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I seem to recall that LLVM had a Chaitin/Briggs register allocator, but looking at today's source, I only see a Linear Scan and some basic block allocators. Does anyone know if a Chaitin/Briggs allocator for LLVM exists and is available? Peter

Hi, We noticed that LLVM has implemented register allocation using PBQP and Briggs as a heuristic for spilling. Is there a direct implementation of the Chaitin-Briggs register allocation algorithm? We intend to modify parts of this algorithm in order to implement a variant of it. It will save us a lot of time if it is already implemented, rather than writing the code from scratch...

On Wed, Oct 3, 2012 at 10:15 AM, Matthieu Moy <Matthieu.Moy at grenoble-inp.fr> wrote: > Preston Briggs <preston.briggs at gmail.com> writes: >> Think about costs asymptotically; that's what matters. Calls and >> returns require constant time, just like addition and multiplication. > > Constant time, but not necessarily constant memory. > > Deep recursion will blow u...

On 11/02/2012 11:02 AM, Hal Finkel wrote: > ----- Original Message ----- >> From: "Tobias Grosser" <tobias at grosser.es> >> To: "preston briggs" <preston.briggs at gmail.com> >> Cc: "Benjamin Kramer" <benny.kra at gmail.com>, "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> >> Sent: Friday, November 2, 2012 12:56:53 PM >> Subject: Re: [LLVMdev] DependenceAnalysis and PR142...

...ainst revison 167719 ? Thanks in advance. On Tue, Nov 13, 2012 at 9:41 AM, Arnaldo <arnaldo.cruz at upr.edu> wrote: > Preston, thanks for the explanation and patch. Now it's printing the > direction and distance values. > > > On Tue, Nov 13, 2012 at 12:22 PM, Preston Briggs <preston.briggs at gmail.com > > wrote: > >> Erkan, you're right. Sorry about that. >> Attached is the most recent version. >> >> Preston >> >> >> >> Hi Preston, >>> I am trying to use DA as well. I used your example and comma...

...example and commands that you > wrote in order to get DA information. > However, it does not report any dependence info. > I am wondering whether your local copy differs from the one on the > repository ? > Thanks. > Erkan. ---------- Forwarded message ---------- From: Preston Briggs <preston.briggs at gmail.com> Date: Wed, Nov 7, 2012 at 12:51 PM Subject: DependenceAnalysis patch To: "llvm-commits at cs.uiuc.edu" <llvm-commits at cs.uiuc.edu>, Chandler Carruth <chandlerc at google.com>, Hal Finkel <hfinkel at anl.gov>, Benjamin Kramer < ben...

Hi, We noticed that LLVM has implemented register allocation using PBQP and Briggs as a heuristic for spilling. Is there a direct implementation of the Chaitin-Briggs register allocation algorithm? We intend to modify parts of this algorithm in order to implement a variant of it. It will save us a lot of time if it is already implemented, rather than writing the code from scratch...

Preston, thanks for the explanation and patch. Now it's printing the direction and distance values. On Tue, Nov 13, 2012 at 12:22 PM, Preston Briggs <preston.briggs at gmail.com>wrote: > Erkan, you're right. Sorry about that. > Attached is the most recent version. > > Preston > > > > Hi Preston, >> I am trying to use DA as well. I used your example and commands that you >> wrote in order to get DA...

...Jr.: http://repository.readscheme.org/ftp/papers/ai-lab-pubs/AIM-443.pdf It's a pretty old paper, but it is exactly about your original question. By the end, you'll probably know more about tail calls as you'll ever need to know :) -- Sean Silva On Wed, Oct 3, 2012 at 1:28 PM, Preston Briggs <preston.briggs at gmail.com> wrote: > On Wed, Oct 3, 2012 at 10:15 AM, Matthieu Moy > <Matthieu.Moy at grenoble-inp.fr> wrote: >> Preston Briggs <preston.briggs at gmail.com> writes: >>> Think about costs asymptotically; that's what matters. Calls and &gt...

...eads to inaccuracies when a range is introduced by a copy. But perhaps I should focus on the links and, as you suggested, the debugging info. Thanks, Preston On Mon, Sep 10, 2018 at 5:02 PM, Matthias Braun <mbraun at apple.com> wrote: > > > On Sep 10, 2018, at 4:53 PM, Preston Briggs <preston.briggs at gmail.com> > wrote: > > > > The underlying liveness datastructure is a list of ranges where each > vreg is alive > > (ranges in terms of instructions numbered). I remember a couple of later > linear scan > > papers describing the same thing...

