrote: > > FWIW, LLILC (https://github.com/dotnet/llilc) uses MCJIT with a custom memory manager to hold onto the binary bits and discard the rest. > > As far as I know it doesn't leak, though

Ah, that's helpful. I knew that I'd need to end up with PTX as text, not a true binary, but I would have figured that it would come out of MCJIT. Thanks for helping to steer me away from the wrong trail. OK, one more question: Can anybody clarify the pros and cons of generating the PTX through the standard LLVM distro, versus using the "libnvvm" that comes with the Cuda SDK?

Thanks for the pointers. Am I correct in assuming that putting the precompiled bitcode into a second module and linking (or using the object caches) would result in ordinary function calls, but would not be able to inline the functions? -- lg On Jan 21, 2014, at 11:55 AM, Kaylor, Andrew <andrew.kaylor at intel.com> wrote: > I would say that the incompatibility is by design. Not

There is no MCJIT support for PTX at the moment (mainly because PTX does not have a binary format, and is not machine code per se). To generate PTX at run-time, you just set up a standard codegen pass manager like you would like an off-line compiler. The output will be a string buffer that contains the PTX, which you can load into the CUDA runtime. As for determining if PTX support is compiled

On Aug 18, 2010, at 10:24 AM, Reid Kleckner wrote: > You can free the machine code yourself by saying > EE->freeMachineCodeForFunction(F) . If you destroy the EE, it will > also free the machine code. Thanks, but unfortunately, this is exactly the opposite of what I want to do. I need to retain the machine code indefinitely, but I want to free all possible other resources that are

YES. My use of LLVM involves an app that JITs program after program and will quickly swamp memory if everything is retained. It is crucial to aggressively throw everything away but the functions we still need to execute. I've been faking it with old JIT (llvm 3.4/3.5) by using a custom subclass of JITMemoryManager that squirrels away the jitted binary code so that when I free the Modules,

Is there a succinct way I can get the full list of which optimization passes are applied, and in what order, for standard clang -O1, -O2, -O3? -- Larry Gritz lg at larrygritz.com

I have an app that's dynamically generating and JITing code, and will have many such cases in the course of its run. They need to be JITed separately, because I need to execute the first batch before I know what the second one will be. Of course, I *still* need to execute the first after the need for the second arises, so I need to retain the JITed machine code for all the functions I

I wonder in what cases FunctionPass is better that Pass. For example, addPassesToEmitAssembly takes PassManger and addPassesToJITCompile takes FunctionPassManager. Another question is about FunctionPassManager::run(Function&) and FunctionPass(Function&). The former calls the later, which is fine, but the latter looks like this: bool FunctionPass::run(Function &F) { if

Hi, I would like to run the -O1 pass sequence followed by -reg2mem from an out of tree project which uses llvm. I am using the following code snippet to do so but in some cases, my method is also vectorising the code, which doesn't happen when running the same sequence(-S -O1 -reg2mem) through opt. Can someone please help me find what I am missing? Thanks, Akash. *

This is sounding rather like getLazyBitcodeModule is simply incompatible with MCJIT. Can anybody confirm that this is definitely the case? Is it by design, or by omission, or bug? Re your option #1 and #2 -- sorry for the newbie questions, but can you point me to docs or code examples for how the linking or object caching should be achieved? If I do either of these rather than seeding my

I have an app that uses LLVM API calls from C++ to generate IR and JIT it for x86 (for subsequent live execution). I'm still using the old JIT, for what it's worth. I want to modify it (for prototype/experimental purposes for now) to JIT PTX (into a big string buffer?). Docs are sketchy. I can wade through it and figure it out by trial and error, but would be so very happy if somebody

Thanks so much! This seems to do the trick. I would have spun my wheels for a long time before discovering all of this, wow. Do I even want to know what additional chickens need to be sacrificed to get this to work on Windows? -- lg > On May 18, 2016, at 1:52 PM, Lang Hames <lhames at gmail.com> wrote: > > Hi Larry, > > You're basically there, but you're hitting

On Aug 17, 2010, at 10:11 AM, Owen Anderson wrote: > In principle this ought to work, if you're careful. Are you sure you're not generating code that calls into functions that got totally inlined away? How would I know? > Are you running the Verifier pass at regular intervals? Yes, both before and after the set of optimization passes. So let me clarify what I'm doing: I

Hi folks, just installed the new llvm 1.9 build and noticed that my code no longer worked. It seems something has changed with addPassesToEmitFile(). First, the arguments to that method changed so that it no longer takes a PassManager, but only a FunctionPassManager. Instead there is a addPassesToEmitWholeFile() method, but that is marked as optional, and when I change my code to