similar to: [LLVMdev] Chaitin-Briggs Register Allocation in LLVM

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. Thanks and

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

> On Sep 11, 2018, at 11:42 AM, Quentin Colombet <quentin.colombet at gmail.com> wrote: > > Le mar. 11 sept. 2018 à 11:23, Preston Briggs > <preston.briggs at gmail.com> a écrit : >> >> Yes, I quite liked the things I've read about the PBQP allocator. >> >> Given what the hardware folks have to go through to get 1% improvements in scalar code,

Yes, I quite liked the things I've read about the PBQP allocator. Given what the hardware folks have to go through to get 1% improvements in scalar code, spending 20% (or whatever) compile time (under control of a flag) seems like nothing. And falling back on "average code" is a little disingenuous. People looking for performance don't care about average code; they care about

On Saturday 01 May 2010 08:34:50 Josef Eisl wrote: > Hello, > > I want learn more about register allocation and do some analysis for a > current research project. After reading some papers (eg. Chaitin, > Briggs) I think its time to get my hands dirty :). Welcome! > First I plan to (re)implement some of the classic approaches to get > familiar with the framework. Before

Hello, I want learn more about register allocation and do some analysis for a current research project. After reading some papers (eg. Chaitin, Briggs) I think its time to get my hands dirty :). First I plan to (re)implement some of the classic approaches to get familiar with the framework. At the beginning the following questions came up: - Is there some documentation about register allocation

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 opportunities. Chaitin was also careful to make sure that the source and destination of a copy didn't interfere unnecessarily (because of the copy alone); that is, his approach to interference was very

David Greene wrote: > On Saturday 01 May 2010 08:34:50 Josef Eisl wrote: >> Hello, >> >> I want learn more about register allocation and do some analysis for a >> current research project. After reading some papers (eg. Chaitin, >> Briggs) I think its time to get my hands dirty :). > > Welcome! > >> First I plan to (re)implement some of the classic

Hi Matthias, Thanks for your hint! It is just for learning and practicing for me, just like migrate DragonEgg http://lists.llvm.org/pipermail/llvm-dev/2017-September/117201.html the motivating is for learning from GCC and LLVM developers. 在 2017年12月19日 10:07, Matthias Braun 写道: > > >> On Dec 18, 2017, at 9:52 AM, Leslie Zhai via llvm-dev >> <llvm-dev at lists.llvm.org

On Sep 26, 2011, at 4:22 AM, Leo Romanoff wrote: > Hi Jakob, > > Thanks for a very interesting description of the new register allocation algorithm in LLVM!!! > > Could you elaborate a bit on the following topics: > > 1) Do you have any plans to publish something more formal and detailed about this algorithm, e.g. a paper or something similar? It would be nice to better

On 11/13/2011 8:57 PM, NAKAMURA Takumi wrote: > AFAIK, on msys, trunk and release_30 is almost fine. > http://bb.pgr.jp/builders/clang-i686-msys Though, here is no builder > on win32 with --enable-shared. I'm having a problem now, building Release Candidate 3 on msys (using msysGit environment, which I find the easiest to set up and keep isolated); with --enable-optimized

Hi All, I've just committed some changes to the PBQP allocator which are designed to make it easier to implement custom register allocation constraints. This is a quick summary of those changes, and of the status of the PBQP allocator in general. First a quick bit of background: The PBQP allocator is based on ideas described in [1]. I implemented this algorithm (with the improved heuristic

Hi Jakob, Thanks for a very interesting description of the new register allocation algorithm in LLVM!!! Could you elaborate a bit on the following topics: 1) Do you have any plans to publish something more formal and detailed about this algorithm, e.g. a paper or something similar?  It would be nice to better understand how this algorithm relates to well-known algorithms described in the

Thanks Lang! I think we can use linear scan as work around for short term. Thanks for your help. Regards Sachin > -----Original Message----- > From: Lang Hames [mailto:lhames at gmail.com] > Sent: Sunday, November 15, 2009 10:08 AM > To: Sachin Punyani - I00202 > Cc: llvmdev at cs.uiuc.edu > Subject: Re: [LLVMdev] Crash in PBQP register allocator > > Hi Sachin, >

Hi Jakob, Hi Andy, First of all, thanks a lot for very elaborative and interesting answers! > It may be more helpful to explain how LLVM's register allocator came > into existence before debating the high level algorithm. > > When I began working on LLVM last October, Jakob was developing an > infrastructure for global live range splitting. It was just becoming > clear

Hi Leslie, I suggest adding these 3 papers to your reading list. Register allocation for programs in SSA-form Sebastian Hack, Daniel Grund, and Gerhard Goos http://www.rw.cdl.uni-saarland.de/~grund/papers/cc06-ra_ssa.pdf Simple and Efficient Construction of Static Single Assignment Form Matthias Braun , Sebastian Buchwald , Sebastian Hack , Roland Leißa , Christoph Mallon , and Andreas

Hi Sachin, Yes. Bernhard Scholz and I have just discussed a fix for this. I hope to commit it in the next few days. I will let you know as soon as it goes in to the mainline. Regards, Lang. On Tue, Dec 15, 2009 at 5:34 PM, <Sachin.Punyani at microchip.com> wrote: > Hi Lang, > > Thanks for your inputs on the problem. I was just curious to know if you > got any opportunity to

Hi all, Just wanted to announce that I've implemented a preliminary version of a Chaitin-Briggs graph coloring register allocator for the LLVM x86 back-end. Right now, as it stands, the allocator works correctly for the benchmarks that I tested it on (from the LLVM test suite and some of the SPEC benchmarks). It performs better than the local register allocator in terms of spills and

Hi Sachin, Confirmed: This is being caused by a subtle issue in the heuristic PBQP solver. Specifically: R1/R2 reductions as currently implemented can, on rare occasions, lead to the heuristic solver failing to find a finite cost solution, even though one exists. The infinite cost solution will always be in violation of some rule of register allocation (failing to handle an interference, or

Hi Lang, Thanks for your inputs on the problem. I was just curious to know if you got any opportunity to work on the solution for this. Regards Sachin > -----Original Message----- > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On > Behalf Of Sachin.Punyani at microchip.com > Sent: Tuesday, November 17, 2009 12:00 PM > Subject: Re: [LLVMdev] Crash