similar to: [LLVMdev] LoopVectorizer

Nadav Rotem <nrotem at apple.com> wrote: > I sent a patch to llvm-commit with a new loop vectorizer. > This is a very simple loop vectorizer, but we have to start somewhere. > With this new loop vectorizer we can already vectorize a good number of loops. > I know that we can improve the new loop vectorizer in a number of ways. > We can implement a precise dependence test, >

Done. Best, Anadi. On Thu, Apr 11, 2013 at 7:01 AM, Nadav Rotem <nrotem at apple.com> wrote: > Hi Anadi, > > Yes, this is a bug in the loop vectorizer. The loop vectorizer expects only > one loop counter (integer with step=1). There is no reason why we should > not handle the case below, and it should be easy to fix. Interestingly > enough if you reverse the order of

Just an FYI: it's often handy to mention the PR number when a thread is concluded by filing a bug. That way other people reading (now, or more importantly, later) can follow the issue through to the bug and its resolution On Apr 11, 2013 4:24 PM, "Anadi Mishra" <reachanadi at gmail.com> wrote: > Done. > > Best, > Anadi. > > > On Thu, Apr 11, 2013 at 7:01

Hi Anadi, Yes, this is a bug in the loop vectorizer. The loop vectorizer expects only one loop counter (integer with step=1). There is no reason why we should not handle the case below, and it should be easy to fix. Interestingly enough if you reverse the order of iterations and count from SIZE to zero, the loop vectorizer would vectorize it. If you open a bugzilla report and assign it to me

----- Original Message ----- > From: "Pekka Jääskeläinen" <pekka.jaaskelainen at tut.fi> > To: "Nadav Rotem" <nrotem at apple.com> > Cc: "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> > Sent: Friday, January 25, 2013 5:35:16 AM > Subject: Re: [LLVMdev] LoopVectorizer in OpenCL C work group autovectorization > > On

Pekka, I am in favor of adding metadata to control different aspects of vectorization, mainly for supporting user-level pargmas [1] but also for DSLs. Before we start adding metadata to the IR we need to define the semantics of the tags. "Parallel_for" is too general. We also want to control vectorization factor, unroll factor, cost model, etc. Doug Gregor suggested to add the

Hi Nadav, I tried your suggestion by changing the condition to : 189 if (LoopVectorize && OptLevel >= 0) 190 MPM.add(createLoopVectorizePass()); and compiled. Then I used the following command: opt -mtriple=x86_64-linux-gnu -vectorize-loops -vectorizer-min-trip-count=6 -debug-only=loop-vectorize -O1-S -o example1_vect.s example1.s where example1.s is IR generated by clang -S

Hi Pekka, > Hi, > > I started to play with the LoopVectorizer of LLVM trunk > on the work-item loops produced by pocl's OpenCL C > kernel compiler, in hopes of implementing multi-work-item > work group autovectorization in a modular manner. > Thanks for checking the Loop Vectorizer, I am interested in hearing your feedback. The Loop Vectorizer does not fit here.

Hi Pekka, hi Nadav, I didn't find the time to read this thread until now, sorry for that. I actually think you are both right :). As for the current status, the loop vectorizer is only able to vectorize inner loops and (I think) does not handle function calls and memory operations well. This will prevent it from vectorizing a large group of OpenCL kernels, and certainly all

Has anyone worked with or used the LLVM backend or compiler for Haskell ?? David On Monday, October 21, 2013 5:26 PM, "llvmdev-request at cs.uiuc.edu" <llvmdev-request at cs.uiuc.edu> wrote: Send LLVMdev mailing list submissions to     llvmdev at cs.uiuc.edu To subscribe or unsubscribe via the World Wide Web, visit     http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev or,

Thanks, that did it! Are there any plans to enable the loop vectorizer by default? From: Nadav Rotem [mailto:nrotem at apple.com] Sent: Wednesday, April 03, 2013 13:33 PM To: Nowicki, Tyler Cc: LLVM Developers Mailing List Subject: Re: Packed instructions generaetd by LoopVectorize? Hi Tyler, Try adding -ffast-math. We can only vectorize reduction variables if it is safe to reorder floating

On 01/25/2013 09:56 AM, Nadav Rotem wrote: > Thanks for checking the Loop Vectorizer, I am interested in hearing your > feedback. The Loop Vectorizer does not fit here. OpenCL vectorization is > completely different because the language itself is data-parallel. You > don't need all of the legality checks that the loop vectorizer has. I'm aware of this and it was my point in

About these disclaimers associated with ivdep and such... You guys are overthinking it. They're just saying you cannot force the compiler to vectorize or parallelize a loop that it knows (can prove!) is not a parallel loop. They are not obliging the compiler to do dependence analysis or alias analysis or anything. For example len = 0; while (A[i]) { i++; len++; } Assert all you want;

----- Original Message ----- > From: "Nadav Rotem" <nrotem at apple.com> > To: "Pekka Jääskeläinen" <pekka.jaaskelainen at tut.fi> > Cc: "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> > Sent: Monday, January 28, 2013 10:45:36 AM > Subject: Re: [LLVMdev] [PATCH] parallel loop awareness to the LoopVectorizer > > Hi Pekka,

Hi Renato, Thanks for working on this. As you said, we don't support pointer reductions. Handling pointer reductions should be straightforward. You can copy the logic for handling RK_IntegerAdd and create a new enum entry for RK_PointerAdd. You will need to detect the relevant patterns (GEP probably) and implement the cost model and vectorization parts. You will need to generate

Hi Nadav, On Thu, Jan 3, 2013 at 1:53 PM, Nadav Rotem <nrotem at apple.com> wrote: > Hi Akira! > > > > > Does the current loop vectorizer inquire about the SIMD capabilities of > the target architecture when it decides whether it is profitable to > vectorize a loop? > > Yes, it uses a cost model to determine the profitability of vectorization. > At the

Hi Nadav, Do you have any small write-up of current design of loop vectorizer?. If so, can you please send it across?. I want to see if there are dependencies such as unrolling for the vectorization. In the design we may also have to consider BB vectorizer and loop vectorizer working well together with no ambiguous requirements/dependencies. Regards, Shivaram -----Original Message-----

Hi Tyler, Try adding -ffast-math. We can only vectorize reduction variables if it is safe to reorder floating point operations. Thanks, Nadav On Apr 3, 2013, at 10:29 AM, "Nowicki, Tyler" <tyler.nowicki at intel.com> wrote: > Hi, > > I have a question about LoopVectorize. I wrote a simple test case, a dot product loop and found that packed instructions are

----- Original Message ----- > From: "Pekka Jääskeläinen" <pekka.jaaskelainen at tut.fi> > To: "Ralf Karrenberg" <Chareos at gmx.de> > Cc: "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> > Sent: Thursday, January 31, 2013 11:15:43 AM > Subject: Re: [LLVMdev] LoopVectorizer in OpenCL C work group autovectorization > > Hi

> I am in favor of adding metadata to control different aspects of > vectorization, mainly for supporting user-level pargmas [1] but also for > DSLs. Before we start adding metadata to the IR we need to define the > semantics of the tags. "Parallel_for" is too general. We also want to control > vectorization factor, unroll factor, cost model, etc. These are used to