similar to: [LLVMdev] LTO question

On Fri, Dec 12, 2014 at 1:59 PM, Diego Novillo <dnovillo at google.com> wrote: > On 12/12/14 15:56, Adve, Vikram Sadanand wrote: >> >> I've been asked how LTO in LLVM compares to equivalent capabilities >> in GCC. How do the two compare in terms of scalability? And >> robustness for large applications? > > > Neither GCC nor LLVM can handle our

(repost the reply using my personal account -- previous reply to the list got hold up) On Thu, Dec 25, 2014 at 11:55 PM, Adve, Vikram Sadanand <vadve at illinois.edu> wrote: > Diego, Teresa, David, > > Sorry for my delayed reply; I left for vacation right after sending my message about this. > > Diego, it wasn't explicit from your message whether LLVM LTO can handle

First, kudos on the ThinLTO results reported in your blog post — they’re impressive and the system sounds really well engineered. I’m starting to try it out on a large piece of software and I’d like to make sure I know what to expect. The blog said it will be available in clang-3.9 but both clang-3.8 and trunk seem to have some degree of support for it. What is the status of ThinLTO in 3.8

Hi Teresa, Impressive results, indeed! (But no less is expected from an Itanium alumni... ;-)) One question, if you don't mind. In the blog post you wrote: "In a few cases ThinLTO even outperforms full LTO, most likely because the higher scalability of ThinLTO allows using a more aggressive backend optimization pipeline (similar to that of a non-LTO build)." Is it due to

> On Jul 22, 2016, at 12:36 PM, Teresa Johnson via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi Vikram, > > Thanks! > > I'm not sure what part got committed in the 3.8 timeframe - it looks like that was released back in March? 3.8 was branched in early January though. It has some of the work-in-progress for ThinLTO, it “could” work in simple cases I

Dear All, Here's a question Vikram and I received. Is the LLVM JIT thread safe? -- John T. -------------- next part -------------- An embedded message was scrubbed... From: "Adve, Vikram Sadanand" <vadve at uiuc.edu> Subject: Fwd: LLVM and threading Date: Thu, 1 Nov 2007 09:48:59 -0500 Size: 3037 URL:

I'm trying to decide whether to use either the MIPS or ARM back ends for course projects in our introductory compiler class. I'd like to use something that has a stable back end, so that the students can use the selector, probably without changes, and do a project on register allocation and stack layout. We don't have MIPS or ARM hardware (other than possibly a few donated Android

On Mon, Sep 4, 2017, at 20:49, Hal Finkel via llvm-dev wrote: > [tying to original thread] > > On 09/04/2017 01:37 PM, Adve, Vikram Sadanand via llvm-dev wrote: > > Hal, Tobias, et al. – > > > > I am strongly in favor of seeing a broader range of loop transformations, supported by strong dependence analysis, added to LLVM, and the Polly infrastructure seems to be by far

> On Jan 20, 2017, at 10:44 AM, Tian, Xinmin via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Sanjoy, the IR would be like something below. It is ok to hoist alloca instruction outside the region. There are some small changes in optimizer to understand region-annotation intrinsic. > > { void main() { > i32* val = alloca i32 > tok =

In this case, inliner is educated to add all local variables to the tag of enclosing parallel region, if there is enclosing parallel region. In our icc implementation, it is even simple, as we have routine level symbol table, the inliner adds ”private” attribute to those local variables w/o checking enclosing scope, the parallelizer does check and use it. Xinmin From: mehdi.amini at apple.com

> On Jan 31, 2017, at 5:38 PM, Tian, Xinmin <xinmin.tian at intel.com> wrote: > >>>>> Ok, but this looks like a “workaround" for your specific use-case, I don’t see how it can scale as a model-agnostic and general-purpose region semantic. > > I would say it is a design trade-off. I’m not sure if we’re talking about the same thing here: my understanding at

Hi Sanjoy, Yes, that's exactly what we have been looking at recently here, but the region tags seem to make it possible to express the control flow as well, so I think we could start with reg ions+metadata, as Hal and Xinmin proposed, and then figure out what needs to be first class instructions. --Vikram Adve > On Jan 19, 2017, at 11:03 PM, Sanjoy Das <sanjoy at

From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] Sent: Tuesday, January 31, 2017 9:03 PM To: Tian, Xinmin <xinmin.tian at intel.com> Cc: Sanjoy Das <sanjoy at playingwithpointers.com>; Adve, Vikram Sadanand <vadve at illinois.edu>; llvm-dev at lists.llvm.org; llvm-dev-request at lists.llvm.org Subject: Re: [llvm-dev] [RFC] IR-level Region Annotations On Jan 31,

> On Jan 20, 2017, at 11:17 AM, Tian, Xinmin <xinmin.tian at intel.com> wrote: > >>>>> This means that the optimizer has to be aware of it, I’m missing the magic here? > > This is one option. > > The another option is that, as I mentioned in our LLVM-HPC paper in our implementation. We have a "prepare phase for pre-privatization" can be invoked

> On Jan 31, 2017, at 6:48 PM, Tian, Xinmin <xinmin.tian at intel.com> wrote: > > Let me try this. > > You can simply consider the prepare-phase (e.g. pre-privatization) were done in FE (actually a library can be used by multiple FEs at LLVM IR level), the region is run with 1 thread, region annotation (scope, single-entry-single-exit) as memory barrier conservatively

> On Jan 31, 2017, at 7:53 PM, Tian, Xinmin <xinmin.tian at intel.com> wrote: > > In this case, inliner is educated to add all local variables to the tag of enclosing parallel region, if there is enclosing parallel region. So isn’t it a good example that shows that your intrinsic *cannot* be opaque and that IR passes need to be modified to handle not only the IR-region

Let me try this. You can simply consider the prepare-phase (e.g. pre-privatization) were done in FE (actually a library can be used by multiple FEs at LLVM IR level), the region is run with 1 thread, region annotation (scope, single-entry-single-exit) as memory barrier conservatively for now (instead of checking individual memory dependency, aliasing via tags which is the actual

> On Jan 31, 2017, at 10:59 PM, Tian, Xinmin <xinmin.tian at intel.com> wrote: > > >   <> > From: mehdi.amini at apple.com <mailto:mehdi.amini at apple.com> [mailto:mehdi.amini at apple.com <mailto:mehdi.amini at apple.com>] > Sent: Tuesday, January 31, 2017 9:03 PM > To: Tian, Xinmin <xinmin.tian at intel.com <mailto:xinmin.tian at

Our department outreach coordinator spotted this and forwarded it to me. It's a lot of speculation but I thought many of you would be interested. --Vikram http://www.cs.uiuc.edu/~vadve http://llvm.org Begin forwarded message: > From: "Jennifer C La Montagne" <jsandone at uiuc.edu> > Date: June 8, 2007 12:53:00 PM CDT > To: "Vikram Sadanand Adve"

Hi, I'm going to club together some responses. I agree that outlining function sub-bodies and passing in the function pointers to said outlined bodies to OpenMP helpers lets us correctly implement the semantics we need. However, unless I severely misunderstood the thread, I thought the key idea was to move *away* from that representation and towards a representation that _allows_