...al variables seems to work if I do it by hand. Kind of embarassing though, don't you think, introducing an indirection to achieve better code? Thanks, Preston On Wed, Dec 9, 2015 at 9:17 AM, Mehdi Amini <mehdi.amini at apple.com> wrote: > > On Dec 9, 2015, at 9:00 AM, Preston Briggs <briggs at reservoir.com> wrote: > > I suppose your view is reasonable, and perhaps common. > My own "taste" has always preferred machine-independent code > that is as simple as possible, so GEPs reduced to nothing more than an > add, etc, i.e., quite risc-like. Then...

On 11/02/2012 10:21 AM, Preston Briggs wrote: > > My initial guess is that a conservative fix is quick and small (make > sure the underlying pointers are loop invariant, otherwise give up). A > better approach would be to somehow turn code like the example into > array references that can be analyzed. I'll need to thi...

...ston On Fri, Nov 2, 2012 at 11:08 AM, Tobias Grosser <tobias at grosser.es> wrote: > On 11/02/2012 11:02 AM, Hal Finkel wrote: > >> ----- Original Message ----- >> >>> From: "Tobias Grosser" <tobias at grosser.es> >>> To: "preston briggs" <preston.briggs at gmail.com> >>> Cc: "Benjamin Kramer" <benny.kra at gmail.com>, "LLVM Developers Mailing >>> List" <llvmdev at cs.uiuc.edu> >>> Sent: Friday, November 2, 2012 12:56:53 PM >>> Subject: Re: [LLVMdev] Dep...

...its/Week-of-Mon-20121112/155651.html - Ben On Tue, Nov 13, 2012 at 9:41 AM, Arnaldo <arnaldo.cruz at upr.edu> wrote: > Preston, thanks for the explanation and patch. Now it's printing the > direction and distance values. > > > On Tue, Nov 13, 2012 at 12:22 PM, Preston Briggs <preston.briggs at gmail.com > > wrote: > >> Erkan, you're right. Sorry about that. >> Attached is the most recent version. >> >> Preston >> >> >> >> Hi Preston, >>> I am trying to use DA as well. I used your example and comma...

----- Original Message ----- > From: "Tobias Grosser" <tobias at grosser.es> > To: "preston briggs" <preston.briggs at gmail.com> > Cc: "Benjamin Kramer" <benny.kra at gmail.com>, "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> > Sent: Friday, November 2, 2012 12:56:53 PM > Subject: Re: [LLVMdev] DependenceAnalysis and PR14241 > &gt...

...en > a Load is not directly linked to an Alloca), so I can identify : > > if ( ( I2 is dependent on I1 ) and ( I3 is dependent on I4 ) ) => I can > check if I3 and I2 are dependent => indirectly I4 is dependent on I1 > > > > On Thu, Jan 24, 2013 at 6:03 PM, Preston Briggs <preston.briggs at gmail.com > <mailto:preston.briggs at gmail.com>> wrote: > > > I tried methods related to point 1) suggested by you, > > but I still have problems of finding dependencies. > > What exactly I want to do: > > > &...

...r own personal code, their important loop, and wonder why there are unnecessary copies right *there* and wasn't this problem solved ages ago? Preston On Tue, Sep 11, 2018 at 11:00 AM, Quentin Colombet < quentin.colombet at gmail.com> wrote: > Le mar. 11 sept. 2018 à 10:23, Preston Briggs > <preston.briggs at gmail.com> a écrit : > > > > Hi, > > > > Using Chaitin's approach, removing a copy via coalescing could expose > more opportunities for coalescing. > > So he would iteratively rebuild the interference graph and check for > more o...

...vel during instruction selection, taking advantage of available instructions. I guess my whole scheme of using opt in this context is probably wrong headed. Thanks On Wed, Dec 9, 2015 at 8:45 AM, Mehdi Amini <mehdi.amini at apple.com> wrote: > > On Dec 9, 2015, at 7:58 AM, Preston Briggs <briggs at reservoir.com> wrote: > > I'm trying to make the IR "better", in a machine-independent fashion, > without having to do any lowering. > > > The question is “would the IR be more canonical” with the representation > you suggest? Why would the optimi...

On Sun, 7 Oct 2012 18:53:59 -0700 Preston Briggs <preston.briggs at gmail.com> wrote: > I'd like a value, call it Bottom, such that > > SE->getAddExpr(Bottom, X) => Bottom > SE->getMulExpr(Bottom, X,) => Bottom > isKnownPredicate(any, Bottom, X) => false > etc. > > > I can write code to make...

> On Sep 10, 2018, at 5:25 PM, Matthias Braun <mbraun at apple.com> wrote: > > > >> On Sep 10, 2018, at 5:11 PM, Preston Briggs <preston.briggs at gmail.com <mailto:preston.briggs at gmail.com>> wrote: >> >> The phi instruction is irrelevant; just the way I think about things. >> The question is if the allocator believes that t0 and t2 interfere. >> >> Perhaps the coalescing examp...