search for: simd

libvorbis does not currently have any simd/vectorization. Following patches add generic framework for simd/vectorization and on top, add ARM-NEON simd vectorization using intrinsics. I was able to get over 34% performance improvement on my Beaglebone Black which is single Cortex-A8 based CPU. You can find more information on metrics and...

Hello all, I am currently working on building a portable SIMD programming model(SIMD within a register) for various platforms, like x86, ARM and so on. I know that LLVM supports SIMD programming on many architectures, so I am thinking of using LLVM to help build this model but I not quite sure whether LLVM can help. The following describes the details of the...

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 AM, Craig Topper <craig.topper at gmail.com> wrot...

hello, i am trying to optimize omp simd loop as follows 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) { c[i]= a[i] + b[i]; } return 0; } i run it using the following command; g++ -...

...ibraries and systems), I believe we have to base sour solution on a standard that describes the mapping from the scalar function to the vector function. Because OpenMP is standard and widely used, we should base our solution on the mechanisms that the standard provides, via the directives `declare simd` and `declare variant`, the latter when used in with the `simd` trait in the `construct` set. Please notice that: 1. The scope of the proposal is not implementing full support for `pragma omp declare variant`. 2. The scope of the proposal is not enabling the vectorizer to do new kind of vec...

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...

...ind not very much user-friendly is having to mangle the isa/mask/vlen/type list by hand. > > > > Would a more C-like syntax be feasible ? > > The syntax I proposed allows user to expose concepts like “linear”, “uniform” and “aligned" parameters, as described in the `declare simd` directive of OpenMP, which is what x86 and aarch64 Vector Function ABIs use to mangle the names. > > I agree with you that having to manually specify the mangling is a bit cumbersome, I am open to suggestions. > > An alternative approach was to make the actual string inside the attri...

Hi, I've done work on predicated SIMD representations for LLVM. If you search through the archives, you may find my "applymask" proposal, which is an attempt at representing predication in a very comprehensive way. I've since stopped pushing the proposal in part because Larrabee's changing fortunes led to a decline o...

...eve we have to base sour solution on a standard > that describes the mapping from the scalar function to the vector > function. > > Because OpenMP is standard and widely used, we should base our > solution on the mechanisms that the standard provides, via the > directives `declare simd` and `declare variant`, the latter when used > in with the `simd` trait in the `construct` set. > > Please notice that: > > 1. The scope of the proposal is not implementing full support for > `pragma omp declare variant`. > 2. The scope of the proposal is not enabling the v...

...ee another solution to this problem. Before, you'd have assembly files with NEON specific code, another with AltiVec specific and so on, and now you'd have C files with each intrinsics, which is better. But, as you said yourself, the semantics of NEON instructions are not the same as other SIMD ISAs, so if you only have the NEON file and want to create an AltiVec version, you'll have to understand both pretty well. Stanislav, If I got it right above, I think it would be better if you could do that transformation in IR, with a mapping infrastructure between each SIMD ISA. Something t...

I'm using Fedora 22 and gcc 4.9.2 to run llvm 3.5.1 on an ARM Juno reference box (cortex A53 & A57). I tried compiling some simple functions like dot product and axpy() into assembly to see if any of the SIMD instructions were generated (they weren't). Perhaps I'm missing some compiler flag to enable it. Does anyone know what the status is for aarch64 generating SIMD instructions? Anyone coordinating or leading this effort? (if there is one) -------------- next part -------------- An HTML attac...

...M documentation but haven't found a definitive list. The clang man page is skimpy on details. From: Arnaud A. de Grandmaison [mailto:arnaud.degrandmaison at arm.com] Sent: Monday, February 09, 2015 2:11 PM To: Ralph Campbell Cc: llvmdev at cs.uiuc.edu Subject: RE: aarch64 status for generating SIMD instructions Which compiler flags have you been using ? There is definitely support for AArch64's SIMD instructions, but their use depends on what the vectorizers can do with your code. From: llvmdev-bounces at cs.uiuc.edu<mailto:llvmdev-bounces at cs.uiuc.edu> [mailto:llvmdev-bounces...

...am in. I want to make DSP code written in C, but with NEON intrinsics "portable" as it is less feasible to rewrite it. > Stanislav, > > If I got it right above, I think it would be better if you could do that > transformation in IR, with a mapping infrastructure between each SIMD ISA. > Something that could represent every possible SIMD instruction, and how > each target represents them, so in one side you read the intrinsics (and > possibly IR operations on vectors), translate to this meta-SIMD language, > then export on the SIMD language that you want. > &g...

Hi everyone, I'm quite new to LLVM, but am working on a project that might need to generate some SIMD code using LLVM. The SIMD code will be using INTEL MIC intrinsics and I'm not sure about the steps and tool set that I need to use to generate those. I also have a confusion on the following problems: 1. Do people usually generate SIMD code at source code level, using __m512? 2. If n...

...rization with function calls ============================================================================== Intel Corporation (3/2/2016) This is a proposal for an initial work towards Clang and LLVM implementation of vectorizing a function annotated with OpenMP 4.5's "#pragma omp declare simd" (named SIMD-enabled function) and its associated clauses based on the VectorABI [2]. On the caller side, we propose to improve LLVM loopVectorizer such that the code that calls the SIMD-enabled function can be vectorized. On the callee side, we propose to add Clang FE support for "#pragm...

...first. But I am not quite familiar with LLVM backend infrastructure. I have some problem on describing the RegisterInfo. Intel GPU launches lots of hardware threads to do GPGPU workload. Each hardware thread has 128 registers(r0-r127), with each one of size 32 byte. Each hardware thread may run in SIMD 8/16/32 way, which maps to 8/16/32 OpenCL working items. And the SIMD width is chosen at compile time (normally chosen according to register pressure, bigger simd width means bigger register pressure). Note each instruction has each own exec-width, which may not be equal to program SIMD width. Norm...

...ble to distinguish what C type generated the signature of > `foo`. > > I don’t know if this is going to be a problem for other architectures, > but this is definitely a problem on AArch64 where we need to be able > to generate the correct vector function signature for a specific > simdlen(N) attached on `foo`. When simdlen(2), for type 1 the vector > type is <4 x i32>, for type 2 is <2 x i64*>, for type 3 is <2 x i64>. > > Therefore, I would like to propose a change to the RFC, which would > move the responsibility off generating the vector function...

Hi Kevin, > *Background* > Almost modern processor families support SIMD instruction sets but the > instruction set designs for each platform have different combinations of > operations. The portable SIMD here is to make an uniform system of SIMD > operations at all power-of-2 field widths. > For example, for simd_add on SSE2, I want to have all the followin...

...ib", but between being coherent with other OSS compilers and closed source compilers, I think the answer is clear. I'm not against the name, I'm just making sure we're not creating problem for ourselves. > -------------------------------- > > 1. `#pragma veclib declare simd [clause, ]`, same as > `#pragma omp declare simd` from OpenMP 4.0+. Why not just use "pragma omp simd"? If I recall correctly, there's an option to allow OMP SIMD pragmas without enabling full OMP, so that we can use it without needing all the headers and libraries, just to c...

...s i64, therefore is not possible to distinguish what C type generated the signature of `foo`. I don’t know if this is going to be a problem for other architectures, but this is definitely a problem on AArch64 where we need to be able to generate the correct vector function signature for a specific simdlen(N) attached on `foo`. When simdlen(2), for type 1 the vector type is <4 x i32>, for type 2 is <2 x i64*>, for type 3 is <2 x i64>. Therefore, I would like to propose a change to the RFC, which would move the responsibility off generating the vector function signature from LLVM...