similar to: [LLVMdev] LLVM vs GCC binary performance

Hi Yuli, > As a developer I'm very excited and interested in the LLVM project. Though my > knowledge of the details is cursory my general understanding is that the SSA > code that LLVM front ends produce is supposed to allow for optimizations that > are unfeasible in GCC. not so, GCC also uses SSA form. I'm not aware of any optimization that LLVM can do that GCC couldn't

On 11 March 2011 14:53, Duncan Sands <baldrick at free.fr> wrote: > There's no magic bullet.  The things to improve that would give you the most > bang for your buck are probably the code generator and auto-vectorization. > Increasing the number of developers would be helpful. I'm not a GCC expert, but their auto-vectorization is not that great. It may be simple to do basic

Hi, How do I anchor z=0 to the white color in a levelplot so that the color changes from cyan to magenta precisely as z changes from negative to positive? Also is it easy to change color scheme, say to blue/red as it's more dramatic? Is there a better function for showing heatmap with a color bar? Thanks in advance for any help, I've played with image, heatmap and levelplot a little and

Hi, Gerolf. We've been a bit quiet for some time. After listening to feedback on the project internally and externally, we decided to take a more generally accepted community development model ---- building up through a collection of small incremental changes ---- than trying to make a big step forward. That change of course took a bit of time, but we are getting close to the first NFC patch

Hi Hideki, Thanks for the interesting writeup! > On Aug 27, 2016, at 7:15 AM, Renato Golin via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > On 25 August 2016 at 05:46, Saito, Hideki via llvm-dev > <llvm-dev at lists.llvm.org> wrote: >> Now, I have one question. Suppose we'd like to split the vectorization decision as an Analysis pass and vectorization

Hi, As a follow up to Patch D23646 <https://reviews.llvm.org/D23646>, I'm trying to figure out if there should be an alignment check and what the correct approach is. Some background: For stores, the pass turns: %i.vec = shuffle <8 x i32> %v0, <8 x i32> %v1, <0, 4, 8, 1, 5, 9, 2, 6, 10, 3, 7, 11> store <12 x i32> %i.vec, <12 x i32>* %ptr

On 1 July 2015 at 17:15, Russell Wallace <russell.wallace at gmail.com> wrote: > I'm proposing that LLVM unilaterally replace most undefined behaviour with > implementation-defined behaviour. That's precisely the problem. Which behaviour? Let's have an example: struct Foo { long a[95]; char b[4]; double c[2]; }; void fuzz(Foo &F) { for (int i=0; i<100;

Thanks for your replies. That was a very useful discussion. I won't recommit on a Friday afternoon, but will do on Monday, as it looks like we agreed again on the direction and the change. Orthogonal to this change, the interesting topics brought up are improved diagnostics, and the cases the vectoriser misses. I will briefly look why this particular case isn't vectorised, but I suspect

So IMO, if we modify the VF calculation for targets/subtargets using TTI where higher VF is supported The vectorizer’s scope will become wider. Did/do you foresee any issue with this? Thanks, Shahid From: Nadav Rotem [mailto:nrotem at apple.com] Sent: Saturday, December 13, 2014 2:47 AM To: Shahid, Asghar-ahmad Cc: llvmdev at cs.uiuc.edu Subject: Re: [LLVMdev] Vectorization factor limitation in

Hi Michael and Florian, ( + llvm-dev for visibility) I would like to quickly follow up on "Pragma vectorize_width() implies vectorize(enable)", which got reverted with commit 858a1ae for 2 reasons, see also that revert commit message. Ignore the assert, that's been fixed now. The other thing is that with the patch behaviour is slightly changed and we could get a diagnostic we

Hi, > The problem I see is that the warning isn't very actionable. Fully agreed. > Good warnings are supposed to be actionable, but what is the developer supposed to do in this case? This diagnostic is unclear. But to be more precise, the first part says the optimisation could not be performed. This is spot on, and an improvement of what we had before because that didn't issue

>I'm just curious as tho which concrete passes would benefit sooner. This all depends on those who are working on other loop xforms, since we currently don't have bandwidth to drive that kind of changes into other loop xforms. That's why when this line of questions pops up, I offer to work together. Short of that, the best we can proactively do is to make vectorizer analyses

Thanks Amara so much for the info! One more question: what do people usually do if they want to generate vectorized code for some existing c/c++ code? Do they usually do C/C++ source level transformation, or do at LLVM's IR level? I know clang supports auto vectorizations, such as loop vectorization and SLP, but they are not flexible enough if we want to do more custom vectorizations or

On 1 July 2015 at 15:20, Russell Wallace <russell.wallace at gmail.com> wrote: > Group all monkey's paw optimisations together, and enable them only if an > extra compiler flag is supplied. Or failing that, at least have a compiler > flag that will disable all of them (while leaving all the safe optimisations > enabled). So, are you suggesting we get rid of all undefined AND

Hi all, At the Barcelona Supercomputing Center, we have been working on an end-to-end vectorizer using scalable vectors for RISC-V Vector extension in context of the EPI Project <https://www.european-processor-initiative.eu/accelerator/>. We earlier shared a demo of our prototype implementation  (https://repo.hca.bsc.es/epic/z/9eYRIF, see below) with the folks involved with LLVM

Thanks for the summary, some more comments inline. On 1 February 2017 at 22:02, Renato Golin <renato.golin at linaro.org> wrote: > On 1 February 2017 at 21:22, Saito, Hideki <hideki.saito at intel.com> wrote: >> I think we are converging enough at the detail level, but having a big >> difference in the opinions at the "vision" level. :) > > Vision is

----- Original Message ----- > From: "Renato Golin" <renato.golin at linaro.org> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: "James Molloy" <James.Molloy at arm.com>, "Nadav Rotem" <nrotem at apple.com>, "Arnold Schwaighofer" > <aschwaighofer at apple.com>, "LLVM Dev" <llvm-dev at

Hello, Quick question to see if I haven't missed anything: I would like convert counting down loops, i.e. loops with a constant -1 step value, to counting up loops, because the vectoriser is able to better deal with these loops (see e.g. D76838 that I was discussing today with Ayal). It looks like LoopSimplifyCFG and IndVarSimplify don't do this. So was just curious if I haven't

Status Update on VPlan ---- where we are currently, and what's ahead of us ==========================================================   Goal: ----- Extending Loop Vectorizer (LV) such that it can handle outer loops, via uplifting its infrastructure with VPlan. The goal of this status update is to summarize the progress and the future steps needed.   Background: ----------- This is related to

On 03/11/2011 12:42 PM, Renato Golin wrote: > On 11 March 2011 14:53, Duncan Sands<baldrick at free.fr> wrote: >> There's no magic bullet. The things to improve that would give you the most >> bang for your buck are probably the code generator and auto-vectorization. >> Increasing the number of developers would be helpful. > > I'm not a GCC expert, but