similar to: [LLVMdev] Pass Manager changes - Pragma optimize

vecremainder/novecremainder: Should the pragma simply call the vectorizer to attempt to vectorize the remainder loop, or should the vectorizer use a different method? > > Something like that. There were patches posted at some point to enable tail-loop vectorization. At this point, I imagine that you'd construct a VPlan with the vectorized tail. Yep, committed in

Hello, I m trying to set vector width using #pragma clang loop vectorize_width(32) but i m getting width 8 for the following kernel; #define M 128 #define N 128 #define SQRT_FUN(x) sqrtf(x) int main(int argc, char** argv) { /* Variable declaration/allocation. */ double float_n = (double)N; double data[N*M]; double corr[M*M]; double mean[M]; double stddev[M]; uint32_t

Hello, We've had a high priority feature request from a number of our customers to provide per-function optimization in our Clang/LLVM compiler. I would be interested in working with the community to implement this. The idea is to allow the optimization level to be overridden for specific functions. The rest of this proposal is organized as follows: - Section 1. describes this new feature

On 8/8/19 2:03 PM, Hal Finkel wrote: Hi, First, as a high-level note, you posted a link to a Google doc, and at the end of the Google doc, you have a list of questions that you'd like answered. In the future, please put the questions directly in the email. For one thing, more people will read your email than will open your Google doc. Second, having the questions in the email should allow a

Hi All, I have a doubt regarding the behavior of LoopAccessAnalysis on incorrect #pragma omp simd with -fopenmp-simd flag. How should the compiler behave if the #pragma omp simd on a loop is incorrect and can be proved by Loop Access Analysis. Here is the sample code. #pragma omp simd for (dim_t p = 0; p < m; ++p) #pragma unroll for (dim_t i = 0; i < 6; ++i) { {

> There is a fundamental problem with the way that ivdep is defined by Intel's current documentation, at least for C/C++. As you note in your Google doc, it essentially says that the optimizer may ignore loop-carried dependencies except for those dependencies it can definitely prove are present. These are not semantics that any other compiler can actually replicate, and is not equivalent to

Hi llvm-dev! We are doing some fuzzy testing using C program generators, and one question that came up when generating a program with both floating point arithmetic and loop pragmas was; Is the loop vectorizer really allowed to vectorize a loop when it can't prove that it is safe to reorder fp math, even if there is a loop pragma that hints about a preferred width. When reading here

> -----Original Message----- > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] > On Behalf Of Renato Golin > Sent: Sunday, December 01, 2013 4:39 AM > To: Evgeniy Stepanov > Cc: LLVM Developers Mailing List > Subject: Re: [LLVMdev] Disabling certain optimizations at -O1? > > On 1 December 2013 10:44, Evgeniy Stepanov <eugeni.stepanov at

I would like to propose that loop pragma `vectorize(disable)` actually means disabling the vectorizer for that loop. This perhaps sounds really obvious (I hope it does), but currently `vectorize(disable)` sets the vectorization width to 1, and that means the vectorizer will run and could perform other tricks such as interleaving. The main reason to change the behaviour is that it will be more what

I'd like to add a pragma support in llvm. I am thinking about using a llvm intrinsic to represent each pragma, such as llvm.pragma (metadata, ...) where metadata describes a pragma. So if an application has: #pragma p1 .. #pragma p2... for (...) The llvm IR would be llvm.pragma (metadata..) // for p1 llvm.pragma (metadata..) // for p2 llvm IR for "for

Hi Francesco, a bit more information. GCC veclib is implemented based on GCC VectorABI for declare simd as well. For name mangling, we have to follow certain rules of C/C++ (e.g. prefix needs to _ZVG ....). David Majnemer who is the owner and stakeholder for approval for Clang and LLVM. Also, we need to pay attention to GCC compatibility. I would suggest you look into how GCC VectorABI can

Hi Xinmin, I have updated the clang patch using the standard name mangling you suggested - I was not fully aware of the C++ mangling convention “_ZVG”. I am using “D” for 64-bit NEON and “Q” for 128-bit NEON, which makes NEON vector symbols look as follows: _ZVGQN2v__Z1fd _ZVGDN2v__Z1ff _ZVGQN4v__Z1ff Here “Q” means -> NEON 128-bit, “D” means -> NEON 64-bit Please notice that although

> > I'm not. :( > I think that this is probably the most important feature for the vectorizer right now. Other features require adding complexity to the vectorizer while this feature is relatively simple. > What kind of pragmas would work for this loop? Something telling that it's safe to speculatively read from m[] at any position? In this reduction case it might be

Hi Michael. Thank for your feedback and questions/comments. See below. >>>>>I think it should be possible to vectorize such loop even without openmp clauses. We just need to gather a vector value from several scalar calls, and vectorizer already knows how to do that, we just need not to bail out early. Dealing with calls is tricky, but in this case we have the pragma, so we can

On 1 December 2013 10:44, Evgeniy Stepanov <eugeni.stepanov at gmail.com> wrote: > Could we move this setting to function attributes? I think this is a good idea. > This would let us support __attribute__((optimize())) in the future, > which is currently ignored. I'm adding #pragma vectorize enable which does more or less the same thing as

Hi Daniel, I increased the size of your test to be 128 but -stats still shows no loop optimized... Xiaochu On Aug 12, 2016 11:11 AM, "Daniel Berlin" <dberlin at dberlin.org> wrote: > It's not possible to know that A and B don't alias in this example. It's > almost certainly not profitable to add a runtime check given the size of > the loop. > > >

Hi Andrey, Thanks. I found even when loop vectorizer and SLP vectorizer are enabled, my simple test still not get optimized. I also tried clang pragma in my test to force vectorization. What do you think is the problem? Test: #define SIZE 8 void bar(int *A, int* B,int K) { #pragma clang loop vectorize(enable) vectorize_width(2) unroll_count(8) for (int i = 0; i < SIZE; ++i) A[i]

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

+llvm-dev properly this time. On Fri, 10 Mar 2017 at 09:42 James Molloy <james at jamesmolloy.co.uk> wrote: > Hi Reid, all, > > +llvm-dev as this RFC involves changes in Clang and LLVM. > > This RFC has stagnated and I think that's partially because the proposal > isn't particularly elegant and is light on details. We've been having a > rethink and have a

The ivdep pragma is designed to do exactly what the name states - ignore vector dependencies.  Cray Research first implemented this in 1978 in their CFT compiler, and has supported it since. This pragma is typically used by application developers who want vectorized code when the compiler cannot automatically determine safety; it is not equivalent to the OpenMP SIMD pragma in that the compiler is