similar to: Issues with omp simd

I even tried following; int main(int argc, char **argv) { const int size = 1000000; float a[size], b[size],c[size]; #pragma omp simd for (int i=0; i<size; ++i) { a[i]=2; b[i]=3; c[i]=4; c[i]= a[i] + b[i]; } return 0; } but the output with and without openmp simd is same. why is that so? On Sun, Dec 31, 2017 at 12:01

i changed my code to following; #pragma omp simd for (int i=0; i<size; ++i) { a[i]=2; b[i]=3; c[i]=4; c[i]= a[i] + b[i]; printf("c value %f",c[i]); } still no effect of omp simd? On Sun, Dec 31, 2017 at 12:26 AM, Craig Topper <craig.topper at gmail.com> wrote: > The for loop has no effect on the observable behavior of

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

Dear all, I have just created a couple of differential reviews to enable the vectorisation of loops that have function calls to routines marked with “#pragma omp declare simd”. They can be (re)viewed here: * https://reviews.llvm.org/D27249 * https://reviews.llvm.org/D27250 The current implementation allows the loop vectorizer to generate vector code for source file as: #pragma omp declare

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) { {

Hi Francesco, This is a huge RFC and I don't think we can discuss all of it at the same time, at least not in a constructive manner. What ends up happening is that people ignore the thread and developers get upset. So, I'll start with the summary, to make sure the overall assumptions in the RFC match the ones I have about it, then we can delve into details. I also think we should not

On 12 December 2016 at 16:49, Francesco Petrogalli <Francesco.Petrogalli at arm.com> wrote: > I am not sure I understand here. In my patch, all I am doing is “vector > symbol awareness generation”. There are no globals that are generated in > the final object file, it is just the TargetLibraryInfoImpl that is being > populated with the info needed by the vectorizer. The

Does it happen due to loop carried dependence? if yes what is the solution to vectorize such codes? please reply. i m waiting. On Jul 1, 2017 12:30 PM, "hameeza ahmed" <hahmed2305 at gmail.com> wrote: > I even tried polly but still my llvm IR does not contain vector > instructions. i used the following command; > > clang -S -emit-llvm stencil.c -march=knl -O3

<div> </div><div> </div><div>Hello,</div><div> </div><div>To me this is an issue in llvm loop vectorizer (if N is large enough to prevent complete unrolling of j-loop).</div><div> </div><div>Woud you mind to share stencil.ll than I would say more definitely what the issue

>VectorClone does more than just mapping a scalar version to a vector one. It builds also the vector version definition by auto-vectorizing the body of the scalar function. To be more precise: VecClone strictly deals with the callee side of the code. Caller side mapping happens in vectorizer (LoopVectorize for the most part, but I don't see why SLPVectorize can't, for example).

On 05/31, Saito, Hideki wrote: > > >This works for variants that are created from definitions in the module but what about #omp declare simd declarations? > > I'm sorry that I haven't digested this thread in its entirety, but let me just deal with this one point for now. > Suppose #pragma omp declare simd is applied to foo(). I'd expect the corresponding Function

On 8 December 2016 at 18:11, Tian, Xinmin via llvm-dev <llvm-dev at lists.llvm.org> wrote: > 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 be extended

Your problem is due to GVN partial reduction elimination (PRE) which introduces a PHI node the current loop vectorizer cannot handle: opt -O3 stencil.ll -pass-remarks=loop-vectorize -pass-remarks-missed=loop-vectorize -pass-remarks-analysis=loop-vectorize remark: <unknown>:0:0: loop not vectorized: value that could not be identified as reduction is used outside the loop remark:

Hi Francesco, did you think about adding the attribute instead of the pragma? It is a common way to express such constructs as function attributes in clang/GCC rather than as pragma. Best regards, Alexey Bataev > 31 мая 2019 г., в 12:18, Francesco Petrogalli via cfe-dev <cfe-dev at lists.llvm.org> написал(а): > > Hi All, > > Thank you for the feedback so far. > > I

Francesco, there won't be any duplication. Most of the declarative OpenMP directives are represented as attributes internally, so, I think, it will be natural to use an attribute here rather than pragma. Best regards, Alexey Bataev > 31 мая 2019 г., в 13:32, Francesco Petrogalli <Francesco.Petrogalli at arm.com> написал(а): > > > >> On May 31, 2019, at 12:00 PM,

>Is this also the case if the user did require lock-step semantic for the code to be correct? Certainly not, but that part is actually beyond OpenMP specification. I suggest looking up ICC's "#pragma simd assert" description and see if the assert feature is something you may be interested in seeing as an extended part of LLVM implementation of OpenMP (declare) simd. Else,

You can define clang specific attribute and later add GCC alias for it. Best regards, Alexey Bataev > 31 мая 2019 г., в 13:46, Francesco Petrogalli <Francesco.Petrogalli at arm.com> написал(а): > > > >> On May 31, 2019, at 12:38 PM, Alexey Bataev <a.bataev at hotmail.com> wrote: >> >> Francesco, there won't be any duplication. Most of the

Yes, this is very similar, but only expressed in terms of clang attributes, which may have different spellings for clang, GCC, c++11 etc. I don't think GCC will implement this as pragma. They added simd attribute instead of pragma. Best regards, Alexey Bataev > 31 мая 2019 г., в 14:43, Francesco Petrogalli <Francesco.Petrogalli at arm.com> написал(а): > > > >> On

Page 22 of OpenMP 5.0 specification (Lines 13/14): When any thread encounters a simd construct, the iterations of the loop associated with the construct may be executed concurrently using the SIMD lanes that are available to the thread This is the Execution Model. The word here is "may" i.e., not "must". Declare simd is not explicitly mentioned here, but requiring